[mpls-tp] draft-boutros-mpls-tp-performance

[Vishwas Manral <[e-mail]>]

Hi,

I noticed some interesting things in the performance monitoring draft.
The most interesting thing is point 4 I have noted.

1. The draft may be trying to measure packet loss but it assumes the
performance messages cannot be lost. This seems like a very
interesting assmption.

2. On the same lines if we assume the above not true, we may need to
define retransmits from senders and no/ ACK NACK retransmits.

3. We also need to define how to identify duplicate messages and how
duplicate packets are to be treated.

4. I also notice to measure packet loss we use the sequence number in
the packets themselves:

To measure packet loss I guess the receiver looks at the gaps in the
sequence numbers. However there are basic issues with this.

Sender sends packet 1 to 100. Receiver receives packet 1 to 80.
Receiver does not know 100 packets are going to be sent, so it says
packet loss is 0 even though there are 20 packets that are lost.

5. I assume it would be good to state that the sequence number of the
first packet is 1. Also if there are wrap arounds what needs to be
done. In my view we should use 64 bit values for sequence numbers, it
is like a packet counter.

Thanks,
Vishwas