CA2095447C - Shortcut network layer routing for mobile hosts - Google Patents

Shortcut network layer routing for mobile hosts

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Publication number
CA2095447C
CA2095447C CA002095447A CA2095447A CA2095447C CA 2095447 C CA2095447 C CA 2095447C CA 002095447 A CA002095447 A CA 002095447A CA 2095447 A CA2095447 A CA 2095447A CA 2095447 C CA2095447 C CA 2095447C
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Canada
Prior art keywords
packet
access station
mobile host
base access
network
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002095447A
Other languages
French (fr)
Other versions
CA2095447A1 (en
Inventor
Charles E. Perkins
Jacob Y. Rekhter
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International Business Machines Corp
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International Business Machines Corp
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Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Publication of CA2095447A1 publication Critical patent/CA2095447A1/en
Application granted granted Critical
Publication of CA2095447C publication Critical patent/CA2095447C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W8/00Network data management
    • H04W8/02Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
    • H04W8/08Mobility data transfer
    • H04W8/082Mobility data transfer for traffic bypassing of mobility servers, e.g. location registers, home PLMNs or home agents
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00Routing or path finding of packets in data switching networks
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/40Network security protocols
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W40/00Communication routing or communication path finding
    • H04W40/02Communication route or path selection, e.g. power-based or shortest path routing
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W40/00Communication routing or communication path finding
    • H04W40/24Connectivity information management, e.g. connectivity discovery or connectivity update
    • H04W40/28Connectivity information management, e.g. connectivity discovery or connectivity update for reactive routing
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W80/00Wireless network protocols or protocol adaptations to wireless operation
    • H04W80/04Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method for routing a packet of information between two hosts that are coupled to a network. Each of the hosts have a unique network address, and at least one of the hosts is a mobile host (10) that does not have a fixed network coupling location. The method includes a first step of (a) transmitting a packet from the mobile host to a second, destination host on the network through a wireless link that is established between the mobile host and a base access station (12) that serves a current physical location of the mobile host. The base access station is coupled to the network via a subnetwork (LAN) (14), and the packet includes a first Internet Protocol (IP) Loose Source Routing (LSR) option that includes a network address of the base access station. A second step (b) receives with the destination host the packet that includes the first IP LSR option. A
third step (c) transmits a further, reply packet from the second host to the mobile host via the base access station in accordance with a path reversal technique wherein the reply packet includes a second IP LSR option that specifies as a first Routing address the network address of the base access station. As a result, the reply packet is directed through the network to the base access station that serves the current physical location of the mobile host, and an optimal, fast routing of the packet is achieved without involving intermediate gateways (16, 18).

Description

209~4~7 YO9-92-09g S~ORTCUT NE~WORK I~YER RO~ G FOR MOBILE HOST5 CROSS-~EFERENCE TO A ~ELATED PATENT APPLICATION:

This patent applica-tion is related to a commonly assigned U.S. Patent Application entitled "Network Address Management for a Wired Network Supporting Wireless Communication to a Plurality of Mobile Users", Serial No. 07/605,592, filed October 29, 1990, by C. E. Perkins.

EIELD OF T~E l~vh~ ON

This invention relates ~enerally to communication methods and apparatus and, in particular, to methods and apparatus for managing network datagram routing in a network that includes mobile users.

RA~KGROUND OF T~E lNv~.llON

Commonly assigned U.S. Patent No. 4,893,307, issued January 9, 1990, "Method and Apparatus for Linking SNA Terminals to an SNA Host Over a Packet Switched Communications Network", D.B. McKay, R.M. Morten and M.P. Marsili, describes an architectural model of the Department of Defense (DoD) protocol suite.

Referring to Eig. 1, the archi.tecture is said to be similar to, but not identical with, the International Standards Organization (ISO) Open Systems Interconnection (OSI) architecture.

A Defense Data Network (DDN) standard establishes criteria for an Internet Protocol (IP) which supports the interconnection of communication LANs. It introduces the Internet Protocol's role and purpose, defines the services provided to users, and specifies the mechanisms needed to support those services. The standard also defines the services required of the lower protocol layer, describes the upper and lower interfaces, and outlines the execution environment services need for implementation.

.-Y09-92-099 2 2~9~4~7 A Transml~sion Control Pro-tocol (TCP) i~ a transport protocol providing connection-oriented, end-to-end reliable data transmi~sion in packet-switched computer LANs and internetworks.

The Internet Protocol (IP) and the Transmission Control Protocol (TCP) are mandatory for use in all DoD packet switching networks which connect or have the potential for utilizing connectivity across network or subnetwork boundaries. Network elements, such as hosts, front-ends, gateways, etc., within such networks which are to be used for internetting must implement TCP/IP.

The Internet Protocol is designed to interconnect packet-switched communication LANs to form an internetwork.
The IP transmits blocks of data, called internet datagrams, from sources to destinations throughout the internet.
Source~ and destinations are hosts located on either the same subnetwork or on connected LANs. The IP is intentionally limited in scope to provide the basic functions necessary to deliver a block of data. Each internet datagram is an independent entity unrelated to any other internet datagrams. The IP does not create connections or logical circuits and has no mechanisms to promote data reliability, flow control, sequencing, or other services commonly found in virtual circuit protocols.

The DDN standard specifies a host IP. As defined in the DoD
architectural model, the Internet Protocol re~ides in the internetwork layer. Thus, the IP provides services to transport layer protocols and relies on the services of the lower network protocol. In each gateway, a system interconnecting two or more LANs, an IP resides above two or more LAN's protocol entities. Gateways implement IP to forward datagrams between LANS. Gateways also implement a routing protocol to coordinate signalling and other .internet control information.

Various Network Access Protocols reslde below the IP and may include, by example, an Ethernet protocol, an X.25 protocol, ' , .... . ~ :. .
.. ~ , .
. . : ' 209~7 and, of particular lnterest herein, a wireless network protocol.

The Internet protocols were originally developed with an assumption that users, each of which is assigned a uni~ue Internet address, would be connected to the network at fixed locations. However, for portabl.e and handheld computers employing a wireless protocol the movement, or migration, of users about the network is typically the rule rather than the exception~ As a result, a problem is created in that the implicit design assumptions of the Internet protocol are violated by this type of usage.

The problem that arises thus relates to providing optimal network layer routing with a mobile host, when network layer address(es) assigned to a host may not bear any network topological significance. The problem arises because of a reguirement for a host to have an identifier that remains fixed, even as the host moves, while at the same time providing sufficient information in the network layer to make network l.ayer routing feasible.

It is thus an object of this invention to provide a method for optimizing network layer routing between a pair of hosts, where at least one of the hosts is mobile and, as a result, does not have a fixed connection location with respect to the network.

It is another object of the invention to provide a method for optimizing network layer routing between a pair of hosts, where at least one of the hosts is mobile, in the context of a network that operates in accordance with the ~.-Internet or an Internet-type protocol.

SUMMARY OF THE lNv~ ON

The foregoing and other problems are overcome and the objects of the invention are realized by a method for routing a packet of information between two hosts that are coupled to a network. Each of the hosts have a uni~le Yo9-92-099 ~ 2095~7 network address, and a-t least one of the hosts is a mobile host that does not have a fixed network coupling location.
The method includes a first step of (a) transmitting a packet from the mobile hGst to a second, destination host on the network through a wireless link that is established between the mobile host and a base access station that serves a current physical location of the mobile host. The base access station is coupled to the network via a subnetwork (LAN), and the packet includes, in a presently preferred embodiment of the invention, an Internet Protocol (IP) Loose Source Routing (hSR) option that includes a network address of the base access station.

A second step (b) receives with the destination host the packet that includes the first LS~ option, and a third step (c) transmits a further packet, typically a reply packet, from the second host to the mobile host via the base access station in accordance with a path reversal technique.
: ' In accordance with the path reversal techni~ua, if a host receives a datagram containing a completed source route, i.e. the pointer points beyond the last address field, the datagram is considered to have reached its final destination. The source route option (recorded route), as received, is passed up to a Transport layer, or to ICMP
message processing. The recorded route is reversed and is used to form a return source route for reply datagrams. When the return source route is built, it is correctly formed even if the the recorded route included the source host.

As a result, the reply packet (datagram) is directed through the network to the base access station that serves the current physical location of the mobile host, and an optimal, fast routing of the packet is achieved without requiring the involvement a mobile router.
. .
In response to the mobile host establishing a wireless link with a second base access station on the same or a different subnetwork, the method includes the steps of determining the network address of the second base access skation with the . ~ . .................... . : .
' .' ,-' ' ~, :,' mobile host; transmittiIIc3 the network address of the second base access station from the mob:ile host to a mobile rou-ter that is coupled between the subnetwork and the network, the transmission including the ne-twork address of the mobile host; and maintaining the network address of the mobile host and the network address of the second base access station with the mobile router.
. :
The mobile router advertises -to the network the network address of the mob:ile router and also the network address of network associ.ated with the mobile hosts.

The step of transmitting the reply packet includes the steps of receiving the reply packet at the base access station;
and determining if the mobile host is currently located within the physical area served by the base access station.

If it is determined that the mobile host is currently located within the physical area served by the base access station, the method forwards the reply packet from the base access station over the wireless link to the mobile host.

If, instead, it is determined that the mobile host is not currently located within the physical area served by the base access station, the method forwards the reply packet from the base access station over the network to the mobile router, if there are no further intermediate addresses within the LSR option. The mobile router then forwards the reply packet to a second base access station that serves a physical location within which the mobile host is currently located.

