What is Marking in QoS ? How to mark packets?

 In this section, we are going to discuss and look at the configuration of marking packets. When we set the TOS (Type of Service) byte with an IP Precedence value or DSCP value this is marking.  In case if you don’t know what is Classification, IP precedence, or DSCPcolor code value click here. I'm assuming you understand Classification.

What is Quality of Service (QOS)?

What is Modular Quality of service CLI (MQC)?

What is Classification and marking? What are IP Precedence and DSCP Values? What is AF and EF?

Let see the configuration:-

Topology:-

Goal:-

• configure the topology as per the diagram. 
• configure IP addresses as per the topology. 
• configure EIGRP AS 65100 and advertise all the directly connected interfaces.
• configure marking on router 1 to mark the packets coming from FastEthernet 0/0 and fwd to router 3 with IP precedence 2 value.
• configure  IP precedence of 3 to ICMP packets on router 2.

R1(config)#interface serial 4/0

R1(config-if)#ip address 12.1.1.1 255.255.255.0

R1(config-if)#no shutdown

R1(config-if)#exit

R1(config)#interface fastEthernet 0/0

R1(config-if)#ip address 192.168.10.1 255.255.255.0

R1(config-if)#no shutdown

R1(config-if)#no keepalive

R1(config-if)#exit

R1(config)#interface loopback 0

R1(config-if)#ip address 1.1.0.1 255.255.255.0

R1(config-if)#interface loopback 1

R1(config-if)#ip address 1.1.1.1 255.255.255.0

R1(config-if)#interface loopback 2

R1(config-if)#ip address 1.1.2.1 255.255.255.0

R1(config-if)#interface loopback 3

R1(config-if)#ip address 1.1.3.1 255.255.255.0

R1(config-if)#exit

R2(config)#interface serial 4/0

R2(config-if)#ip address 12.1.1.2 255.255.255.0

R2(config-if)#no shutdown

R2(config-if)#exit

R2(config)#interface serial 4/1

R2(config-if)#ip address 23.1.1.1 255.255.255.0

R2(config-if)#no shutdown

R2(config-if)#exit

R2(config)#interface fastEthernet 0/0

R2(config-if)#ip address 192.168.20.1 255.255.255.0

R2(config-if)#no shutdown

R2(config-if)#no keepalive

R2(config-if)#exit

R2(config)#interface loopback 0

R2(config-if)#ip address 2.2.0.2 255.255.255.0

R2(config-if)#interface loopback 1

R2(config-if)#ip address 2.2.1.2 255.255.255.0

R2(config-if)#interface loopback 2

R2(config-if)#ip address 2.2.2.2 255.255.255.0

R2(config-if)#interface loopback 3

R2(config-if)#ip address 2.2.3.2 255.255.255.0

R2(config-if)#exit

R3(config)#interface serial 4/1

R3(config-if)#ip address 23.1.1.2 255.255.255.0

R3(config-if)#no shutdown

R3(config-if)#exit

R3(config)#interface fastEthernet 0/0

R3(config-if)#ip address 192.168.30.1 255.255.255.0

R3(config-if)#no keepalive

R3(config-if)#exit

R3(config)#interface loopback 0

R3(config-if)#ip address 3.3.0.3 255.255.255.0

R3(config-if)#interface loopback 1

R3(config-if)#ip address 3.3.1.3 255.255.255.0

R3(config-if)#interface loopback 2

R3(config-if)#ip address 3.3.2.3 255.255.255.0

R3(config-if)#interface loopback 3

R3(config-if)#ip address 3.3.3.3 255.255.255.0

R3(config-if)#exit

R1(config)#router eigrp 65100

R1(config-router)#network 12.1.1.1 0.0.0.0

R1(config-router)#network 1.1.0.1 0.0.0.0

R1(config-router)#network 1.1.1.1 0.0.0.0

R1(config-router)#network 1.1.2.1 0.0.0.0

R1(config-router)#network 1.1.3.1 0.0.0.0

R1(config-router)#network 192.168.10.1 0.0.0.0

R1(config-router)#end

R2(config)#router eigrp 65100

R2(config-router)#network 12.1.1.2 0.0.0.0

R2(config-router)#network 2.2.0.2 0.0.0.0

R2(config-router)#network 2.2.1.2 0.0.0.0

R2(config-router)#network 2.2.2.2 0.0.0.0

R2(config-router)#network 2.2.3.2 0.0.0.0

R2(config-router)#network 192.168.20.1 0.0.0.0

R2(config-router)#network 23.1.1.1 0.0.0.0

R2(config-router)#exit

R3(config)#router eigrp 65100

