Subject: Re: ospf te doc

From: "Dovolsky, Dan" <[email-masked]>
Date: Wed, 21 Aug 2002 16:50:37 -0400

I think, the Reserved field should not be checked at all on receive. All 32 bits of LSA ID should be treated as LSA ID. This allows more flexibility for backward compatibility for future reuse of Reserve field.

Dan Dovolsky
Movaz Networks.

-----Original Message-----
From: Kireeti Kompella [mailto:[email-masked]]
Sent: Wednesday, August 21, 2002 4:42 PM
To: [email-masked]
Subject: ospf te doc

Hi All,

Here's what the updated section 2.2 of the ospf te doc
(draft-katz-yeung-ospf-traffic-07.txt) looks like:

2.2. LSA ID

   The LSA ID of an Opaque LSA is defined as having eight bits of type
   and 24 bits of type-specific data.  The Traffic Engineering LSA uses
   type 1.  The remaining 24 bits are broken up into eight bits of
   reserved space (which SHOULD be zero on transmission and ignored on
   receipt) and sixteen bits of instance:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       1       |    Reserved   |           Instance            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Instance field is an arbitrary value used to maintain multiple
   Traffic Engineering LSAs.  A maximum of 65536 Traffic Engineering
   LSAs may be sourced by a single system.  The LSA ID has no
   topological significance.

The issues are
a) what should the wording regarding the "Reserved" field be?
b) how should TE LSAs received with "illegal" values be treated?
   (for example in the wording as above, how should a TE LSA with
   a non-zero Reserved field be treated)?

One suggestion is to require the "Reserved" field to be zero, much
as John Moy requires the Opaque ID to be zero in a Grace LSA.  A
TE LSA received with a non-zero Reserved field is to be treated as
an unknown Opaque LSA (how are unknown Opaque LSAs treated?  Dropped?
Flooded?).

Thoughts?  Other suggestions?

Kireeti.

---

From: Kireeti Kompella <[email-masked]>
Date: Wed, 21 Aug 2002 16:23:49 -0700

Hi Dan,

> I think, the Reserved field should not be checked at all on receive. All 32 bits of LSA ID should be treated as LSA ID. This allows more flexibility for backward compatibility for future reuse of R…

Will making the Instance field 24 bits (i.e., the full Opaque ID) work
for you?

Kireeti.

---

From: Acee Lindem <[email-masked]>
Date: Wed, 21 Aug 2002 19:41:52 -0400

> Will making the Instance field 24 bits (i.e., the full Opaque ID) work

Kireeti,

I'd put in a vote for this. In fact, this is how my implementation
interprets the TE opaque LSA ID today.

--
Acee

---

From: Alex Zinin <[email-masked]>
Date: Wed, 21 Aug 2002 19:15:27 -0700

Since this is about one of my AD-review comments, I thought
I would speak up...

I'd like to encourage people to share what their implementations
do with this field in the OSPF LSDB and in the TE DB. (Drop me
a message unicast if you don't feel comfortable speaking up on
the list.)

Thanks.

--
Alex