Re: [spring] Beyond SRv6.

["Zafar Ali (zali)" <[e-mail]>]

Hi Ron,

MPLS tool kit was created as IP tool kit (ICMP) was not sufficient to debug an MPLS subsystem.

By bringing in the “label mapping table” in IPv6 network, you have inherited the same problem industry has solved for MPLS OAM during the last ~20 years.

Thanks

Regards … Zafar

From: Ron Bonica <[e-mail]>
Date: Friday, September 6, 2019 at 2:23 AM
To: "Zafar Ali (zali)" <[e-mail]>, Srihari Sangli <[e-mail]>, Tarek Saad <[e-mail]>, Rob Shakir <[e-mail]>, SPRING WG List <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: RE: [spring] Beyond SRv6.

Ali,

Nothing so complicated is required. At most, PING and TRACEROUTE with RFC 5837 extensions.

                                                                 Ron




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From: Zafar Ali (zali) <[e-mail]>
Sent: Friday, September 6, 2019 2:18 AM
To: Ron Bonica <[e-mail]>; Srihari Sangli <[e-mail]>; Tarek Saad <[e-mail]>; Rob Shakir <[e-mail]>; SPRING WG List <[e-mail]>; [e-mail]
Cc: Zafar Ali (zali) <[e-mail]>
Subject: Re: [spring] Beyond SRv6.

Hi Ron,

Please see in-line.

Thanks

Regards … Zafar

From: Ron Bonica <[e-mail]<mailto:[e-mail]>>
Date: Friday, September 6, 2019 at 1:57 AM
To: "Zafar Ali (zali)" <[e-mail]<mailto:[e-mail]>>, Srihari Sangli <[e-mail]<mailto:[e-mail]>>, Tarek Saad <[e-mail]<mailto:[e-mail]>>, Rob Shakir <[e-mail]<mailto:[e-mail]>>, SPRING WG List <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: RE: [spring] Beyond SRv6.

Inline…..



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From: Zafar Ali (zali) <[e-mail]<mailto:[e-mail]>>
Sent: Friday, September 6, 2019 1:42 AM
To: Srihari Sangli <[e-mail]<mailto:[e-mail]>>; Tarek Saad <[e-mail]<mailto:[e-mail]>>; Ron Bonica <[e-mail]<mailto:[e-mail]>>; Rob Shakir <[e-mail]<mailto:[e-mail]>>; SPRING WG List <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Cc: Zafar Ali (zali) <[e-mail]<mailto:[e-mail]>>
Subject: Re: [spring] Beyond SRv6.

<snip>

Hi Srihari,

> DA manipulation along the hop (shifting as the draft proposes) on each router and reconstructing the DA - can make it harder to debug when
              > there is problem.



It has been clarified during the Spring WG session in Montreal. Repeating the same –



  *   The original segment list is maintained by using the non-Reduced flavor (in which case the SID list is fully preserved in the SRH).

[RB] At the cost of encoding efficiency. 50% decrease !!


In reality, debugability is a huge issue in CRH proposal.

[RB] In reality, the debuggability characteristics of SRv6+ are very similar to those of SR-MPLS. We have the same mapping from a short identifier (SRv6+ SID or SR-MPLS Label) to an IPv6 address.

[RB] So, would you like to argue that debuggability is a huge issue in SR-MPLS?

[ZA] Not at all. SR-MPLS uses MPLS OAM tool kit defined in https://tools.ietf.org/html/rfc8029<https://urldefense.com/v3/__https:/tools.ietf.org/html/rfc8029__;!8WoA6RjC81c!TkBkBFPiX8_HzpxayXHu3zPmLXGXoQv2JitOPuzsxDMSS0wZKsKN68a_insHhyXn$>.
[ZA] Are you suggesting you will introduce something similar to RFC8029?

                                                              Ron


For example,
the CRH requires an IPv6 address to the “labels” mapping table (Yuck!).
An operator cannot determine the path packet will take by looking at CRH.
Have you realized how painful it will be for the operator to:

  *   Walk the CRH,
  *   Map each per-node "local labels" to its associated IPv6 address,
  *   Repeat the process for the entire label chain encoded in CRH.
Not to mention, this requires the operators to get the "mapping table" from each node in the network.



Thanks



Regards … Zafar



<snip>