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Community Member

Diff between CIR and CAR

I couldnt understand the difference between Committed Information Rate (CIR) and Committed Access Rate (CAR). Both are applied for policing the traffic. Can some one explain me in detail.

Many Thanks,

Saran

3 REPLIES
Community Member

Re: Diff between CIR and CAR

Good Day Saran,

CAR - is an older method to rate-limit traffic on a Cisco device. It is configurable, but it is done seperately from Cisco new modular QoS approach.

http://www.cisco.com/en/US/docs/ios/11_1/feature/guide/CAR.html

CIR - Committed Info Rate is used in traffic shaping and policing using Cisco's newer QoS method.

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800a3a25.shtml

hope this helps.

Community Member

They are the same from

They are the same from protocol's view. The CIR word came from some nephew software engineer of some one. Hired before he/she got CCIE, he/she was allowed to leave a mark in history without innovation. We all have been colleagues of a person like that. It should have been called "CAR on MQC", which does not sound very cool, does it? It should not be called Information Rate. Where is the information? Router1 or Router2 or Server1 or Server2, or all, or both? It is customary to call digital data in transit "data", and called signal when data is modulating carrier wave, not information.

I was being nice to say "without innovation". In reality, it is a total flop. The access rate conveys ideas of hardware limitation with ISP , for example frame-relay clock rate is proportional to access rate. On top of access rate, the adjective "committed" conveys the economical operation done manually by operators.That nephew didn't know it and thought others wouldn't notice the missing noun for the adjective "committed" in CIR. Where is the information rate of your frame-relay for the ISP to commit?

The word CIR needs to be eliminated for cisco to advance innovation.

Community Member

They are the same from

They are the same from protocol's view. The CIR word came from some nephew software engineer of some one. Hired before he/she got CCIE, he/she was allowed to leave a mark in history without innovation. We all have seen colleagues of a person like that while we work as programmers programming everyday. It should have been called "CAR on MQC", which does not sound very cool, does it? It should not be called Information Rate. Where is the information? Router1 or Router2 or Server1 or Server2, or all, or both? It is customary to call digital data in transit "data", and called signal when data is modulating carrier wave, not information.

I was being nice to say "without innovation". In reality, it is a total flop. The access rate conveys ideas of hardware limitation with ISP , for example frame-relay clock rate is proportional to access rate. On top of access rate, the adjective "committed" conveys the operation done manually by operators.That nephew didn't know it and thought others wouldn't notice the missing noun for the adjective "committed" in CIR. Where is the information rate of your frame-relay for the ISP to commit? 

The word CIR needs to be eliminated for cisco to advance innovation.

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