Method and apparatus for connecting network segments

• US 6,483,852 B1
• Filed: 12/14/1998
• Issued: 11/19/2002
• Est. Priority Date: 12/15/1997
• Status: Expired due to Term

• Current Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Original Assignee: Inria Institut National de Recherche EN Informatique et EN Automatique
• Inventors: Jacquet, Philippe, Muhlethaler, Paul
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): SPAFFORD, TIMOTHY J
• Application Number:
  US09/210,456
• Time in Patent Office: 1,436 Days
• Field of Search: 370/356, 370/389, 370/392, 370/401, 370/402, 370/403, 370/404, 370/405, 370/406, 370/466
• US Class Current: 370/466
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 45/02 Topology update or discovery

Abstract

A connection device connects a radio network and a cabled network communicating respectively by way of messages encapsulated according to radio and cable protocols, and includes a storage module containing a routing table, and a processing module for managing exchanges of data as a function of the routing table. The processing module includes a management module capable on the one hand of disencapsulating a message received from the radio network, in order to extract routing information therefrom and then to compare this information with the routing table in order to choose at least one re-sending network for the message, and on the other hand of re-encapsulating the message in the radio network format or according to a mixed radio format, having radio and cable capsules, depending on whether the re-sending network chosen is the radio network or the cabled network, with a view to re-sending it in the chosen re-sending network segment.

Claims

1. Apparatus for connection between a segment of a “

main”

network communicating by way of messages provided with a main capsule complying with a protocol based on a first format and at least one segment of at least one “

ancillary”

network communicating by way of messages provided with an ancillary capsule complying with a protocol based on a second format, said apparatus comprising;

a storage module able to store at least one routing table; and

a processing module able to manage data exchanges according to the said routing table, said processing module including

a management module having means to disencapsulate a message received from the said main network, by withdrawing its main capsule, so as to extract routing information therefrom, means to compare the said information with the said stored routing table in order to choose, from amongst the main and ancillary networks, at least one re-sending network segment for the said disencapsulated message and additionally to add to the said disencapsulated message a main capsule or a mixed capsule, including a main capsule and an ancillary capsule, depending on whether the re-sending network chosen is the main network or an ancillary network so as to send a thus re-encapsulated message, and means to add to said re-encapsulated message a protocol code designating the format of the segment of the main network from which the said received message came.

2. Apparatus according to claim 1, wherein said main network is a radio network and said at least one ancillary network is a cabled network.

3. Apparatus according to claim 2, wherein the format of a said radio network is chosen from at least the format of the “

HIPERLAN”

standard and the format of IEEE 802.11, and wherein the format of a said cabled network is chosen from at least the ISO standards for the standards IEEE 802.3, 802.5 and 802.14.

4. Apparatus according to claim 2, wherein the management module is able to extract, from a so-called “

service”

message, issuing from the main network, service information relating to modifications to the said routing table, so as to update this routing table.

5. Apparatus according to claim 4, wherein the management module has means to control the sending of service messages, not only at local request of a higher stage, but also as a transmission relay between distant connection devices, for exchanging routing information for updating the routing tables of each one.

6. Apparatus according to claim 5, wherein the said service messages are intended for the exchange of routing information for updating the routing tables of the said interconnection devices.

7. Apparatus according to claims 5, wherein the said processing means maintain at least one list of stations of the network segments which they receive, and are able to transmit this list in the form of the said service messages, which enables them mutually to maintain a list of the stations which receive them from the service messages which they receive.

8. Apparatus according to claim 1, wherein said main and ancillary networks are radio networks.

9. Apparatus according to claim 8, wherein the format of a said radio network is chosen from at least the format of the “

HIPERLAN”

standard and the format of IEEE 802.11.

10. Apparatus according to claim 1, wherein, in the case of reception of a message to be relayed by at least one other connection device, referred to as “

intermediate”

, said management module has means to place the address of the said intermediate device in the capsule of the chosen ancillary re-sending network.

11. Apparatus according to claim 1, wherein said ancillary network segment is arranged so as to permit the use of group addresses each designating a predetermined set of connection devices.

12. Apparatus according to claim 11, wherein the management module is arranged to process so-called “

broadcast”

messages intended for several destinations in the said main network and passing over at least one of the said ancillary networks using a group address.

13. Apparatus according to claim 1, wherein said management module has means to determine the format of the main network in a message provided with a mixed capsule, so that the routing information for the said message is analysed only in the case of the presence of such a format.

14. Apparatus according to claim 13, wherein said means to add to said re-encapsulated message a protocol code designating the format of the segment of the main network from which the said received message came further comprises means to determine the said format by detecting the said protocol code.

15. Apparatus according to claims 1, wherein the management module is arranged to process so-called “

service”

messages issuing from ancillary network segments.

16. Apparatus according to claim 15, wherein the said service messages of an ancillary network are service messages of the main network provided with at least one ancillary capsule.

17. Apparatus according to claim 15, wherein some of the said service messages have a group address.

18. Apparatus according to claim 1, wherein the management module has means to transmit to a so-called “

higher”

processing layer the data contained in a message which has arrived at its destination.

19. Apparatus according to claim 18, wherein the management module has means to add to a message created locally by the said higher processing stage, a main capsule or a mixed capsule according to the said re-sending network segment determined according to the destination address of the said message and the said routing table, so as to send the said encapsulated message in the determined re-sending network segment.

20. Apparatus according to claims 19, wherein the processing means also maintain a topological directory designating at least some of the stations with which they can communicate, directly or indirectly, and define the route or routes of this communication.

21. Apparatus according to claim 20, wherein the processing means is arranged to optimize the choice of the sending (or re-sending) segment or segments as a function of at least one predetermined criterion.

22. Apparatus according to claim 21, wherein the criterion is chosen according to the characteristics of the main and ancillary networks.

23. Method of exchanging data, via a connection device having means for storing at least one routing table, between a segment of a “

main”

network communicating by way of messages provided with a main capsule complying with a protocol based on a first format and at least one segment of at least one “

ancillary”

network communicating by way of messages provided with an ancillary capsule complying with a protocol based on a second format, comprising the steps of;

(a) withdrawing the main capsule of a message received by the connection device from the main network so as to extract routing information therefrom,

(b) comparing the extracted information with the stored routing table in order to choose, from amongst the said main and ancillary networks, at least one re-sending network segment for the said disencapsulated message,

(c) adding a main capsule or a mixed capsule to a disencapsulated message, said mixed capsule including a main capsule and an ancillary capsule, depending on whether the chosen re-sending network is the main network or an ancillary network, so as to permit the thus re-encapsulated message to be re-sent in the chosen re-sending network segment, and

(d) adding to the re-encapsulated message a protocol code designating the format of the segment of the main network from which the message received in step (a) came.