Sunday, January 31, 2010

Shaping and Policing Traffic

Sorry I have been quiet lately.  Been reading alot in the Exam Guide, and hitting some labs up.  I recently downloaded the INE V1 Free Chapter, which was actually QoS stuff, and worked through it.  I grabbed some pretty good info, inluding how to configure sla monitors as jitters to generate voice traffic on a network.  Heres the config for that:

[on the router you want to generate traffic]
ip sla monitor 1
 type jitter dest-ipaddr dest-port 16384 codec g729a
 freq 1
timeout 1000
ip sla monitor schedule 1 life forever start-time now

[on the router you want to send packets back]
rtr responder, OR ip sla monitor responder

You can of course change the port numbers, ip address, and codec used.  It works pretty darn good if you want to make sure your classes and or policies are doing what they are suppose to.

I was also going through the Lab Portfolio for the exam and found a couple of different ways to police and shape traffic.  You can actually do it in your policy-maps, or at the interface level which is the legacy configuration method.  The policy-maps just allow you a bit more granularity, and flexibility as you can apply them to multiple interfaces.  Here are the configs:

Traffic Shaping 

[GTS (Generic Traffic Shaping)]
interface multilink 1
traffic-shape rate

 class class-default
  shape average [bps]
interface multilink 1
 service-policy output DEFAULT_SHAPING

Rate-Limiting (aka policing)

[CAR (committed access rate policing)]
interface multilink 1
rate-limit output 56000 1500 4000 conform-action continue exceed-action drop

 class class-default
  police rate 56000 conform-action transmit exceed-action drop
interface multilink 1
 service-policy output DEFAULT_POLICING

Now you can do other things that transmitting or dropping the packets like marking, or re-marking them.  I just wanted to show you all a basic example of how this could be done within a policy-map, or at the interface level.  Good to know more than one way to do things when troubleshooting a problem, or attempting the CCIE lab :)

Good link:

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