[OSPF] Re: Comments on draft-berger-ospf-rfc2370bis-00.txt

Lou Berger <lberger@labn.net> Thu, 16 November 2006 19:53 UTC

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Date: Thu, 16 Nov 2006 14:53:16 -0500
To: Acee Lindem <acee@cisco.com>
From: Lou Berger <lberger@labn.net>
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Subject: [OSPF] Re: Comments on draft-berger-ospf-rfc2370bis-00.txt
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         See responses in-line below.

Should the corrected version go in as draft-berger or draft-ietf?


At 07:03 PM 11/13/2006, Acee Lindem wrote:

>Hi Lou,
>My main comment is on section 5 (6 is your draft). The draft adds
>mandatory reachability checking for AS scoped opaque LSAs.
>If we add mandatory reachability checking, it should be for all
>opaque types rather reading like the constraint is unique to AS scoped
>opaque LSAs (type 11s).

valid point.

>I also think we should put the question as to whether the checking
>should be madatory or relaxed a bit to allow an application to check
>less frequently if the opaque data is stale.

What benefit would this have?

>Detailed comments:
>Section 2, third paragraph - "aligned" rather than "qaligned".


>Section 3, "Section 7" rather than "Section 7."

>Section 3.1 - Type 9  LSA - "keep" rather than "keepk".

yes.  Also I added the following to the beginning of the section:
  Section 13 of [OSPF] describes the OSPF flooding procedure.
  Those procedures MUST be followed as defined except where
  modified in this section.

>I believe we
>                    should discard a link-local LSA received from a 
> neighbor not
>                    on the interface (text similiar to type 11).

okay, updated as follows:
   o If the Opaque LSA is type 9 (the flooding scope is link-local)
     and the interface that the LSA was received on is not the same
     as the target interface (e.g., the interface associated with a
     particular target neighbor), the Opaque LSA SHOULD be discarded
     and not acknowledged, and MUST NOT be flooded out that interface
     (or to that neighbor).  An implementation SHOULD keep track of
     the IP interface associated with each Opaque LSA having a
     link-local flooding scope.

>Section 3.1, Since the area ID is not in the LSA header, the bullet on
>                   area flooding is confusing. It should say something to the
>                   effect of only flooding type 10 LSAs out interfaces in the
>                   LSA's associated area.

okay, updated as follows:
   o If the Opaque LSA is type 10 (the flooding scope is area-local)
     and the area associated with Opaque LSA (as identified during
     origination or from a received LSA's associated OSPF packet
     header) is not the same as the area associated with the target
     interface, the Opaque LSA MUST NOT be flooded out the interface.
     An implementation SHOULD keep track of the OSPF area associated
     with each Opaque LSA having an area-local flooding scope.

>I don't care if it said this in RFC 2370
>                   and everyone knew what it implied.

I don't know how to interpret the text otherwise...

>Section 3.1, 2nd to last paragraph: "An opaque" rather than "a opaque".


>Swap sections 5 and 6 since "inter-area" is more the "meat" of the draft.


>In fact, if the opaque MIB objects are all covered in the new MIB, we can
>probably remove the "management section".

done, section will read:

   The updated OSPF MIB provides explicit support for opaque LSAs and
   SHOULD be used to support implementations of this document.  See
   Section 12.3 of [MIB-UPDATE] for details.  In addition to this section,
   implementation supporting [MIB-UPDATE] will include opaque LSAs in
   all appropriate generic LSA objects, e.g., ospfOriginateNewLsas,
   ospfOriginateNewLsas and ospfLsdbTable.

BTW just sent WG mail on one inconsistency between 2370 and the updated MIB.

>Section 6 (will be 5)
>5. Opaque LSA Validation
>Opaque LSAs are not processed during the SPF calculation as described in
>section 16 of [OSPF]. However, they are subject to the same reachability
>constraints as the base LSA types. This implies that originating router
>MUST be reachable for the advertised application specific data to be
>considered valid.
>5.1 Inter-Area Considerations
>Section 5.1
>   Type-9 opaque LSAs and type-10 opaque LSAs do not have this problem
>   as a receiving router can detect an a loss of reachability 
> through the intra-area
>   SPF calculation.
>Section 5.1
>   To enable OSPF routers in remote areas to check availability of the
>   originator of link-state type 11 opaque LSAs, the orignators of
>    type-11 opaque LSAs are considered Autonomous System Border
>    Routers (ASBRs) and will advertise themselves as such.

>Section 5.1 - Remove "It is important to note that this solution MUST NOT ..."
>This is redundant.

which part is redundant, just the sentence you are asking to be 
removed?  I agree that it is redundant with 2328, but I thin 
mentioning it is still useful.  Will rephrase to remove directive.

>Remove numbered items (1) and (2), these actions ARE NOT new to
>opaque LSAs. Make (3) a separate paragraph rather than numbered

But inclusion of type-11 originate routers as ASBR is new.  Will 
rephrase to make clear that existing ospf requirements apply.

How about:
The procedures related to inter-area opaque LSAs are as follows:

(1) An OSPF router that is configured to originate AS-scope opaque
     LSAs advertise themselves as ASBRs and MUST follow the related
     requirements related to setting of the  Options field E-bit in
     OSPF Hello packets and LSA headers as specified in [OSPF].

(2) When ....

>Section 10.1 - Correct NSSA reference to RFC 3101.


>Section 12.1 - Add D and MT bits with informative references to [RFC 4576]
>and the [OSPF-MT] drafts. "All eight bit ..." rather than "Six bits..".


>General - Replace "stub area" with "stub or NSSA areas".


Great comments.

Much thanks.

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