WAN Protocols
We’ll be focusing on these five technologies in the following sections:
- ISDN
- Frame Relay
- PPP
- ATM
- MPLS
Integrated Services Digital Network
ISDN is a digital, point-to-point WAN technology capable of maximum transmission speeds of about 1.5 Mbps (Primary Rate Interface [PRI]), although speeds of 128 Kbps (Basic Rate Interface [BRI]) are more the reality within a SOHO environment.
ISDN uses the same UTP wiring as POTS, yet it can transmit data at higher speeds. But that’s where the similarity ends. The main thing that makes ISDN different from a regular POTS line is how it utilizes the copper wiring. Instead of carrying an analog voice signal, it carries digital signals, which also happens to be the key behind several more vital differences.
First, a computer connects to the 128 Kbps ISDN line via an ISDN terminal adapter (TA) that’s often incorrectly referred to as an ISDN modem. An ISDN TA is not a modem because it doesn’t convert a digital...
