Re: [Isis-wg] [spring] carrying IPv6 and IPv4 packets using SPRING/SR with MPLS dataplane

Hi,
another method been used to differentiate IPv4 and IPv6 payload over MPLS LSP by LERs:
*       IPv4 Explicit Null label for IPv4 payload;
*       IPv6 Explicit Null label for IPv6 payload.

        Regards,
                Greg

-----Original Message-----
From: spring [mailto:spring-bounces@ietf.org] On Behalf Of Stefano Previdi (sprevidi)
Sent: Tuesday, September 02, 2014 9:39 AM
To: Chris Bowers
Cc: spring@ietf.org; isis-wg@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:sprevidi@cisco.com]
> Sent: Tuesday, September 02, 2014 10:21 AM
> To: Chris Bowers
> Cc: spring@ietf.org<mailto:spring@ietf.org>; isis-wg@ietf.org<mailto:isis-wg@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<mailto:spring@ietf.org>
>> https://www.ietf.org/mailman/listinfo/spring
>

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