Document: draft-ietf-dime-nai-routing-02
Reviewer: Pete McCann
Review Date: 2009-08-03
IETF LC End Date: 2009-08-04
IESG Telechat date: unknown

Summary: Two major issues need discussion


Major issues:

The draft seems to address only routing of Request commands.  What about Answers?  Are Diameter proxies required to re-write the Origin-Realm and Origin-Host AVPs as the request gets routed?
Are they required then to maintain state to map the responses back to the originating realm?  The processing rules seem to strip off the decoration from the NAI; there might be a need for the home AAA server to know the path that was taken through the network (routing the Answer commands is only one possible reason).  Maybe the solution is to provide a decorated Origin-Realm that is recomputed by each hop.


> 4.2. Ensuring Backwards Compatibility
>
>   Implementations compliant to this specification MUST define a new
>   Diameter application.  This requirement is set to guarantee
backwards
>   compatibility with existing Diameter implementations, applications
>   and deployments.  Diameter agents not compliant with this
>   specification will not advertise support for these new applications
>   that implement the enhanced routing solution based on Decorated NAIs
>   and will therefore be bypassed.

This requirement troubles me; does this mean that every Diameter application will need to define a whole set of Application-IDs, based on the cross-product of every feature that gets introduced?  Maybe this is a general problem with Diameter application versioning, and it's too late to fix it.  Is there a better way to somehow indicate support for this feature?


Minor issues:


Nits/editorial comments:

End of Section 3:

>   [RFC5113] Section 2.3. also discusses NAI decoration related issues
>   with EAP [RFC3748] in general.
Seems there is an extra period after "Section 2.3".  Suggest changing
the reference pointer to text, i.e.,
>   Section 2.3 of RFC5113 also discusses NAI decoration related issues
>   with EAP [RFC3748] in general.

Section 4.1:

>   an uniform
SHOULD BE:
>   a uniform

Section 6:
>   In this case the NAS to the Diameter server AAA communication rely
on
SHOULD BE:
>   In this case the NAS to Diameter server AAA communication relies on
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