In response to a reception of an packet by the mobile router from the network, the packet not including a LSR option and having the network address of the mobile host as a destination address, the method includes the steps of (a) converting the received packet into an packet that includes a LSR option, the LSR option being provided by the mobile router with the network address of the base access station that is serving the physical location within which the ' , , ,' ~ ' ' ; ' ' ~' ' ', ~ . ' , , ' ' .

YO9-92-099 6 2 0 ~ 7 mobile host is currently located; (b) fQrwarding the converted packet from the mobile router to the base access station that serves the physical location within which the mobile host is currently located; and (c) receiving the converted packet and forwarding the received converted packet from the base access station, over the wireless link, to the mobile host.

B~IEF DESCRIPTION OF TH~ DRAWING

The above set forth and other features of the invention are made more apparent in the ensuing Detailed Description of the Invention when read in conjunction with the attached Drawing, wherein:

Fig. 1 is a prior art architectural diagram of the Defense Data Network;

Fig. ~ is a block diagram showing a plurality of mobile hosts in bidirectional wireless communication with two LAMS
via a plurality of base access stations;

Fig. 3a illustrates a format of an Internet Datagram Header;

Fig. 3b illustrates a format of a Loose Source and Record Route (LSSR) option employed in the OPTION field of Fig. 3a;
and Figs. 4 and 5 are each a flowchart that illustrate an aspect of the method of the invention.
i ~ D~TAIL~D DESCRIPTION OF TffE INVENTION

It is noted that the method described in detail below is applicable to hosts that use either the IP, or a protocol known as the Connectionless-Mode Network Service Protocol (CLNP), as the network layer pro-tocol. IP is de~cribed in detail in a document entitled "Internet Protocol Darpa Internet Program Protocol Specification~ September 1981, RFC:791. CLNP is described in a document entitled "Protocol - .
.
.

' Yos-92-oss 7 209~ ~7 for providing connec-tlonless-mocle network service", I~O
8473. Although the ensuing descriptton is made sp~cifically with reference to the IP, it should be realized that support for CLNP may be accomplished using the same techniques. As such, the teaching of the invent:ion is not intended to be limited in scope to only ne-tworks that employ IP.

Raference is made to Fig. 2 where there is illustrated a communications area network 1. The network 1 includes one or more local area networks (LANs) 14. Each LAN 14 includes a wiraless network comprised of at least one Mobile Host tMH) 10 in wireless communication with one or more Base Access Stations (BAS) 12. Each of the BASs 12 i9 bidirectionally coupled to one of the wired LANs 14, also referred to herein as Level 2 subnetworks. In the presently preferred embodiment of the invention the wireless medium is comprised of infraxed (IR) radiation, although other embodiments may employ an RF wireless medium. Each of the BASs 12 has associated therewith a communications coverage area, or cell 11, which may or may not overlap one one another.
Communication between MHs 10, and from a MH 10 to other entities coupled to the network, is through the BASs 12, via the LAN 14. Communication between the BASs 12 is primarily via the LAN 14.

One suitable embodiment for the BASs 12 and the MHs 10 is disclosed in commonly assigned U.S. Patent 5,068,916, issued November 26, 1991, entitled "Coordination of Wireless Medium Among A Plurality Of Base Stations", by C. G. ~arrison and Peter D. Hortensius. It should be realized, however,~that the teaching of tha invention may be embodied within a number of different types of wireless network embodiments.

If there is more than one Level 2 subnetwork (L~N), then each of the LANs 14 preferably includes at least one local gateway (GW) 16 for coupling the MH 10, via the BAS 12 and the LAN 14, to a gateway 18. The connection between the local gateways 16 and the gateway 18 may be via some arbitrary number of additional gateways. The gateway 18 is also coupled to remote network users who may be dispersad .. , . , . , . ,~ . . . . . .

;. . , ., ~ , .
. ~ , , .

Yo9-92-099 8 2 0 9 r~ 7 over a wide geographic area. The local gateways 16 may each be an "intelligent" BAS, or may be a separate dedicated network entity as shown. The gateway 18 is preferably a data processor having suitable network adapter~ and an archival facility.

An IP address consists of ~our bytes, or 32 bits, that are partitioned into a LAN identification and a Host identification. By example, an I]? address may have the form 123.45.67.12. In the absence of a subnet mask, the first one, two, or three bytes encode a LAN address. For example, the LAN address may be encoded as 123 (byte 1) and 45 (byte 2). The remaining bits generally encode Host address information. In the example provided Host (12) may have up to 64K IP addresses associated therewith, as encoded in the third and fourth bytes.

It is assumed in the ensuing description that each MH 10 has a Network Layer Address (IP address or an NSAP). This address is referred to as a "permanent address" that does not change as the MH 10 mi.grates between Level 2 subnetworks. However, it is within the scope of the .invention to provide dynamic creation of such a "permanent"
address for the MH 10, as is described in the aforementioned commonly assigned U.S. Patent Application entitled "Network Address Management for a Wired Network Supporting Wireless Communication to a Plurality of Mobile Users", Serial. No.
07/605,592, filed October 29, 1990, by C. E. Perkins. As such, the gateway 18 may include components for maintaining and allocating pseudo-IP addresses to the MHs lO, as described in the above referenced commonly assigned U.S.
Patent Application S.N. 07/605,592.
i It is also assumed that each MH 10 has at least one server, referred to herein as a Mobile Router (MR) 20. The functionality of the MR 20 is included within the gateway 18, and is shown as such in Fig. 2. The MR 20 serves two functions.

.. . .. ~, .. . .

~9~7 Y09-92-09g 9 Firstly, the MR 20 i5 used as a "proxy" for "p2rmanent addresses" assigned to MHs 10. In other words, the MR 20 advertises reachability (via rou-ting protocols) to the addresses of the MHs 10 for which it acts as a proxy. It should be noted that such an advertisement has no implications on the actual Level 2 subnetworks that the MR
20 is attached to.

Secondly, as a MH 10 moves between different Level 2 subnetworks, the MR 20 that is currently acting as a proxy for that MH 10 is informed of the MHs 10 location, via the BAS 12, as described in detail below.

For redundancy, a MH 10 may have more than one MR 20 associated therewith. Thus, there is no reskriction implied or intended as to the number of MRs 20 associated with a single MH 10, although the MH 10 will own but a single IP
address.

It is also assumed herein that a given MH 10 can ascertain a Network Layer address of the MR 20 that serves as its proxy by way of, by example only, a MH system management function, or by a static configuration.

From a network layer routing point of view, a given MH 10 is always considered to be attached to the one of the Level 2 subnetworks as defined by the permanent IP address or pseudo-IP address of the MH 10. An MR 20 associated with a given MH 10 functions as the closest network layer gateway to the MH 10.

Each MH 10 maintains its network connectivity by accepting service from the BAS 12 that transmits data to and receives data from the mobile host during the time that the MH 10 is within a coverage area served by the BAS 12. For example, if the wireless communication occurs in the infrared (IR) fre~uency spectrum, a BAS 12 would be limited to servicing mobile hosts within infrared range of the BAS 12. As was noted above, the area served by a BAS 12 i~ referred to as a "cell", and cells served by different BASs 12 may overlap.

i, ,~ .- .
.. ..

2~9~
Yo9-92-~99 1~

As seen in Fig. 2, a given MH 10l may be positioned within an overlap between two or more cells 11 and, as a result, in some embodiments of the inventiorl may be serviced hy each of the associated BASs 12. However, service by more than one BAS 12 is not required and, thus, the teaching of the invention may also be practiced in a wireless network wherein only one BAS 12 may be assigned responsibility, at any given time, for a MH 10.

It is also assumed that a given M~ 10 can ascertain khe n~twork layer address of a BAS 12 (or one of the interfaces of the BAS 12) serving the current cell wherein the MH 10 is located, and that a BAS 12 can ascertain network layer addresses of all operational MHs 10 within the cell served by the BAS 12. Both of these assumptions are based on the bidirectional communications capability that exists between a BAS 12 and the MEl(s) 10 with the associated cell 11.

As the MH 10 moves or migrates, the set of the BAS(s) 12 that the MH 10 can reach within a Level 2 subnetwork (within a single network layer hop) may change. As employed herein, a network layer hop is considered to be a transmission between two network entities without involving intermediate network entities. The method of the invention requires that a MH 10 notify the associated MR(s) 20 of such changes by supplying the MR(s) 20 with the address(es) of -the BAS(s) 12 that are currently reachable by the MH 10. The MR 20 maintains this information within a MH/BAS MAP 20a, wherein the IP address of each MH lO is associated with one or more IP addresses of the BASs 12.

An aspect of this invention is the use of an IP feature known as a Loose Source Record Routing, or Loose Source Routing (LSR) option. By e~ploiting the LSR option in a novel fashion within the context of a wireless network having migrating MHs 10, the invention enables a packet from a source host to bypass the MR 20 and to be routed instead directly to the BAS 12 tha-t serves the MH 10 that is the destination for the packet.

. ,~

' Y09-92~099 ll 2 ~ 4 7 As seen in Fig. 3a, the contents of an internet datagram header includes an OPTIONS field. Options may or may not appear in a datagram. What is optional is their transmission in any particular datagram, not -their implementation. That is, the OPTIONS must be imple~ented by all IP modules (hosts and gateways). The option type of particular relevance herein i9 the LSR option, which is used to route an internet datagram based on information supplied by the source of the datagram.

Re~erring to Fig. 3b, the LSR option provides a m~ans for the source of an internet datagram to supply routing information to be used by the gateways in forwarding the datagram to the destination, and to record the route information.

The LSR option begins with the option type code (131). The second octet is the option length, the length including the option type code, the length octet, a Pointer octet, and length-3 octets of Routing Data. The third octet is the Pointer into the Route Data, and which indicates the octet which begins the next source address to be processed. The Pointer is relative to this option, and the smallest legal value for the Pointer is four.

