The MPLS WG Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] [mpls] lsp trace route question
Hi All, I have a question for lsp trace route in scenario where
label stack of depth n ( n>1) is required to reach the destination. In such
cases how many FEC elements would be there in FEC stack of echo request? If
there would be only one FEC element corresponding to destination (not tunnel
end point) then how does the intermediate LSR makes the FEC to label matching
processing (section 4.3 of draft-ietf-mpls-lsp-ping-70). I am assuming the intermediate LSR is not aware of the destination
FEC. If the FEC stack contains same number of elements as there
are tunnels then FEC to label matching processing could be done… so is it
mandatory in case of tunnels that the trace route echo request contains all
tunnel endpoints the LSP traverses. While “ping” mode echo request
can contain only destination FEC element as only egress LSR control plane is
going to do all that check. Another question I have is why the FEC matching is started
from bottom of both the stacks, as intermediate router would not be aware of
the bottom most label and FEC and as per section 4.3 step 3 in this case it
would reply with a return code 4 “Replying router has no mapping for the
FEC at stack-depth” Thanks in advance Amit Goyal _______________________________________________ mpls mailing list mpls@lists.ietf.org https://www1.ietf.org/mailman/listinfo/mpls |
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