what is diff between Route-map,policy-map & Class-map

Tompeshwar Lal · ‎05-17-2010

Dear Sir,

Can anybody tell me

what is diff between Route-map,policy-map & Class-map.

Thanks in Adv.

Tompeshwar Sahu

Calin C. · ‎05-17-2010

Without going into complex technical details:

class-map, is used to classify packets based on like ACL, ToS, protocol and on; this will be used in the policy-map

policy-map, uses class-map to apply different QoS policies to different groups of traffic

Both commands below are used for QoS and more specifically for MQS

For more technical explanation: http://www.cisco.com/en/US/docs/ios/12_2/qos/configuration/guide/qcfmdcli.html

route-map, as the command name implies, it's used mainly for routing purposes like PBR, fine tuning in IP Routing protocols (BGP, OSPF...) and so on; a route-map is classifying traffic based on Prefix-list and ACL matching traffic at L3 AND L4 in OSI layer stack.

For more technical explanation: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008047915d.shtml

I hope this helps. If not let us know.

taboeric · ‎07-30-2015

Something would like your advice.:

I have a router with 3 interface. On interface A (traffic in), I created a class-map using NBAR commands to match-any protocol ms-update, the policy-map to set dscp to 1 and applied to an interface. On the same interface, I have another policy-map to match an ACL with ip any any permit dscp 1 & deny any any, and set to next hops to interface B. There is a lowest cost route on interface C that all traffic is default to route (traffic out).

When I show the policy-map of the interface A, the ms-update service has been set to dscp 1 however the other policy-map is not able to set the next hop and all traffic continues to route to interface C.

How can I fix the issue? It is ideal to have 1 policy map doing QoS and policy route..

Thanks

Ganesh Hariharan · ‎05-17-2010

Dear Sir,

Can anybody tell me

what is diff between Route-map,policy-map & Class-map.

Thanks in Adv.

Tompeshwar Sahu

Hi Tompeshwar Sahu,

Route maps are similar to access lists, and are used when the route that a packet takes needs to be altered. When a route map is applied to an interface, packets on that interface are tested against conditions that are configured using match commands. If the conditions are met, an action can be taken. Actions are defined using set commands and can be used modify the packet or routes (this is the major difference between access lists and route maps).

Class map defines a traffic classification: network traffic that is of interest to you.

A policy map defines a series of actions (functions) that you want applied to a set ofclassified inbound traffic.

Hope to help !!

Ganesh.H

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