The Route Data is composed, t~pically, o~ a series of internet addresses. Each internet address is 32 bits, or four octets. If the Pointer is greater than the length, that is the Pointer points beyond the last address entry in the Route Data, the source route is empty (and the recorded route full) and the routing is then based on the datagram Destination Address Field (Fig. 3a).

If the address in the Destination Address Field has been reached, and the Pointer is not greater than the length, the next address in the source route replaces the address in the Destination Address Field, and the recorded route address replaces the Source Address just used, and the Pointer is increased by ~our.

:" : ;; , - , , .

2 ~ 7 The recorded route address is the internet module's own internek address, as kllown in the environment into which this datagram is being forwarded.

The procedure of replacing the source route with the recorded route (though it is in the reverse of the order re~uired to be used as a source route) means that the LSR
option (and the IP header as a whole) remains a constant length as the datagram progresses through the internet.

This option is referred to as a Loose Source Route because the gateway 18 (MR 20) or host IP is allowed to use any route of any number of intermediate gateways to reach the next address in the route.

As employed by the invention, the LSR option includes a list of network layer addresses of the BAS(s) 12 serving the current location of the MH 10, and employs the Pointer to point to one of the addresses. It i3 a specified requirement of the Network Layer Protocol that responses to packets that use the LSR option be delivered along the reverse of the path specified by the packet initiating the response (e.g.
the packet from the MH 10). Thus, it follows that forwarding of the response packets is determined by the addresses specified by the LSR option, .t.e. the addresses of the BAS(s) 12 of the cell(s) presently serving the MH 10. A~ a result of the use of -the LSR option, a single IP header conveys information both about the identity of the MH 10, in the ~orm of the Destination Address of the packet, as well as about the topological location of the MH lO, in the form of the BAS 12 address entry or entries of the LSR option Route Data fields.

When one source host sends a Network Layer Protocol~Data Unit (NPDU) to another host (destination), and if the destination is the MH 10, then there exists only one of two possible conditions:

a) the source host is initiating a data stream to the destination, with no ~09-92 099 13 2~5~

previous knowledge of the destination host's whereabouts; or b) the source hos-t is sending data to the destination in response to some previous transmission by that destination host.

In the case (a), and as seen in the flow chart of Fig. 4, the NPDU is delivered in accordance with conventional IP
routing from the source host to the MR 20 which has previou~ly advertised reachabillty to the destination address (Block A). Upon receipt of the NPDU, the MR 20 makes a determination if the NPDU has a LSR option (Block B). If N0, and in that the MR 20 maintains a record of the network layer address(es) of the BAS(s) 12 that serve the cell(s) that the destination MH 10 is presently located (BAS/MH MAP
20a), the MR 20 creates an empty LSR option in the NPDU
(Block C). That is, an LSR option is created wherein the Route Data is empty, and wherein the Pointer points to the first (null) Route Data address.
. , Control then passes to Block D, as it also does if the determination at Block B is YES. That is, if YES at Block B, the incoming NPDU already contains a Loose Source Route option.
I

The MR 20 operates at Block D to ~irst append the content of the IP header Destination Address field to the end of the LSR option Route ~ata. At this point, the Destination Address is the address of the MH 10 to which the NPDU is directed. The MR 20 then increases the LSR option Length accordingly. Next, the MR 20 accesses the MH/BAS Map 20a to retrieve the address of a BAS 12 khat is responsible for the ~H 10 to which the NPDU is dixected. The address of the responsible BAS 12 is then inserted into the Destination Address of the NPDU.

At Block E the MR 20 forwards the NPDU, in accordance with the address in the Destination Address field, to the BAS 12 2~9~7 Y09-92-099 1~

that i8 currently responsible for the MH 10 to which the NPDU is directed.

It is noted that for condition (a) the LSR option will typically not be on. However, if the datagram is first sourced by another MEI lO, and assuming that, in accordance with the invention, all MH 10 sourced datagrams are always sent with the LSR option turned on, then the YES condition at Block B will be satisfied.

In the case (b) the source host will have previously received a packet from the destination MH 10 specifying the return path to the destination MH 10, using the Loose Source Routing option of the Network Layer Protocol. The network will (as required) attempt to deliver the packet to the destination, which was taken from the next address in the list of addres es specified with the LSR option. The destination address will, in accordance with the invention, correspond to a BAS 12 that is presently serving the destination MH 10.

As a MH 10 moves from one Level 2 subnetwork to another, its current cell and, thus, BAS 12, also change. If the traffic between a pair of hosts is bidirectional, then the recipient of an NPDU directly notifies the originator of the NPDU of its movement by inserting the address of the new BAS 12 as the Destination Address. This occurs when the recipient host sends NPDUs back to the originating host. According to the "Host Requirements", specified by i'Requirements for Internet Hosts Communications Layers", by R. Braden, RFC 1122 (10/89), when a host receives a Network Layer NPDU destined to it with the LSR option in the NPDU, the host is required to reverse the Source Route and use it to form the return source route for reply datagrams. This operation is specified in detail in Section 3.2.1.8 of the above referenced RFC 1122.

That is, and in accordance with thi~ path reversal techni~ue that is employed by the teaching of the invention, if a host receives a datagram containing a completed source route, .

. . , . ~ . .

Y09-92-099 15 ~9~447 i.e. the pointer pOilltS beyond the last address field, the datagram is consldered to have reached its final destination. The source route option (recorded route), as received, is passed up to the Transport layer, or to ICMP
message processing. The recorded route is reversed and is used to form a ret~lrn source rout~ for reply datagrams. When the return source route is built, it is correctly formed even if the recorded route included the source host.

Furthermore, and as is specified in Section 3.2.1.8 of the RFC 1122, if a source-routed datagram is fragmented, each fragment will contain a copy of the source route. Since the processing of IP options (including a source route) must precede reassembly, the original datagram will not be reassembled until the final destination is reached.

For example, a source routed datagram is to be routed from a source (S) host to a destination (D) host via gateways Gl, G2, ... Gn. ~n ambiguity may exist in the specification as to whether the source route option in a datagram sent out by S shoulfl be (A) or (B~:

(A~: ~ >>G2, G3, .. Gn, D} (correct), or (B): ~S, >>G2, G3, ...Gn, D} (incorrect), where >> represents the Pointer. If (A) is sent, the datagram received at D will contain the option:

~Gl, G2, ... Gn >>}, with S and D as the IP source and destination addresses, respectively. If (B) were sent, the datagram received at D
would again contain S and D as the IP source and destination addresses, but the option would be:

~S, Gl, ... Gn>>}, i.e., the originating host would be the first hop in the route.

In accordance with the teaching of the invention, when a MH
10 moves from one Level 2 subnetwork to another, while , :.

.... ..
. . .

Yo9-92-Og9 16 2 ~ 7 communicating with another hos-t, only the first NPDU sent to the MH 10 would go through the MR 20 that acts as the proxy for the MH 10. The remainder of the NPDUs then flow in~tead to the MH 10 directly through the BAS 12 currently servicing the MH 10, as indicated by the LSR Option.

In accordance witll the invention the use of the LSR Option, in effect, produce~ a "shortcut routing" between a pair of hosts. The shortcut routing significantly improves the optimality of routin~ between host~, when at least one of the hosts is mobile and does not have a fixed point of connection to the network.

As the MH 10 moves, the cell and BASs 12 to which it is connected through, by example, the bidirectional IR wireless link, also changes. In the process of moving from one cell to another it is possible for a MH 10 to be located in more than one cell, such as the MH 10' of Fig. 2, and to thus be able to receive service from more than one BAS 12. To facilitate shortcut routing the MH 10 may, but is not required to, insert the addresses of all the relevant BASs into the Loose Source Route option. The order in which the~e addresses are specified in the Loose Source Route option may be irrelevant, or may be based on criteria such as signal strength, with the BAS 12 having the highest signal strength being listed first.

As a result, it is typically unnecessary to involve the MR(s) 20 that act as proxies for the MH lO as the MH 10 moves. This technique yields even a greater optimality in routing. It should be noted, however, that the MH 10 must inform the MR 20 of any changes in the identlties of the BAS~ that are serving the MH lO, in that such changes amount to changes to the topology of the Level 2 subnetwork containing the "permanent" address of the MH 10.

By supplying the associated BAS 12 addres~ in each reply NPDU, a MH 10 informs the originator of the packet traffic about its most current network location. By using the address of the BAS 12 recipient (supplied in the reply Y09-92-09~ 17 209~ 7 NPDUs), the originator of -the traf~ic is enabl2d, in effect, to track the mos-t current location of -the recipient of the traffic. Such -tracking enables the construction of optimal routes between a pair of hosts, using the facilities of the IP, while at the same time minimizing -the involvement of the MR(sj 20.

As seen in the flowchart of Fig. 5, when a BAS 12 receives an NPDU with the I,SR option (Block A), the BAS 12 first examines the last LSR option address data entry, i.e. the address of the mobile host 10. The BAS 12 then determines at Block B whether the addressed MH 10 is "up" (i.e. currently located within the cell served by the BAS 12). If the MH 10 is not up, the BAS 12 deletes its own IP address from the Destination Address field (Block C). The BAS 12 then determines at Block D if there are any intermediate LSR
option addresses before the last LSR option address of the MH 10. If N0, the BAS 12 forwards the NPDU to the MR 20, and processing continues in accordance with the flowchart of Fig. 4. If YES at Block D, the BAS 12 advances the Pointer în the LSR option to the next address entry (Block F) and proceeds to forward the NPDU to the next entry in the LSR
option (Block G).

