[Bier] comments on draft-zzhang-bier-tether-03

[<[e-mail]>]

Hi Jeffrey, co-authors,






I have read the newest version of draft "draft-zzhang-bier-tether". I think it's well written and helpful for BIER deployment.



And I have some comments:


1. In section 3 about the IGP/BGP signaling, because a Helper can help more than one non-BFR node, there will be more than one Helped Node sub-sub-TLV shown in the signaling. But one helped prefix MUST be shown only once.


So one sentence about it may be added in the section to make it more clear.






2. About the IGP SPF calculation procedure, IMO it's better to explain the algorithm modification of [RFC8279] section 6.9. Like:

This sentence may be added in Step 2:


But the node's prefix SHOULD be noted for Helping check.

A Step 4 may be added:


When BFR-B finds that one node signals as the helper of one or more helped nodes, BFR-B MUST check if the helped node is bypassed. If the helped node is bypassed, BFR-B SHOULD replace the existed tunnel from BFR-B that bypass the helped node with the helper node as the child node. If more than one helper existed for a helped node, the one which has the highest priority is selected.





Thanks,


Sandy