how to change interface output rate?

kjwlasc01 · ‎07-02-2011

I am in the process of getting a video stream transmitted out (using a Vbrick) to a customer on the internet, but our tests thus far are showing that the vast majority of the UDP packets are not getting through our router.

In my router configuration, I see the following:

Class queue-ICMP/UDP

bandwidth percent 25

police 8000 1500 1500 conform-action transmit exceed-action drop

Additionally, for "sh int Fa 1/2", where this Vbrick is, I see that whenever my Vbrick is transmitting to our customer, the 5 minute output rate seems to be limited to 1000 bits/sec, 2 packets/sec, when it needs to be more like 100000 bits/sec, 200 packets/sec.

I'm guessing that between the configuration itself and the interface, I need to raise the output limit to allow more packets through?

Joseph W. Doherty · ‎07-02-2011

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Posting

Instead of guessing, if you look at the service-policy's stats while you're transmitting the video stream, the policer's stats should reveal if the policer is dropping packets. If it is, then yes, it may need to be adjusted to allow a higher transmission rate.

It would also help you if you knew what the video stream's bandwidth requirement are. This is usually "known" characteristic of the video source.

If you're unable to find the specs for the necessary bandwidth for the video, you can find what's necessary in various ways, perhaps the simplest being to define a temporary class just for this stream and check that class's stats while the stream is live.

You also might see if you can determine the purpose of the existing policy's configuration. It seems a bit unusual, to me, to reserve 25% of the interface's bandwidth and then police it to 8 Kbps. If one purpose is to restrict unknown ICMP/UDP bandwidth consumption, then a class dedicated to video, or at least this video, might be a good idea. (I.e. the temporary class, mentioned above, might become a new permanent class.)

kjwlasc01 · ‎07-02-2011

Thanks for the reply-

1. We conducted a monitor of the incoming traffic to our customer over hte last several days- they are reporting to me that they are only receiving a flatlined transmission rate from us of 8K with minimal packets, which I would assume corresponds to the 8K policing that is currently in our router configuration. They are barely able to formulate a video picture on their end due to the lack of packets, and when they are, it is severely degraded and pixelated.

2. I apologize for the confusion on the bandwidth percentage- I confirmed with my team, the original number had been 1%, but my guys had thought that if they increased this to 25% and lowered another section that was not being used to 1% that this would achieve the results we require. (It didn't.)

3. The transmission rate that we are expecting is 128K (for reference, the direct video input into our Vbrick is 3036000 bits/sec, 323 packets/sec- our goal is to have something significantly scaled down from that, obviously, but 1000 bits/sec, 2 packets/sec is clearly not enough).

I have considered changing the 8K policing to be what we require at 128K, but I'm not sure that would have a direct affect on what appears to be a cap on the output transmission rate for this interface- prior to transmission, is there a command that allows me view the current output limit settings for this interface, and potentially change those (if that's what is required)?

Joseph W. Doherty · ‎07-02-2011

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.

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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

If your customer is only seeing 8 Kbps, I too would suspect the 8 Kbps policer. Do you have access to this device runtime stats? If you do, displaying stats while the video stream is active would reveal more.

What kind of interface and what's its bandwidth? What does the rest of the policy look like?

As mention in my first post, you might want to define a new class just for this video stream. If the class is limited to just the intended video source, you shouldn't have much of a need to police it, just a need to insure it reserves enough bandwidth for the requirements of the video stream (which you believe is only 128 Kbps).

E.g.

Class queue-VBRICK-video

bandwidth 128

kjwlasc01 · ‎07-05-2011

Update- When we removed the 8K police line, nothing changed- the 5 min output rate was still 1000 bits/sec.

Next we did a "sh access list" to see where the information was coming and going at, and we noticed the following:

1. Under "Extended IP access list OUTBOUND" there is no "permit udp any any". There are however all the other ones (I've taken the ACL numbers out for simplicity):

deny udp any any eq 245 log

deny udp any any eq biff log

deny udp any any eq bootpc log

deny udp any any eq bootps log

deny udp any any eq netbios-dgm log

deny udp any any eq netbios-ns log

deny udp any any eq netbios-ss log

deny udp any any eq rip log

deny udp any any eq sunrpc log

deny udp any any eq talk log

deny udp any any eq time log

deny udp any any eq who log

deny udp any any eq xdmcp log

permit ip any any (517974 matches)

It seems to me that we're missing "permit udp any any" here.

Additionally, we noticed the following section:

Extended IP access list queue-ICMP/UDP

10 deny udp any any eq domain (532 matches)

20 deny udp any eq domain any

30 deny udp any any eq snmp

40 deny udp any any eq snmptrap

50 permit udp any any (108796 matches)

60 permit icmp any any (6234 matches)

so we changed it to say

10 permit udp any any eq domain

That increased the 5 min output rate to 2000 bits/sec, but no change on the 2 packets/sec.

I get the sense that the UDP output on this router was not set up properly- I'll add the "permit udp any any" to the OUTBOUND section, any other ideas for me to consider?

Joseph W. Doherty · ‎07-05-2011

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

Yes, as before, consider defining a dedicated class for this video.