If the MH 10 is up (YES at Block B), the BAS 12 processes the LSR option by inserting its Destination Address into the LSR option Route Data at the current Pointer location. The BAS 12 also takes the last Route Data address, that is the address of the MH 10, and puts the MH 10 address into the Destination Address. The BAS 12 advances the Pointer beyond the end of the LSR option (Block H), and delivers the NPDU
directly to the MH 10 that is specified in the datagram header Destination Address (Block I). If the BAS 12'advances the pointer beyond the last entry in the LSR, the forwarding of the NPDU is directly to that MH 10; otherwise the NPDU
will be forwarded to the MR 20 associated with~ the destination MH 10. This occurs because the BAS 12 forwards the NPDU to the appropriate gateway, just as any agent would forward the packet to the MR 20, and all gateways have a :

YO9-9~-099 1~

record of tha routing lnformation adver-tised by the MR 20 for the address of the MH(s) s~rved by the MR 20.

Receiving an NPDU with a MH 10 does not require any ~pecial processing, other than advancing the pointer beyond the end of the LSR option (if require!d) prior to ar,y further processing so as to conform to the LSR option specification.
In addition, for every incoming packet the MH 10 stores the portion of the LSR Option that ~oes not have addresses of the BAS(s) 12 directly reachable by the MH 10. Such a LSR
Option fragment may indicate, for example, the BAS(s) 12 that serve the originator of the packet if the originator is also a MH 10, or any host using the LSR option for any reason.

Sending an IP packet to another host involves constructing a LSR option as a concatenation of the BAS(s) 12 directly reachable by the MH 10, followed by the LSR extracted from the packet(s) received from that host (if any). The LSR
pointer is set to point beyond the list of the BAS(s) 12 directly reachable by the MH 10, in that there is no need for the MH 10 to route the packet to the BAS(s) that serve the MH 10. This constructed LSR option is then inserted within the outgoing packet.

Some previous approaches for forwarding NPDUs between a pair of hosts attached to different Level 2 subnetworks involve datagram encapsulation by the MRs 20 and BASs 12. Moreover, st least one of these approaches ("IP-based Protocols for Mobile Internetworking", Ioannidis, J., Duchamp, D., Maquire, G., Proceedings SIGCOMM 1991) requires ubiquitous knowledge of the actual location of all the mobile hosts within a routing domain. That knowledge, in turn, may require significant information exchange between all the BASs 12 within the routing domain. For inter-domain connectivity the routing always involves a BAS 12 located in the "home" domain of a mobile host.

The present invention provides advantages over these previous approaches. Firstly, it does not requira flooding - ~ , .

Yo9-92-099 19 2~95~7 the network wi-th information, about actual locations of mobile hosts, to all the BASs 12 within a domain, as in the immediately above referenced proposal, in that for each MH
10 only the associated MR 20 has to maintain the location information, in the form of a MH 10, BAS 12 mapping.

Secondly, in many cases routes between MH lOs that involve inter-domain mobility are likely to be shorter than the routes obtained with above referenced proposal.

Thirdly, by restricting the knowledge of M~I 10 movements to only the MH 10 itself, and the MR 20 of that MH 10, the teaching of the invention significantly simplifies security implications and authentication requirements.

Fourthly, by avoiding datagram encapsulation the invention avoids potentially detrimental performance implications associated with the fragmentation that may be necessary to accomplish encapsulation.

Fifthly, by avoiding datagram encapsulation the teaching of the invention reduces the amount of protocol information carried by NPDUs.

Finally, by avoiding datagram encapsulation the method of the invention reduces the overhead that otherwise would be imposed on BASs 12. That is, for most NPDUs the BASs 12 function as pure IP routers, without any knowledge of whether the NPDUs are destined to mobile or non-mobile hosts.

While the invention has been particularly shown and described with respect to a preferred embodiment thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.

- . . , . , :
.

Claims (20)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A method for routing a packet of information between a first host and a second host that are coupled to a network, each of the hosts having a unique network address, wherein at least one of the hosts is a mobile host that does not have a fixed network coupling location, comprising the steps of:
transmitting a packet from the mobile host to the second host on the network through a wireless link that is established between the mobile host and a first base access station that serves a current physical location of the mobile host, the first base access station being coupled to the network via a subnetwork, the packet including a first Loose Source Routing LSR option that includes a network address of the first base access station and possibly at least one further network address;
receiving with the second host the packet that includes the first LSR option; and transmitting a further packet from the second host to the mobile host, via the first base access station and the wireless link, in accordance with a path reversal technique such that the further packet includes a second LSR option that includes the network address of the first base access station that was included within the first LSR option, whereby the further packet is directed through the network to the first base access station that serves the current physical location of the mobile host.
2. A method as set forth in claim 1 and further comprising the steps of:
in response to the mobile host establishing a wireless link with a second base access station on the same or a different subnetwork, transmitting the network address of the second base access station from the mobile host to a mobile router that is coupled between said same or different subnetwork and the network, the transmission including the network address of the mobile host; and maintaining, with the mobile router, the network address of the mobile host and the network address of the second base access station.
3. A method as set forth in claim 2 and including a step of transmitting to the network from the mobile router the network address of the mobile router and the network address of the mobile host.
4. A method as set forth in claim 2 wherein, in response to a reception of a packet by the mobile router from the network, the packet not including an LSR option and having the network address of the mobile host as a destination address, the method includes the steps of:
converting the received packet into a packet that includes a newly created LSR option, the newly created LSR option being provided by the mobile router with the network address of the mobile host, the received packet further being provided with a destination address of a base access station that is serving the physical location within which the mobile host is currently located;
forwarding the converted packet from the mobile router to the base access station that serves the physical location within which the mobile host is currently located; and receiving the converted packet and forwarding the received converted packet from the base access station over the wireless link to the mobile host.
5. A method as set forth in claim 1 wherein the step of transmitting the further packet includes the steps of:
receiving the further packet with the first base access station; and determining if the mobile host is currently located within the physical area served by the first base access station;
if it is determined that the mobile host is currently located within the physical area served by the first base access station, forwarding the further packet from the first base access station over the wireless link to the mobile host; else if it is determined that the mobile host is not currently located within the physical area served by the first base access station, and if it is determined that the second LSR option does not include a network address other than the network address of the mobile host, forwarding the further packet from the first base access station over the subnetwork to a mobile router that is coupled between the subnetwork and the network; and forwarding the further packet from the mobile router to a second base access station that serves a physical location within which the mobile host is currently located.
6. A method as set forth in claim 5 wherein, if it is determined that the mobile host is not currently located within the physical area served by the first base access station, the step of forwarding the further packet from the first base access station over the subnetwork to the mobile router includes an initial step of deleting the address of the first base access station from the further packet.
7. A method as set forth in claim 5 wherein, if it is determined that the mobile host is currently located within the physical area served by the first base access station, the step of forwarding the further packet from the first base access station over the wireless link to the mobile host includes an initial step of advancing an LSR option address pointer beyond a last LSR option network address.
8. A method as set forth in claim 5 wherein, if it is determined that the mobile host is not currently located within the physical area served by the first base access station, the method includes a step of:
deleting the network address of the first base access station from the further packet; and, if it is determined that the LSR option includes a further network address other than the network address of the mobile host, the method further includes the steps of:
advancing a LSR option address pointer to the next, further network address; andforwarding the packet to the next network address.
9. A method as set forth in claim 1 wherein the wireless link is an infrared radiation link.
10. A method for routing a packet of information between two hosts that are coupled to a network, each of the hosts having a unique network address, wherein at least one of the hosts is a mobile host that does not have a fixed network coupling location, comprising the steps of:
in response to a reception of a packet from the network by a mobile router, the packet not including an LSR option and having the network address of the mobile host as a destination address, converting the received packet into a packet that includes an LSR option, the LSR option being provided by the mobile router with the network address of the mobile host, the received packet further being provided with a destination address of a base access station that is serving, with a wireless communication link, a physical location within which the mobile host is currently located;
forwarding the converted packet from the mobile router to the base access station that serves the physical location within which the mobile host is currently located; and receiving the converted packet and forwarding the received converted packet from the base access station over the wireless link to the mobile host.
11. A method as set forth in claim 10 wherein the step of receiving the converted packet includes the steps of:
determining if the mobile host is currently located within the physical area served by the base access station;
if it is determined that the mobile host is currently located within the physical area served by the base access station, forwarding the converted packet from the base access station over the wireless link to the mobile host; else if it is determined that the mobile host is not currently located within the physical area served by the base access station, and if it is determined that the LSR option does not include a network address other than the network address of the mobile host, forwarding the converted packet from the base access station to the mobile router; and forwarding the converted packet from the mobile router to another base access station that serves a physical location within which the mobile host is currently located.
12. A method as set forth in claim 10 wherein the wireless link is an infrared radiation link.
13. A method as set forth in claim 10 wherein the network address and the destination address are Internet addresses.
14. A method as set forth in claim 10 wherein the steps of receiving and forwarding are accomplished using an Internet Protocol.
15. A mobile host having a network address, the mobile host comprising:

