Subject: mboned: draft-ietf-mboned-msdp-deploy-06.txt comments...

From: Jerome Durand <[email-masked]>
Date: Thu, 23 Mar 2006 16:37:37 +0100

As discussed during the MBoned WG meeting... I'm trying to redesign MSDP 
in my ISP network and I tried to use the draft for finding the best way 
to do it. Here are my comments:

1°) First this doc is of great importance. It is very difficult to find 
information about ways to deploy MSDP. Thanks to the authors! (even if I 
was a bit sad when I saw there was no ISP authoring that stuff...)

2°) In our setup we have multiple route-reflectors, as in most of 
networks. Section 3.4 should explain the implication of having multiple 
route-reflectors.

3°) Section 2.2 says it is common to have fewer MSDP routers, located 
deeper in the middle of the network. It should be mentionned how then 
redundancy is achieved for MSDP customers: after discussing with Mike, 
appears that customers can setup several MSDP peerings. This raises 
maybe questions:
   - multi-attached customers?
   - MBGP implications?
   - loops avoidance?
   - peering between the inner MSDP routers? (mesh-group, pre-RFC3618, 
RFC3618??)

3bis°) What if the customer also has several MSDP core routers?

   MSDP-cust-A---                     ---------MSDP-ISP-1
                 \                   /
               border-cust----border-ISP
                 /                   \
   MSDP-cust-B---                     ---------MSDP-ISP-2

(note that this scenario will more likely happen when you interconnect 2 
ISPs) How do we setup the MSDP peerings in that case? Do we have 4 peerings?
MSDP-cust-A  <->  MSDP-ISP-1
MSDP-cust-A  <->  MSDP-ISP-2
MSDP-cust-B  <->  MSDP-ISP-1
MSDP-cust-B  <->  MSDP-ISP-2

These are real questions raised by a real operator trying to deploy the 
thing :)

4°) General comment about the way things are presented in the doc... I 
would have preferred to see a doc having the title "how to deploy 
MSDP?". In other words, I think the doc does not give enough 
recommendations on the choices to make when designing MSDP. It is too 
much open to any design solution. After having read the doc I still have 
too many options.

I'm happy to work on real text at a latter stage.

Jerome
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