Two things to ask here:
A) I tried a lot to find the answer to this on the cisco website but couldnt track it anywhere so far.
Basically wanted to confirm if i could use GTS on 1921 routers? It seems it doesnt support it cos when i was trying to run the command on the g0/1 interface of the router, it did not like "tarffic-shape" keyword at all. I could only see "rate-limit" (CAR) as the option available.
I am still new to these concepts and all I wanted to achieve was to set my outbound speed to 6 Mbps as thats what the ISP is providing me.
B) I was advised that GTS was the simplest option to choose from, but when I realized that the router wasnt liking it, I thought of using CAR but then wasnt able to understand the best value for burst size and excess burst size that i should use.
I read on the cisco website that they recommend the following formula,
normal burst= configured rate * (1 byte)/ (8 bits) * 1.5 sec
excess burst = 2 * normal burst
But honestly, i did not follow this properly to decide what value should i use?
Thanks in advance!
CAR is not a replacement for GTS it uses policing instead of shaping
Shaping delays traffic in excess of the committed rate, policing drops traffic in excess. So CAR is much more intrunsive on traffic.
In modern routers you can achieve the equivalent of GTS using modular QoS
shape average 6000000
interface type x/y
description your WAN interface to provider
service-policy SHAPE-6Mbps output
you can check the operations of the policy-map with
show policy-map interface
Hope to help
Thanks for replying -after your suggestion, I read about the Modular QoS and realised that there was an option “bandwidth” that I could use in the class-map config mode. Wouldn’t you reckon that would be better if my intent is to set the bandwidth on the interface?
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
The CBWFQ bandwidth statement, in non-LLQ classes sets a minimum value. What Giuseppe suggested would be the GTS equivalent.