CCNA – Frame Relay 2
Note: If you are not sure about Frame Relay, please read our Frame Relay Tutorial.
An example of the output of this command is shown below:
From the output we can see the local DLCI (102 & 103) and the status of the PVC configured on the router (both are defined, active).
To configure subinterface for Frame Relay, first we have to remove the IP address from the physical interface and choose a Frame Relay encapsulation. An example of configuring Frame Relay on a subinterface is shown below:
interface Serial0/1.12 point-to-point
ip address 10.1.1.2 255.255.255.252
frame-relay interface-dlci 304
Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with your Cisco router when typing the command Router(config-if)#encapsulation frame-relay ? on a WAN link. Below is the output of this command (notice Cisco is the default encapsulation so it is not listed here, just press Enter to use it).
Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively.
HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.