RE: Extension Header Insertion

["Adrian Farrel" <[e-mail]>]

Hi Ron,

 

I think we can jump to a quick answer on this because
draft-ietf-spring-srv6-network-programming-05 says:

 

   We assume that the SRH may

   be present multiple times inside each packet.

 

Thus we may assume that the proponents of Extension Header insertion do
think that it is acceptable to insert a second routing header into a packet
that already has one.

 

And 8200 is clear when it says:

   Each extension header should occur at most once, except for the

   Destination Options header, which should occur at most twice (once

   before a Routing header and once before the upper-layer header).

 

So draft-ietf-spring-srv6-network-programming-05 includes a false assumption
which need to be either removed or secured through an update to 8200.

 

Ideally, I suppose, draft-ietf-6man-segment-routing-header would have
contained the clarification that the SRH could be present multiple times
(updating 8200 as it went).

 

Cheers,

Adrian

 

From: ipv6 <[e-mail]> On Behalf Of Ron Bonica
Sent: 09 December 2019 03:04
To: 6man <[e-mail]>
Subject: Extension Header Insertion 

 

Folks,

 

This question is posed primarily to the proponents of Extension Header
insertion. 

 

Do you think that it is acceptable to insert a second routing header into a
packet that already has one, so the resulting packet looks like the
following:

 

*	IPv6 header
*	SRH
*	SRH
*	Upper-layer header

 

Would this be common in TI-LFA?

 

                                                                      Ron

 

 

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