means for bidirectionally communicating with a data communications network through a first base access station over a wireless communications link, the first base access station serving a wireless communications cell that encompasses a current physical location of the mobile host; and means for transmitting an information packet to the data communications network, the information packet being transmitted over the wireless communications link to the first base access station, the information packet including a first Loose Source Routing LSR option that includes a network address of the first base access station.
16. A mobile host as set forth in claim 15 and further comprising means for receiving an information packet from the data communications network, the information packet being received from the first base access station over the wireless communications link, the received information packet including a second LSR option that includes the network address of the first base access station.
17. A mobile host as set forth in claim 15 and further comprising means, responsive to the mobile host establishing a wireless communications link with a second base access station, for transmitting the network address of the second base access station from the mobile host to a mobile router that is coupled to the network, the transmission including the network address of the mobile host.
18. A mobile host as set forth in claim 15 wherein said means for bidirectionally communicating includes means for transmitting and receiving infrared radiation signals.
19. A data communications system for routing a packet of information over a network, comprising:
at least one mobile host having a network address, said at least one mobile host not having a fixed network coupling location, said at least one mobile host including means for bidirectionally communicating with a wireless communications link;
at least one base access station that is coupled to the network and that serves a communication cell by means of the wireless communication link; and a mobile router having means for transmitting information packets to the network and means for receiving information packets from the network, said mobile router further including means, responsive to a reception of an information packet from the network, the packet not including a Loose Source Routing LSR option and having a network address of a mobile host as a destination address, for converting the received information packet into a converted packet that includes a LSR
option, said converting means providing the LSR option with the network address of the mobile host and also providing the converted packet with a destination address of a selected base access station that is serving, through the wireless communication link, a communication cell within which the mobile host was last known to be located.
20. A data communications system as set forth in claim 19 wherein said mobile router further includes means for forwarding the converted packet to said selected base access station having the destination address, and wherein said selected base access station includes means for receiving the converted packet and means for transmitting the received packet over the wireless communication link to the mobile host.
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Families Citing this family (249)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPQ504100A0 (en) 2000-01-11 2000-02-03 Notron (No. 325) Pty Limited A method for distribution of streamed data packets on a switched network utilising an intelligent distribution network
US5517618A (en) * 1992-02-10 1996-05-14 Matsushita Electric Industrial Co., Ltd. Mobile migration communications control device
US5583996A (en) * 1993-03-16 1996-12-10 Bell Communications Research, Inc. Method and system for shortcut routing over public data networks
WO1995001020A1 (en) * 1993-06-25 1995-01-05 Xircom, Incorporated Virtual carrier detection for wireless local area network with distributed control
FI940093A0 (en) * 1994-01-10 1994-01-10 Nokia Mobile Phones Ltd Foerfarande Foer oeverfoering av data and datagraenssnittenhet
US5636216A (en) * 1994-04-08 1997-06-03 Metricom, Inc. Method for translating internet protocol addresses to other distributed network addressing schemes
US6701370B1 (en) * 1994-06-08 2004-03-02 Hughes Electronics Corporation Network system with TCP/IP protocol spoofing
US5553075A (en) * 1994-06-22 1996-09-03 Ericsson Ge Mobile Communications Inc. Packet data protocol for wireless communication
US5570084A (en) * 1994-06-28 1996-10-29 Metricom, Inc. Method of loose source routing over disparate network types in a packet communication network
US5598536A (en) * 1994-08-09 1997-01-28 Shiva Corporation Apparatus and method for providing remote users with the same unique IP address upon each network access
US5490139A (en) * 1994-09-28 1996-02-06 International Business Machines Corporation Mobility enabling access point architecture for wireless attachment to source routing networks
DE4438522C2 (en) * 1994-10-31 1997-08-21 Ibm Device for the transmission of data streams in data communication networks
US5533026A (en) * 1995-03-06 1996-07-02 International Business Machines Corporation Communication system including method and apparatus for maintaining communications with a mobile terminal
FI97840C (en) * 1995-03-09 1997-02-25 Nokia Technology Gmbh A method of transmitting and generating a hypertext document and a hypermedia service to a mobile receiver
US5887256A (en) * 1995-05-04 1999-03-23 Interwave Communications International, Ltd. Hybrid cellular communication apparatus and method
US5577029A (en) * 1995-05-04 1996-11-19 Interwave Communications Cellular communication network having intelligent switching nodes
US5953651A (en) * 1995-05-04 1999-09-14 Interwave Communications International, Ltd. Cellular adjunct to a public wired network
US5818824A (en) * 1995-05-04 1998-10-06 Interwave Communications International, Ltd. Private multiplexing cellular network
US5842138A (en) * 1995-05-04 1998-11-24 Interwave Communications International Ltd. Configuration-independent methods and apparatus for software communication in a cellular network
US5734699A (en) 1995-05-04 1998-03-31 Interwave Communications International, Ltd. Cellular private branch exchanges
US6418324B1 (en) 1995-06-01 2002-07-09 Padcom, Incorporated Apparatus and method for transparent wireless communication between a remote device and host system
US5757783A (en) * 1995-06-15 1998-05-26 Lucent Technologies Inc. Method and apparatus for routing ATM cells in an AD-ATM LAN
US5651002A (en) * 1995-07-12 1997-07-22 3Com Corporation Internetworking device with enhanced packet header translation and memory
WO1997008838A2 (en) * 1995-08-14 1997-03-06 Ericsson Inc. Method and apparatus for modifying a standard internetwork protocol layer header
US6009469A (en) * 1995-09-25 1999-12-28 Netspeak Corporation Graphic user interface for internet telephony application
US6185184B1 (en) 1995-09-25 2001-02-06 Netspeak Corporation Directory server for providing dynamically assigned network protocol addresses
US6108704A (en) * 1995-09-25 2000-08-22 Netspeak Corporation Point-to-point internet protocol
US6226678B1 (en) 1995-09-25 2001-05-01 Netspeak Corporation Method and apparatus for dynamically defining data communication utilities
US5841764A (en) * 1995-10-30 1998-11-24 Ericsson Inc. Method and apparatus for permitting a radio to originate and receive data messages in a data communications network
US5781534A (en) * 1995-10-31 1998-07-14 Novell, Inc. Method and apparatus for determining characteristics of a path
US5732074A (en) * 1996-01-16 1998-03-24 Cellport Labs, Inc. Mobile portable wireless communication system
US5781550A (en) * 1996-02-02 1998-07-14 Digital Equipment Corporation Transparent and secure network gateway
JP2838998B2 (en) * 1996-02-07 1998-12-16 日本電気株式会社 Mobile terminal and mobile network
US5856974A (en) * 1996-02-13 1999-01-05 Novell, Inc. Internetwork address mapping gateway
US5754774A (en) * 1996-02-15 1998-05-19 International Business Machine Corp. Client/server communication system
US5673322A (en) * 1996-03-22 1997-09-30 Bell Communications Research, Inc. System and method for providing protocol translation and filtering to access the world wide web from wireless or low-bandwidth networks
JP2842524B2 (en) * 1996-06-06 1999-01-06 日本電気株式会社 Multicast group configuration method and multicast communication network
US6011790A (en) * 1996-06-07 2000-01-04 Bell Mobility Cellular Inc. Wireless terminal data network communication
JP2853662B2 (en) * 1996-06-18 1999-02-03 日本電気株式会社 Mobile host compatible network
US5940758A (en) * 1996-06-28 1999-08-17 Lucent Technologies Inc. Wireless handset paging utilizing connection endpoint service identifiers
US5863653A (en) * 1996-07-09 1999-01-26 Life Energy Industry Inc. Rayon fiber containing tourmaline particles and method for the preparation thereof
JPH1032610A (en) * 1996-07-12 1998-02-03 Nec Corp Virtual private network constituting method in mobile data communication
CA2212121C (en) 1996-08-02 2010-03-30 Symbol Technologies, Inc. Improvements in data retrieval
CA2213984A1 (en) * 1996-08-22 1998-02-22 Norand Corporation Enhanced mobility and address resolution in a wireless premises based network
US5987011A (en) * 1996-08-30 1999-11-16 Chai-Keong Toh Routing method for Ad-Hoc mobile networks
US5884179A (en) * 1996-09-16 1999-03-16 Ericsson Inc. Optimized routing of terminating calls within a mobile telecommunications network
US6058422A (en) * 1996-09-17 2000-05-02 Lucent Technologies Inc. Wireless internet access system
US6570871B1 (en) 1996-10-08 2003-05-27 Verizon Services Corp. Internet telephone service using cellular digital vocoder
US6202060B1 (en) 1996-10-29 2001-03-13 Bao Q. Tran Data management system
US6041358A (en) * 1996-11-12 2000-03-21 Industrial Technology Research Inst. Method for maintaining virtual local area networks with mobile terminals in an ATM network
KR100201075B1 (en) * 1996-12-02 1999-06-15 김기천 Hybrid state packet switching protocol
US8982856B2 (en) 1996-12-06 2015-03-17 Ipco, Llc Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods
US7054271B2 (en) 1996-12-06 2006-05-30 Ipco, Llc Wireless network system and method for providing same
US6300946B1 (en) 1997-01-29 2001-10-09 Palm, Inc. Method and apparatus for interacting with a portable computer
JP3382806B2 (en) * 1997-02-13 2003-03-04 日本電気株式会社 Slave station
US6233327B1 (en) 1997-02-14 2001-05-15 Statsignal Systems, Inc. Multi-function general purpose transceiver
US5912878A (en) * 1997-02-27 1999-06-15 Motorola, Inc. Method and end station with improved user reponse time in a mobile network
US6144671A (en) * 1997-03-04 2000-11-07 Nortel Networks Corporation Call redirection methods in a packet based communications network
US6542497B1 (en) 1997-03-11 2003-04-01 Verizon Services Corp. Public wireless/cordless internet gateway
CA2283964C (en) * 1997-03-12 2008-05-06 Nomadix, Llc Nomadic translator or router
US5958007A (en) * 1997-05-13 1999-09-28 Phase Three Logic, Inc. Automatic and secure system for remote access to electronic mail and the internet
US6122276A (en) * 1997-06-30 2000-09-19 Cisco Technology, Inc. Communications gateway mapping internet address to logical-unit name
US6141690A (en) * 1997-07-31 2000-10-31 Hewlett-Packard Company Computer network address mapping
US6829477B1 (en) 1997-08-27 2004-12-07 Interwave Communications International, Ltd. Private multiplexing cellular network
US6035324A (en) * 1997-08-28 2000-03-07 International Business Machines Corporation Client-side asynchronous form management
US6070184A (en) * 1997-08-28 2000-05-30 International Business Machines Corporation Server-side asynchronous form management
US6049833A (en) * 1997-08-29 2000-04-11 Cisco Technology, Inc. Mapping SNA session flow control to TCP flow control
US6128662A (en) * 1997-08-29 2000-10-03 Cisco Technology, Inc. Display-model mapping for TN3270 client
US6105060A (en) * 1997-09-05 2000-08-15 Worldspace, Inc. System for providing global portable internet access using low earth orbit satellite and satellite direct radio broadcast system
