Re: [Lsr] Flow Control Discussion for IS-IS Flooding Speed

Hi Les & all,

Watching this discussion I would like to state that IMO going with
transmitter based rate limiting (I would not call it flow control) is much
easier option to deploy and operate. It also has no dependency across other
side of p2p adj which is a very important factor. The only issue here is if
generation of [P|C]SNPs is fast enough.

Receiver based flow control is simple in flow theory however I have a
feeling that if we are to go that path we would be much better to actually
run ISIS flooding over DC-TCP and avoid reinventing the wheel.

Thx,
Robert.

On Wed, Feb 19, 2020 at 3:26 AM Les Ginsberg (ginsberg) <ginsberg@cisco.com>
wrote:

> Two recent drafts advocate for the use of faster LSP flooding speeds in
> IS-IS:
>
>
>
> https://datatracker.ietf.org/doc/draft-decraene-lsr-isis-flooding-speed/
>
> https://datatracker.ietf.org/doc/draft-ginsberg-lsr-isis-flooding-scale/
>
>
>
> There is strong agreement on two key points:
>
>
>
> 1)Modern networks require much faster flooding speeds than are commonly in
> use today
>
>
>
> 2)To deploy faster flooding speeds safely some form of flow control is
> needed
>
>
>
> The key point of contention between the two drafts is how flow control
> should be implemented.
>
>
>
> https://datatracker.ietf.org/doc/draft-decraene-lsr-isis-flooding-speed/
> advocates for a receiver based flow control where the receiver advertises
> in hellos the parameters which indicate the rate/burst size which the
> receiver is capable of supporting on the interface. Senders are required to
> limit the rate of LSP transmission on that interface in accordance with the
> values advertised by the receiver.
>
>
>
> https://datatracker.ietf.org/doc/draft-ginsberg-lsr-isis-flooding-scale/
>  advocates for a transmit based flow control where the transmitter monitors
> the number of unacknowledged LSPs sent on each interface and implements a
> backoff algorithm to slow the rate of sending LSPs based on the length of
> the per interface unacknowledged queue.
>
>
>
> While other differences between the two drafts exist, it is fair to say
> that if agreement could be reached on the form of flow control  then it is
> likely other issues could be resolved easily.
>
>
>
> This email starts the discussion regarding the flow control issue.
>
>
>
>
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