Summary

The basic IOS configuration commands for each LAN and WAN protocol discussed in this chapter are summarized in Table 3-2 and in the following list. Now that you understand the LAN and WAN technologies that operate on the data link layer of the OSI reference model, we move on to discussing the network layer and configuring the Cisco IOS devices for the Internet Protocol (IP).

• The interface major command is used to identify an interface by name and to begin configuring it. Naming conventions exist for fixed devices, devices with interchangeable interface cards, and devices with VIP cards.

• Adding a description of each interface with the description subcommand is recommended for efficient administration and record keeping. The description appears in the show interfaces output for an interface.

• The shutdown command causes an interface to be administratively down.

• The encapsulation subcommand specifies the format of the data sent and the data-link protocol for an interface. LAN interfaces don't require this configuration usually, but WAN interfaces often do.

Table 3-2. Summary of IOS Configuration Commands for LAN and WAN

Protocol	Relevant Commands	Description/Purpose
Ethernet and Fast Ethernet	media-type {aui, 10baseT, mii, 100basex}	Tells the router which connection is active on the interface: AUI, RJ-45, or MII.
Fast Ethernet and Gigabit Ethernet	full-duplex	Enables full-duplex communication on an interface.
Token Ring	ring-speed {4 16}	Specifies ring speed as 4 Mbps or 16 Mbps.
	early-token-ring	Enables early token release on an interface.
X.25	x25 address x121 address	Defines the local X.121 address on an X.25 serial interface.
	x25 ips; x25 ops	Configures, respectively, the input packet size and output packet size on the serial interface.
	x25 win; x25 wout	Configures, respectively, the input window size and output window size.
Frame Relay	frame-relay interface-dlci	Sets the address DLCI on the interface.
	frame-relay lmi-type	Sets the LMI type on the interface.
ATM	atm pvc	Specifies the permanent virtual circuits that exist on a given interface.
DSL	set bridging	Sets the bridging options on a Cisco600 (CBOS only).
	set interface	Sets interface parameters on a Cisco600 (CBOS only).
ISDN	isdn switch-type	Specifies the type of switch to which the IOS device is connected.
	isdn spid1; isdn spid2	Specifies the SPID numbers for each BRI interface.
	pri- group timeslots	Specifies relevant time slots for the controller interface.
T1	framing	Specifies the framing protocol for channels on the controller interface.
	linecode	Specifies the line-encoding protocol for channels on the controller interface.

Table 3-3. Summary of EXEC Commands for LAN and WAN

Command	Description
show frame pvc	Displays statistics for Frame Relay permanent virtual circuits.
show frame svc maplist :	Displays statistics for Frame Relay switched virtual circuits.
show interfaces	Displays statistics for device interfaces.
show x25 vc	Displays statistics for X.25 virtual circuits.