Subject: [Gen-art] Gen-ART review of draft-ietf-netlmm-grekey-option-06.txt

From: "Spencer Dawkins" <[email-masked]>
Date: Tue, 21 Apr 2009 13:14:28 -0500

I have been selected as the General Area Review Team (Gen-ART) reviewer for
this draft (for background on Gen-ART, please see
http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html).

Please wait for direction from your document shepherd or AD before posting a
new version of the draft.

Document: draft-ietf-netlmm-grekey-option-06.txt
Reviewer: Spencer Dawkins
Review Date: 21 April 2009
IESG Telechat date: 23 April 2009
Summary: This draft is almost ready for publication as a Proposed Standard.
I did have some questions about 2119 SHOULD/SHOULD NOT usage in the
document.

Major issues: None.

Minor issues: See below.

Nits/editorial comments:

I agree with Ralph's note about using acronyms consistently (MAG being the
example I noticed first).

Is "vanilla" a clearly-understood term of art? :-)

---------------------

4.2.  Operational Summary

   o  If the mobile access gateway includes the GRE Key option in the
      Proxy Binding Update for a specific mobile node and the local
      mobility anchor accepts the Proxy Binding Update by sending a
      Proxy Binding Acknowledgement with a success status code (less
      than 128) other than <GRE KEY OPTION NOT REQUIRED>, but without
      the GRE Key option, then the mobile access gateway MUST consider
      that the local mobility anchor does not support GRE Key option as
      per this specification.  The mobile access gateway SHOULD NOT
      include the GRE Key option in any subsequent Proxy Binding Update
      message that is sent to that LMA.

Spencer (minor): Why is this a SHOULD NOT (and not a MUST NOT)?

o  If the mobile access gateway sent a Proxy Binding Update message
      without the GRE Key option, but the received Proxy Binding
      Acknowledgement has the Status Code <GRE KEY OPTION REQUIRED>,
      indicating that the GRE encapsulation and GRE key is required, the
      mobile access gateway SHOULD resend the Proxy Binding Update
      message with the GRE Key option.  If the MAG does not support the

Spencer (minor): Why is this a SHOULD (and not a MUST)?

      GRE Key option, the MAG MAY log the event and possibly raise an
      alarm to indicate a possible misconfiguration.

   o  If the MAG has successfully negotiated GRE encapsulation and
      exchanged the GRE keys with the LMA for a specific mobility
      session, the MAG SHOULD NOT include the GRE Key option in the de-
      registration Proxy Binding Update.

Spencer (minor): Why is this a SHOULD NOT (and not a MUST NOT)?

7.2.  TLV-header Tunneling Negotiation

   The mobile access gateway negotiates the format for tunneling payload
   traffic during Proxy Mobile IPv6 registration procedure.  If the
   mobile access gateway is required to use the TLV-header UDP
   encapsulation format, the mobile access gateway MUST set the TLV-
   header Format (T) flag in the Proxy Binding Update message sent to
   the local mobility anchor.  If the local mobility anchor supports the
   TLV-header UDP tunneling format, the LMA SHOULD set the TLV-header
   Format (T) flag in the Proxy Binding Acknowledgement.  Otherwise, the
   TLV-header Format (T) flag is cleared.  The setting of the TLV-header
   Format (T) flag in the Proxy Binding Acknowledgement indicates to the
   mobile access gateway that it MUST use the TLV-header UDP
   encapsulation format for all packets tunneled to the LMA for the
   entire duration the mobile node is attached to the mobile access
   gateway.  The TLV-header UDP tunneling format SHOULD NOT change
   during a Binding Lifetime Extension Proxy Binding Update (re-
   registration) from the same mobile access gateway.

Spencer (minor): Why is this a SHOULD NOT (and not a MUST NOT)?

7.4.  Local Mobility Anchor Operation

   When the local mobility anchor receives a Proxy Binding Update
   encapsulated in UDP and containing the IPv4 home address option, it
   needs to follow all the steps in [RFC5213] and [ID-PMIP6-IPv4].  In
   addition, if the TLV-header Format (T) flag is set in the Proxy
   Binding Update, the local mobility anchor needs to determine whether
   it can accept the TLV-header UDP based encapsulation format.  If it
   does, it SHOULD set the TLV-header Format (T) flag in the Proxy
   Binding Acknowledgement.  Otherwise, the LMA MUST NOT set the TLV-

Spencer (minor): Why is this a SHOULD (and not a MUST)?

   header Format (T) flag in the Proxy Binding Acknowledgement.