A Leased Line, A Leased Circuit, A Point-to-Point Link, and A WAN Link

A Leased Line, A Leased Circuit, A Point-to-Point Link, and A WAN Link

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Before you needed this new WAN link, the telco had thought about supporting lots of customers in Atlanta and Cincinnati. In anticipation of future business, they installed gear and additional cabling. That equipment and cabling together can take the bits sent by R1 over the cable to the Atlanta CO, deliver them across the telco network, and send the bits to R2 in Cincinnati. Of course, the telco does the same with bits coming into the Cincinnati CO, delivering those to the Atlanta CO and then out to R1.

Regardless of what happens between the COs, as far as the routers are concerned, when they send data on that cable, the other router gets it. The details of how the telco does things inside its network are important if you work for the telco, but the goal of this chapter is simply to briefly highlight how the two routers could communicate.