ZyXEL Communications Prestige 642M series, User Manual

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Prestige 642M Series ADSL Bridge
3-4 Internet Access
3.5 VPI & VCI
Be sure to use the correct Virtual Path Identifier (VPI) and Virtual Channel Identifier (VCI) numbers
supplied by the telephone company. The valid range for the VPI is 1 to 255 and for the VCI is 32 to 65535
(0 to 31 is reserved for local management of ATM traffic). Please see the
VPI & VCI Appendix for more
information.
3.6 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.
3.6.1 VC-based multiplexing
In this case, by prior mutual agreement, each protocol is assigned to a specific virtual circuit, e.g., VC1
carries IP, VC2 carries IPX, etc. VC-based multiplexing may be dominant in environments where dynamic
creation of large numbers of ATM VCs is fast and economical.
3.6.2 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, e.g., if charging heavily depends on the
number of simultaneous VCs.
3.7 Encapsulation
Be sure to use the encapsulation method required by your ISP. The Prestige supports the following
methods.
3.7.1 PPP
Please refer to RFC 2364 for more information on PPP over ATM Adaptation Layer 5 (AAL5). Refer to
RFC 1661 for more information on PPP.
3.7.2 RFC 1483
RFC 1483 describes two methods for Multiprotocol Encapsulation over ATM Adaptation Layer 5 (AAL5).
The first method allows multiplexing of multiple protocols over a single ATM virtual circuit (LLC-based
multiplexing) and the second method assumes that each protocol is carried over a separate ATM virtual
circuit (VC-based multiplexing). Please refer to the RFC for more detailed information.
3.8 Internet Access Configuration
Menu 4 allows you to enter the Internet Access information in one screen. Menu 4 is actually a simplified
setup for one of the remote nodes that you can access in Menu 11. Before you configure your Prestige for
Internet access, you need to collect your Internet account information from your ISP and telephone
company.
Use the following table to record your Internet Account Information. Note that if you are using PPP then
the only ISP information you need is a login name and password.