Last Call Review of draft-ietf-mpls-entropy-lsp-ping-03
review-ietf-mpls-entropy-lsp-ping-03-opsdir-lc-bradner-2016-08-31-00

I did an OPS-DIR review of Label Switched Path (LSP) and Pseudowire (PW) Ping/Trace over
 MPLS Network using Entropy Labels (EL) (draft-ietf-mpls-entropy-lsp-ping-04)

The draft extends the existing MPLS LSP Ping and Traceroute multipath mechanisms to
 support LSPs that use an Entropy Label.

The primary operational impact of this technology is to provide an additional tool for network
 operators to debug their networks - a good thing.

I found the draft a bit hard to follow, it seems to be more a collection of data points than a
 clear narrative but I do not think it is worth a rewrite to make it easier to understand.

I found one thing that raises an operational concern - the next to last paragraph in 
section 2 says: “All LSRs along the LSP need to be able to understand the new flags 
and the new multipath information type.” But I do not see a mechanism discussed to check to 
see if that is the case  (like the high order two bits of IPv6 options).  If there is a 
mechanism it might be good to describe it, if there is not, a statement that 
verifying this condition is outside of the scope of the draft would be helpful

The same paragraph goes on to say  “It is also required that the initiating 
LSR can select both the IP destination address and label to use when 
transmitting MPLS echo request packets.” It might be helpful to say under 
what conditions this is or is not the case.

Otherwise, the draft seems ready for publication.

 

Scott