Rfc 1483; Multiplexing; Vc-Based Multiplexing; Llc-Based Multiplexing - ZyXEL Communications ADSL2+ Ethernet/USB Gateway 660RU-Tx Series User Manual

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Prestige 660RU-Tx Series User's Guide

3.1.1.4 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.

3.1.2 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.

3.1.2.1 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.

3.1.2.2 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.

3.1.3 VPI and VCI

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.

3.1.4 Internet Access Wizard Setup: First Screen

In the SITE MAP screen click Wizard Setup to display the first wizard screen.
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Chapter 3 Wizard Setup

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