Subject: RE: [Idr] signalled prefix limit as an IDR WG work item

From: "Susan Hares" <[email-masked]>
Date: Tue, 11 May 2004 21:05:48 -0400

Tony:

<working group chair hat on>

Your vote (per John's/Sue's) suggested
addition of this topic is: NO. 

Please confirm.  Also do you at 
this time represent a vendor,
a service provider or a valued
researcher/expert? (pick any set
out of the three)?

<working group chair hat off> 

Sue

-----Original Message-----
From: Tony Li [mailto:[email-masked]]
Sent: Tuesday, May 11, 2004 8:08 PM
To: Susan Hares
Cc: Parantap Lahiri; Jeffrey Haas; Pedro Roque Marques; [email-masked]
Subject: Re: [Idr] signalled prefix limit as an IDR WG work item

FWIW, I'm having a hard time understanding why we want the prefix limit 
signaled.

I understand the reason to limit the damage that can be caused by a 
peer, but if
we are concerned about that level of damage, we cannot ignore the 
vulnerability
that any signaled limit is also bogus, either through maliciousness, 
poor
implementation, or human error.

In other words, if we're trying to add a sanity check, we need a sanity 
reference
that isn't provided by the patient.  ;-)

Tony

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---

From: Tony Li <[email-masked]>
Date: Tue, 11 May 2004 18:41:02 -0700

Sue,

a) As has been pointed out to me privately, my comments below are the 
result of
a complete misinterpretation of what's being proposed.  Please consider 
my comment
withdrawn.

b) I still don't see the point.

c) My comments represent no one other than myself, an interested 
onlooker.

Tony

---

From: Tony Li <[email-masked]>
Date: Tue, 11 May 2004 18:41:02 -0700

Sue,

Tony

---

From: Pedro Roque Marques <[email-masked]>
Date: Tue, 11 May 2004 19:08:33 -0700 (PDT)

> a) As has been pointed out to me privately, my comments below are
> the result of a complete misinterpretation of what's being proposed.
> Please consider my comment withdrawn.

Would you mind sharing ? because i still don't understand what is
being proposed. I understand the part about an integer (or a set)
being passed around... but the actual behavior seems to be undefined. 

I am all for vendor differentiation but i think that for
interoperability reasons one needs to define at least which BGP
speaker (the limiting or limited one) needs to have the external
knowledge necessary to have a session survive when the limited router
is (mis)configured to advertise more prefixes than the limit.
 
> b) I still don't see the point.

If the session does not survive then the added benefit would be at
most an earlier warning to the operator of the side that is
limited. Cease sub-codes already indicate that the limit has been
exceeded and give you the value.

If the point is to have the bgp session survive, then extra
information is required. If that information is already present in the
'limiting' side (e.g. transit provider) one could argue that the limit
does not need to be passed around in bgp.

If on the other hand the extra information is configuration on the
limited side... that does indeed seem to fall into the potential trap
you indicated previously. i.e. trying to protect against misconfig of
the client via more config...

i would argue that the WG should not take this item unless someone can
explain how its going to be used and what advantages does it
bring. But then maybe its is just me that is confused.

  Pedro.

---

From: Pedro Roque Marques <[email-masked]>
Date: Tue, 11 May 2004 19:08:33 -0700 (PDT)

Pedro.