The MPLS WG Archive

[Paul Langille <langille@crescentnets.com>]

    Hi Tom. I agree with you (and Mani) that you need
the triplet < Tunnel index, Tunnel Instance and Source address> to uniquely
identify a tunnel. Good catch.
    So now I am wondering, do you need the tunnel cookie
(since it is the source address and the tunnel index)? Could you also give
some brief examples as to how this would work with bi-directional tunnels.
(I may be a bit confused by the mplsTunnelDirection object.)

            Thanks
            Paul

"Thomas D. Nadeau" wrote:

 
    Hi,

I would like to modify the mplsTunnelEntry to include

a few more objects as well as indexes. I wanted to

bring these changes to the list for discussion before

adding them to the TE MIB due to the fact that they

constitute a significant change, and we did not want to

surprise anyone. This change comes from my implementation

experience with the current version of the MIB, so it is

grounded in an actual implementation.

 

I would like to add five additional values to the mplsTunnelTable

as well as augment the current indexes with two more indexes:

 

mplsTunnelSrcAddrType     INTEGER,

mplsTunnelSrcAddrIPv4 InetAddresIPv4,

mplsTunnelSrcAddrIPv6 InetAddresIPv6,

     Now let me explain why. When you want to examine the tunnel
     entry at a midpoint, it is possible for tunnelId/tunnelInstance
     collisions to occur because the mplsTunnelId + mplsTunnelInstance
     variables are not guaranteed to be unique within an MPLS domain.
     A simple example of this occurs when LSR A has tunnelId = 1,
     tunnelInstance = 0 and LSR B has tunnelId = 1, tunnelInstance = 0
     which utilize the same next hop, LSR C. If one examines the
     tunnel table at LSR C, it is impossible to distinguish both tunnels;
     hence, the third index. A fourth index is required because we need
     to support V6 addresses.

     An additional benefit of the added indexes is that one can now
     sort tunnelEntries based on src address, which is quite useful
     at mid-points and tunnel tails. For this same reason, it might be
     useful to add the tunnel destination address to the indexes of
     this table as well.

     --Tom

--
Paul Langille               
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