10-21-2015 12:43 PM - edited 03-05-2019 02:33 AM
Hello, so I'm trying to police voice (EF) traffic outbound from the router and limit it to 1.536Mbps.
We're doing this to match our carrier's CAR profile. However, when I show the policy-map stats, it looks as if my exceed action happens before the traffic volume gets to 1.536Mbps.
Config:
interface GigabitEthernet0/1
description MPLS
ip address 7 255.255.255.255
service-policy output MyPolicyMap
!
class-map match-any VOICE
match ip dscp ef
!
policy-map MyPolicyMap
class VOICE
police 1536000 19200 conform-action transmit exceed-action set-dscp-transmit af41
RTR-1#sh policy-map interface g0/1
GigabitEthernet0/1
Service-policy output: MyPolicyMap
Class-map: VOICE (match-any)
750486 packets, 235065040 bytes
5 minute offered rate 64000 bps, drop rate 0000 bps
Match: ip dscp ef (46)
police:
cir 1536000 bps, bc 19200 bytes
conformed 748830 packets, 233225375 bytes; actions:
transmit
exceeded 1656 packets, 1839665 bytes; actions:
set-dscp-transmit af41
conformed 58000 bps, exceeded 1000 bps
I can run this command every 5 seconds and the exceeded counter continues to climb while the 5 minute offered rate never reaches the cir of 1536000. What am I missing here? How can I see the true EF rate?
(I've even set the "load-interval" to 30 seconds. Never hits 1536000)
Thanks,
Robert
Solved! Go to Solution.
10-21-2015 06:02 PM
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Posting
cir 1536000 bps, bc 19200 bytes
Bc/CIR = Tc
19200 bytes * 8 bytes/bit / 1536000 bps = .1 sec or 100 ms
Not within the example subsecond range I noted, but still subsecond.
Actual traffic is always at line rate. The policer "counts" amount of traffic within Tc, and drops excess with that Tc.
10-21-2015 01:01 PM
Disclaimer
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.
Liability Disclaimer
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.
Posting
The policer is marking overrate traffic based on its Tc value, which is usually in the millisecond range (usually something like 4 to 25 ms).
10-21-2015 01:24 PM
Joseph, thanks for the comment. Can you please explain your comment in relation to the show command I've posted?
10-21-2015 06:02 PM
Disclaimer
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.
Liability Disclaimer
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.
Posting
cir 1536000 bps, bc 19200 bytes
Bc/CIR = Tc
19200 bytes * 8 bytes/bit / 1536000 bps = .1 sec or 100 ms
Not within the example subsecond range I noted, but still subsecond.
Actual traffic is always at line rate. The policer "counts" amount of traffic within Tc, and drops excess with that Tc.
10-22-2015 01:03 PM
Thanks Joseph!
I bumped the burst value up to 192000. That made our interval 125ms. Since then, we're not seeing too many marked packets.
10-22-2015 03:04 PM
Robert,
You might also consider doing "load-interval 30" on your interface which will give you 30sec instead of 5 minute average bandwidths. Still probably not granular enough to see if you actually exceed your rates but it'll look a little better.
..
10-22-2015 03:12 PM
trfinkenstadt, thanks for the suggestion. Not sure how much that changes the results, but, it does provide a more frequent metric and a little better graph.
10-22-2015 05:20 PM
BTW, I figure your Tc is now 1 second, a 10x increase. (NB: That's not to say its bad doing this. However, you did say your were trying to match your carrier. If you burst higher then the carrier's measurement allows, they might drop.)
10-21-2015 01:06 PM
What is the Platform and the software version you are using?
10-21-2015 01:18 PM
4331 running IOS-XE
sr4300-universalk9.03.15.01.S.155-2.S1-std.SPA.bin
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