Subject: Questions/suggestions regarding "draft-ietf-l2vpn-vpls-ldp-mac-opt-04.txt"

From: "Paz Pentelka" <[email-masked]>
Date: Mon, 27 Jun 2011 22:00:16 +0300

Dear Authors,

Following review of "draft-ietf-l2vpn-vpls-ldp-mac-opt-04.txt
<http://potaroo.net/ietf/idref/draft-ietf-l2vpn-vpls-ldp-mac-opt/rfcmark
up?repository=/away/ietf&url=/away/ietf/all-ids/draft-ietf-l2vpn-vpls-ld
p-mac-opt-04.txt> " I have a couple of questions/suggestions - 

1 - According to 4.1.2

Note that if a MAC Flush TLV is not understood by a receiver then it 

may result in undesired action. For example if a MAC Flush Parameters 

TLV is received with N=1 and receiver does not understand that TLV 

then it would result in flushing of all MACs learned in the VSI 

except the ones learned over the PW. The MAC Flush TLV SHOULD be 

placed after the existing TLVs in MAC Flush message in [RFC4762
<http://potaroo.net/ietf/idref/draft-ietf-l2vpn-vpls-ldp-mac-opt/#ref-RF
C4762> ].   

I would like to propose a solution to avoid the undesired flushing at
PEs implementing [RFC4762] that are not supporting the new optimization
- if PE-1 (according to the diagram below) can send MAC Flush Parameters
TLV but doesn't send MAC Address TLV, there will not be incorrect
flushing.

2- In a case where the primary spoke PW is down (according to the
diagram below), there can be a case in which there are many other PWs
connected between the 2 PEs that are down (due to physical link down for
instance). In this case, is there a way to send MAC flush for different
PW's/VPLS's with a single LDP MAC message (for better messaging
scalability)? Such option can be defined using sub-TLVs, for example.

                                 PE-1                         PE-3 
                               +--------+                  +--------+

                               |        |                  |        | 
                               |   --   |                  |   --   |  
   Customer Site 1             |  /  \  |------------------|  /  \  |->

     CE-1               /------|  \ s/  |                  |  \S /  |  
       \     primary spoke PW  |   --   |           /------|   --   |  
        \             /        +--------+          /       +--------+  
         \    (MTU-s)/              |    \        /             | 
          +--------+/               |     \      /              | 
          |        |                |      \    /               |  
          |   --   |                |       \  /                | 
          |  /  \  |                |      H-VPLS Full Mesh Core| 
          |  \S /  |                |       / \                 | 
          |   --   |                |      /   \                |  
         /+--------+\               |     /     \               | 
        /     backup spoke PW       |    /       \              | 
       /              \        +--------+         \--------+--------+  
      CE-2             \       |        |                  |        |  
   Customer Site 2      \------|  --    |                  |  --    |  
                               | /  \   |------------------| /  \   |->

                               | \s /   |                  | \S /   |  
                               |  --    |                  |  --    |  
                               +--------+                  +--------+

                                 PE-2                         PE-4 
 
Thanks in advance,
Paz.