Subject: RE: [L1vpn] Issues and concerns about Basic Mode OSPF Discovery

From: "MEURIC Julien RD-CORE-LAN" <[email-masked]>
Date: Wed, 10 May 2006 19:26:32 +0200

Hi Lou, hi all.

I think Adrian (thanks by the way) was trying to summarize the points
already argued so as to build a clear list and avoid message storm. I'm
not going to add much new information, but please see in line.

-----Original Message-----
From: Lou Berger [mailto:[email-masked]] 

[...]

>1. We need to have only one solution
>
>I'm inclined to agree with this. It is not helpful to the industry 
>to have two solutions in the same space. However, if there are 
>significantly different applicabilities this would be a justification.
>
>My interpretation of the discussion in Dallas was that we would not 
>make this decision at this time.

I agree, there was a definite sentiment to let both approaches 
progress for now and "let the market decide".  IMO Experience has 
shown that a good decision point will come when it's time for 
implementation reports.

[JM] However, some are still in favor of a single solution. Personally,
I think it is better to make standardization proactive rather than
reactive.

>2. The L1VPN solution should be aligned with the L2/L3VPN solutions
>
>We need to be clear to what extent the Basic Mode discovery problem 
>is the same as / different from the L3VPN problem.

agree with your point.  To the general point my question is why?

[JM] I assume you agree with the 2nd sentence but not the 1st one (if
I'm wrong, please go to the next stage). As a carrier, I would prefer to
avoid as many procedure changes as possible; therefore if the analysis
reveals the IGP solution will be limited to the basic mode, it will be
detrimental to its deployment (OK, for me it doesn't change much, but
that may be of high significance for an undecided carrier).

>3. The Basic Mode discovery solution must extend to the Extended Mode

Why?  Also, this implies this isn't possible with OSPF, I don't think 
this is clear.  And would like those who have made the point to state 
why it does not.

[JM] Not guilty! :-) I have not stated it does not, but I agree on the
"MUST extend".

>4. There are scaling concerns with using OSPF in this way.
>
>A couple of comments on scaling.
>- It is certainly safe to assume that in the near term, the size of
optical
>  networks will not come close to the current size of OSPF packet
>  networks.
>- OSPF used in this way will not need to handle external routes, and
>  this saving more than outwieghs the cost of Basic Mode discovery
>- The "per-port" nature of L1VPN connectivity means that there is
>   no multiplexing of VPNs to a CE-PE link (athough a single PE may
>   give access to multiple VPNs).

I think you make excellent points and see no need to add to 
it.  Again, if there are those who have further objections, they 
should raise them on this list.

[JM] Sorry for repeating, but that clearly suggests that when networks
will get bigger, migration to BGP will be necessary; and even if
protocol change will not be the most tricky part, procedures will have
to change. Moreover, in this case we will finally be aligned with L2/3
VPNs, thus wonderring why not beginning with BGP from day 1...

>5. This is 'naturally' an iBGP function not an IGP function

well that's nice.  and my IGP is better than yours - hah!

More seriously, if there's a technical point here can someone help me
find it.

[JM] The simple point here is that there is a tool widely used *inside*
ASes to carry *external* information between edge nodes, and this is
iBGP. Is the autodiscovery function really compliant with the "I" in
"IGP"?
"I can surely use the hammer* I'm holding to drive a screw into a plank,
but I prefer to take a screwdriver." ;-)

*(famous tool for those who read IETF Journal)

[...]

BTW, I really don't like the "dark smoky-room" approach being taken 
here.  If a WG participant/AD/etc. has an issue, then they should 
raise it themselves and not ask the WG chair to do it for them.  If 
they don't care enough to raise it themselves, then IMO we, the WG, 
shouldn't waste our time on it!

Lou

[JM] And that is why I started the discussion on the list before. As
said above, summarization is always welcome, we cannot blame the effort.

Regards,

Julien

_______________________________________________
L1vpn mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/l1vpn