01-31-2014 02:15 PM - edited 03-04-2019 10:13 PM
Getting a 30MB ethernet handoff from our ISP and I want to rate limit a sub-interface (VLAN 100) to 10M of it so that the group of people in that VLAN 100 do not suck up all 30MB with their downloads.
Would this be what I need to put?
interface GigabitEthernet0/0.100
rate-limit input 10485760 20000 40000 conform-action transmit exceed-action drop
rate-limit output 10485760 20000 40000 conform-action transmit exceed-action drop
I don't really know exactly what the burst rate #'s are supposed to be or mean. If anyone can explain that I'd appreciate it. I just dreamed 20000 and 40000 up out of thin air.
01-31-2014 02:58 PM
Dawn,
Based on your calculation (and you can simplify this with 10000000), you would take your normal rate * .125 * 1.5. That would get:
10000000 * .125 * 1.5 = 1875000
Excess burst is 2 * normal burst:
1875000 * 2 = 3750000
So, you would put:
rate-limit input 10000000 1875000 3750000 conform transmit exceed drop
rate-limit output 10000000 1875000 3750000 conform transmit exceed drop
From the Cisco doc:
Burst size—Also called the Committed Burst (Bc) size, it specifies in bits (or bytes) per burst how much traffic can be sent within a given unit of time to not create scheduling concerns. (For a shaper, such as GTS, it specifies bits per burst; for a policer, such as CAR, it specifies bytes per burst.)
When extended burst is configured and this scenario occurs, the flow is allowed to borrow the needed tokens to allow the packet to be sent. This capability exists so as to avoid tail-drop behavior, and, instead, engage behavior like that of Random Early Detection (RED).
HTH,
John
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01-31-2014 03:08 PM
so what time period is the Burst allowed for? 5 seconds or 10 minutes or an hour?
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