Hitless switchover bandwidth sharing in a communication network

Abstract

Described is a node comprising a switch fabric and first and second ingress modules. The first ingress module receives a first stream of packets from a first physical path through the network; forwards a copy of the first stream of packets to an intermodule communication channel; selects packets from the first stream of packets and a copy of a second stream of packets for forwarding to the switch fabric. The second ingress module receives the second stream of packets from a second physical path through the network; forwards the copy of the second stream of packets to the intermodule communication channel; and selects packets from the copy of the first stream of packets and the second stream of packets for forwarding to the switch fabric based on sequence numbers in the packets.

What is claimed is: 
     
         1 . A node for a packet communication network, the node comprising:
 a switch fabric; and   first and second ingress modules,   the first ingress module being adapted:   the first ingress module being adapted:
 to receive a first stream of packets from a first physical path through the network; and 
 to forward a copy of the first stream of packets to an intermodule communication channel; 
 to receive a copy of a second stream of packets from the second ingress module; and 
 when selected to forward packets to the switch fabric, to select packets from the first stream of packets and the copy of the second stream of packets for forwarding as a single packet stream to the switch fabric based on sequence numbers in the packets; 
   the second ingress module being adapted:
 to receive the second stream of packets from a second physical path through the network; and 
 to forward the copy of the second stream of packets to the intermodule communication channel. 
   
     
     
         2 . The node of  claim 1 , wherein the first ingress module is selected based on a protection control signal. 
     
     
         3 . The node of  claim 1 , wherein at least some of the packets in the first stream of packets have sequence numbers that are the same as the least some of the sequence numbers in the second stream of packets. 
     
     
         4 . The node of  claim 1 , wherein the first ingress module is adapted, on failure of the first physical path through the network when the first ingress module is selected, to select packets for forwarding to the switch fabric, to select packets from the copy of the second stream of packets for forwarding to the switch fabric. 
     
     
         5 . The node of  claim 4 , wherein the second ingress module is adapted, on failure of the second physical path through the network when the second ingress module is selected, to select packets for forwarding to the switch fabric, to select packets from the copy of the first stream of packets for forwarding to the switch fabric. 
     
     
         6 . The node of  claim 1 , wherein the first ingress module is adapted, on failure of the second ingress module, to select packets from the first stream of packets for forwarding to the switch fabric. 
     
     
         7 . The node of  claim 1 , wherein the first ingress module is adapted, when selected to forward packets to the switch fabric, to select packets from the first and second stream of packets for forwarding to the switch fabric based on sequence numbers by comparing the sequence numbers to expected sequence numbers. 
     
     
         8 . The node of  claim 7 , wherein the packets in the single packet stream are in an order based on the sequence numbers of those packets. 
     
     
         9 . The node of  claim 1 , wherein:
 the node comprises a label switched router;   the first packet stream comprises a packet stream of a label switched path; and   the second packet stream comprises a packet stream of a label switched path.   
     
     
         10 . The node of  claim 9 , wherein:
 the first packet stream comprises a packet stream of a first label switched path;   the second packet stream comprises a packet stream of a second label switched path; and   the single stream of packets forwarded by the first ingress module to the switch fabric when the first ingress module is selected comprises a packet stream of a third label switched path.   
     
     
         11 . A method of operating a node for a packet communication network, the method comprising:
 operating a first ingress module:
 to receive a first stream of packets from a first physical path through the network; 
 to forward a copy of the first stream of packets to an intermodule communication channel; 
 to receive a copy of a second stream of packets from a second ingress module; and 
 when selected to forward packets to the switch fabric, to select packets from the first stream of packets and the copy of the second stream of packets for forwarding as a single packet stream to the switch fabric based on sequence numbers in the packets; 
   operating the second ingress module:
 to receive the second stream of packets from a second physical path through the network; and 
 to forward the copy of the second stream of packets to the intermodule communication channel. 
   
     
     
         12 . The method of  claim 11 , wherein the first ingress module is selected based on a protection control signal. 
     
     
         13 . The method of  claim 11 , wherein at least some of the packets in the first stream of packets have sequence numbers that are the same as at least some of the sequence numbers in the second stream of packets. 
     
     
         14 . The method of  claim 11 , comprising operating the first ingress module, on failure of the first physical path through the network when the first ingress module is selected, to select packets for forwarding to the switch fabric, to select packets from the copy of the second stream of packets for forwarding to the switch fabric. 
     
     
         15 . The method of  claim 14 , comprising operating the second ingress module, on failure of the second physical path through the network when the second ingress module is selected, to select packets for forwarding to the switch fabric, to select packets from the copy of the first stream of packets for forwarding to the switch fabric. 
     
     
         16 . The method of  claim 11 , comprising on failure of the second ingress module, operating the first ingress module to select packets from the first stream of packets for forwarding to the switch fabric. 
     
     
         17 . The method of  claim 11 , comprising operating the first ingress module, when selected to forward packets to the switch fabric, to select packets from the first and second streams of packets for forwarding towards the switch fabric based on sequence numbers by comparing the sequence numbers to expected sequence numbers. 
     
     
         18 . The method of  claim 17 , wherein the packets in the single packet stream are in an order based on the sequence numbers of those packets. 
     
     
         19 . The method of  claim 11 , wherein:
 the node comprises a label switched router;   the first packet stream comprises a packet stream of a label switched path; and   the second packet stream comprises a packet stream of a label switched path.   
     
     
         20 . The method of  claim 19 , wherein:
 the first packet stream comprises a packet stream of a first label switched path;   the second packet stream comprises a packet stream of a second label switched path; and   the single stream of packets forwarded by the first ingress module to the switch fabric when the first ingress module is selected comprises a packet stream of a third label switched path.