[c-nsp] QoS for VoIP basics
Adam Greene
maillist at webjogger.net
Fri Dec 1 11:40:55 EST 2006
Thanks to those who replied to my questions.
Setting the link to full duplex corrected the issue.
However, now voice quality is great no matter whether I enable or disable
qos on the switches.
That's more a limitation of my test environment, though, than the qos
itself, I think.
What I *really* need is
- a good TCP / UDP traffic generator (right now I'm using TCPLoad which
is so ancient I don't even know who made it). I'm considering MGEN
(http://cs.itd.nrl.navy.mil/products/) but that's UDP only.
- a better way to test VoIP quality. I'm simply subjectively gauging call
quality by talking through (2) SIP phones which establish peer-to-peer
communications after initial call setup via a SIP server. Some free software
that provides MOS ratings based on latency, jitter, etc and allows
simulation of multiple calls would be ideal. Perhaps I'm dreaming that there
could be a free software available for this.
Adam
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Adam Greene
> Sent: Tuesday, November 28, 2006 3:17 PM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] QoS for VoIP basics
>
> Hi,
>
> I am trying to master basic QoS concepts in a test lab before deploying
> general policies for our network:
>
>
>
> 3750 |both connections 10/half
> | | |
> vlan700| |vlan710 |
> | | |
> 2950
> || ||
> || || |all connections 100/full
> PC A--- | | --PC B |
> | | |
> VoIP A-- --VoIP B |
>
>
> My aim is to make the VoIP traffic crystal clear no matter how much
> traffic I push between the two PC's.
>
> Here are my configs:
>
> ====
> 2950
> ====
>
> wrr-queue bandwidth 100 1 1 0
> wrr-queue cos-map 1 0 1 2 3 4 6 7
> wrr-queue cos-map 4 5
> !
> class-map match-all VoIP
> match access-group 100
> !
> !
> policy-map All_Phone_Traffic_46
> class VoIP
> set ip dscp 46
> !
> access-list 100 permit ip any any
>
> PLUS the ports into which VoIP A and B plug are configured with
> "service-policy input All_Phone_Traffic_46"
>
>
>
> ====
> 3750
> ====
>
> (note that the following was generated via the "auto qos voip trust"
> interface command)
>
> mls qos map cos-dscp 0 8 16 26 32 46 48 56 mls qos srr-queue input
> bandwidth 90 10 mls qos srr-queue input threshold 1 8 16 mls qos
> srr-queue input threshold 2 34 66 mls qos srr-queue input buffers 67 33
> mls qos srr-queue input cos-map queue 1 threshold 2 1 mls qos srr-queue
> input cos-map queue 1 threshold 3 0 mls qos srr-queue input cos-map
> queue 2 threshold 1 2 mls qos srr-queue input cos-map queue 2 threshold
> 2 4 6 7 mls qos srr-queue input cos-map queue 2 threshold 3 3 5 mls
> qos srr-queue input dscp-map queue 1 threshold 2 9 10 11 12 13 14
> 15
> mls qos srr-queue input dscp-map queue 1 threshold 3 0 1 2 3 4 5 6 7
> mls qos srr-queue input dscp-map queue 1 threshold 3 32 mls qos
> srr-queue input dscp-map queue 2 threshold 1 16 17 18 19 20 21
> 22 23
> mls qos srr-queue input dscp-map queue 2 threshold 2 33 34 35 36 37 38
> 39 48
> mls qos srr-queue input dscp-map queue 2 threshold 2 49 50 51 52 53 54
> 55 56
> mls qos srr-queue input dscp-map queue 2 threshold 2 57 58 59 60 61 62
> 63
> mls qos srr-queue input dscp-map queue 2 threshold 3 24 25 26 27 28 29
> 30 31 mls qos srr-queue input dscp-map queue 2 threshold 3 40 41 42 43
> 44 45
> 46 47
> mls qos srr-queue output cos-map queue 1 threshold 3 5 mls qos
> srr-queue output cos-map queue 2 threshold 3 3 6 7 mls qos srr-queue
> output cos-map queue 3 threshold 3 2 4 mls qos srr-queue output cos-map
> queue 4 threshold 2 1 mls qos srr-queue output cos-map queue 4
> threshold 3 0 mls qos srr-queue output dscp-map queue 1 threshold 3 40
> 41 42 43 44 45
> 46 47
> mls qos srr-queue output dscp-map queue 2 threshold 3 24 25 26 27 28 29
> 30 31 mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51
> 52 53
> 54 55
> mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61
> 62 63
> mls qos srr-queue output dscp-map queue 3 threshold 3 16 17 18 19 20 21
> 22 23
> mls qos srr-queue output dscp-map queue 3 threshold 3 32 33 34 35 36 37
> 38 39
> mls qos srr-queue output dscp-map queue 4 threshold 1 8 mls qos
> srr-queue output dscp-map queue 4 threshold 2 9 10 11 12 13 14
> 15
> mls qos srr-queue output dscp-map queue 4 threshold 3 0 1 2 3 4 5 6 7
> mls qos queue-set output 1 threshold 1 138 138 92 138 mls qos queue-set
> output 1 threshold 2 138 138 92 400 mls qos queue-set output 1 threshold
> 3 36 77 100 318 mls qos queue-set output 1 threshold 4 20 50 67 400 mls
> qos queue-set output 2 threshold 1 149 149 100 149 mls qos queue-set
> output 2 threshold 2 118 118 100 235 mls qos queue-set output 2
> threshold 3 41 68 100 272 mls qos queue-set output 2 threshold 4 42 72
> 100 242 mls qos queue-set output 1 buffers 10 10 26 54 mls qos queue-set
> output 2 buffers 16 6 17 61 mls qos
>
> PLUS the two ports which connect to the 2950 are configured with:
>
> srr-queue bandwidth share 10 10 60 20
> srr-queue bandwidth shape 10 0 0 0
> mls qos trust dscp <-- (this was autoconfigured as trust cos, but I
> changed it to dscp) auto qos voip trust
>
>
>
> Unfortunately, when I pump 10Mbps (100 TCP streams) between PC A and B,
> the voice still chops up.
>
> Any hints? Maybe I'm missing something obvious.
>
> Thanks,
> Adam
> _______________________________________________
> cisco-nsp mailing list cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
> _______________________________________________
> cisco-nsp mailing list cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
> _______________________________________________
> cisco-nsp mailing list cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
>
>
>
>
More information about the cisco-nsp
mailing list