ZyXEL ADSL Prestige 660HW-61 91-004-361001 Manual Do Utilizador

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91-004-361001
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Prestige 660H/HW Series User’s Guide
 Splitters and Microfilters
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Virtual Circuit Topology
ATM is a connection-oriented technology, meaning that it sets up virtual circuits over which 
end systems communicate. The terminology for virtual circuits is as follows:
• Virtual Channel Logical connections between ATM switches
• Virtual Path A bundle of virtual channels
• Virtual CircuitA series of virtual paths between circuit end points
Figure 255   Virtual Circuit Topology
Think of a virtual path as a cable that contains a bundle of wires. The cable connects two 
points and wires within the cable provide individual circuits between the two points. In an 
ATM cell header, a VPI (Virtual Path Identifier) identifies a link formed by a virtual path; a 
VCI (Virtual Channel Identifier) identifies a channel within a virtual path. 
The VPI and VCI identify a virtual path, that is, termination points between ATM switches. A 
series of virtual paths make up a virtual circuit. 
Your ISP (Internet Service Provider) should supply you with VPI/VCI numbers.