Re: [Lsr] FW: New Version Notification for draft-bonica-lsr-ip-flexalgo-00.txt

[Peter Psenak <[e-mail]>]

Gyan,

On 02/10/2020 18:30, Gyan Mishra wrote:
> All,
> 
> With SRv6 and IP based flex algo a generic question as it applies to 
> both. Is it possible to have within a single IGP domain different sets 
> of nodes or segments of the network running different algorithms.  

absolutely.

> From 
> both drafts it sounds like all nodes have to agree on same algorithm 
> similar to concept of metric and reference bandwidth all have to have 
> the same style metric and play to the same sheet of music.

all participating nodes need to agree on the definition of the flex-algo 
and advertise the participation. That's it.

> If there was 
> a way to use multiple algorithms simultaneously based on SFC or services 
> and instantiation of specific algorithm based on service to be 
> rendered.  Doing so without causing a routing loop or sub optimal 
> routing.  

you can certainly use multiple algorithms simultaneously and use algo 
specific paths to forward specific traffic over it. How that is done 
from the forwarding perspective depends in which forwarding plane you 
use. Flex-algo control plane is independent of the forwarding plane.


>I thought with flex algo that there exists a feature that on 
> each hop there is a way to specify which algo to use hop by hop similar 
> to a hop by hop policy based routing.

no, there is no hop-by-hop classification, that is problematic and does 
not scale for high speeds. Classification is done at the ingress only.

thanks,
Peter

>