bandwidth prioritise for videoconferencing

[Shibu1978]

Dear All,

I am working on Videoconferencing solution between two location.  locations are now being connected through IPSEC site to site VPN.  Since we are having a common internet link for VPN as well other corporate use we have to prioritize the internet bandwidth for Videconferencing. is there any way i can prioritise videoconferencing traffic by ports?  following are the configs done on the cisco 2801 router with Version 12.4(15)T10.

!
interface FastEthernet0/1
description ILL_12Mbps
bandwidth 20480
ip address 94.*.*.180 255.255.255.248
duplex auto
speed auto
priority-group 1
!

ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 94.*.*.*

!
!
no ip http server
no ip http secure-server
ip pim ssm default

access-list 199 permit ip host 94.*.42.* host 78.*.*.130 ( VPN peer IPs both ends)
priority-list 1 protocol ip high list 199

Interface status

===========

RTR2800-1#sh int fa0/1

FastEthernet0/1 is up, line protocol is up

  Hardware is Gt96k FE, address is 0026.9973.1893 (bia 0026.9973.1893)

  Description: ILL_12Mbps

  Internet address is 94.**.*/29

  MTU 1500 bytes, BW 20480 Kbit/sec, DLY 100 usec,

     reliability 255/255, txload 76/255, rxload 141/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/s, 100BaseTX/FX

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:14, output 00:00:00, output hang never

  Last clearing of "show interface" counters 20w2d

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 142056

  Queueing strategy: priority-list 1

  Output queue (queue priority: size/max/drops):

     high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0

  5 minute input rate 11369000 bits/sec, 1407 packets/sec

  5 minute output rate 6146000 bits/sec, 1294 packets/sec

     1784913934 packets input, 1423704351 bytes

     Received 663164 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog

     0 input packets with dribble condition detected

     1632564072 packets output, 2742941351 bytes, 0 underruns

     0 output errors, 0 collisions, 4 interface resets

     411055 unknown protocol drops

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier

     0 output buffer failures, 0 output buffers swapped out

Thanks

Shibu

[siddhartham · Accepted solution]

QoS is a a end to end configuration. You can mark the traffic based on ports and allocate bandwidth on your router but if your service provider doesn't follow the same marking (no need to be exact) then all the traffic will be treated as same.

Since you are using a site to site VPN over public internet, you won't get any benifit on marking packets on your router becuase onece the packets leaves your router the next router will strip off the markings and treat all packets as normal traffic.

I think the video conferencing ports differ from vendor to vendor, you should be able to find them in their product documentation.If you are not sure about the ports you can always match by access-list.

[Shibu1978]

Thanks Siddhartham,

Meanwhile is there any other config required other than i pasted for priroitising the Videoconferencing from my side....if i go with a leased line between location avoiding internet vpn does this config work for me.

[siddhartham]

According to your config, everything that matches access-list 199 (all traffic between 2 sites-- in your case)  will be placed in High Queue.This won't prioritize the video traffic since access-list 199 is matching all the traffic between 2 sites and its not a best practice to assing high queue to the video conference traffic because this may lead to traffic starvation, according to cisco only latency sensitive traffic (voice) is supposed to go to High queue. Using CBWFQ over PQ will give you more flexibilty in defining bandwidths for different traffic flows.Below are the link that explains PQ and CBWFQ

http://ardenpackeer.com/tutorials/qos-voip/configuring-priority-queuing/

http://www.cisco.com/en/US/docs/ios/12_0t/12_0t5/feature/guide/cbwfq.html

https://blogs.manageengine.com/netflowanalyzer/2011/07/18/class-based-weighted-fair-queuing-for-better-traffic-management

[Joseph W. Doherty]

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

I am working on Videoconferencing solution between two location.  locations are now being connected through IPSEC site to site VPN.  Since we are having a common internet link for VPN as well other corporate use we have to prioritize the internet bandwidth for Videconferencing. is there any way i can prioritise videoconferencing traffic by ports?  

Can you prioritize by ports?  Sure, however sharing an Internet link and performing QoS is only fully effective if you manage all the bandwidth utilization to/from your Internet ports.  Internet ports dedicated for single p2p VPN, or non-oversubscribed aggregate multiple shaped p2p, often can work as well as p2p leased lines.  However, if, for example, you share this link for "normal" Internet access, you've lost control of bandwidth management (unless your ISP allows you to define a QoS egress policy from them to you).

PS:

On your 2801, with your IOS version, you might find NBAR helpful too.

PPS:

If your Internet bandwidth is not exactly the interface's bandwidth, your PQ won't be fully effective as it will only trigger with interface congestion, when you want it to trigger as you hit your contracted bandwidth.

[Shibu1978]

Thanks both,

We have only 20 MB internet bandwidth at the moment . But the interface speed is 100 MB.

My requirement

============

To have dedicated 3 MB to Videoconferencing at any any point of time. even when the link utilization touches 20 MB the Videoconferencing traffic should get 3 MB.

Is there any way i can achive this? is it possible with router ?

[Joseph W. Doherty]

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

Not 100% certain about whether this NBAR is supported on your router and/or whether it will match your video conferencing, but something like:

Class-map match-any Video

match protocol rtp video

Policy-map Example

class video

priority 3000

class class-default

fair-queue

policy-map shapeExample

class class-default

shape average 20000000 200000

service-policy Example

interface fastethernet0/1

service-policy output shapeExample