[c-nsp] ASR9k Bundle QoS in 6.0.1

[Adam Vitkovsky]

> Saku Ytti
> Sent: Thursday, May 12, 2016 3:30 PM
>
> On 12 May 2016 at 16:35, Mark Tinka <mark.tinka at seacom.mu> wrote:
> > Remember that load sharing comes before policing. So if your load
> > sharing is unbalanced, you will drop traffic before the actual policer
> > limit has been hit. I've found that the only way to fix this is to
> > perform per-packet load balancing, as per-flow load balancing may not
> > always be equally distributed across member links of the LAG.
>
> Juniper today also has adaptive load-balancing, which essentially adds one
> layer of abstraction between hash-result and egress port. This way, on this
> interim-table, they can change how many hash-results go to interface A how
> many to B.
> Compliment this with control-plane monitoring of traffic rates in A and B, and
> if some elephant flow is staying in B, adaptive load-balancing can reduce how
> many hash-results hit B, diverting larger share of traffic to A.
>
>
I would love to see how this adaptive thing actually works as my understanding is that the mechanism is flow oblivious. So the only thing it can do is to blindly try to shuffle the flows around (not knowing which one is the elephant flow as it's not recording per flow rates) in search of better bundle members load distribution and with ever-changing flows that's a hard ask.




adam











        Adam Vitkovsky
        IP Engineer

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