MPLS Bytes Label Switched in the LFIB

In an MPLS implementation, when viewing the output of the show mpls forwarding-table command, there is a column headed as Bytes Label Switched, as seen in the example below:

Device# show mpls forwarding-table
Local Outgoing      Prefix            Bytes label Outgoing       Next Hop       
Label Label or VC   or Tunnel Id      switched  interface                     
16    Aggregate     IPv6              0             
17    Aggregate     IPv6              0                 
18    Aggregate     IPv6              0                 
19    Pop Label     192.168.99.64/30  0         Se0/0         point2point    
20    Pop Label     192.168.99.70/32  0         Se0/0         point2point      
21    Pop Label     192.168.99.200/32 0         Se0/0         point2point    
22    Aggregate     IPv6              5424    
23    Aggregate     IPv6              3576 
24    Aggregate     IPv6              2600

This value shows the number of bytes switched with this incoming label. The total value includes the size of the outgoing label and the Layer 2 header as well.

If you see values of 0, this means that this particular label is not being used to switch traffic. Note however that traffic will increase this counter only if the traffic is entering the route labeled. If the traffic is entering on the head end of the LSP, that is, from the customer, and it is plain IP traffic, then CEF switches it, and this value will remain zero.

Links

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-9/command_reference/b_169_9400_cr/mpls_commands.html#id_136254