The MPLS WG Archive

[Wang Yu <wangyu7707@263.net>]

Eric Gray,
    Hello, thank you very much!
    But the third question is still not clear.

   Next Hop Control Block = Next Hop Trigger Control Block ? 

    Could you explain it?
    Thank you again.

            Wang Yu
            wangyu7707@263.net

-----------------
01-4-25 10:14:00 You wrote:
>Yu,
>
>    Hello.  Please see my earlier answer on this subject at:
>
>    http://cell.onecall.net/mhonarc/mpls/2001-Mar/msg00009.html
>
>    If this does not clear up your questions below, let me know.
>
>Thanks!
>--
>Eric Gray
>
>You wrote:
>
>> Hi, everybody,
>>
>> Here are some questions about MPLS LDP State Machine.
>> Can someone give me explanation?
>> Thanks in advance.
>>
>> 1. Trigger Control Block is discribed unclearly in "LDP State Machine"(draft-ietf-mpls-ldp-state-04.txt).
>> (1)what is it on earth?
>> (2)what is its function?
>> (3)what information does it contain?
>> (4)how does it operation?
>> (5)how does it interwork with LSP control block?
>>
>> 2.Next Hop Control Block is discribed unclearly in "LDP State Machine"(draft-ietf-mpls-ldp-state-04.txt).
>>    I have the same questions about Next Hop Control Block as 1.
>>
>> 3.Next Hop Control Block = Next Hop Trigger Control Block ?
>>
>> In draft-ietf-mpls-ldp-state-04.txt,
>> -------------------------------------------
>> 3.2.1 LSP Control Block
>>
>>    For each LSP, an LSP Control Block is defined which may contain the
>>    following information:
>>      - Upstream Label Request ID (assigned by the upstream LSR),
>>                 which is the 'Message Id' in the Label Request Message
>>                 received from the upstream LSR.
>>      - Downstream Label Request ID (assigned by this LSR itself),
>>                 which is 'Message Id' in the Label Request Message sent to
>>                 the     downstream LSR.
>>      - Upstream LDP Identifier
>>      - Downstream LDP Identifier
>>      - State
>>      - FEC
>>      - Upstream Label (assigned by this LSR)
>>      - Downstream Label (assigned by the downstream LSR)
>>      - Trigger Control Block Pointer, (Only used at the ingress LSR
>>                 of a LSP) that points to the control block that triggers
>>                 setting up this LSP or tearing down this LSP.
>>      - Next Hop Control Block Pointer, which points to the control
>>        **********************
>>                 block which is used for switching over to a better LSP.
>> ---------------------------------------------------------------------
>>   Is Next Hop Control Block = Next Hop Trigger Control Block?
>>
>>             Yu Wang
>>             wangyu7707@263.net