Re: END SID Without SRH

[Tom Herbert <[e-mail]>]

On Fri, Jun 7, 2019 at 7:26 AM Ron Bonica
<rbonica=[e-mail]> wrote:
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> Darren,
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> This isn’t a blocker. Just a surprising behavior that never struck me before.
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> Assume that an SRv6 router receives a packet whose destination address is an END SID. The packet does not contain any extension headers at all.
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> If the next header after the IPv6 header is IPv4 or IPv6, the router removes the outer header and forwards the payload.
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> If the next header after the IPv6 header is TCP, the router discards the packet and sends an ICMP Parameter Problem message back to the source.

Ron,

Extrapolating as to why you think this is surprising behavior (please
correct me if this is wrong), but as I read it, this would be true for
any transport protocol and allows the possibility of hosts that don't
even know what segment routing is to receive the parameter error. For
instance, if someone were just innocently pinging the router's
address, which happens also to be an END SID, the source of the ping
would get the parameter error. In that case, the host might not even
know what segment routing is and much less have any clue why its
getting a parameter problem pointing to the nexthdr field for an
otherwise simple IPv6 packet.

Tom

>
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> Am I reading the spec correctly?
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>                                             Ron
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