|
WAN connections may take any number of forms. A WAN makes data
connections across a broad geographic area using many different types
of technology. These WAN services are usually leased from service
providers. Among these WAN connection types are leased line,
circuit-switched, and packet-switched.
 For each
type of WAN service, the customer premises equipment (CPE), often a
router, is the data terminal equipment (DTE). This is connected to the
service provider using a data circuit-terminating equipment (DCE)
device, commonly a modem or channel service unit/data service unit (CSU/DSU).
This device is used to convert the data from the DTE into a form
acceptable to the WAN service provider.
Perhaps the most commonly used router interfaces for WAN services
are serial interfaces. Selecting the proper serial cable is as easy as
knowing the answers to four questions:
- What is the type of connection to the Cisco device? Cisco
routers may use different connectors for the serial interfaces.
 The
interface on the left is a Smart Serial interface. The interface on
the right is a DB-60 connection. This
makes the selection of the serial cable connecting the network
system to the serial devices a critical part in setting up a WAN.
- Is the network system being connected to a DTE or DCE device?
DTE and DCE are the two types of serial interfaces that devices use
to communicate. The key difference between these two is that the DCE
device provides the clock signal for the communications on the bus.
The device documentation should specify whether it is DTE or DCE.
- What signaling standard does the device require?
 For each
different device, a different serial standard could be used. Each
standard defines the signals on the cable and specifies the
connector at the end of the cable. Device documentation should
always be consulted for the signaling standard.
- Is a male or female connector required on the cable?
 If the
connector has visible projecting pins, it is male. If the connector
has sockets for projecting pins, it is female.
| |
Lab Activity
Lab Exercise: Connecting WAN Interfaces
This lab is to identify the serial
interfaces on the router and identify and locate the proper
cables to interconnect the routers.
|
|
|
| |
Interactive Media Activity
Drag and Drop: Connecting WAN Interfaces
When the student has completed this activity, the student
will be able to identify the correct components and order for
connecting two routers connected via WAN serial interfaces.
|
|
|
|
Web Links