US 8,014,380 B2Granted

Method and system for automatically establishing a return label switched path

AssigneeAlcatel Lucent

InventorHaydn Marc Lewis

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Abstract

A method and apparatus for unilaterally forming a bi-directional label switched path between first and second routing devices in a network is disclosed. The method of the preferred embodiment is comprised of the steps of: sending a first LSP path message comprising a first bi-directional indicator from the first routing device to the second routing device; and automatically sending a second LSP path message from the second routing device to the first routing device in response to the first bi-directional indicator. The resulting two unidirectional label switched paths may be associated with one another at the endpoints to form a bi-directional LSP. The bi-directional indicator is preferably an RSVP protocol opaque object used in part to specify the router resources required for the return LSP, which may be different than the resource requirements of the forward LSP specified in the first LSP path message.

Claims28

Dependent claims

A method of forming a bi-directional label switched path (LSP) between a first routing device and second routing device, the method comprising the steps of:

(a) sending a first LSP setup request message comprising a first bi-directional indicator from the first routing device to the second routing device, wherein sending the first LSP setup request message causes a message exchange initiated by the first LSP setup request message to establish a first unidirectional label switched path from the first routing device to the second routing device, wherein the first LSP setup request message is a first RSVP PATH message including a Record Route Object and wherein sending the first LSP setup request message includes causing an address of each transit routing device through which the first RSVP PATH message propagates between the first routing device to the second routing device to be recorded within the Record Route object as the first RSVP PATH message propagates between the first routing device to the second routing device;
(b) automatically sending a second LSP setup request message from the second routing device to the first routing device in response to the first bi-directional indicator, wherein sending the second LSP setup request message causes a message exchange initiated by the second LSP setup request message to establish a second unidirectional label switched path from the second routing device to the first routing device, wherein sending the second LSP setup request message includes sending the second LSP setup request message over a path that the first LSP setup request message was sent such that the second unidirectional label switched path propagates over the path of the first unidirectional label switched path in an opposite direction as the first unidirectional label switched path, wherein sending the second LSP setup request message over the path that the first LSP setup request message was sent includes accessing the address of each transit routing device through which the first LSP setup request message propagated between the first routing device to the second routing device from the Record Route Object and causing the second LSP setup message to propagate through each transit routing device through which the first LSP setup request message propagated such that the second unidirectional label switched path propagates over the same path as the first unidirectional label switched path during an entire duration of time that the bi-directional LSP is established;
and
(c) said routing devices between which said first and second unidirectional LSPs are formed periodically sending refresh messages between each other to maintain said first and second unidirectional LSPs through creation and utilization of information provided by the Record Route Object thereby ensuring that said first and second unidirectional LSPs continue to traverse a common path during the entire duration of time that the bi-directional LSP is established.

1 more element

A system for establishing a bi-directional label switched path (LSP) between endpoints, the system comprising:

(a) a first routing device for sending a first LSP setup request message from the first routing device;
and
(b) a second routing device for automatically sending a second LSP setup request message from the second routing device to the first routing device upon receipt of the first LSP setup request message;
wherein the first LSP setup request message comprises a first bi-directional indicator;
wherein, between the first routing device and the second routing device, a first unidirectional label switched path and a second unidirectional label switched path are established in response to respective first and second message exchanges initiated by the first and second LSP setup request messages, respectively;
wherein the first LSP setup request message is a first RSVP PATH message including a Record Route Object;
wherein sending the first LSP setup request message includes causing an address of each transit routing device through which the first RSVP PATH message propagates between the first routing device to the second routing device to be recorded within the Record Route object as the first RSVP PATH message propagates between the first routing device to the second routing device;
wherein sending the second LSP setup request message includes sending the second LSP setup request message over a path that the first LSP setup request message was sent such that the second unidirectional label switched path propagates over the path of the first unidirectional label switched path during an entire duration of time that the bi-directional LSP is established;
and
wherein sending the second LSP setup request message over the path that the first LSP setup request message was sent includes accessing the address of each transit routing device through which the first LSP setup request message propagated between the first routing device to the second routing device from the Record Route Object and causing the second LSP setup message to propagate through each transit routing device through which the first LSP setup request message propagated such that the second unidirectional label switched path propagates over the same path as the first unidirectional label switched path;
whereby label encapsulated data are transmitted bi-directionally between the first routing device and the second routing device over the same path;
and
wherein said routing devices between which said first and second unidirectional LSPs are formed periodically sending refresh messages between each other to maintain said first and second unidirectional LSPs through creation and utilization of information provided by the Record Route Object thereby ensuring that said first and second unidirectional LSPs continue to traverse a common path during the entire duration of time that the bi-directional LSP is established.

