QoS LAN and WAN

[JustForVoice_2]

Hi

I have received a complain from one of my customer that they have a quality issue in the VoIP calls between two branches.

I  tried to troubleshoot and I found that there is a jitter. while there  is no QoS applied between the branches, I am going to add QoS as below:

Access switches; Configuration:

mls qos

mls qos map cos-dscp 0 8 16 24 32 46 48 56

Access Switches; IP Phones Ports:

mls qos trust device cisco-phone

mls qos trust cos

Access Switches; Trunk interfaces:

mls qos trust dscp

Core switch:

mls qos trust dscp

Router: (LAN Interface)

mls qos trust dscp

Router: (WAN Interface)

interface fast 0/0

bandwidth 2000

auto qos voip

I am sorry if it is silly but this is the first time I am trying to implement QoS.

[JustForVoice_2]

No one used QoS before

[Tagir Temirgaliyev]

suppose you need policy map on Router: (WAN Interface)

and you need service level agreement with provider

[Chris Deren]

Here is my view on QoS (I use it on all deployments), if you are not comfortable with it you will do more damage than good, In your scenario start out with WAN QoS, you did not specify what WAN connection is in place, is it MPLS, PPP, etc?

If MPLS unless you have contracted for specific real time class with carrier they will not honor your EF markings and in fact drop it.  You need to configure your CE router to match the PE router so this this coordinated effort with the carrier.

If this is PPP, what is the bandwidth between these sites? Typically with links >1.5 Mbps all you need is LLQ configuration.

As to LAN QoS do not use AutoQoS, read Cisco QoS SRND and CUCM SRND for recommadned configuration for your switches, different switches have different queuing mechanisms so there is no one fit all config template. In fact different Line Cards on switches and supervisors will drive different queuing.

HTH,

Chris

[JustForVoice_2]

Hi Chris,

thank you for your reply.

the problem that I have is the following:

Multi-site deployment, all communications between the branches are OK, except one branch where there are too many applications and the speed is 1M, MPLS. The setup in the branch is very simple, it is only one switch and one router.

all what I need is to configure the router to dedicate 100k for VoIP calls.

For Switch I have no issues with QoS configuration. while I have the problem with calls over the WAN all what I need is to trust the marking that I did in the Access switch. To do this I think I need to configure access list to check DSCP values.

Access-list in class-map and the class-map inside policy-map where the policing is configured.

then apply service-policy on the WAN interface.

Please correct me if I am wrong?

[ronpatel]

Hi

Best document we have is QOS SRND. This has sample config also.

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book.html

Regards

Ronak Patel

[JustForVoice_2]

Thank you Ronak,

I am browsing the document, please if you have any notes on what I added now (in response to Chris Deren) please let me know.

+5 for you and Chris.

[JustForVoice_2]

Hi,

after some studying, this is what I think the correct solution:

Access switches:

mls qos

mls qos map cos-dscp 0 8 16 24 32 46 48 56

IP Phones Ports:

mls qos trust device cisco-phone

mls qos trust cos

Trunk interfaces:

mls qos trust dscp

Router:

class-map match-any VoIP-RTP

   match ip dscp ef

class-map match-any VoIP-Control

   match ip dscp cs3

   match ip dscp af31

policy-map VoIP-Policy

   class VoIP-RTP

       priority percent 10 ! It is 1M link and I need to dedicate 100 K

class VoIP-Control

   bandwidth percent 5

class class-default

   fair-queue

interface Gig 0/0

description To Service provider

bandwidth 1000 ! it is 1M link

service-policy output VoIP-Policy

Please if anyone has any suggestion or if I am wrong please correct me.

[Chris Deren]

This should be fine for what you are trying to do.

Chris

[JustForVoice_2]

Thanks Chris,

Just to make sure that you toke care about the following:

priority percent 10

! It is 1M link and I need to dedicate 100 K

bandwidth 1000

! it is 1M link

thanks in advanced

[Chris Deren]

Yes, badwidth statement is in kbps, so 1000 -- > 10 Mb.

You can issue "sh policy-map interface x/x" which will actually show you the bandwidth.

Chris

[JustForVoice_2]

Yes, badwidth statement is in kbps, so 1000 -- > 10 Mb.

                                                           1000 --> 1 M

Am I right?

and regarding the command:

priority percent 10

depending on the bandwidth command under the interface, true??

[Chris Deren]

Correct, this is actually the preferred method.

Chris

[JustForVoice_2]

Thank you too much, I will try the configuration and let you know.

[Tagir Temirgaliyev]

here u need 1 parent policy and 1 child police

like this

policy-map child

class one

  priority 50

  set precedence 3

class two

  priority 156

  set precedence 3

class three

  priority 280

  set precedence 3

class Cl_ICMP

  shape average 10000

class voice

  priority 100

  set precedence 5

class class-default

policy-map parent

class class-default

  shape average 1000000

  service-policy child

and more impotant

is ageement with provider

where provider must give you

for example 10% real time traffic