Patent ID: 8014380

Claim:
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.