Subject: [mpls] "Detecting MPLS date plane failure in Inter-AS and inter-provider scenarios"

From: Michael <[email-masked]>
Date: Tue, 13 Feb 2007 09:38:11 +0800

Hi, Thomas & George:

Good to hear. 

Best, 

Michael

  ----- Original Message ----- 
  From: Thomas D. Nadeau 
  To: Michael 
  Cc: [email-masked] 
  Sent: Monday, February 12, 2007 10:40 PM
  Subject: Re: question

  Michael,

  Can you please post this question to the MPLS mailing list
  so that the WG can benefit from our response?

  --Tom

    Hi, Thomas & George:

    I read your draft "Detecting MPLS date plane failure in Inter-AS and inter-provider scenarios", Maybe I do not fully understand what you are talking, but some part is a little bit confusing:

     Note that only combinations of 1+2 or 3+4 may be used.

      Failed Node AS Number:

       This field may contain the AS number in which the node where
       the failure was detected resides. If no AS number is indicated,
       this field MUST contain 0s.

      Failed Node IP Address:

       If the interface to the downstream LSR is numbered, then the Address
       Type MUST be set to IPv4 or IPv6, the Downstream IP Address MUST be
       set to either the downstream LSR's Router ID or the interface address
       of the downstream LSR, and the Downstream Interface Address MUST be
       set to the downstream LSR's interface address.

       If the interface to the downstream LSR is unnumbered, the Address
       Type MUST be Unnumbered, the Downstream IP Address MUST be the down-
       stream LSR's Router ID (4 octets), and the Downstream Interface
       Address MUST be set to the index assigned by the upstream LSR to the
       interface.

      Failed Node AS Number:

       This field may contain the AS number in which the node where
       the failure was detected resides. If no AS number is indicated,
       this field MUST contain 0s.

      Failed Node Contact String:

    >>>>in this section, you describe "Failed Node AS Number:" two times, I think it unnecessary.

    In addition, some terms are not used consistently, for example: in section 7.1.3, you define two stacks which are "the return stack" and "the trace stack", however in section 7, you use term "the reply stack", although I know you really mean "the return stack".

    Last but not least, in section 7, as I tell, "the trace stack" always have more more element than "the reply stack", except the top element in the trace stack, the remaining elements in the trace stack is same to those in "the reply stack". So here there exists some redundant information, I have one suggestion: maybe we can borrow the idea from "IP record route option", only one stack is maintained, and one more field called "pointer" is defined to help to the locate the ASBR along the return path.

    Best,

    Michael

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