ZyXEL Communications Prestige 650H-17, Руководство пользователя, Страница: 57 / 200

Prestige 650H-17 ADSL Router
Internet Access 3-11
FIELD DESCRIPTION EXAMPLE
When you have completed this menu, press [
ENTER
] at the prompt “Press ENTER to Confirm…” to save
your configuration, or press [
ESC
] at any time to cancel.
3.9 VPI and VCI
Be sure to use the correct Virtual Path Identifier (VPI) and Virtual Channel Identifier (VCI) numbers
supplied by your telephone company. 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 Appendices for more
information.
3.10 Multiplexing
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.
3.10.1 VC-based Multiplexing
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.
3.10.2 LLC-based Multiplexing
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.
3.11 Encapsulation
Be sure to use the encapsulation method required by your ISP. The Prestige supports the following
methods.
3.11.1 ENET ENCAP
The MAC Encapsulated Routing Link Protocol (ENET ENCAP) is only implemented with the IP network
protocol. IP packets are routed between the Ethernet interface and the WAN interface and then formatted so