02-16-2018 08:45 AM - edited 03-08-2019 01:53 PM
Hi,
I have extended a branch over 1gig Fibre on which we have 200Mbits of bandwidth. The Interface is configured as an access port on vlan 5. The depth of QOS options are quite detailed. Can anyone give me some pointers on how to rate limit to 200Mbits on my interface for all traffic? I would have though this one would be simple, but a little stuck.
interface TenGigabitEthernet1/0/11
description xxxxxx
switchport access vlan 5
switchport mode access
bandwidth 200000
ip flow monitor Solar_mon_input input
ip flow monitor Solar_mon_output output
end
The Switches are 3850 both ends
Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 16 WS-C3850-12XS 03.07.03E cat3k_caa-universalk9 INSTALL
Solved! Go to Solution.
02-16-2018 09:13 AM
Hello Lee,
Correct. More appropriately, it catches all traffic not identified by another class. However, since you don't have any other classes, it would catch all traffic.
02-16-2018 08:50 AM
Hello Lee,
You will need to apply a service policy with a policer in order to limit the traffic.
The bandwidth command does not actually limit the traffic on the interface. It just changes how certain statistics and metrics are calculated.
The config will look something like this
policy-map POLICE
class class-default
police 200000000 <---Double check my math but that should be 200Mbps
int te1/0/11
service-policy out POLICE
Hope that helps!
02-16-2018 08:52 AM
02-16-2018 09:05 AM
Hello Lee,
Understood. Sounds like you want a shaper more than a policer. The configuration will be roughly the same:
policy-map SHAPE
class class-default
shape average percent 20
If it is a tengig link, you might need to do 2 percent rather than 20 percent. However, you are still limited by the buffers on the 3850 so if your traffic is constantly higher than 200Mbps, you could still see drops.
Hope that helps. Thanks!
02-16-2018 09:11 AM
Hi,
Thanks again, so I have this... will the Class class-default match all traffic with all markings? Its been a while since I have performed any QOS configuration.
Policy Map 200mbits
Class class-default
Average Rate Traffic Shaping
cir 200000000 (bps)
Int TE1/0/11
service-policy output 200mbits
Lee.
02-16-2018 09:13 AM
Hello Lee,
Correct. More appropriately, it catches all traffic not identified by another class. However, since you don't have any other classes, it would catch all traffic.
02-16-2018 09:15 AM
02-16-2018 10:01 AM - edited 12-05-2019 08:41 AM
Just to add to the other posts that show shaping for your SP's 200 Mbps, something you could bump into, might be how your 3850 counts bps vs. how the SP counts bps.
SP's often count bps for all bits on the wire. I.e. if they limited your gig link to 100 Mbps, you should obtain the same actual bps capacity of a FE link.
I'm unsure all Cisco shapers or policers account for all L2 overhead. If they don't, and your SP does, you many need to set your shaper (or policer) about 10 to 15% slower than your SP rate to insure you don't overrun it.
02-19-2018 01:18 AM
Thank you.
Lee.
12-05-2019 03:14 AM
Thanksssss a lot that meets my requirement
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide