Subject: [mobile-ip] RFC3220 clarification issues

From: Samita Chakrabarti <[email-masked]>
Date: Sat, 16 Mar 2002 17:54:39 -0800 (PST)

The following issues and questions were raised at the Connectathon 2002
event in March. 

Minor interoperability issues detected from RFC3220:

Section 3.5.2 says:

3.5.2. Mobile-Home Authentication Extension

   Exactly one authorization-enabling extension MUST be present in all
   Registration Requests, and also in all Registration Replies generated
   by the Home Agent.

   However, draft is not clear about the error code if multiple MN-HA extension
   headers were present. Should this be poorly formatted request ?

  Section 3.7.2.1 has a contradictory statement which should be corrected:
  
    If no Mobile-Foreign
   Authentication Extension is found, or if more than one Mobile-Foreign
   Authentication Extension is found, or if the Authenticator is
   invalid, the foreign agent MUST *silently* discard the Request and
   SHOULD log the event as a security exception.  The foreign agent also
   SHOULD send a Registration Reply to the mobile node with Code 67.

   If the FA silently discards the packet how should it send a reply to
   the MN ?

  Thanks, 
   -Samita

---

From: Charlie Perkins <[email-masked]>
Date: Sat, 16 Mar 2002 22:16:52 -0800

Hello Samita,

I guess we should not have to have rfc3220bis for this!

>    headers were present. Should this be poorly formatted request ?

That would seem appropriate to me.  There are probably other
such illegal formations that are not explicitly indicated by their
own error code, and they all would reasonably share that one
you suggest.

>    If the FA silently discards the packet how should it send a reply to

You are right that this is poor wording.  The intention was that the
Registration Request should not be sent on to the home agent, since
it was already rejected.  So, if one insisted on finding an arcane
interpretation to allow this, we could say that the "Request" is
discarded, and the Reply was newly generated.  But I already agree
with you that this isn't what people usually mean by "silently discard".

Regards,
Charlie P.