Re: [spring] Spring SR question??

Thanks Jeff

I was looking for just vanilla SR-MPLS support natively using IPV6 data
plane.

After reading a bit I confirmed below that both address families IPv4 and
IPv6 data planes are supported with SR-MPLS.

That is exactly what I was looking for.

When reading RFC 8402 Segment Routing Architecture specification it talks
about the two flavors SR-MPLS reuse of MPLS LDPv4 data plane and with SRv6
use of IPv6 data plane.  So I was under the impression that it was not
supported.

When I first read through RFC 8660 I skipped over the critical section
 2.5.1 which goes into discussion about FEC encoding assuming that it was
mentioned that both v4 and v6 data planes are supported.

 It would have been nice if that were more clearly stated explicitly then
just assumed that IPv6 data plane is supported with SR-MPLS.

So in RFC 8660 it does talk about IPv6 only in section 2.5.1  FEC encoding
below:

The address family is represented by 8 bits, where IPv4 is
         encoded as 100, and IPv6 is encoded as 110.  These numerical
         values are mentioned to guide implementations.  If other
         numerical values are used, then the numerical value of IPv4
         MUST be less than the numerical value for IPv6.

      -  All addresses are represented in 128 bits as follows:

         o  The IPv6 address is encoded natively.

         o  The IPv4 address is encoded in the most significant bits,
            and the remaining bits are set to zero.

      -  All prefixes are represented by (8 + 128) bits.

         o  A prefix is encoded in the most significant bits, and the
            remaining bits are set to zero.

         o  The prefix length is encoded before the prefix in an 8-bit
            field.

As far as the SR-MPLS / SRv6 interworking that is something to
definitely dig into on a separate discussion on interesting use cases
which there are few specifications  on namely the one mentioned RFC
8663 SR-MPLS over IP using RFC 4023 MPLSoGRE removing GRE and using
IPv6.  There are also some controller based interworking options as
well.

Thanks for the reference to the nanog link on SR interworking.

Gyan

On Tue, Jun 23, 2020 at 7:30 PM Jeff Tantsura <jefftant.ietf@gmail.com>
wrote:

> Gyan,
>
> In SR-MPLS, either over IPv4 or IPv6 the data-plane is MPLS (rfc8660)
> If MPLS is tunneled over IP, e.g MPLS over GRE, MPLS over UDP, etc, then
> data-plane is that of outer encapsulation - rfc8663 as the best example,
> e.g outer header would be IPv4/IPv6+UDP
> Since bindings (SIDs) need to be distributed, you’d need a label
> distribution protocol, with IPv6 that would be IS-IS, OSPFv3 or BGP
> (or  controller based).
> Vendor support for that is rather limited, I don’t recall any.
> Other option to distribute label bindings over IPv6 would be LDPv6 + v6
> IGP, I recall Junos implementation, there could be more.
> There’s quite interesting discussion on NANOG -
> https://mailman.nanog.org/pipermail/nanog/2020-June/208111.html
>
> Hope this helps
>
> Cheers,
> Jeff
> On Jun 23, 2020, 1:52 PM -0700, Gyan Mishra <hayabusagsm@gmail.com>,
> wrote:
>
>
>
> Thanks Ron!
>
> Gyan
>
> On Tue, Jun 23, 2020 at 3:51 PM Ron Bonica <rbonica@juniper.net> wrote:
>
>> Gyan,
>>
>>
>>
>> You can signal SR-MPLS over a network that has IPv6 enabled, but does not
>> have IPv4 enabled.
>>
>>
>>
>>                                                    Ron
>>
>>
>>
>>
>>
>>
>>
>> Juniper Business Use Only
>>
>> *From:* spring <spring-bounces@ietf.org> *On Behalf Of* Gyan Mishra
>> *Sent:* Tuesday, June 23, 2020 1:20 PM
>> *To:* SPRING WG <spring@ietf.org>
>> *Subject:* [spring] Spring SR question??
>>
>>
>>
>> *[External Email. Be cautious of content]*
>>
>>
>>
>>
>>
>> All
>>
>>
>>
>> SR-MPLS utilizes IPv4 data plane and and can service v4 v6 edges  6to4
>> softwire mesh framework from the VPN overlay aspect..
>>
>
>>
>> Can SR-MPLS use IPV6 data plane?
>>
>>
>>
>> Reason why I am asking is that it is very simple to get from LDPv4 core
>> to SR-MPLS core.
>>
>>
>>
>> However if you have an existing brown field SP core and your end goal is
>> to get to SRv6 - how can you easily get there.
>>
>>
>>
>> So my thoughts are you can use SR-MPLS as a stepping stone so to speak to
>> get to SRv6.
>>
>>
>>
>> To that end you could use Greg Mirsky draft of tunneling SR-MPLS in SRV6
>> interoperability and use other inter operability drafts.
>>
>>
>>
>> But let’s say you prefer to get from point A go point B seamlessly and
>> native naturally without any translation.
>>
>>
>>
>> An analogy would be migratory to IPV6 instead of using translation
>> technology tunnels you dual stand the entire network and use ds-lite or LSN
>> or 6RD to close the gap.
>>
>>
>>
>> So my thoughts on getting to the “end state” SRv6 are we follows:
>>
>>
>>
>> MPLS LDPv4
>>
>>
>>
>> MPLS LDPv6
>>
>>
>>
>> SR-MPLS v6
>>
>>
>>
>> Once you have a v6 core and you have decommissioned LDPv6 you now have
>> the v6 data plan ready to go to get to SRv6
>>
>>
>>
>> SRv6
>>
>>
>>
>> Only caveat with this idea is I am not sure if SR-MPLS supports IPv6 data
>> plane v6 label binding.
>>
>>
>>
>>
>>
>> Kind Regards
>>
>>
>>
>> Gyan
>>
>>
>>
>> --
>>
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>>
>>
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>>
>> *Gyan Mishra*
>>
>> *Network Solutions Architect *
>>
>>
>>
>> *M 301 502-1347 13101 Columbia Pike
>> <https://www.google.com/maps/search/13101+Columbia+Pike+%0D%0A+Silver+Spring,+MD?entry=gmail&source=g> * Silver
>> Spring, MD
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>>
>>
>>
> --
>
> <http://www.verizon.com/>
>
> *Gyan Mishra*
>
> *Network Solutions A**rchitect *
>
>
>
> *M 301 502-1347 13101 Columbia Pike
> <https://www.google.com/maps/search/13101+Columbia+Pike+Silver+Spring,+MD?entry=gmail&source=g> *Silver
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*Gyan Mishra*

*Network Solutions A**rchitect *

*M 301 502-134713101 Columbia Pike *Silver Spring, MD