3Com S330 manual Service

152CHAPTER 4: CONFIGURING PATHBUILDER S330/S310 MODULES, PORTS, AND APPLICATIONS

Frame Relay Virtual Circuit Parameters If the serial port is configured as a Frame Relay port, you must set the following virtual circuit parameters in addition to the common Shaper Number, Priority, and Early Packet Discard parameters:

Interworking Mode—The Frame Relay/ATM interworking mode: Network or

Service.

Start/End Frame Relay DLCI—The starting and ending Frame Relay data link connection identifiers: 16...991. These DLCIs are used to identify a Frame Relay local connection. This parameter applies only if the Interworking Mode is set to Network.

Encapsulation Mode—The encapsulation data goes around the data packet and is used to identify the packet; enter 1 (Transparent) or 2 (Translation).

Transparent—This mode is used for point-to-point frame relay interconnection. See Figure 123. Frame Relay Forum 8 (FRF.8) Service Interworking for this is being implemented. There are two modes at which FRF.8 specifies a mode which is transparent and is in fact 1490 over ATM.

Translation—This mode is used in cases when you have ATM devices that do not support 1490 as a protocol across their ATM trunks; for example, when you have a PathBuilder S330/S310 terminating the ATM network at one end and an ATM-ready device, such as a router with an OC-3 UNI, at the other end. Typically these ATM-ready devices do not support 1490 as a protocol across their ATM trunks, so you have to do LLC_SNAP (1483) per FRF.8. Mode 1F does 1490 to 1483 translation. See Figure 124.

Figure 123 FRF.8 Transparent Encapsulation Mode

DLCI

VCC

DLCI

FRR ATM FRR

RFC 1490

RFC 1433 Encapsulated

RFC 1490