Hi Enke,

If we are going to take a long time to reach any consensus,
I would rather not change the OPEN size.

The gain with large MESSAGE is
within the UPDATE processing. Having large MESSAGE will drastically
reduce the processing of attributes per NLRI [1]. Having a smaller OPEN
is something we can decide ignore at the moment, there is no problem a
larger OPEN fixes today.

I would advocate to just change the draft to
clarify that all MESSAGEs but OPEN are affected and be done with it. Let
progress by step: this one is very easy to implement, anything more
would require more code and therefore is less likely to get in
production soon (it seems to be the lesson coming from RFC 8092).

I
would then advocate to look at extending the OPEN as another draft (that
we can then argue for years until there is pressure from the operational
to get consensus and another draft with happen instead :p), it does not
delay the benefit of 65k UPDATEs.

Thomas

[1] BGP was designed in a
time where CPU and memory were expensive. So it does did not disjoint
ATTRIBUTE and NRLI. They were both were packed in a same message to be
processed together (but if someone want to create new named attribute
messages and a new attribute to use to link it to an UPDATE - I am all
in favour to even reduce the CPU load on my routers).

On 2017-03-09
20:09, Enke Chen wrote: 

> Hi, Folks:
> 
> Let me add some specifics:
>

> Case 1: large OPEN only
> 
> If the local speaker is only interested
in getting the session established using a
> large OPEN, then it SHOULD
go ahead with the large OPEN and deal with the issue
> administratively
upon receiving a NOTIFICATION due to the large OPEN size. In this
> case
the remote speaker has to be upgraded to support the large message
capability.
> 
> Case 2: Prefer a large OPEN, but can live with a normal
size, predefined OPEN
> 
> Option 1: Start with a large OPEN. In case a
NOTIFICATION is received due to the
> large OPEN size, fall back to
using the predefined normal size OPEN.
> 
> Option 2: Start with the
normal size OPEN. If the OPEN from the remote speaker
> does not
contains the large message capability, proceed with the session
>
establishment. Otherwise send a CEASE message (with a new subcode) and
>
terminate the session (before sending the KEEPALIVE), and then start a
>
new session with the large OPEN.
> 
> With either Option, there should
be no impact on the GR or LLGR as the session
> did not reach the
ESTABLISHED state with the first OPEN.
> 
> Option 1 is more preferred
when the local speaker has the knowledge that the
> capability is
supported by the remote speaker based on the previous OPEN or via
>
administrative means. It also does not require any new protocol
definitions (like
> a new CEASE subcode).
> 
> In addition, I believe
that the large OPEN will not be needed any time soon and
> by the time
it is needed the large message capability should have been widely
>
deployed. Thus I think Option 1 is good and there should be no need to
specify
> Option 2.
> 
> Thanks. -- Enke
> 
> On 3/9/17 6:41 AM, Randy
Bush wrote:
> 
>>> Thank you for sharing this scenario. It would indeed
work at the small cost (or perhaps not so small) to require an extra
round trip at setup time which is most likely un-avoideable whatever is
done.
>> then a double open. i.e. a 4096 open which has the extended
capability exchange and then an optional extended open randy
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