[c-nsp] policer in case of burstable IP transit service

[Tim Jackson]

I think if you actually look at the agreement with the cell carrier, they
are aware that the 50 meg policer will be applied to the full "Layer 2"
rate, which covers the ethernet frame, incl dot1q etc.. Most of the carrier
agreements for the big providers have been this way.. They also usually
specify a relatively small bc/burst interval for any of their traffic..
(they'd rather see traffic dropped than buffered for any longer than
1-2msec)

Something to check.. Nobody likes to give extra BW away for free,
especially once these guys start getting ready to upgrade and find out they
really have 75meg instead of 50..

--
Tim


On Mon, Sep 3, 2012 at 8:49 PM, Aaron <aaron1 at gvtc.com> wrote:

> Hi Martin, I provide cell backhaul for a cell phone carrier in my
> area....they pay for 50 mbps.  They have a gige connection to my
> switch/router (asr901).  My testing showed that small frame sizes (64 byte)
> would result in needing a traffic contract of 70 or 75 mbps for them to see
> the 50 mbps data rate they wanted.....however, I recall that frames of 1500
> (or maybe it was ~9000) bytes allowed them less overhead and I could
> contract at ~50 mbps....so I went ahead with the 75 mbps to ensure a good
> experience for them regardless of pdu size.... also, when I created the
> policers, I saw that IOS created an automatic committed burst (bc)...i'm
> not
> sure how it did that but it did.  I left that in place as I believe it
> causes the policer to be not-so-strict and allow for some bursting...again,
> a better experience for them is what I was hoping for.
>
> Not sure if this is the answer you were looking for but thought I'd share.
>
> Aaron
>
> 901#sh run in g0/5 | in policy
>  service-policy input pm
>
> 901#sh policy-map
>   Policy Map pm
>     Class class-default
>      police cir 75000000 bc 2343750
>        conform-action transmit
>        exceed-action drop
>
> 901#sh policy-map int g0/5
>  GigabitEthernet0/5
>
>   Service-policy input: pm
>
>     Class-map: class-default (match-any)
>       0 packets, 57939250 bytes
>       30 second offered rate 1000 bps, drop rate 0000 bps
>       Match: any
>       police:
>           cir 75000000 bps, bc 2343750 bytes
>         conformed Packet count - n/a, 57939250 bytes; actions:
>           transmit
>         exceeded Packet count - n/a, 0 bytes; actions:
>           drop
>         conformed 1000 bps, exceeded 0000 bps
> 901#
>
>