Re: draft-ietf-ipngwg-p2p-pingpong-00.txt vs RFC4443

[Fernando Gont <[e-mail]>]

Hi, Pekka,

>> It is clear that there is one more action done on the packet with 
>> RFC4443. But this has no impact on shipping ASIC based routers. It
>> is difficult to say though if some smaller routers could be
>> impacted.
> 
> This, and what Ole Troan wrote on interface lookup, is interesting.
> 
> RFC4443 requires checking that destination address matches the subnet
>  prefix.  Is this the hot issue?
> 
> Note that pingpong-00 document did not have this requirement;

AFAICT, it does. It says: "....and the destination address on the packet
seems to be on-link (in terms of Neighbor Discovery) on the
point-to-point interface". Or am I missing something?


> the
> specification was different (incoming/outgoing interface).  Does this
>  have different implications on the feasibility of implementation?

It seems that the point is not really that of reduced performance, but
rather that complying with this requirement would require a change in
the silicon?

If that's the case (i.e., no real performance implications), then it
looks like an appropriate fix for this issue. -- which does not
necessarily argue against /127 prefixes, as there are other reasons for
using them (or, put another way, let's not correlate *this* with the
fight over /127 prefixes).



> FWIW, "Packet may be forwarded back on the received interface" is 
> actually, AFAIK, used in certain PE routerscenarios where you ping 
> yourself over a p2p link.

Is the echo request/response really forwarded back on the received
interface? (isn't the *response* that is forwarded back on the received
interface?)

Thanks!

Kind regards,
-- 
Fernando Gont
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