Re: [Bier] Feedback on draft-eckert-bier-rbs-00

[Toerless Eckert <[e-mail]>]

Thanks, Ice - also Tony/Greg feedback/mails..

want to incooporate feedback into draft updates, hence no quick reply here,
as to other discus here.

Cheers
    Toerless


On Thu, Nov 10, 2022 at 01:32:51AM +0000, IJsbrand Wijnands wrote:
> Dear Authors,
> 
> Here is some feedback on the RBS encoding. This is based on my understanding of the draft and discussion with Toerless today.
> 
> 1. It seems that when a BIER router is parsing the RecursiveUnit, the length of the BitString is derived from the length of the BIFT Table on the router processing the packet. To me that seems very tricky as the length of the BIFT table might change when interfaces/adjacencies get added and removed. There might always be transient cases where the length of the BitString in the packet might be different from the router’s BIFT Table. If that happens, the complete parsing of the RBS packet goes to sh*t. It would be good to somehow add the length of the BitString inside the RBS header to prevent these cases from happening and be more defensive.
> 
> 2. The BIFT table has a Recursive flag to indicate if a BIER node has downstream receivers. This is also required to correctly parse the RBS header. In my mind this should not be a property of the BIFT table. A bier node might have nodes connected to it, but that doesn’t mean they are part of the tree. The recursive flag should be part of the encoded tree inside the RBS header.
> 
> Thx,
> 
> Ice.
> 

-- 
---
[e-mail]