Telecommunication network with fast-reroute features

• US 20040081085A1
• Filed: 06/30/2003
• Published: 04/29/2004
• Est. Priority Date: 07/01/2002
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Cetin, Riza, De Cnodder, Stefaan Jozef
• Granted Patent: US 7,372,845 B2
• Time in Patent Office: Days
• US Class Current: 370/225
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A telecommunication network with fast-reroute features wherein a method is used to release, by means of a “Path_Tear Message”, a Label Switched Path [LSP] established between linked routers (A, B, C, D, E). The routers are linked in cascade according to a Main Path (AB, BC, CD, DE) and are further linked in another order according to at least one Detour Path (ac, ce; bd). The Path_Tear Message includes a tag indicating, in each router, whether this Path_Tear Message should be immediately forwarded towards a downstream-located router or not. It is thereby possible to obtain a faster release of any unused Label Switched Path [LSP] than waiting for a timeout of 1 to 2 minutes, as it is currently the case.

Claims

1. A method to release, by means of a Path_Tear Message, a Label Switched Path (LSP) established between linked routers (A, B, C, D, E) of a telecommunication network,

said routers being linked in cascade according to a Main Path (AB, BC, CD, DE) and being further linked in another order according to at least one Detour Path (ac, ce, bd),

characterized in that said Path_Tear Message includes a tag indicating, to the router receiving said Path_Tear Message, whether said Path_Tear Message should be immediately forwarded towards a downstream-located router.

2. The release method according to claim 1, characterized in that said Path_Tear Message is received, in the receiving router, via a said Detour Path (ac, ce, bd) linking an upstream-located router to said receiving router.

3. The release method according to claim 1, characterized in that said tag further indicates through which of said Main Path (AB, BC, CD, DE) or said Detour Path (ac, ce, bd) or both, starting from the receiving router, said Path_Tear Message should be immediately forwarded towards said downstream-located router.

4. The release method according to claim 1, characterized in that, for said router receiving said Path_Tear Message, said release method further comprises a step of releasing all the Label Switched Paths (LSP) arriving at this receiving router from upstream-located routers via said Main Path (AB, BC, CD, DE) and via said Detour Path (ac, ce, bd) linking said upstream-located routers and said receiving router.

5. The release method according to claim 1, characterized in that said tag further indicates which Label Switched Paths (LSPs) to release, and in that, for the router receiving said Path_Tear Message, said release method comprises a step of releasing immediately each Label Switched Path indicated by said tag.

6. The release method according to claim 5, characterized in that said tag is a Sender Template whereof can be derived the Label Switched Paths to release.

14. The telecommunication network according to any of the claims 7 to 13, characterized in that said routers are adapted to operate according to the release method as mentioned in any of the claims 1 to 6.

7. A telecommunication network with a plurality of routers (A, B, C, D, E) interconnected via links through which Label Switched Paths (LSP) are established,

said routers being linked in cascade according to a Main Path (AB, BC, CD, DE) and being further linked in another order according to at least one Detour Path (ac, ce;

bd),

and said routers being adapted to transmit a Path_Tear Message towards downstream-located routers, said Path_Tear Message indicating that a Label Switched Path (LSP) has to be released,

characterized in that the router transmitting said Path_Tear Message is adapted to include in said Path_Tear Message a tag indicating, to the router receiving said Path_Tear Message, whether said Path_Tear Message should be immediately forwarded towards a downstream-located router,

and in that the receiving router is adapted

to detect said tag in said received Path_Tear Message,

to release each Label Switched Path indicated by said tag, and,

according to said tag, to forward immediately said Path_Tear Message towards said downstream-located router.

8. The telecommunication network according to claim 7, characterized in that said tag further indicates through which path said Path_Tear Message should be forwarded downstream,

and in that, according to said tag, said receiving router is further adapted to forward immediately said Path_Tear Message towards said downstream-located router through said Main Path (AB, BC, CD, DE) or through said Detour Path (ac, ce, bd) or through both.

9. The telecommunication network according to claim 7, characterized in that said receiving router is adapted to release all the Label Switched Paths (LSPs) arriving at said receiving router from upstream-located routers via said Main Path (AB, BC, CD, DE) and via said Detour Path (ac, ce, bd) linking said upstream-located routers and said receiving router.

10. The telecommunication network according to claim 7, characterized in that said tag further indicates which Label Switched Paths (LSPs) to be released,

and in that said receiving router is adapted to release immediately each Label Switched Path indicated by said tag.

11. The telecommunication network according to claim 7, characterized in that said receiving router is further adapted to transmit, towards an upstream-located router, a Reserved_Tear Message including a said tag,

in that said upstream-located router is adapted to transmit said Reserved_Tear Message towards a downstream-located router,

and in that said downstream-located router is adapted

to immediately generate a Path_Tear Message including said tag, and

to immediately forward said Path_Tear Message towards another downstream-located router.

12. The telecommunication network according to claim 7, characterized in that both said Main Path (AB, BC, CD, DE) and at least one Detour Path (ac, ce;

bd) arrive at said receiving router.

13. The telecomniunication network according to claim 7, characterized in that said telecommunication network is a Multi-Protocol Label Switching [MPLS] telecommunication network.