[Bier] comments on draft-ietf-bier-ipv6-requirements-06

[[e-mail]]

Hi authors,



I have some comments for this draft.





1. In section 2 problem statement, only the situation across non-BFR node (if I understand right, you mean BIER incapable node) is mentioned. 

In fact, some nodes just don't recognize BIER Ethernet type, but can also do BIER forwarding according to BIER header. This situation should also be included.




2. In section 3.1, 

"Reassembly/Re-fragmentation of a packet has to be executed on each

   BFR in such case."

I think the description of "reassembly/re-fragmentation function" is wrong.  

If some packet needs to be fragmented, BFIR does the fragment, and the fragmented packet is BIER payload, it won't be executed in BFR.

And the same with IPSEC ESP. The ESP is also the BIER payload, and the intermediate BFRs will not see it and execute it.

 


3. In section 3.2,

IPv6 extension header is described here. We know there are many IPv6 extension headers, the EHs encapsulation way may be different according to vendor's implementation and operator's deployment. 

And further, there are many options defined in HBH and DOH. In this situation, if BIER header is encoded in any of them, how to locate the BIER header and guarantee the fast forwarding?

If two or more extension header existed, how do we know there is a BIER header existed which must be used for forwarding?

If fragment EH is also carried in the packet, how do we know it need or needn't to be executed?




Thanks,

Sandy