R3(config-router)#network 23.1.1.2 0.0.0.0

R3(config-router)#network 23.1.1.2 0.0.0.0

R3(config-router)#network 192.168.30.1 0.0.0.0

R3(config-router)#network 3.3.0.3 0.0.0.0

R3(config-router)#network 3.3.1.3 0.0.0.0

R3(config-router)#network 3.3.2.3 0.0.0.0

R3(config-router)#network 3.3.3.3 0.0.0.0

R3(config-router)#exit

*Oct 14 17:14:20.351: %DUAL-5-NBRCHANGE: EIGRP-IPv4 65100: Neighbor 23.1.1.1 (Serial4/1) is up: new adjacency

R1(config)#access-list 111 permit IP host 192.168.10.1 host 192.168.30.1

R1(config)#class-map TEST

R1(config-cmap)#match access-group 111

R1(config-cmap)#exit

R1(config)#policy-map TEST-POLICY

R1(config-pmap)#class TEST

R1(config-pmap-c)#set ip precedence 3

R1(config-pmap-c)#end

R1(config)#interface serial 4/0

R1(config-if)#service-policy output TEST-POLICY

R1(config-if)#END

*Oct 14 17:19:48.795: %SYS-5-CONFIG_I: Configured from console by console

R1#ping 192.168.30.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.30.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 44/52/72 ms

R1#show policy-map interface serial 4/0

 Serial4/0

  Service-policy output: TEST-POLICY

    Class-map: TEST (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0000 bps, drop rate 0000 bps

      Match: access-group 111

      QoS Set

        precedence 3

          Packets marked 0

    Class-map: class-default (match-any)

      262 packets, 17710 bytes

      5 minute offered rate 0000 bps, drop rate 0000 bps

      Match: any

R1#show run class-map

Building configuration...

Current configuration: 57 bytes

!

class-map match-all TEST

 match access-group 111

end

R2(config)#class-map ICMP-TRAFFIC

R2(config-cmap)#match protocol icmp

R2(config-cmap)#exit

R2(config)#policy-map QoS

R2(config-pmap)#class ICMP-TRAFFIC

R2(config-pmap-c)#set ip precedence 2

R2(config-pmap-c)#exit

R2(config-pmap)#exit

R2(config)#interface serial 4/1

R2(config-if)#service-policy output QoS

R2(config-if)#EXIT

R2(config)#exit

R2#show policy-map interface serial 4/1

 Serial4/1

  Service-policy output: QoS

    Class-map: ICMP-TRAFFIC (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0000 bps, drop rate 0000 bps

      Match: protocol icmp

      QoS Set

        precedence 2

          Packets marked 0

    Class-map: class-default (match-any)

      11 packets, 857 bytes

      5 minute offered rate 0000 bps, drop rate 0000 bps

      Match: any

R2#show run class-map

Building configuration...

Current configuration: 62 bytes

!

class-map match-all ICMP-TRAFFIC

 match protocol icmp

end

R2#ping 192.168.30.1 source 192.168.20.1 repeat 123456789

Type escape sequence to abort.

Sending 123456789, 100-byte ICMP Echos to 192.168.30.1, timeout is 2 seconds:

Packet sent with a source address of 192.168.20.1

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 

{ quit }

Success rate is 99 percent (11951/11952), round-trip min/avg/max = 1/13/64 ms

R2#show run class-map

Building configuration...

Current configuration: 62 bytes

!

class-map match-all ICMP-TRAFFIC

 match protocol icmp

end

R2#show policy-map interface serial 4/1

 Serial4/1

  Service-policy output: QoS

    Class-map: ICMP-TRAFFIC (match-all)

      11952 packets, 1243008 bytes

      5 minute offered rate 29000 bps, drop rate 0000 bps

      Match: protocol icmp

      QoS Set

        precedence 2

          Packets marked 11952

    Class-map: class-default (match-any)

      259 packets, 17278 bytes

      5 minute offered rate 0000 bps, drop rate 0000 bps

      Match: any

R1#traceroute 192.168.30.1 source 192.168.10.1

Type escape sequence to abort.

Tracing the route to 192.168.30.1

VRF info: (vrf in name/id, vrf out name/id)

  1 12.1.1.2 52 msec 44 msec 48 msec

  2 23.1.1.2 92 msec 48 msec 44 msec