The MPLS WG Archive

["Tan Su Wei" <swtan@mmu.edu.my>]

Dear All,
    Thanks for answering my question.
As Kireeti wrote:
    > Perhaps we've gone off on an tangent here.  The question
    > as I understood it is "when a *data* packet arrives at
    > the egress, can we know which ingress and which LSP it
    > travelled on?" -- and the answer is, not without some
    > extracurricular work.
    >
    > Tan, can you clarify your question?

and my question is exactly as above. I'm sorry if there is any
misunderstanding.
For the posted answer from Mr. Eric Gray

    It is possible to know the LSP traversed, only if
    the LSP is "identified".  This is possible with either
    CR-LDP (using LSP-ID) or RSVP-TE (using SESSION).

Lets if the LSP is "identified" using either lspid or session object (during
the LSP setup time, right?) , to know the lsp and ingress the *data* packet
from, is that mean we need adding a field in the data packet on this
information? (Maybe ip header option field?).
Since information get from the incoming label and interface might be
incorrect when there is LSP merge.
Is my interpretation correct?

    Thank you for your reply.

Regards
Tan Su Wei