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VPI’s & VCI’s
2.3. 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.
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VC-based multiplexing
Each protocol is assigned to a specific virtual circuit, e.g., VC1carries IP, VC2
carries IPX, etc. VC-based multiplexing may be dominant in environments
where dynamic creation of large numbers of ATM VCs in fast and economical.
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LLC-based multiplexing
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.
2.4. PPPoE
When using SP3353 as a PPPoE client, the PCs on the LAN see only Ethernet and
are not aware of PPPoE. This alleviates the administrator from having to manage
the PPPoE clients on the individual PCs.
