On Sep 3, 2014, at 12:55 AM, Chris Bowers wrote: > 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?
yes. > 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. that's correct. Note that we don't really have documented a use case for the algorithm field. Yet another way to do multi-topology... in case we don't have enough of them already... s. > > Thanks, > Chris > > -----Original Message----- > From: Stefano Previdi (sprevidi) [mailto:[email protected]] > Sent: Tuesday, September 02, 2014 11:39 AM > To: Chris Bowers > Cc: [email protected]; [email protected] > 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:[email protected]] >> Sent: Tuesday, September 02, 2014 10:21 AM >> To: Chris Bowers >> Cc: [email protected]; [email protected] >> 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 >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/spring >> > _______________________________________________ spring mailing list [email protected] https://www.ietf.org/mailman/listinfo/spring
