From: brett spunt (bspunt_2000@yahoo.com)
Date: Thu Jun 26 2008 - 00:33:30 ART
Hi Muhammad,
There are a number of potential issues at hand here..
If you can not use DSCP/COS in the network, still see the following for issues I see in the config
1. Remove the following:
ppp multilink fragment delay 1 (normally should be 10ms)
ppp multilink interleave (not needed for links over 768kb)
2. identify voice payload using L4 information and put only this traffic into LLQ
3. create a CBWFQ for signaling traffic using L4 information. Give it 64kb and you'll be fine
4. remove the traffic shaping from the default queue. If you want to do class based shaping, you want to setup a "nested qos policy"...
see the following config snippet..
class-map match-any Voice-QoS
match ip dscp ef
match ip rtp 16384 16383
class-map match-any Mark-Voice-Signaling
match ip dscp af31
match ip dscp cs3
!
policy-map Voice-QoS
class Voice-QoS
priority 4096
class VOICE-Signal
bandwidth 32
class class-default
fair-queue
random-detect dscp-based
!
policy-map Shape_Nested_QOS
description traffic shaping and QOS WAN policy
class class-default
shape average 10000000
service-policy Voice-QoS
!
interface gig0/1.25
service-policy output Shape_Nested_QOS
___________________________________
Brett Michael Spunt, CCIE No. 12745
Senior Consultant
Convergence Practice, AT&T Consulting
http://www.att.com/consulting
Bs3757@att.com
Your world. Delivered.
--- On Tue, 6/24/08, Muhammad Ahmed <faisal3541@hotmail.com> wrote:
> From: Muhammad Ahmed <faisal3541@hotmail.com>
> Subject: RE: OT - VoIP QoS over PPP Multilink - VoIP quality issues
> To: ccielab@groupstudy.com
> Date: Tuesday, June 24, 2008, 7:50 PM
> resending the configuration with line breaks. do not know
> what happened
> there.
>
> class-map match-any GOLD
> match access-group 105
> policy-map MEX_Priority
> class GOLD
> priority 1544
> class class-default
> fair-queue
> random-detect
> shape average percent 93 10 ms
> interface Multilink1
> ip address 10.63.0.1 255.255.0.0
> ip flow ingress
> ip flow egress
> load-interval 30
> ppp multilink
> ppp multilink interleave
> ppp multilink group 1
> ppp multilink fragment delay 1
> ppp timeout multilink lost-fragment 0 200
> service-policy output MEX_Priority
>
>
>
>
> > From: faisal3541@hotmail.com> To:
> ccielab@groupstudy.com> Subject: OT - VoIP
> QoS over PPP Multilink - VoIP quality issues> Date: Tue,
> 24 Jun 2008 21:44:24
> -0500> > Hello guys,> > Sorry for the OT. I
> need some advise on a VoIP quality
> issue over PPP> Multilink bundle. If a question sounds
> stupid, its probably
> because it is> stupid. I do not know much about QoS and
> practically do not
> know anything> about VoIP.> > I have configured
> the following on the PPP
> Multilink bundle and I just want> the to ensure there is
> no other
> configuration required to optimize VoIP> packets over
> the bundle.> > I am
> using 3 T1's to form the bundle and PPP Multilink
> Multiclass is> configured on
> the serial interfaces to sequence non-fragmented VoIP
> packets as> well. One
> way delay variation between the fastest and the slowest T1
> is ~8ms,> which
> quite frankly I do not know if 8ms is within the jitter
> tolerance level> for
> VoIP. End-to-end, one-way, latency between the phones is
> about 12ms> through
> the fastest T1 and 22ms through the slowest T1. Access-list
> 105 is> matching
> the IP addresses of the VoIP phones which have static IP
> addresses.> It
> matches any packet destined to VoIP phones at the remote
> site. I am hoping>
> matching VoIP phone IP addresses would match any and all
> VoIP packets that>
> should be treated through the QoS policy. Please confirm if
> this would not>
> match all packets. I know I should probably tag VoIP
> packets with DSCP or>
> Precedence at the VoIP phone boundary switch but I do not
> manage these>
> switches and I cannot convince the switch administrator to
> implement the>
> correct configuration fast enough. fragment delay of 1 ms
> results in a>
> fragment size of 184 bytes which I am assuming would be
> large enough to frame>
> the largest VoIP packet, please confirm. Multilink bundle
> is congested with>
> data traffic. I do know there are packet drops, for both
> PPP multiclass Class>
> 0 and 1, which are probably causing the entire VoIP quality
> issue but since>
> this is my first deployment of QoS I am not confident and
> do not feel like I>
> have the command on it to definitively say that my
> configuration is correct>
> for QoS so I can start looking at resolving the drop packet
> issue with>
> whichever T1 is at fault. The total VoIP payload through
> the bundle is>
> ~800kbytes during peak usage. I configured 1.544Mbps for no
> apparent reason>
> other than to avoid built in policing on the priority
> policy.> > Best Regards
> and thanks for reading my misery. :)> Muhammad> >
> BTW, the QoS policy has been
> removed for testing the T1's for faults so I> would
> not be able to provide any
> "show" command outputs.> > class-map
> match-any GOLD match access-group 105>
> policy-map MEX_Priority class GOLD priority 1544 class
> class-default>
> fair-queue random-detect shape average percent 93 10 ms>
> interface Multilink1
> ip address a.b.c.d 255.255.0.0 ip flow ingress ip flow>
> egress load-interval
> 30 ppp multilink ppp multilink interleave ppp multilink>
> group 1 ppp multilink
> fragment delay 1 ppp timeout multilink lost-fragment 0>
> 200 service-policy
> output MEX_Priority> > > >
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