3Com S330 manual Translation Encapsulation Mode

Configuring Virtual Circuits 153

Figure 124 Translation Encapsulation Mode

DLCI

VCC

ATM Router with FRR IWF

FRR ATM

Translation

RFC 1490 RFC 1483

DE-CLP /CLP-DE—DE to CLP / CLP to DE mapping. DE to CLP defines the value to which CLP will be set in outgoing ATM cells. CLP to DE mapping defines the value to which DE will be set from incoming ATM cells in outgoing Frame Relay frames.

Direct—Mode 1 mapping; matches DE value to CLP value. When the serial port is in this mode, it does not translate between Frame Relay (NLPID) encapsulation, rather it send it straight through the ATM network, possibly onto a Frame Relay network or device.

Always 0 —Mode 2 mapping, with the CLP field mapped to a constant value of 0. Mode 2 is an operational method for indicating data congestion to either the ATM or Frame Relay network. Mode 2 allows for translation between NLPID and LLC-SNAP encapsulation. It is used when connecting a Frame Relay device or network to a non-Frame Relay device or network. For example, if the PathBuilder S330/S310 is connecting a router/FRAD over an ATM network (public or private) and at the other site a router with an ATM OC3/STM-1 UNI is connected to the WAN network, typically the router OC3/STM-1 UNI does not support NLPID and requires mode 2 mapping so that the packet can be encapsulated to LLC-SNAP.

Always 1—Mode 2 mapping, with the CLP field mapped to a constant value of 1. Mode 2 is an operational method for indicating data congestion to either the ATM or Frame Relay network. Mode 2 allows for translation between NLPID and LLC-SNAP encapsulation. It is used when connecting a Frame Relay device or network to a non-Frame Relay device or network. For example, if the PathBuilder S330/S310 is connecting a router/FRAD over an ATM network (public or private) and at the other site a router with an ATM OC3/STM-1 UNI is connected to the WAN network, typically the router OC3/STM-1 UNI does not support NLPID and requires mode 2 mapping so that the packet can be encapsulated to LLC-SNAP.

Start/End FR-SSCSDLCI—The starting and ending Frame Relay data link connection identifiers of the remote ATM Frame Relay host: 16...991.