RE: draft-morin-l3vpn-mvpn-considerations

["NAPIERALA, MARIA H, ATTLABS" <mnapierala at att.com>]

Hi Thomas,
thanks for the reply. See my responses in-line.

Maria 

-----Original Message-----
From: Thomas Morin [mailto:thomas.morin at orange-ftgroup.com] 
Sent: Monday, December 17, 2007 5:01 PM
To: NAPIERALA, MARIA H, ATTLABS
Cc: Ron Bonica; l3vpn at ietf.org
Subject: RE: draft-morin-l3vpn-mvpn-considerations

Hi Maria,

NAPIERALA, MARIA H, ATTLABS wrote:
> The draft is a very good start but there are still some outstanding
> mandatory design aspects that need to be addressed: 
> - support of non-static RP solutions like BSR. There are current large
> MVPNs in SP network that use BSR

I agree (see reply to Eric) that our draft can mention BSR support.
There is only one currently proposed approach for BSR support, applying
to both the Full PIM peering approach and the BGP approach, so there
isn't that much to "compare", but the current requirement for MI-PMSI
for BSR support, even in the case where BGP is used for C-multicast
routing, has to be mentioned.

<maria> yes, I agree. The need for MI-PMSI should be stated as the only
currently available solution for BSR. Since there are existing MVPN
deployments that use BSR, it needs to be supported.

> - what is still missing in this draft as well as in RFC4834 is the
> requirement to support PIM Bidir on CE-PE links. This requirement is
> coming, e.g., from large financial firms for which using PIM-SM for
> certain business critical applications does not scale. Not to mention
> the SP :-))
> - support of "PIM-like" Anycast-RP by allowing multiple RP's to send
> traffic in parallel 

The two points above would look to me as belonging to the mvpn
requirement document (RFC4834). 

<maria> actually, those requirements are already stated in
draft-mnapierala-mvpn-part-reqt-00.

The requirement for CE-PE bidir-PIM is actually already in that
document. 

<maria> that's true but RFC4834 only "recommends" PIM-Bidir support on
PE-CE interfaces. The draft-mnapierala-mvpn-part-req makes it a
requirement. We have many large VPN customers requiring it.

The way of supporting bidir-PIM is definitely distinct in the
BGP approach and in the Full PIM peering approach, but it seems to me
that both should be able to support it. Do you think that
mvpn-consideration should discuss the relative advantage of the
different proposals for bidir-PIM support ?

<maria> Definitely.

For the other requirement, the better is probably to explain to solution
draft authors, what would be the need. Do you think that it could help
distinguish one of the proposed approaches ?

<maria> surely. Some of the argumentation from a service provider point
of view is in draft-mnapierala-mvpn-part-reqt.

> - the recommended approach for a source PE to decide when to start
> transmitting customer multicast traffic on a S-PMSI (namely, the
source
> PE waits for a pre-configured period of time) is not satisfactory in
my
> opinion. A different approach is proposed in
> draft-mnapierala-mvpn-rev-03

Is this something mvpn-consideration should talk about to help
distinguish a better approach among the proposed ones ?

<maria> I think so. There are multiple approaches and they should be
compared in this aspect. 

> Also, I would suggest that "co-located RP" recommendation is removed
> from the document. Co-locating C-RP on PE should not be positioned as
a
> mandatory mechanism in MVPN, which this draft is addressing.

As I said earlier, mvpn-considerations does not at all push this feature
as mandatory at all.

<maria>  What confused me is, quoting from the draft section 1: 
"The aim of this document is to leverage the already expressed
requirements [RFC4834] to identify the mechanisms that the authors
believe are good candidates for being part of a core set of MANDATORY
mechanisms which can be used to provide a base for interoperable
solutions." (my underline of "mandatory").
I also think that in a "big scheme of things" co-locating C-RP with PE
is an insignificant recommendation... This is already supported by
vendors and if a service provider wants to use it, it is free to do so
:-)
 

> I might have comments but wanted to send those COB today. 

As I told you in Prague, your comments and contributions to this draft
are always welcome. 

<maria> surely!

Thanks,

-Thomas



> -) ---------- Forwarded message ----------
> -) Date: Mon, 10 Dec 2007 16:11:28 -0500
> -) From: Ron Bonica <rbonica at juniper.net>
> -) To: l3vpn at ietf.org
> -) Subject: draft-morin-l3vpn-mvpn-considerations
> -) 
> -) Folks,
> -) 
> -) Unless I hear an objection before COB Friday, this document will
> become
> -) a WG draft.
> -) 
> -)                                       Ron
> -) 
> 
>