US6640108B2 (en) 1997-09-11 2003-10-28 Interwave Communications International, Ltd. Cellular communication system
SE9703327L (en) * 1997-09-12 1999-03-13 Ericsson Telefon Ab L M Method and apparatus for data communication
NO326260B1 (en) 1997-09-29 2008-10-27 Ericsson Telefon Ab L M Method of routing calls from a terminal in a first telecommunications network to a terminal in a second telecommunications network
US6665285B1 (en) 1997-10-14 2003-12-16 Alvarion Israel (2003) Ltd. Ethernet switch in a terminal for a wireless metropolitan area network
US6907048B1 (en) 1997-10-14 2005-06-14 Alvarion Israel (2003) Ltd. Method and apparatus for transporting ethernet data packets via radio frames in a wireless metropolitan area network
US7002941B1 (en) 1997-10-14 2006-02-21 Alvarion Israel (2003) Ltd. Method and apparatus for synchronizing fast ethernet data packets to radio frames in a wireless metropolitan area network
WO1999020016A1 (en) 1997-10-14 1999-04-22 Winnet Mcs, Inc. Method and apparatus for maintaining a predefined transmission quality in a wireless man network
US6539031B1 (en) 1997-10-14 2003-03-25 Innowave Eci Wireless Systems Ltd. Adaptive countermeasures for wireless communication of fast ethernet data packages
US6480477B1 (en) 1997-10-14 2002-11-12 Innowave Eci Wireless Systems Ltd. Method and apparatus for a data transmission rate of multiples of 100 MBPS in a terminal for a wireless metropolitan area network
US6147993A (en) * 1997-10-14 2000-11-14 Cisco Technology, Inc. Method and apparatus for implementing forwarding decision shortcuts at a network switch
US6985451B1 (en) 1997-10-14 2006-01-10 Alvarion Israel (2003) Ltd. Method and apparatus for baseband transmission between a top floor unit and an outdoor unit in a terminal for a wireless metropolitan area network
US6618366B1 (en) * 1997-12-05 2003-09-09 The Distribution Systems Research Institute Integrated information communication system
FI113445B (en) * 1997-12-18 2004-04-15 Nokia Corp Mobile Internet Protocol
FI980024A (en) * 1998-01-07 1999-07-08 Nokia Networks Oy A cellular radio system and a method for connecting a base station to a cellular radio system
US7450560B1 (en) * 1998-03-05 2008-11-11 3Com Corporation Method for address mapping in a network access system and a network access device for use therewith
US6147986A (en) * 1998-03-06 2000-11-14 Lucent Technologies Inc. Address updating of wireless mobile terminal hosts affiliated with a wired network
US6415329B1 (en) * 1998-03-06 2002-07-02 Massachusetts Institute Of Technology Method and apparatus for improving efficiency of TCP/IP protocol over high delay-bandwidth network
WO1999050974A1 (en) * 1998-03-30 1999-10-07 Motorola Inc. Method for routing data in a communication system
FI110987B (en) * 1998-03-31 2003-04-30 Nokia Corp Method of connecting data transfer streams
US5930472A (en) * 1998-04-29 1999-07-27 Motorola, Inc. Method and apparatus in a wireless communication system for splitting a browser functionality between a wireless client and an infrastructure portion
US7010302B1 (en) * 1998-05-08 2006-03-07 Ntt Docomo, Inc. Packet transmission method, packet transmission system and packet data transmission medium on mobile communications network system
GB2353923A (en) * 1998-05-29 2001-03-07 Palm Inc Method and apparatus for communicating information over low bandwith communications networks
US6343318B1 (en) 1998-05-29 2002-01-29 Palm, Inc. Method and apparatus for communicating information over low bandwidth communications networks
US6397259B1 (en) 1998-05-29 2002-05-28 Palm, Inc. Method, system and apparatus for packet minimized communications
US7025209B2 (en) 1998-05-29 2006-04-11 Palmsource, Inc. Method and apparatus for wireless internet access
JP3587984B2 (en) 1998-06-04 2004-11-10 株式会社日立製作所 Mobile communication system, packet gateway device, location information management method, and location information notification method
JP3581251B2 (en) * 1998-06-16 2004-10-27 株式会社東芝 Communication system, data packet transfer method, router device, and packet relay device
US6914893B2 (en) 1998-06-22 2005-07-05 Statsignal Ipc, Llc System and method for monitoring and controlling remote devices
US6437692B1 (en) 1998-06-22 2002-08-20 Statsignal Systems, Inc. System and method for monitoring and controlling remote devices
US8410931B2 (en) 1998-06-22 2013-04-02 Sipco, Llc Mobile inventory unit monitoring systems and methods
US6891838B1 (en) 1998-06-22 2005-05-10 Statsignal Ipc, Llc System and method for monitoring and controlling residential devices
US6356548B1 (en) 1998-06-29 2002-03-12 Cisco Technology, Inc. Pooled receive and transmit queues to access a shared bus in a multi-port switch asic
SE519523C2 (en) * 1998-06-30 2003-03-11 Ericsson Telefon Ab L M Mobile LAN where hosts connected to the LAN can perform packet data communication with hosts in external networks
KR100390397B1 (en) * 1998-07-13 2003-08-19 엘지전자 주식회사 method for transmitting data in internet conncetion device
DE19832290B4 (en) * 1998-07-17 2011-12-08 Telefonaktiebolaget Lm Ericsson (Publ) Communication system and method for establishing connections between terminals of a first and a second communication network
WO2000008788A1 (en) * 1998-08-07 2000-02-17 Elzind Ihab H Cellular internet protocol modem network
US6230012B1 (en) * 1998-08-07 2001-05-08 Qualcomm Incorporated IP mobility support using proxy mobile node registration
US6445715B1 (en) 1998-08-27 2002-09-03 Cisco Technology, Inc. Dynamic trunk protocol
US6295296B1 (en) 1998-09-08 2001-09-25 Cisco Technology, Inc. Use of a single data structure for label forwarding and imposition
US8060656B2 (en) * 1998-10-09 2011-11-15 Netmotion Wireless, Inc. Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
US7293107B1 (en) * 1998-10-09 2007-11-06 Netmotion Wireless, Inc. Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
US8078727B2 (en) 1998-10-09 2011-12-13 Netmotion Wireless, Inc. Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
US7778260B2 (en) 1998-10-09 2010-08-17 Netmotion Wireless, Inc. Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
US7136645B2 (en) 1998-10-09 2006-11-14 Netmotion Wireless, Inc. Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
US6947398B1 (en) * 1998-11-13 2005-09-20 Lucent Technologies Inc. Addressing scheme for a multimedia mobile network
US7246168B1 (en) 1998-11-19 2007-07-17 Cisco Technology, Inc. Technique for improving the interaction between data link switch backup peer devices and ethernet switches
US6452921B1 (en) 1998-11-24 2002-09-17 International Business Machines Corporation Method and system within a computer network for maintaining source-route information at a router bypassed by shortcut communication
US6704318B1 (en) 1998-11-30 2004-03-09 Cisco Technology, Inc. Switched token ring over ISL (TR-ISL) network
US6563832B1 (en) 1998-11-30 2003-05-13 Cisco Technology, Inc. Token ring bridge distributed in a switched fabric
US8713641B1 (en) 1998-12-08 2014-04-29 Nomadix, Inc. Systems and methods for authorizing, authenticating and accounting users having transparent computer access to a network using a gateway device
US8266266B2 (en) 1998-12-08 2012-09-11 Nomadix, Inc. Systems and methods for providing dynamic network authorization, authentication and accounting
US7194554B1 (en) 1998-12-08 2007-03-20 Nomadix, Inc. Systems and methods for providing dynamic network authorization authentication and accounting
US6654359B1 (en) 1998-12-11 2003-11-25 Lucent Technologies Inc. Wireless access to packet-based networks
US6625145B1 (en) 1998-12-30 2003-09-23 Telefonaktiebolaget Lm Ericsson (Publ) Use of lower IP-address bits
US7216348B1 (en) 1999-01-05 2007-05-08 Net2Phone, Inc. Method and apparatus for dynamically balancing call flow workloads in a telecommunications system
US6501746B1 (en) 1999-01-08 2002-12-31 Cisco Technology, Inc. Mobile IP dynamic home address resolution
WO2000041418A1 (en) * 1999-01-08 2000-07-13 Motorola Inc. Routing data in an ip-based communication system
US6466571B1 (en) * 1999-01-19 2002-10-15 3Com Corporation Radius-based mobile internet protocol (IP) address-to-mobile identification number mapping for wireless communication
US6707809B1 (en) 1999-02-25 2004-03-16 Utstarcom, Inc. Method for forwarding data to idle mobile nodes, and home agent control node for use in the method
US7650425B2 (en) 1999-03-18 2010-01-19 Sipco, Llc System and method for controlling communication between a host computer and communication devices associated with remote devices in an automated monitoring system
FI108834B (en) 1999-03-29 2002-03-28 Nokia Corp IP mobility management in a mobile communication system
GB2348570B (en) 1999-03-31 2003-03-05 Ericsson Telefon Ab L M Mobile internet access
US7474660B1 (en) 1999-03-31 2009-01-06 Cisco Technology, Inc. MAC address extension to maintain router information in source routed computer networks
CA2304695A1 (en) * 1999-04-20 2000-10-20 Lucent Technologies Inc. Mobile terminal and method of preventing loss of information for the mobile terminal
US6401127B1 (en) 1999-05-04 2002-06-04 Cisco Technology, Inc. Adaptive timer for LLC type 2 reliable transport in a computer network
US6360272B1 (en) * 1999-05-28 2002-03-19 Palm, Inc. Method and apparatus for maintaining a unified view of multiple mailboxes
DE60037914T2 (en) * 1999-06-04 2009-04-09 Ntt Docomo, Inc. Multicasting data in a mobile IP communications network
US7882247B2 (en) 1999-06-11 2011-02-01 Netmotion Wireless, Inc. Method and apparatus for providing secure connectivity in mobile and other intermittent computing environments
JP3307894B2 (en) 1999-06-22 2002-07-24 三菱電機株式会社 Communication method
US20040160917A1 (en) * 1999-06-22 2004-08-19 Eliznd Ihab H. Multibeam antenna for a wireless network
US6330499B1 (en) 1999-07-21 2001-12-11 International Business Machines Corporation System and method for vehicle diagnostics and health monitoring
US6714541B1 (en) 1999-08-10 2004-03-30 Cisco Technology, Inc. Method and apparatus for encoding bridging/switching information within a routing information filed in a token ring environment
EP2802189A3 (en) 1999-08-12 2015-03-18 Elad Barkan Add-on base station for cellular network expansion
US6788680B1 (en) * 1999-08-25 2004-09-07 Sun Microsystems, Inc. Defferrable processing option for fast path forwarding
US6163250A (en) * 1999-08-31 2000-12-19 International Business Machines Corporation System and method for sensing objects on surface of vehicle
EP1083768A1 (en) * 1999-09-08 2001-03-14 TELEFONAKTIEBOLAGET LM ERICSSON (publ) A method for facilitating data transmission
US7010590B1 (en) * 1999-09-15 2006-03-07 Datawire Communications Networks, Inc. System and method for secure transactions over a network
US6799204B1 (en) 1999-10-22 2004-09-28 Telcordia Technologies, Inc. Method and system for dynamic registration and configuration protocol
WO2001031822A1 (en) * 1999-10-22 2001-05-03 Telcordia Technologies, Inc. Method and system for dynamic registration and configuration protocol
US6529983B1 (en) 1999-11-03 2003-03-04 Cisco Technology, Inc. Group and virtual locking mechanism for inter processor synchronization
KR100624642B1 (en) * 1999-12-15 2006-09-14 주식회사 케이티 Private wireless local access network system for integrated communication service
US6845094B1 (en) * 1999-12-16 2005-01-18 Ut Starcom, Inc. Network address translation based internet protocol mobility
US6785738B1 (en) 1999-12-23 2004-08-31 Cisco Technology, Inc. ARP packet to preserve canonical form of addresses
JP3693230B2 (en) * 1999-12-27 2005-09-07 株式会社エヌ・ティ・ティ・ドコモ Packet communication system
US6748403B1 (en) 2000-01-13 2004-06-08 Palmsource, Inc. Method and apparatus for preserving changes to data
US6847819B1 (en) * 2000-01-31 2005-01-25 Qualcomm Incorporated Adaptive transport TCP/IP phone management
EP1126678A1 (en) * 2000-02-16 2001-08-22 Lucent Technologies Inc. Privacy for mobile terminal in telecommunications network
US6892237B1 (en) 2000-03-28 2005-05-10 Cisco Technology, Inc. Method and apparatus for high-speed parsing of network messages
