Chapter 7 Internet Setup

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.

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.

7.3.3 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.

7.3.4 IP Address Assignment

A static IP is a fixed IP that your ISP gives you. A dynamic IP is not fixed; the ISP assigns you a different one each time. However the encapsulation method assigned influences your choices for IP address.

IP Assignment with PPPoA or PPPoE Encapsulation

If you have a dynamic IP, then the IP Address and Gateway IP Address fields are not applicable (N/A). If you have a static IP, then you only need to fill in the IP Address field and not the Gateway IP Address field.

IP Assignment with RFC 1483 Encapsulation

In this case the IP address assignment must be static.

7.3.5 Always-On Connection (PPP)

An always-on connection is a dial-up line where the connection is always up regardless of traffic demand. The P-660RU-Tx does two things when you specify an always-on connection. The first is that idle timeout is disabled. The second is that the P-660RU-Tx will try to bring up the connection when turned on and

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P-660RU-Tx User’s Guide