Configuring Virtual Circuits 153
Figure 124 Translation Encapsulation Mode
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-SSCS DLCI—The starting and ending Frame Relay data link
connection identifiers of the remote ATM Frame Relay host: 16...991.
ATMFRR
Translation
RFC 1483
RFC 1490
VCCDLCI
ATM Router with FRR IWF