US6505269B1 (en) 2000-05-16 2003-01-07 Cisco Technology, Inc. Dynamic addressing mapping to eliminate memory resource contention in a symmetric multiprocessor system
KR100369807B1 (en) * 2000-08-05 2003-01-30 삼성전자 주식회사 Packets transmission method for mobile internet
US7158497B2 (en) * 2000-08-31 2007-01-02 Nortel Networks Limited Methods and apparatus for supporting micro-mobility within a radio access network
KR20020026657A (en) * 2000-10-02 2002-04-12 유태로 Base station for providing a communication line through local area network using a packet router in next-generation mobile communication network
GB2367978A (en) * 2000-10-07 2002-04-17 Marconi Comm Ltd Communications protocol for connecting a mobile terminal to a node using internet protocol
US6832207B1 (en) 2000-11-28 2004-12-14 Almond Net, Inc. Super saturation method for information-media
US7372868B2 (en) * 2000-12-14 2008-05-13 Intel Corporation Mobile agent connectivity
US7269482B1 (en) * 2001-04-20 2007-09-11 Vetronix Corporation In-vehicle information system and software framework
CN1138427C (en) * 2001-05-30 2004-02-11 华为技术有限公司 Phonetic channel exchange method for calling adaptation in mobile communication system
US7450578B2 (en) * 2001-06-01 2008-11-11 Fujitsu Limited Method of addressing and routing data
JP4715041B2 (en) * 2001-06-11 2011-07-06 株式会社日立製作所 Communications system
US20050198379A1 (en) 2001-06-13 2005-09-08 Citrix Systems, Inc. Automatically reconnecting a client across reliable and persistent communication sessions
US7562146B2 (en) 2003-10-10 2009-07-14 Citrix Systems, Inc. Encapsulating protocol for session persistence and reliability
US6870956B2 (en) * 2001-06-14 2005-03-22 Microsoft Corporation Method and apparatus for shot detection
US20030016668A1 (en) * 2001-07-17 2003-01-23 Antonio Mugica Method of device-to-device communications in hybrid distributed device control networks
US7103011B2 (en) * 2001-08-30 2006-09-05 Motorola, Inc. Use of IP-multicast technology for 2-party calls in mobile communication networks
US7644171B2 (en) 2001-09-12 2010-01-05 Netmotion Wireless, Inc. Mobile networking system and method using IPv4 and IPv6
US8489063B2 (en) 2001-10-24 2013-07-16 Sipco, Llc Systems and methods for providing emergency messages to a mobile device
US7480501B2 (en) 2001-10-24 2009-01-20 Statsignal Ipc, Llc System and method for transmitting an emergency message over an integrated wireless network
US7424527B2 (en) 2001-10-30 2008-09-09 Sipco, Llc System and method for transmitting pollution information over an integrated wireless network
US7647422B2 (en) 2001-11-06 2010-01-12 Enterasys Networks, Inc. VPN failure recovery
US7023828B2 (en) * 2001-11-19 2006-04-04 Motorola, Inc. Method and apparatus for a mobile node to maintain location privacy from selected correspondent nodes
US7190668B1 (en) 2001-11-27 2007-03-13 Nokia Corporation Method of anchoring flows
AU2002365829A1 (en) * 2001-12-03 2003-06-17 Ram Gopal Lakshmi Narayanan Context filter in a mobile node
AU2002353270A1 (en) * 2001-12-03 2003-06-17 Nokia Corporation Policy based mechanisms for selecting access routers and mobile context
US7409549B1 (en) 2001-12-11 2008-08-05 Cisco Technology, Inc. Methods and apparatus for dynamic home agent assignment in mobile IP
US7593373B2 (en) 2001-12-12 2009-09-22 At&T Intelectual Property Ii, Lp Snoop-and-shortcut routing method for better mobility support on networks
US7607171B1 (en) 2002-01-17 2009-10-20 Avinti, Inc. Virus detection by executing e-mail code in a virtual machine
US9652613B1 (en) 2002-01-17 2017-05-16 Trustwave Holdings, Inc. Virus detection by executing electronic message code in a virtual machine
US7661129B2 (en) 2002-02-26 2010-02-09 Citrix Systems, Inc. Secure traversal of network components
US7984157B2 (en) 2002-02-26 2011-07-19 Citrix Systems, Inc. Persistent and reliable session securely traversing network components using an encapsulating protocol
US7284057B2 (en) * 2002-02-27 2007-10-16 Cisco Technology, Inc. Methods and apparatus for Mobile IP Home Agent clustering
US7606938B2 (en) 2002-03-01 2009-10-20 Enterasys Networks, Inc. Verified device locations in a data network
KR100424620B1 (en) * 2002-03-27 2004-03-25 삼성전자주식회사 Apparatus and method for providing mobility of mobile node among the sub-networks in wireless local area network
US7587498B2 (en) * 2002-05-06 2009-09-08 Cisco Technology, Inc. Methods and apparatus for mobile IP dynamic home agent allocation
DE60218144T2 (en) 2002-06-19 2007-10-31 Motorola, Inc., Schaumburg Method and device for route optimization in nested mobile networks
US7274741B2 (en) * 2002-11-01 2007-09-25 Microsoft Corporation Systems and methods for generating a comprehensive user attention model
US7127120B2 (en) * 2002-11-01 2006-10-24 Microsoft Corporation Systems and methods for automatically editing a video
US7116716B2 (en) * 2002-11-01 2006-10-03 Microsoft Corporation Systems and methods for generating a motion attention model
US20040088723A1 (en) * 2002-11-01 2004-05-06 Yu-Fei Ma Systems and methods for generating a video summary
US7707310B2 (en) * 2002-11-20 2010-04-27 Cisco Technology, Inc. Mobile IP registration supporting port identification
ATE492085T1 (en) 2003-01-28 2011-01-15 Cellport Systems Inc A SYSTEM AND METHOD FOR CONTROLLING APPLICATIONS' ACCESS TO PROTECTED RESOURCES WITHIN A SECURE VEHICLE TELEMATICS SYSTEM
US7164798B2 (en) * 2003-02-18 2007-01-16 Microsoft Corporation Learning-based automatic commercial content detection
US7260261B2 (en) 2003-02-20 2007-08-21 Microsoft Corporation Systems and methods for enhanced image adaptation
US20040264503A1 (en) * 2003-06-30 2004-12-30 Microsoft Corporation Method and system for providing a virtual protocol interlayer
US7400761B2 (en) * 2003-09-30 2008-07-15 Microsoft Corporation Contrast-based image attention analysis framework
US7471827B2 (en) * 2003-10-16 2008-12-30 Microsoft Corporation Automatic browsing path generation to present image areas with high attention value as a function of space and time
US7702817B2 (en) * 2003-10-28 2010-04-20 Microsoft Corporation Wireless network access technologies for retrieving a virtual resource via a plurality of wireless network interfaces
US7012913B2 (en) * 2003-11-25 2006-03-14 Nokia Corporation Apparatus, and associated method, for facilitating communication of unfragmented packet-formatted data in a radio communication system
US7477894B1 (en) 2004-02-23 2009-01-13 Foundry Networks, Inc. Methods and apparatus for handling wireless roaming among and across wireless area networks
US7580403B2 (en) 2004-02-26 2009-08-25 Enterasys Networks, Inc. Status transmission system and method
US7756086B2 (en) 2004-03-03 2010-07-13 Sipco, Llc Method for communicating in dual-modes
US8031650B2 (en) 2004-03-03 2011-10-04 Sipco, Llc System and method for monitoring remote devices with a dual-mode wireless communication protocol
US7346370B2 (en) * 2004-04-29 2008-03-18 Cellport Systems, Inc. Enabling interoperability between distributed devices using different communication link technologies
US20050243857A1 (en) * 2004-04-30 2005-11-03 Padcom, Inc. Simultaneously routing data over multiple wireless networks
JP4429083B2 (en) * 2004-06-03 2010-03-10 キヤノン株式会社 Shading type coordinate input device and coordinate input method thereof
US9053754B2 (en) 2004-07-28 2015-06-09 Microsoft Technology Licensing, Llc Thumbnail generation and presentation for recorded TV programs
US7986372B2 (en) * 2004-08-02 2011-07-26 Microsoft Corporation Systems and methods for smart media content thumbnail extraction
US7945945B2 (en) * 2004-08-06 2011-05-17 Enterasys Networks, Inc. System and method for address block enhanced dynamic network policy management
US7347628B2 (en) 2004-11-08 2008-03-25 Enterasys Networks, Inc. Optical interface identification system
US7548936B2 (en) 2005-01-12 2009-06-16 Microsoft Corporation Systems and methods to present web image search results for effective image browsing
WO2006081206A1 (en) 2005-01-25 2006-08-03 Sipco, Llc Wireless network protocol systems and methods
IES20050376A2 (en) 2005-06-03 2006-08-09 Asavie R & D Ltd Secure network communication system and method
US8086232B2 (en) 2005-06-28 2011-12-27 Enterasys Networks, Inc. Time synchronized wireless method and operations
EP1739893A1 (en) * 2005-06-30 2007-01-03 Matsushita Electric Industrial Co., Ltd. Optimized reverse tunnelling for packet switched mobile communication systems
US20070112811A1 (en) * 2005-10-20 2007-05-17 Microsoft Corporation Architecture for scalable video coding applications
US8180826B2 (en) * 2005-10-31 2012-05-15 Microsoft Corporation Media sharing and authoring on the web
US7599918B2 (en) 2005-12-29 2009-10-06 Microsoft Corporation Dynamic search with implicit user intention mining
WO2007147080A1 (en) 2006-06-16 2007-12-21 Almondnet, Inc. Media properties selection method and system based on expected profit from profile-based ad delivery
US8280758B2 (en) 2006-06-19 2012-10-02 Datonics, Llc Providing collected profiles to media properties having specified interests
US7907621B2 (en) * 2006-08-03 2011-03-15 Citrix Systems, Inc. Systems and methods for using a client agent to manage ICMP traffic in a virtual private network environment
US8275895B1 (en) 2006-12-21 2012-09-25 Crimson Corporation Systems and methods for establishing a trusted dynamic host configuration protocol connection
US7861260B2 (en) 2007-04-17 2010-12-28 Almondnet, Inc. Targeted television advertisements based on online behavior
US8321936B1 (en) 2007-05-30 2012-11-27 M86 Security, Inc. System and method for malicious software detection in multiple protocols
US8027293B2 (en) * 2007-07-16 2011-09-27 Cellport Systems, Inc. Communication channel selection and use
WO2009055061A1 (en) 2007-10-25 2009-04-30 Trilliant Networks, Inc. Gas meter having ultra-sensitive magnetic material retrofitted onto meter dial and method for performing meter retrofit
US8138934B2 (en) 2007-11-25 2012-03-20 Trilliant Networks, Inc. System and method for false alert filtering of event messages within a network
EP2215550A1 (en) 2007-11-25 2010-08-11 Trilliant Networks, Inc. Energy use control system and method
EP2215556B1 (en) 2007-11-25 2019-08-28 Trilliant Networks, Inc. System and method for transmitting power status notifications in an advanced metering infrastructure network
EP2215616B1 (en) 2007-11-25 2016-08-17 Trilliant Networks, Inc. Communication and message route optimization and messaging in a mesh network
US8699377B2 (en) 2008-09-04 2014-04-15 Trilliant Networks, Inc. System and method for implementing mesh network communications using a mesh network protocol
US8289182B2 (en) 2008-11-21 2012-10-16 Trilliant Networks, Inc. Methods and systems for virtual energy management display
WO2010105038A1 (en) 2009-03-11 2010-09-16 Trilliant Networks, Inc. Process, device and system for mapping transformers to meters and locating non-technical line losses
EP2494768B1 (en) * 2009-10-30 2017-12-06 Nec Corporation Method and system for supporting the selection of communication peers in an overlay network
WO2012027634A1 (en) 2010-08-27 2012-03-01 Trilliant Networkd, Inc. System and method for interference free operation of co-located tranceivers
WO2012037055A1 (en) 2010-09-13 2012-03-22 Trilliant Networks Process for detecting energy theft
EP2641137A2 (en) 2010-11-15 2013-09-25 Trilliant Holdings, Inc. System and method for securely communicating across multiple networks using a single radio
US9282383B2 (en) 2011-01-14 2016-03-08 Trilliant Incorporated Process, device and system for volt/VAR optimization
WO2012103072A2 (en) 2011-01-25 2012-08-02 Trilliant Holdings, Inc. Aggregated real-time power outages/restoration reporting (rtpor) in a secure mesh network
US8856323B2 (en) 2011-02-10 2014-10-07 Trilliant Holdings, Inc. Device and method for facilitating secure communications over a cellular network
WO2012122310A1 (en) 2011-03-08 2012-09-13 Trilliant Networks, Inc. System and method for managing load distribution across a power grid
US9001787B1 (en) 2011-09-20 2015-04-07 Trilliant Networks Inc. System and method for implementing handover of a hybrid communications module

