Wuxi MitraStar Technology Co. Ltd DSL100HNUT1V3 User Manual

Chapter 5    WAN Setup

48

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 a separate ATM virtual circuit (VC-based 

multiplexing) carries each protocol. Please refer to RFC 1483 for more detailed information.

There are two conventions to identify what protocols the virtual circuit (VC) carries. Use the 

multiplexing method required by your ISP.

In this case, by prior mutual agreement, each protocol uses 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.

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.

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.

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. The Single User Account feature can be enabled or disabled if you have 

either a dynamic or static IP. However the encapsulation method assigned influences your choices 

for IP address and ENET ENCAP gateway.

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 Address assigned by your ISP, then they should also assign you a Subnet 

Mask and a Gateway IP Address.

In this case the IP address assignment must be static.