Stefano, Thanks. I have a similar question regarding node-SID index values for different algorithms. Does each node need to advertise a unique index value for each algorithm? For example, in a network supporting 3 algorithms, would each node need to be assigned 3 unique index values for IPv4 forwarding?
I was hoping to be able to assign a single unique index value to each node, and then have each node advertise a different label block for each algorithm. This would achieve the same result as assigning a unique index value for each node for each algorithm, and it would simplify network operations. The current versions of the ISIS and OSPF SR extensions don't appear to support advertising a different label block for each algorithm, but I wanted to make sure I'm not misreading the drafts. Thanks, Chris -----Original Message----- From: Stefano Previdi (sprevidi) [mailto:sprev...@cisco.com] Sent: Tuesday, September 02, 2014 11:39 AM To: Chris Bowers Cc: spring@ietf.org; isis...@ietf.org Subject: Re: [spring] carrying IPv6 and IPv4 packets using SPRING/SR with MPLS dataplane On Sep 2, 2014, at 6:17 PM, Chris Bowers wrote: > Stefano, > > Thanks. Is there a mechanism to advertise different label blocks for v4 and > v6 and have a single unique index value associated with the node? there's a mechanism that allows you to advertise multiple label blocks and the index is used across all of them (see isis/ospf sr extensions drafts). Not sure if you need to explicitly advertise the af of the label block knowing that a sid corresponds to a prefix which implies its af. s. > This would still result in different label values being used for v4 and v6 > packets destined for the same node, but the network operator only has to > assign a single unique index value to each node. > > Chris > > -----Original Message----- > From: Stefano Previdi (sprevidi) [mailto:sprev...@cisco.com] > Sent: Tuesday, September 02, 2014 10:21 AM > To: Chris Bowers > Cc: spring@ietf.org; isis...@ietf.org > Subject: Re: [spring] carrying IPv6 and IPv4 packets using SPRING/SR with > MPLS dataplane > > Hi Chris, > > On Sep 2, 2014, at 5:12 PM, Chris Bowers wrote: >> Has there been any discussion about how to carry both IPv6 and IPv4 packets >> with SPRING/SR MPLS labels? From what I can tell, neither >> draft-filsfils-spring-segment-routing-04 nor >> draft-filsfils-spring-segment-routing-mpls-03 addresses this scenario. > > > sid's are assigned to ip addresses (e.g. intf addresses). A node having two > loopbacks (v4/v6) will have a sid for the ipv4 address and another one for > the ipv6. > > Then you compute your spt's or explicit paths based on your af-topology and > you pick the right sid's stack. > > >> In the context of shortest-path forwarding using Node-SID labels, there >> would seem to be two main approaches to consider. One could distinguish >> between IPv6 and IPv4 packets by using two different Node-SID labels for the >> same node. > > > correct. this is same as above: one sid per address (one for v4 and one for > v6). > > s. > > >> Or one could use IPv6 and/or IPv4 Explicit Null labels pushed on the bottom >> of the label stack by the SR ingress router. >> >> Do the authors of these drafts or other working group participants have an >> opinion on the best way to address this scenario? >> >> Thanks, >> Chris >> >> >> >> _______________________________________________ >> spring mailing list >> spring@ietf.org >> https://www.ietf.org/mailman/listinfo/spring > _______________________________________________ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
