US6711152B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Routing over large clouds
Assignee: AT&T Inc
•
Filing: 1999-07-06
•
Granted: 2004-03-23
•
Expires: 2019-07-06
Abstract
Abstract The present invention discloses an efficient architecture for routing in a very large autonomous system where many of the layer 3 routers are attached to a common connection-oriented layer 2 subnetwork, such as an ATM network. In a preferred embodiment of the invention, a permanent topology of routers coupled to the subnetwork is connected by permanent virtual circuits. The routers can further take advantage of both intra-area and inter-area shortcuts through the layer 2 network to improve network performance. The routers pre-calculate shortcuts using information from link state packets broadcast by other routers and store the shortcuts to a given destination in a forwarding table, along with corresponding entries for a next hop along the permanent topology. The present invention allows the network to continue to operate correctly if layer 2 resource limitations preclude the setup of additional shortcuts.
Inventors
- 👤 Charles Robert Kalmanek, Jr.
- 👤 Anthony G Lauck
- 👤 Kadangode K. Ramakrishnan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:29
CPC Classifications
H; H04; H04L; H04L45/00; H04L45/02; H04L45/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
81 words
A communications network comprising: a connection-oriented non-broadcast multiple access network; a permanent topology of routers coupled to the non-broadcast multiple access network and interconnected by virtual circuits, the routers further comprising: means for precomputing a shortcut path through the non-broadcast multiple access network; a forwarding table comprising a first entry along a path through the permanent topology and a second entry along the precomputed shortcut path; and means for establishing a virtual circuit to another router along the precomputed shortcut path.
Claim 2
Dependent Claim
81 words
A communications network comprising: a connection-oriented non-broadcast multiple access network; a permanent topology of routers coupled to the non-broadcast multiple access network and interconnected by virtual circuits, the routers further comprising: means for precomputing a shortcut path through the non-broadcast multiple access network; a forwarding table comprising a first entry along a path through the permanent topology and a second entry along the precomputed shortcut path; and means for establishing a virtual circuit to another router along the precomputed shortcut path.
Claim 3
Dependent Claim
20 words
The communication network of claim 1 wherein the virtual circuits interconnecting the permanent topology of routers are permanent virtual circuits.
Claim 4
Dependent Claim
13 words
The communication network of claim 1 wherein the shortcut is an intra-area shortcut.
Claim 5
Dependent Claim
13 words
The communication network of claim 1 wherein the shortcut is an inter-area shortcut.
Claim 6
Dependent Claim
26 words
The communication network of claim 1 wherein the routers further comprise means for receiving and processing link state packets containing connectivity information broadcast by another router.
Claim 7
Dependent Claim
26 words
The communication network of claim 1 wherein the routers further comprise means for receiving and processing link state packets containing shortcut information broadcast by another router.
Claim 8
Dependent Claim
16 words
The communication network of claim 1 wherein the non-broadcast multiple access network is an ATM network.
Claim 9
Independent Claim
100 words
A method of operating a router in a communication network coupled to a connection-oriented non-broadcast multiple access network comprising the steps of: receiving a link state packet; using information in the link state packet to compute a permanent path to a destination address; using information in the link state packet to precompute a shortcut path through the connection-oriented non-broadcast multiple access network to the destination address; and storing in a forwarding table a first entry to a router along the permanent path and a second entry to a router along the shortcut path through the connection-oriented non-broadcast multiple access network.
Claim 10
Independent Claim
100 words
A method of operating a router in a communication network coupled to a connection-oriented non-broadcast multiple access network comprising the steps of: receiving a link state packet; using information in the link state packet to compute a permanent path to a destination address; using information in the link state packet to precompute a shortcut path through the connection-oriented non-broadcast multiple access network to the destination address; and storing in a forwarding table a first entry to a router along the permanent path and a second entry to a router along the shortcut path through the connection-oriented non-broadcast multiple access network.
Claim 11
Dependent Claim
28 words
The method of claim 8 wherein the shortcut path through the connection-oriented non-broadcast multiple access network is to a router on the permanent path to the destination address.
Claim 12
Dependent Claim
30 words
The method of claim 8 further comprising the step of setting up a virtual circuit along the shortcut path through the connection-oriented non-broadcast multiple access network to the destination address.
Claim 13
Dependent Claim
15 words
The method of claim 8 wherein the non-broadcast multiple access network is an ATM network.
References Cited (Backward Citations)
US5408469A
Cited
US5497368A
Cited
US5583862A
Cited
US6249820B1
Cited
US5699347A
Cited
US5917820A
Cited
US6421321B1
Cited
US5909441A
Cited
US6304912B1
Cited
US6167052A
Cited
US6314105B1
Cited
US6418476B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-03-23 | 2007-09-22 | 2008-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-03-23 | 2011-09-22 | 2012-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-03-23 | 2015-09-22 | 2016-03-23 | $7700.00 | Window Closed / Lapsed |