User guide

Internetworking Primer A-13

LANs and WANs

Conﬁguring Token Ring

The only option you must conﬁgure Token Ring interfaces is the ring speed. The following

example shows the commands you typically enter to conﬁgure the ring speed on a Token

Ring network:

Router(config)# interface tokenring 0

Router(config-if)# ring-speed 16

Other useful commands are:

• show interface—an EXEC command that displays information about interfaces

attached to the access server.

• [no] shutdown—a conﬁg-interface subcommand, that enables or disables operation of

the conﬁgured interface.

Timesaver You may also need to enter the command multiring if the Token Ring

interface on the access server is sending routed packets (such as IP, IPX, or AppleTalk) to

a source-route bridged environment. The command multiring tells the access server or

router to try to ﬁnd devices on the other side of source-route bridges.

LAN Addressing

The data link layer deﬁnes an addressing scheme that is used by all LAN devices. A

device’s address is generally burned into the chips on the network interface components

that connect the device to the LAN. These addresses are 48-bits in length, which is

represented by a hexadecimal string (for example, 0000.0C0A.3E2E).

The IEEE provides each manufacturer of network interface cards with a block of addresses,

and the manufacturers program the cards they make with these unique addresses. These

addresses are called Media Access Control (MAC) addresses, since MAC is a sublayer

within Layer 2 of the OSI reference model.

Cisco products use addresses from the pool 0000.0Cxx.xxxx for all devices and all

interfaces. Enter the EXEC command show interface to see the Layer 2 address:

Router# show interface

Ethernet0 is up, line protocol is up

Hardware is Lance, address is 0000.0c14.2622 (bia 0000.0c14.2622)