Subject: [NSIS] GIST WGLC comments

From: Roland Bless <[email-masked]>
Date: Thu, 03 May 2007 01:29:02 +0200

Hi,

First of all: this is a very complete and well written protocol
specification.  It provides a lot of background on protocol design
choices. Well done! Despite its relatively large page volume, it's
straightforward implementable (speaking as an implementer).

I still have some remarks/comments (and maybe more to come
after the interop):

- 5.3.2.1:
  Option to disable MUST be disabled by default...might be
  confusing...in the following paragraph:

   Implementations MAY provide an option to disable the setting of RAO
   on Q-mode packets on a per-destination prefix basis; however, the
   option MUST be disabled by default and MUST only be enabled when it
   has been separately verified that the the next GIST node along the
   path to the destination is capable of intercepting packets without
   RAO.

- Why is the magic number at all necessary?
  I don't see the case that non-GIST data packets carry
  the same RAO and get accidently caught. Likewise, if
  RAO is not used in special cases, it could be ensured
  that normal data flows will not use destination port 4,
  too?

- Error for Wrong/Missing Magic number:
  I would recommend to send back an "Incorrect Encapsulation"
  error (maybe also with additional corresponding subcode)
  since the magic number is not really part of the common header.
  Furthermore: since we will not parse the message with the
  wrong magic number, I don't know what to fill into the
  common-error-header, esp. protocol version is also unknown.

- Why is the Hello-ID object not optional?
  This was observed by Max Laier while implementing the current
  proposal. If the Hello-ID is only required when r=1, we could
  omit it if r=0 and no response is required. So instead of
  setting Hello-ID=0 we simply could omit it. This would also
  reduce number or error cases: we do not have to deal with a
  forbidden hello-ID==0.

- Using the SII handle to get back to the same next hop
  is probably not so easy. What if there is no existing MA
  that could be reused. Should a new MA be set up? How could
  this be done along the "old path". More guidance on this
  topic would be nice...

Regards,
 Roland

_______________________________________________
nsis mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/nsis