Subject: Re: Fwd: draft-ietf-l3vpn-mvpn-considerations-05

From: Yakov Rekhter <[email-masked]>
Date: Mon, 14 Dec 2009 07:51:24 -0800

Maria,

> 6. The appendix states that "we propose here a rough estimation of the
> load of PEs". And it is in fact a very *rough* estimation and not even a
> complete *rough* estimation as it almost dismisses ASM analysis. The
> appendix treats different and, in fact, not comparable kinds of
> "processing" as *equal* and uses the same unit "m.e" to measure them.
> For example, the first row in the table in section A.1.1.1, says that to
> process the first join on the upstream PE takes "1 m.e" and that the
> same amount of processing, "1 m.e", is required on every other PE in
> MVPN. Clearly, the amount of processing on the upstream PE to which the
> joined is destined is not the same as the "processing" on other PEs. Any
> other PE than the upstream PE will simply discard this Join because the
> neighbor address in the PIM Join is not this PE address. While the
> upstream PE has to create the (s,g) state in the control plane, program
> the data plane for forwarding, and send Join (s,g) message upstream.
> This is by any measure much more processing than discarding the Join
> based on the address. Yet, it is assumed that the resources used in both
> cases are the same.

To address the above I would propose to replace: 

   Though the type of processing, messages and states, may vary with the
   different approaches, we propose here a rough estimation of the load
   of PEs, in terms of number of messages processed and number of
   control plane states maintained. 

with the following:

   Though the overhead of message processing and the state overhead
   may vary between different approaches, and even within the same
   approach between different equipments (PEs or RRs), we propose
   here a rough estimation of the load of PEs, in terms of number
   of messages processed and number of control plane states maintained.

Yakov.