Traffic Engineering with MPLS

　　 
　　Modular QoS CLI 有以下三种形式：
　　Class map—How you define what traffic you're interested in
　　
　　Policy map—What you do to the traffic defined in a class map
　　

　　Service policy—How you enable a policy map on an interface
　　
　　定义Class Map
　　The first step in using MQC is to build a class map. Not surprisingly, you do this with the class-map command:
　　
　　
　　vxr12(config)#class-map ?
　　WORD class-map name
　　match-all Logical-AND all matching statements under this classmap
　　match-any Logical-OR all matching statements under this classmapm
　　
　　The match-all and match-any keywords let you specify whether traffic matches this class, if it matches all the rules in this class or any of them, respectively. The default is match-all.
　　
　　You create a class by giving it a name. This puts you in a submode called config-cmap:
　　
　　vxr12(config)#class-map voice
　　vxr12(config-cmap)#?
　　QoS class-map configuration commands:
　　description Class-Map description
　　exit Exit from QoS class-map configuration mode
　　match classification criteria
　　no Negate or set default values of a command
　　rename Rename this class-mapm
　　
　　The most useful option under config-cmap is match, which lets you define the traffic you want to match with this class map. Its options are as follows:
　　
　　
　　vxr12(config-cmap)#match ?
　　aclearcase/" target="_blank" >ccess-group Access group
　　any Any packets
　　class-map Class map
　　cos IEEE 802.1Q/ISL class of service/user priority values
　　destination-address Destination address
　　fr-de Match on Frame-relay DE bit
　　input-interface Select an input interface to match
　　ip IP specific values
　　mpls Multi Protocol Label Switching specific values
　　not Negate this match result
　　protocol Protocol
　　qos-group Qos-group
　　source-address Source addressm
　　
　　
　　举例
　　class-map match-all voice
　　match mpls experimental 5
　　policy-map llq
　　class voice
　　priority percent 30
　　
　　This defines a class that matches any MPLS traffic that has the EXP bits set to 5 and then defines a policy for that traffic that gives the traffic 30 percent of a link's bandwidth. The policy map hasn't been enabled on an interface yet; you'll see that in a minute.
　　
　　You can match multiple values with the same line using the following command sequence:
　　
　　class-map match-any bronze-service
　　match mpls experimental 0 1
　　
　　This matches any packets that have an MPLS EXP of 0 or 1. As with route maps, multiple values specified within the same match clause (such as match mpls experimental 0 1) are implicitly ORed together; a packet can't have both EXP 0 and EXP 1, so this implicit ORing makes sense.
　　
　　You can also match more than one criteria within a class, and you can use the match-any and match-all statements to decide how you want to match traffic. For example, the following policy matches traffic that has MPLS EXP 5 or traffic that entered the router on interface POS3/0:
　　
　　class-map match-any gold
　　match mpls experimental 5
　　match input-interface POS3/0
　　The following policy matches any traffic that has MPLS EXP 5 and that came in on interface POS3/0:
　　
　　class-map match-all gold
　　match mpls experimental 5
　　match input-interface POS3/0
　　
　　vxr12#show class-map
　　Class Map match-all gold (id 2)
　　Match mpls experimental 5
　　Match input-interface POS3/0
　　
　　Class Map match-any class-default (id 0)
　　Match any
　　
　　Class Map match-all voice (id 3)
　　Match mpls experimental 5
　　Policy Map
　　After you define the class maps you want to match, you need to associate the class of traffic with a behavior. You create the behavior with the policy-map command, which, like class-map, puts you in a special submode:
　　
　　vxr12(config)#policy-map ?
　　WORD policy-map name
　　
　　vxr12(config)#policy-map llq
　　vxr12(config-pmap)#?
　　QoS policy-map configuration commands:
　　class policy criteria
　　description Policy-Map description
　　exit Exit from QoS policy-map configuration mode
　　no Negate or set default values of a command
　　rename Rename this policy-map
　　Under the config-pmap submode, you specify the class you want to match. This puts you in the config-pmap-c submode:
　　
　　vxr12(config)#policy-map llq
　　vxr12(config-pmap)#class voice
　　vxr12(config-pmap-c)#?
　　QoS policy-map class configuration commands:
　　bandwidth Bandwidth
　　exit Exit from QoS class action configuration mode
　　no Negate or set default values of a command
　　police Police
　　priority Strict Scheduling Priority for this Class
　　queue-limit Queue Max Threshold for Tail Drop
　　random-detect Enable Random Early Detection as drop policy
　　service-policy Configure QoS Service Policy
　　set Set QoS values
　　shape Traffic Shaping
　　
　　class-map match-any voice
　　match mpls experimental 5
　　policy-map llq
　　class voice
　　priority percent 30
　　
　　class-map match-all business
　　match mpls experimental 3 4
　　class-map match-all voice
　　match mpls experimental 5
　　policy-map business-and-voice
　　class voice
　　priority percent 30
　　class business
　　bandwidth percent 60
　　class class-default
　　bandwidth percent 10
　　
　　Service Policy
　　vxr12(config-if)#service-policy ?
　　history Keep history of QoS metrics
　　input Assign policy-map to the input of an interface
　　output Assign policy-map to the output of an interface
　　
　　vxr12(config-if)#service-policy out
　　vxr12(config-if)#service-policy output ?
　　WORD policy-map name
　　
　　vxr12(config-if)#service-policy output llq
　　##############################
　　vxr12#show policy-map interface pos3/0
　　POS3/0
　　
　　Service-policy output: llq
　　
　　Class-map: voice (match-all)
　　0 packets, 0 bytes
　　5 minute offered rate 0 bps, drop rate 0 bps
　　Match: mpls experimental 5
　　Weighted Fair Queuing
　　Strict Priority
　　Output Queue: Conversation 264
　　Bandwidth 30 (%)
　　Bandwidth 46500 (kbps) Burst 1162500 (Bytes)
　　(pkts matched/bytes matched) 0/0
　　(total drops/bytes drops) 0/0
　　
　　Class-map: class-default (match-any)
　　21 packets, 15744 bytes
　　5 minute offered rate 3000 bps, drop rate 0 bps
　　Match: any

原文转自：http://www.ltesting.net