The MPLS WG Archive

[Shen Gangxiang <EGXShen@ntu.edu.sg>]

Hi, Adrian,

Thanks for your draft! I have some doubts on this draft:

1. Draft uses FT Protection TLV to secure the FT message. However, in LDP
specification, there is a field Message ID in each LDP message. It seems
that there is some redundancy on this ID inforamtion. I guess it is possible
to dirctly use the Message ID field to secure those FT messages.
2. After sender sends an FT message, it will receive an ACk message from the
reciever as a confirmation. Following this rule, we may further consider
some special situations:
(a) TCP connection between LSRs is working properly, but some FT messages
can't be confirmed because their receiver can't send back the corresponding
ACK messages due to some other reasons rather than TCP disconnection. 
(For example, in CR-LDP, peer A sends a Label Request message L1 to peer B,
but peer B can't ACK it because peer B's downstream can't provide Label
Mapping message due to something wrong)      
(b)In a Label Request message with FT sequence number S, there could be more
than one FECs, e.g. {FEC1, FEC2,...,FECn}. For these FECs, the mapping
labels may arrive at the node at the different time, and some labels may
even not be able to arrive due to the reasons like in (a). So how should we
deal with such a kind of situation? How will we send the ACK sequence
number?

Many thanks for any comment!

Gangxiang