[rbridge] last call comment

Jeff Pickering jeffpick at broadcom.com
Wed Jul 1 10:53:34 PDT 2009

     Section 4.5.1

   "When building the tree number j, remember all possible equal cost

   parents for node N. After calculating the entire "tree" (actually,

   directed graph), for each node N, if N has "p" parents, then order

   the parents according to 7-byte ID. For tree j, choose N's parent as

   choice j mod p."

   I really dont like the idea of keeping all P parents, esp in an environment

   like fat tree where there may be dozens (64?) of upstream equal cost parents (times thousands of nodes).

      To require this will be a huge overhead. That said, we should at least say whether "order the parents"

      means starting with lowest or highest.

     Section 4.5.2

      "In this case, R1-R2 adjacencies are ordered as follows, with

      the one "most preferred" adjacency being the one that R1 transmits

      to R2 on, and the one that R2 accepts traffic from R1 on:"

      The way I read this, the statement is meaningless, R1 and R2 both transmit to each other. So

      either the intent is to say R1 (or R2) is the RB closer to the root. Or the intent is to say that depending

      on whether traffic is flowing towards or away for the root, you may choose a different adjacency. Whichever

      interpretation is intended should be clarified.

    Section 4.5.2

    "Most preferred are those established by P2P Hellos with tie-

    breaking among those based on preferring the one with the

    numerically highest Extended Circuit ID."

       According to rfc 5303, there is no concept of a shared extended circuit ID, only the ext cid advertised by

       each side. So this should be state which RBs ext cid is intended.


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