Subject: [L1vpn] Autodiscovery Protocol

From: "MEURIC Julien RD-CORE-LAN" <[email-masked]>
Date: Thu, 23 Mar 2006 17:35:00 +0100

Hi all.

Allow me to get back to the issue raised during the L1VPN meeting: the autodiscovery protocol.

I think it is clear for everyone that BGP really fits the job. Thus I do not see why we would need to add an IGP to do less things. Lots of drawbacks were even pinpointed during the meeting: more flooding, less scalability, no AS crossing, less flexibility (full mesh)... but no real advantage.

What is more, as Kireeti said, starting with 2 different solutions is likely to bring more problems than solve any. Since something needs to be added, I am not sure that extending an IGP (or both if we do not want to preclude any option...) will be easier/quicker than using BGP. And if, despite this, some consider it as a 1st step, then I think we do not need to make it a standard.

So I am in favour of BGP autodiscovery, but BGP only.

Best regards,

Julien

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From: "Igor Bryskin" <[email-masked]>
Date: Thu, 23 Mar 2006 11:57:32 -0500

Julien,

Thanks for the comments. Please, see in-line.

Igoe

----- Original Message ----- 
From: "MEURIC Julien RD-CORE-LAN" <[email-masked]>
To: <[email-masked]>
Sent: Thursday, March 23, 2006 11:35 AM
Subject: [L1vpn] Autodiscovery Protocol

Hi all.

Allow me to get back to the issue raised during the L1VPN meeting: the
autodiscovery protocol.

I think it is clear for everyone that BGP really fits the job. Thus I do not
see why we would need to add an IGP to do less things. Lots of drawbacks
were even pinpointed during the meeting: more flooding, less scalability, no
AS crossing, less flexibility (full mesh)... but no real advantage.

IB>> Just a couple. 1) No need for BGP. Untill now operators of L1 layer
networks don't seem to find any use for BGP, and unlikely to deploy BGP for
the purpose of one application some time soon 2) IGP solution facilitates
easier integration with TE, which is very important for GMPLS based control
plane

What is more, as Kireeti said, starting with 2 different solutions is likely
to bring more problems than solve any. Since something needs to be added, I
am not sure that extending an IGP (or both if we do not want to preclude any
option...) will be easier/quicker than using BGP.

IB>> As was pointed out on the meeting, this is not an argument of a sort
RSVP-TE vs CR-LDP. The architecture (basic mode) clearly assumes the
protocol independence of L1VPN auto-discovey mechanism. The OSPF extensions
are very simple, the application is required now and based on OSPF could be
delivered quickly. What happens if the BGP solution proves to be a better
one (as it happened in the past) ?
Than the OSPF solution could be simply thrown away and replaced by the BGP
one.

Igor

 And if, despite this, some consider it as a 1st step, then I think we do
not need to make it a standard.

Best regards,

Julien

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From: "Igor Bryskin" <[email-masked]>
Date: Thu, 23 Mar 2006 12:41:07 -0500

Hi,

I just spoke to the OSPF WG chairs and pointed out to the problem of
advertising of AS-scope opaque LSAs (the one that was discussed on L1VPN
WG).
The chairs have agreed that this is an obvious flaw in the protocol which
needs to be fixed. They even proposed on the spt a very simple solution how
to fix the problem with zero changes on ABRs required. We agreed to work
together and present a draft on the next IETF.

This would enable to remove the validation part from the OSPF based L1VPN
auto-discovery draft and make the solution ridicuosly simple.

Igor

----- Original Message ----- 
From: "Igor Bryskin" <[email-masked]>
To: "MEURIC Julien RD-CORE-LAN" <[email-masked]>;
<[email-masked]>
Sent: Thursday, March 23, 2006 11:57 AM
Subject: Re: [L1vpn] Autodiscovery Protocol

---

From: dimitri papadimitriou <[email-masked]>
Date: Thu, 23 Mar 2006 19:23:46 +0100

not so simple, imho the issue is driven by

o) time - depending on need's importance vs urgency, if dynamic PTI 
tables population is to be there in a couple of month, or in a couple of 
years (would like to point out that understimating the time it may take 
to convince l1/trans networks to make use of BGP may be impacting)

o) cost - can be seen both ways is there a need to have a single 
protocol for LxVPN (x = 1, 2, 3) or is there a need to have a single 
protocol for L1/TE operations ? so it depends whether operators are 
looking for integrating their TE operations (including VPN or not) or 
VPN operations (including TE or not);

o) perf - concerning the protocol perf. we're discussing path vector vs 
link-state protocol so impact/properties are different by nature but TE 
processing overhead/impact would be worth investigated (note that this 
depends on the problem statement e.g. what would be the impact of 
progressively incorporating TE specific mechanisms for L1(VPN) into BGP 
if such need is identifed ?)

MEURIC Julien RD-CORE-LAN wrote:

> I think it is clear for everyone that BGP really fits the job. Thus I
> do not see why we would need to add an IGP to do less things. Lots of
> drawbacks were even pinpointed during the meeting: more flooding,
> less scalability, no AS crossing, less flexibility (full mesh)... but
> no real advantage.
> 
> What is more, as Kireeti said, starting with 2 different solutions is
> likely to bring more problems than solve any. Since something needs
> to be added, I am not sure that extending an IGP (or both if we do
> not want to preclude any option...) will be easier/quicker than using
> BGP. And if, despite this, some consider it as a 1st step, then I
> think we do not need to make it a standard.
> 
> _______________________________________________ L1vpn mailing list 
> [email-masked] https://www1.ietf.org/mailman/listinfo/l1vpn
> 
> .
>