Ccna routing and Switching Complete Study Guide

Packet switching    This is a WAN switching method that allows you to share bandwidth 

with other companies to save money, just like a super old party line, where homes shared 

the same phone number and line to save money. Packet switching can be thought of as a 

network that’s designed to look like a leased line yet it charges you less, like circuit switch-

ing does. As usual, you get what you pay for, and there’s definitely a serious downside to 

this technology. If you need to transfer data constantly, well, just forget about this option 

and get a leased line instead! Packet switching will only really work for you if your data 

transfers are bursty, not continuous; think of a highway, where you can only go as fast as 

the traffic—packet switching is the same thing. Frame Relay and X.25 are packet-switching 

technologies with speeds that can range from 56 Kbps up to T3 (45 Mbps).

MultiProtocol Label Switching (MPLS) uses a combination of both circuit 

switching and packet switching.

WAN Support

Cisco supports many layer 2 WAN encapsulations on its serial interfaces, including HDLC, 

PPP, and Frame Relay, which map to the Cisco exam objectives. You can view them via the 

encapsulation ?

 command from any serial interface, but understand that the output you’ll 

get can vary based upon the specific IOS version you’re running:

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