Ingress gateway selection for a shortest path bridging network to support inter domain multicast routing
In a Shortest Path Bridge (SPB) network comprising a plurality of backbone edge bridges (BEBs), a gateway controller of the SPB network, establishes a link using Multicast Source Discovery Protocol (MSDP) with an external network domain; discovers via the link a source of a multicast stream originating outside of the SPB network; and determines a subset of the plurality of BEBs that are able to receive the multicast stream from the source. Once that occurs, the gateway controller selects a one of the subset of the plurality of BEBs to be a sole gateway BEB for the multicast stream; and then transmits to each of the subset of the plurality of BEBs an indication of the sole gateway BEB selected for the multicast stream.
1. A method for a Shortest Path Bridge (SPB) network with a plurality of backbone edge bridges (BEBs), the method comprising:
establishing, by a gateway controller of the SPB network, a Multicast Source Discovery Protocol (MSDP) link with an external network domain as a sole MSDP link with the external network domain for the SPB network;
discovering, by the gateway controller and via the MSDP link, a source of a multicast stream originating outside of the SPB network;
determining, by the gateway controller, a subset of the plurality of BEBs configured to receive the multicast stream from the source;
selecting, by the gateway controller, a BEB from the subset of the plurality of BEBs to be a sole gateway BEB for the multicast stream; and
transmitting, by the gateway controller and to each of the BEBs in the subset of the plurality of BEBs, an indication of the sole gateway BEB selected for the multicast stream.
2. The method of claim 1 , wherein the sole gateway BEB and the gateway controller are separate devices in the SPB network.
3. The method of claim 1 , comprising:
exporting, by the gateway controller and to the external network domain, information about one or more multicast streams originating from the SPB network.
4. The method of claim 1 , wherein the subset of the plurality of BEBs comprises a first BEB and a second BEB.
5. The method of claim 4 , wherein each of the first and second BEB has a respective associated external route cost to the source, and wherein selecting the sole gateway BEB comprises selecting the first BEB or the second BEB having a lower associated external route cost.
6. The method of claim 4 , wherein each of the first and second BEB has a respective associated route prefix match with an IP address of the source, and wherein selecting the sole gateway BEB comprises selecting the first BEB or the second BEB having a higher route prefix match.
7. The method of claim 4 , wherein a respective hash value is calculated for each of the first and second BEB based on one or more respective predetermined identifying characteristics, and wherein selecting the sole gateway BEB comprises selecting the first BEB or the second BEB having a lower associated hash value.
8. The method of claim 1 , comprising:
subsequent to transmitting the indication of the sole gateway BEB selected for the multicast stream, determining a change in an attribute of a route between one of the subset of the plurality of BEBs and the source,
selecting, by the gateway controller, a different one of the subset of the plurality of BEBs to be an updated sole gateway BEB for the multicast stream; and
transmitting, by the gateway controller and to each of the BEBs in the subset of the plurality of BEBs, an indication of the updated sole gateway BEB selected for the multicast stream.
9. The method of claim 8 , wherein the change comprises a change in an external cost of the route.
10. The method of claim 8 , wherein the change comprises a link failure along the route.
11. A gateway controller in a Shortest Path Bridge (SPB) network with a plurality of backbone edge bridges (BEBs), comprising:
a memory device storing executable instructions;
a processor in communication with the memory device, wherein executing the executable instructions by the processor causes the processor to:
establish a Multicast Source Discovery Protocol (MSDP) link with an external network domain as a sole MSDP link with the external network domain for the SPB network;
discover, via the MSDP link, a source of a multicast stream originating outside of the SPB network;
determine a subset of the plurality of BEBs configured to receive the multicast stream from the source;
select a BEB from the subset of the plurality of BEBs to be a sole gateway BEB for the multicast stream; and
transmit to each of the BEBs in the subset of the plurality of BEBs an indication of the sole gateway BEB selected for the multicast stream.
12. The gateway controller of claim 11 , wherein the sole gateway BEB and the gateway controller are separate devices in the SPB network.
13. The gateway controller of claim 11 , wherein executing the executable instructions by the processor causes the processor to:
export, to the external network domain, information about one or more multicast streams originating from the SPB network.
14. The gateway controller of claim 11 , wherein the subset of the plurality of BEBs comprises a first BEB and a second BEB.
15. The gateway controller of claim 14 , wherein each of the first and second BEB has a respective associated external route cost to the source; and wherein executing the executable instructions by the processor causes the processor to:
select the sole gateway BEB by selecting the first BEB or the second BEB having a lower associated external route cost.
16. The gateway controller of claim 14 , wherein each of the first and second BEB has a respective associated route prefix match with an IP address of the source; and wherein executing the executable instructions by the processor causes the processor to:
select the sole gateway BEB by selecting the first BEB or the second BEB having a higher route prefix match.
17. The gateway controller of claim 14 , wherein a respective hash value is calculated for each of the first and second BEB based on one or more respective predetermined identifying characteristics; and wherein executing the executable instructions by the processor causes the processor to:
select the sole gateway BEB by selecting the first BEB or the second BEB having a lower associated hash value.
18. The gateway controller of claim 11 , wherein executing the executable instructions by the processor causes the processor to:
subsequent to transmitting the indication of the sole gateway BEB selected for the multicast stream, determine a change in an attribute of a route between one of the subset of the plurality of BEBs and the source;
select a different one of the subset of the plurality of BEBs to be an updated sole gateway BEB for the multicast stream; and
transmit to each of the BEBs in the subset of the plurality of BEBs an indication of the updated sole gateway BEB selected for the multicast stream.
19. The gateway controller of claim 18 , wherein the change comprises a change in an external cost of the route.
20. The gateway controller of claim 18 , wherein the change comprises a link failure along the route.
21. The method of claim 1 , wherein the transmitting further comprises:
transmitting, by the gateway controller, a gateway assignment table specifying the sole gateway BEB selected for the multicast stream to each of the subset of the plurality of BEBs.