Re: [bess] SRv6 versus SR-MPLS

["Joel M. Halpern" <[e-mail]>]

I just realized reading this note from Greg that he was arguing for 
something different than I understood.  To that degree, I apologize to 
Greg.  My comments do not reflect on Greg's Unified SID work.

Yours,
Joel

PS: Greg, just so you know waht error I made, I connected U-SID with the 
uSID drafts.  Again, sorry, I misread and misunderstood your note.  Yes, 
you referenced your draft.

On 10/6/2019 11:29 AM, Greg Mirsky wrote:
> Hi Joel,
> thank you for reviewing U-SID draft. I'm looking forward to reading a 
> more detailed analysis.
> 
> Regards,
> Greg
> 
> On Sat, Oct 5, 2019 at 8:18 PM Joel M. Halpern <[e-mail] 
> <mailto:[e-mail]>> wrote:
> 
>     No Greg, uSID does not bring all the benefits of SRv6 while using
>     shorter SIDs.
>     It also violates the basic IP archtiecture really abdly.
> 
>     Yours,
>     Joel
> 
>     On 10/5/2019 7:44 PM, Greg Mirsky wrote:
>      > Hi Gyan,
>      > you're asking very good questions and your arguments are all
>     correct.
>      > But I think that now there are several proposals that address
>     what is
>      > considered the scalability issue of SRv6. Among these is the
>     Unified SID
>      > for SRv6
>      > <https://datatracker.ietf.org/doc/draft-mirsky-6man-unified-id-sr/>.
>      > U-SID benefits from all the advantages SRH provides while adding a
>      > higher density of SIDs thus allowing stricter path control.
>      >
>      > Regards,
>      > Greg
>      >
>      > On Fri, Oct 4, 2019 at 10:02 PM Gyan Mishra
>     <[e-mail] <mailto:[e-mail]>
>      > <mailto:[e-mail] <mailto:[e-mail]>>> wrote:
>      >
>      >
>      >     In line possible answers
>      >
>      >     Sent from my iPhone
>      >
>      >     On Oct 4, 2019, at 8:22 PM, Gyan Mishra
>     <[e-mail] <mailto:[e-mail]>
>      >     <mailto:[e-mail]
>     <mailto:[e-mail]>>> wrote:
>      >
>      >>
>      >>     Bess,
>      >>
>      >>     What is the benefit of SRv6 over SR-MPLS for greenfield
>      >>     deployments or existing mpls deployments.
>      >>
>      >     I think I answered my own question but please chime in with your
>      >     thoughts..
>      >
>      >     This NANOG document talks about the state of TE with
>     providers and
>      >     currently the big show stopper with SRv6 which removes it off the
>      >     table as a possibility is the SID depth and larger packet
>     size given
>      >     that customers are set to 9100 and the core is 9216 so when
>     adding
>      >     in mpls overhead vpn labels and Ti-LFA EH insertion at PLR
>     node to
>      >     PQ node that adding in the entire SID list for long TE paths that
>      >     have huge SID depth makes SRv6 not viable at this point.
>      >
>      >
>     https://pc.nanog.org/static/published/meetings/NANOG73/1646/20180627_Gray_The_State_Of_v1.pdf
>      >
>      >     For existing implementations it appears from my research a no
>      >     brainer to go with SR-MPLS as that is a painless seamless
>     migration
>      >     but SRv6 due to SID depth issues and given limited head room from
>      >     customer MTU to the  backbone MTU today we are over the limit
>     with
>      >     larger SID depth for Ti-LFA paths or non protected paths.  Until
>      >     that is addressed SRv6 unfortunately may not get much
>     traction with
>      >     service providers which I think due to the SRv6 issues
>     ....uSID and
>      >     SRv6+ may tend to be more viable and more attractive.
>      >
>      >
>      >
>      >
>      >>     Regards,
>      >>
>      >>     Gyan Mishra ____
>      >>
>      >>     IT Network Engineering & Technology ____
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>     <mailto:[e-mail]>
>      >>     <mailto:[e-mail]
>     <mailto:[e-mail]>>____
>      >>
>      >> www.linkedin.com/in/GYAN-MISHRA-RS-SP-MPLS-IPV6-EXPERT
>     <http://www.linkedin.com/in/GYAN-MISHRA-RS-SP-MPLS-IPV6-EXPERT>
>      >>     <http://www.linkedin.com/in/GYAN-MISHRA-RS-SP-MPLS-IPV6-EXPERT>
>      >>
>      >>
>      >>     Sent from my iPhone
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