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4644461A (en) * 1983-04-29 1987-02-17 The Regents Of The University Of California Dynamic activity-creating data-driven computer architecture
JPH0638600B2 (en) * 1983-12-28 1994-05-18 株式会社東芝 Local area network system
GB2167274A (en) * 1984-11-14 1986-05-21 Philips Electronic Associated Local area network
US4706081A (en) * 1984-12-14 1987-11-10 Vitalink Communications Corporation Method and apparatus for bridging local area networks
EP0196347B1 (en) * 1985-04-02 1989-08-16 International Business Machines Corporation Infrared communication system
US4665519A (en) * 1985-11-04 1987-05-12 Electronic Systems Technology, Inc. Wireless computer modem
US4807222A (en) * 1986-08-25 1989-02-21 American Telephone And Telegraph Company At&T Bell Laboratories Cordless accessed high-speed high-capacity local area networks
CA1290020C (en) * 1987-02-09 1991-10-01 Steven Messenger Wireless local area network
US4876742A (en) * 1987-03-23 1989-10-24 Gary Vacon Apparatus and method for providing a wireless link between two local area network systems
EP0328100B1 (en) * 1988-02-10 1995-06-21 Nec Corporation High throughput communication method and system for a digital mobile station when crossing a zone boundary during a session
US4893307A (en) * 1988-02-29 1990-01-09 International Business Machines Corporation Method and apparatus for linking SNA terminals to an SNA host over a packet switched communications network
US4914652A (en) * 1988-08-01 1990-04-03 Advanced Micro Devices, Inc. Method for transfer of data between a media access controller and buffer memory in a token ring network
US5040175A (en) * 1990-04-11 1991-08-13 Ncr Corporation Wireless information transmission system
US5068916A (en) * 1990-10-29 1991-11-26 International Business Machines Corporation Coordination of wireless medium among a plurality of base stations
US5159592A (en) * 1990-10-29 1992-10-27 International Business Machines Corporation Network address management for a wired network supporting wireless communication to a plurality of mobile users
US5210753A (en) * 1991-10-31 1993-05-11 International Business Machines Corporation Robust scheduling mechanm for efficient band-width usage in muliticell wireless local networks

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US5442633A (en) 1995-08-15

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