QoS configuration on router

[Difan Zhao]

Hello guys,

I'm practicing for my CCIE lab. I'm trying to configure a very simple policy map to classify traffics and allocate bandwidth. I have tried it on a GNS3 virtual router 3725 as well as a real-world router 1841. However the "max-reserved-bandwidth" doesn't seem to do anything on the 1841 router with the

15.0(1)M3 IOS. I manually set the bandwidth on the Fa0/0 to be 1000kbps. The "max-reserved-bandwidth" is left to be the default which is 75%. I got the error when I apply the policy-map (allocated 751kbps) to the interface on the 3725 but not on the 1841.

!

class-map match-all data

match ip dscp af31  af32  af33

class-map match-all video

match ip dscp af41

class-map match-all voice

match ip dscp ef

!

policy-map qos

class voice

  bandwidth 200

class video

  bandwidth 300

class data

  bandwidth 200

class class-default

  bandwidth 51

!

On the 3725:

(config-if)#service-policy output qos

I/f FastEthernet0/0 class class-default requested bandwidth 51 (kbps), available only 50 (kbps)

On the 1841 I don't have the error. I will get the error when I allocate more than the interface bandwidth. In the config I allocated 301kbps to the "class-default" class.

(config-if)# service-policy output qos

Insufficient bandwidth 1000 kbps for the bandwidth guarantee (301)

I'm wondering if anything has changed on the newer IOS. Please recommend me an IOS for my 1841 router since I still prefer to do some real-world lab on it...

thanks,

Difan

[andrew.prince]

You should really just use the iOS ver that is in the lab. I believe it is 12.4 advanced ip services.

[Difan Zhao]

Hi Andrew,

Thanks for the advice. I just found the device list for the CCIE R&S on the Cisco learning network website. They do use 1841. The software is 12.4T. It didn't specify the detailed release though. I will pick a newest "MD" one and try it out.

I still want to know why the 15.0 doesn't work the same as the 12.4. Is Cisco changing the way they do QoS again on the new releases?

Thanks!

Difan

[andrew.prince]

Well to be honest when you jump from 12.4 to 15 and you change the licensing model, my thoughts are - cisco are not going to bundle all features into the iOS anymore without a license.