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Implementing Frame Mode MPLS

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This chapter covers configuring Cisco Express Forwarding, verifying CEF, troubleshooting CEF, configuring MPLS on a Frame Mode interface, and configuring MTU size in label switching.
This chapter is from the book

This chapter is from the book

This chapter provides information and commands concerning the following topics:

  • Configuring Cisco Express Forwarding
    • - Verifying CEF
    • - Troubleshooting CEF
  • Configuring MPLS on a Frame Mode interface
  • Configuring MTU size in label switching

Configuring Cisco Express Forwarding

To enable MPLS, you must first enable Cisco Express Forwarding (CEF) switching.

Router(config)#ip cef

Enables standard CEF

Router(config)#ip cef distributed

Enables dCEF

Router(config)#no ip cef

Disables CEF globally

Router(config)#interface fastethernet 0/1

Moves to interface configuration mode

Router(config-if)#ip route-cache cef

Enables CEF on the interface

Verifying CEF

Router#show ip cef

Displays entries in the forwarding information base (FIB)

Router#show ip cef summary

Displays a summary of the FIB

Router#show ip cef unresolved

Displays unresolved FIB entries

Router#show ip cef fastethernet 0/1

Displays the FIB entry for the specified interface

Router#show ip cef fastethernet 0/1 detail

Displays detailed information about the FIB for the interface

Router#show cef drop

Displays packets that are dropped due to adjacencies that are incomplete or nonexistent

Troubleshooting CEF

Router#debug ip cef

Displays debug information for CEF

Router#debug ip cef drop

Displays debug information about dropped packets

Router#debug ip cef access-list x

Displays information from specified access lists

Router#debug ip cef receive

Displays information about packets received by IP CEF

Router#debug ip cef events

Displays general CEF events

Router#debug ip cef prefix-ipc

Displays updates related to IP prefix information

Router#debug ip cef table

Produces a table showing events related to the FIB table

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