10 more elements

A non-transitory computer-readable medium containing computer-executable instructions for controlling at least one routing device to perform a method of forming a bi-directional label switched path (LSP) between a first routing device and second routing device, the method comprising the steps of:

(a) sending a first LSP setup request message comprising a first bi-directional indicator from the first routing device to the second routing device, wherein sending the first LSP setup request message causes a message exchange initiated by the first LSP setup request message to establish a first unidirectional label switched path from the first routing device to the second routing device, wherein the first LSP setup request message is a first RSVP PATH message including a Record Route Object, wherein sending the first LSP setup request message includes causing an address of each transit routing device through which the first RSVP PATH message propagates between the first routing device to the second routing device to be recorded within the Record Route object as the first RSVP PATH message propagates between the first routing device to the second routing device;
(b) automatically sending a second LSP setup request message from the second routing device to the first routing device wherein sending the second LSP setup request message causes a message exchange initiated by the second LSP setup request message to establish a second unidirectional label switched path from the second routing device to the first routing device, wherein sending the second LSP setup request message includes sending the second LSP setup request message over a path that the first LSP setup request message was sent such that the second unidirectional label switched path propagates over the path of the first unidirectional label switched path in an opposite direction as the first unidirectional label switched path, and wherein sending the second LSP setup request message over the path that the first LSP setup request message was sent includes accessing the address of each transit routing device through which the first LSP setup request message propagated between the first routing device to the second routing device from the Record Route Object and causing the second LSP setup message to propagate through each transit routing device through which the first LSP setup request message propagated such that the second unidirectional label switched path propagates over the same path as the first unidirectional label switched path during an entire duration of time that the bi-directional LSP is established;
and
(c) said routing devices between which said first and second unidirectional LSPs are formed periodically sending refresh messages between each other to maintain said first and second LSPs through creation and utilization of information provided by the Record Route Object thereby ensuring that said first and second unidirectional LSPs continue to traverse a common path during the entire duration of time that the bi-directional LSP is established.

1 more element

A method of forming a bi-directional label switched path (LSP) between a first routing device and second routing device, the method comprising the steps of:

(a) sending a first LSP setup request message from the first routing device to the second routing device, wherein sending the first LSP setup request message causes a message exchange initiated by the first LSP setup request message to establish a first unidirectional label switched path from the first routing device to the second routing device, wherein the first LSP setup request message is a first RSVP PATH message including a Record Route Object, wherein sending the first LSP setup request message includes causing an address of each transit routing device through which the first RSVP PATH message propagates between the first routing device to the second routing device to be recorded within the Record Route object as the first RSVP PATH message propagates between the first routing device to the second routing device;
(b) sending a second LSP setup request message from the second routing device to the first routing device whenever the first LSP setup request message of the first LSP setup request message comprises a bi-directional indicator, wherein sending the second LSP setup request message causes a message exchange initiated by the second LSP setup request message to establish a second unidirectional label switched path from the second routing device to the first routing device, wherein sending the second LSP setup request message includes sending the second LSP setup request message over a path that the first LSP setup request message was sent such that the second unidirectional label switched path propagates over the path of the first unidirectional label switched path during an entire duration of time that the bi-directional LSP is established, and wherein sending the second LSP setup request message over the path that the first LSP setup request message was sent includes accessing the address of each transit routing device through which the first LSP setup request message propagated between the first routing device to the second routing device from the Record Route Object and causing the second LSP setup message to propagate through each transit routing device through which the first LSP setup request message propagated such that the second unidirectional label switched path propagates over the same path as the first unidirectional label switched path;
and
(c) said routing devices between which said first and second unidirectional LSPs are formed periodically sending refresh messages between each other to maintain said first and second unidirectional LSPs through creation and utilization of information provided by the Record Route Object thereby ensuring that said first and second unidirectional LSPs continue to traverse a common path during the entire duration of time that the bi-directional LSP is established.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 10/392,141Filed 18 Mar 2003 · us provisional application
Priority: 3 Jul 2002
Published: US 2004/0004955 A18 Jan 2004
Granted: 6 Sep 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04L 47/825
Miscellaneous aspects: involving tunnels, e.g. MPLS
H04L 12/4633
Interconnection of networks: interconnection of networks using encapsulation techniques, e.g. tunneling
H04L 45/00
Routing or path finding of packets in data switching networks
H04L 45/36
Routing or path finding of packets in data switching networks: backward learning