Re: [spring] Spring SR question??

[Gyan Mishra <[e-mail]>]

Robert

Understood.

This is for brown field existing LDPv6 core.

The thought was migration from LDPv6 fo SRV6.

So with LDPv6 it’s simple to go to SR-MPLS v6  as you are reusing the MPLS
data plane. So I was thinking of using that a simple stepping stone to get
to SRv6 end state.  We would  stay at SR-MPLSv6 phase and don’t have to
rush to SRv6 as we now gain all the SR benefits of SR-TE  per vrf coloring
features, Ti-LFA FRR and flex algo etc.

As SRv6 matures with the variety of SRH compression techniques to overcome
MSD issues and those get flushed out and also with PPR-Preferred Path
Routing etc all become standards we can then migrate to SRv6.

Kind Regards

Gyan


On Wed, Jun 24, 2020 at 5:24 AM Robert Raszuk <[e-mail]> wrote:

> Gyan,
>
> > I was looking for just vanilla SR-MPLS support natively using IPV6 data
> plane.
>
> MPLS is a data plane. There is no SR-MPLS using IPv6 data plane (with
> exceptions of encap).
>
> Your choice of data planes are:
>
> IPv4
> IPv6
> MPLS
>
> SR-MPLS uses MPLS data plane (with exceptions of encap) not IPv6 data
> plane.
>
> You can use any control plane to distribute SR-MPLS SIDs (or indexes for
> that matter) and match it against SPT computed against your IGP topology
> ... no problem here.
>
> But let's make sure we do not create more confusion here.
>
> Last if your ultimate goal is to migrate LDPv4 to SRv6 I find it strange
> that you would even consider transition via SR-MPLS. IMHO no need.
>
> Cheers,
> R.
>
>
>
>
>
> On Wed, Jun 24, 2020 at 8:56 AM Gyan Mishra <[e-mail]> wrote:
>
>>
>> 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 <[e-mail]>
>> 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 <[e-mail]>,
>>> wrote:
>>>
>>
>>>
>>> Thanks Ron!
>>>
>>> Gyan
>>>
>>> On Tue, Jun 23, 2020 at 3:51 PM Ron Bonica <[e-mail]> 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 <[e-mail]> *On Behalf Of* Gyan Mishra
>>>> *Sent:* Tuesday, June 23, 2020 1:20 PM
>>>> *To:* SPRING WG <[e-mail]>
>>>> *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
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> <https://www.google.com/maps/search/13101+Columbia+Pike+%0D%0A+Silver+Spring,+MD?entry=gmail&source=g>
>>>>
>>>>
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>>>>
>>>> *Gyan Mishra*
>>>>
>>>> *Network Solutions Architect *
>>>>
>>>>
>>>>
>>>> *M 301 502-1347 13101 Columbia Pike
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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>
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>>
>> <http://www.verizon.com/>
>>
>> *Gyan Mishra*
>>
>> *Network Solutions A**rchitect *
>>
>>
>>
>> *M 301 502-134713101 Columbia Pike
>> <https://www.google.com/maps/search/13101+Columbia+Pike+%C2%A0+Silver+Spring,+MD?entry=gmail&source=g> *Silver
>> Spring, MD
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>>
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<http://www.verizon.com/>

*Gyan Mishra*

*Network Solutions A**rchitect *



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