Hi Alia,
> -----Original Message-----
> From: Alia Atlas [mailto:akat...@gmail.com]
> Sent: Thursday, December 03, 2015 11:07 AM
> To: The IESG
> Cc: draft-ietf-bess-virtual-sub...@ietf.org; aret...@cisco.com;
> bess-cha...@ietf.org; martin.vigour...@alcatel-lucent.com; bess@ietf.org
> Subject: Alia Atlas' Discuss on draft-ietf-bess-virtual-subnet-06: (with
> DISCUSS)
>
> Alia Atlas has entered the following ballot position for
> draft-ietf-bess-virtual-subnet-06: Discuss
>
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>
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
>
> Thank you for a clear and well-written document. I have one point that is
> peripheral to most of the draft.
>
> In Section 4.3, it says:
>
> " In addition, for any other
> applications that generate intra-subnet traffic with TTL set to 1,
> these applications may not work properly in the Virtual Subnet
> context, unless special TTL processing for such context has been
> implemented (e.g., if the source and destination addresses of a
> packet whose TTL is set to 1 belong to the same extended subnet,
> neither ingress nor egress PE routers should decrement the TTL of
> such packet. Furthermore, the TTL of such packet should not be
> copied into the TTL of the transport tunnel and vice versa)."
>
> The idea of not decrementing TTL is quite concerning. I can conjecture cases
> where there is a routing loop between the relevant PEs - during reconvergence
> when a host moves from one datacenter to another is a trivial case.
>
> One approach may be to ask why a packet would have a TTL of 1 and determine
> if this case must be resolved. Another might detecting a loop back to an
> out-of-datacenter PE and dropping the packet. I'm sure you can develop other
> good ideas and solutions.
How about doing the following text change:
" In addition, for any other
applications that generate intra-subnet traffic with TTL set to 1,
these applications may not work properly in the Virtual Subnet
context, unless special TTL processing and loop-prevention mechanisms for
such context have been
implemented. Details about such special TTL processing and loop-prevention
mechanisms are outside the scope of this document."
Best regards,
Xiaohu
>
>
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