By default, whenever any QoS marked traffic is sent into an SP environment, it is maintained from the source device until it hits the destination device.

We'll Telnet from IOS17 to IOS18 and look at wireshark outputs from CSR1 towards CSR3 and then CSR5 out to IOS18.


IOS17#telnet 10.101.18.18 /source-interface loopback 101
​IOS18>en
% No password set

The above output shows the MPLS header with EXP 6.

Here we see that the CS6 IPv4 packet header is visible.


IOS18# show ip access-lists 
Extended IP access list QOS
    10 permit ip any any dscp cs1
    20 permit ip any any dscp cs2
    30 permit ip any any dscp cs3
    40 permit ip any any dscp cs4
    50 permit ip any any dscp cs5
    60 permit ip any any dscp cs6 (250 matches)
    70 permit ip any any dscp cs7
    80 permit ip any any
Extended IP access list QoS_MARKINGS
    10 permit tcp any eq telnet any
    15 permit tcp any any eq telnet (26 matches)
    20 permit ip any any (77 matches)

​
IOS18#show policy-map control-plane input 
 Control Plane 

  Service-policy input: PM_COPP

    Class-map: CM_COPP (match-any)  
      250 packets, 17469 bytes
      5 minute offered rate 0000 bps
      Match: access-group name QOS
        250 packets, 17469 bytes
        5 minute rate 0 bps

    Class-map: class-default (match-any)  
      213 packets, 24513 bytes
      5 minute offered rate 0000 bps, drop rate 0000 bps
      Match: any