ZyXEL Communications Corporation P663HN51 Manuale Utente

P-663HN-51 User’s Guide

A WAN (Wide Area Network) is an outside connection to another network or the 
Internet.

Be sure to use the correct Virtual Path Identifier (VPI) and Virtual Channel 
Identifier (VCI) numbers assigned to you. The valid range for the VPI is 0 to 255 
and for the VCI is 32 to 65535 (0 to 31 is reserved for local management of ATM 
traffic). Please see the appendix for more information.

There are two conventions to identify what protocols the virtual circuit (VC) is 
carrying. Be sure to use the multiplexing method required by your ISP.

In this case, by prior mutual agreement, each protocol is assigned to a specific 
virtual circuit; for example, VC1 carries IP, etc. VC-based multiplexing may be 
dominant in environments where dynamic creation of large numbers of ATM VCs is 
fast and economical.

In this case one VC carries multiple protocols with protocol identifying information 
being contained in each packet header. Despite the extra bandwidth and 
processing overhead, this method may be advantageous if it is not practical to 
have a separate VC for each carried protocol, for example, if charging heavily 
depends on the number of simultaneous VCs.