• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 631
  • Last Modified:


Looking for some help on QoS configuration. Below is how the network is laid out. All Voip phones will be communicating over bonded T1's back to HQ's CUCM server.

Building 1             Building 2                                                          
     |                           |
 2960G              2x2960G(stack)                    
           \             /(connected via fiber etherchannel)
         Central BLDG.
                    |            Bonded T1's back to HQ
                 2811-----------------------------------------2851----cisco 6509--CUCM 7.1

I currently have QoS configured on the 2960's in both bldg's. Do I also need some kind of qos statements on the etherchannel interfaces on the 3560 switch?

Also will I need qos on the gi0/1 interface connecting to the 2811 router?
I believe I will need some qos on the router since this is where the bandwidth comes in. There are only 2 bonded T1's so that limits me to 3mbps.

Will I also need statements on the 2851 router as well as the interface connecting to the 6509?

Any help is appreciated.
2 Solutions
You need them everywhere your voice traffic goes through; if you only do it on the switches, it's pretty much useless as the further you go away the more saturated the network will get (ona verage)
jwil320Author Commented:
Can you give me some examples of qos on the cisco routers?
policy-map VOICE-COS
  class class-default
   set cos dscp  

interface FastEthernet0/X(.X)
service-policy output VOICE-COS    
Nothing ever in the clear!

This technical paper will help you implement VMware’s VM encryption as well as implement Veeam encryption which together will achieve the nothing ever in the clear goal. If a bad guy steals VMs, backups or traffic they get nothing.

remember to enable ip cef for packet marking
jwil320Author Commented:
do I also need to apply this to the serial interfaces? Or on the multilink interface? along with a bandwidth command?

ip cef is enabled.
you can set a bandwidth if you want although basic cos usually does it, and yeah, you probably need to do it on your wan interfaces as well
1) QoS should be configured from LAN to WAN.
Switches ...
mls qos
on all interfaces
int f0/0
mls qos trust cos

WAN ...ie router...........

class-map match-any Vpice
 description Video Conference
 match ip dscp af41  --------------------dscp bit marked video s/w on machine if diffrent change it.
 match ip dscp af42
 match access-group name Video -------also u can use IP access-list to prioritize.

class-map match-any RTP
 description [ VOIP Audio ]
 match protocol rtp audio

interface GigabitEthernet0/2
des **** LAN Interface ****
service-policy input QOS-IN

policy-map QOS-IN
 description [ Re-Classify ]
 class RTP
  set dscp ef
 class VIDEO
  set ip dscp af21


interface GigabitEthernet0/2
des **** WAN Interface ****
service-policy output QOS-OUT

policy-map QOS-OUT
 class REAL-TIME
  priority percent 25
class Application
  bandwidth percent 15
class-map match-any REAL-TIME
 description REAL-TIME Traffic
 match ip dscp ef

class-map match-any VIDEO
 description Video Conference
 match ip dscp af41
 match ip dscp af42
 match ip dscp af43
 match access-group name Video
1. Enable QoS on all LAN switches: "mls qos"
2. Trust COS on all switch-to-switch connections: "mls qos trust cos"
3. Enable outbound queuing on the routed interface facing your provider.
    The percent to allocate for voice will depend on the codec used and amount of simultaneous calls.
    a. If you trusted your phones from the access port, they should already be coming across with the
        correct dscp/cos values up through to the router. That being said, match those dscp values and
        allocate the amount of bandwidth you want to reserve.

class-map VOICE
  match ip dscp ef
  match ip dscp cs3
  match ip dscp af31
policy-map QOS-OUT
  class VOICE
    priority percent X            <---Low latency queue for voice payload
    bandwidth percent X      <---Reserved for voice signaling
  class class-default           <---Everything else
interface Multilink 1
   service-policy output QOS-OUT
You can monitor this policy by issuing the command "show policy-map interface mul1".
This takes care of your outbound queuing, you will want to ensure that your provider is also providing QoS in their network for your inbound traffic.
jwil320Author Commented:
Thanks guys this helped a lot.

Featured Post

Veeam Disaster Recovery in Microsoft Azure

Veeam PN for Microsoft Azure is a FREE solution designed to simplify and automate the setup of a DR site in Microsoft Azure using lightweight software-defined networking. It reduces the complexity of VPN deployments and is designed for businesses of ALL sizes.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now