Configuring serial interfaces

- Next I'm going to demonstrate how to configure…the serial interface on the West router…for connectivity over to the North router.…Serial interfaces are used for synchronous data…connections to your wide area network,…which normally is a service provider, or an ISP.…In our sample topology,…you can see that the serial interface…down there on the West router,…is connected to the North router,…using a lightning bolt, it's a red cable,…and that's called a DTE/DCE cable.…

Now typically routers are not connected back-to-back,…as is depicted in this topology,…but rather are connected through a telephone network…and that requires some type of a modem…that is installed on each side of the connection.…In the packet tracer topology,…the connection is not typical, its atypical,…because it's back-to-back connections,…and as such, it's going to require one side of the link,…the non-standard side, we call it the DCE side,…to actually provide the clocking for the serial connection.…

Clocking is a function typically provided…by either a modem or a CSU/DSU,…