Cisco 2501 - Router - EN Bedienungsanleitung PDF herunterladen (Seite 56)

234

Chapter 4

Introduction to the Cisco IOS and SDM

Remember, administratively down means that you need to type no shutdown under the

interface. Notice that Serial0/0/0 is up/down, which means that the physical layer is good and

carrier detect is sensed but no keepalives are being received from the remote end. In a nonpro-

duction network, like the one I am working with, the clock rate isn’t set.

Verifying with the show protocols Command

The show protocols command is a really helpful command you’d use in order to quickly see

the status of layers 1 and 2 of each interface as well as the IP addresses used.

Here’s a look at one of my production routers:

Router#sh protocols

Global values:

Internet Protocol routing is enabled

Ethernet0/0 is administratively down, line protocol is down

Serial0/0 is up, line protocol is up

Internet address is 100.30.31.5/24

Serial0/1 is administratively down, line protocol is down

Serial0/2 is up, line protocol is up

Internet address is 100.50.31.2/24

Loopback0 is up, line protocol is up

Internet address is 100.20.31.1/24

Using the show controllers Command

The show controllers command displays information about the physical interface itself.

It’ll also give you the type of serial cable plugged into a serial port. Usually, this will only be

a DTE cable that plugs into a type of data service unit (DSU).

Router#sh controllers serial 0/0

HD unit 0, idb = 0x1229E4, driver structure at 0x127E70

buffer size 1524 HD unit 0, V.35 DTE cable

cpb = 0xE2, eda = 0x4140, cda = 0x4000

Router#sh controllers serial 0/1

HD unit 1, idb = 0x12C174, driver structure at 0x131600

buffer size 1524 HD unit 1, V.35 DCE cable

cpb = 0xE3, eda = 0x2940, cda = 0x2800

Notice that serial 0/0 has a DTE cable, whereas the serial 0/1 connection has a DCE cable.

Serial 0/1 would have to provide clocking with the clock rate command. Serial 0/0 would

get its clocking from the DSU.

Let’s look at this command again. In Figure 4.7, see the DTE/DCE cable between the two

routers? Know that you will not see this in production networks!

47020.book Page 234 Wednesday, January 2, 2008 4:31 PM

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 ... 75 76

Keine Kommentare

Cisco 2501 - Router - EN Bedienungsanleitung Seite 56