3Com SuperStack II PathBuilder S330 Reference Manual page 162

148 C 4: C
HAPTER ONFIGURING
P B S330/S310 M
ATH UILDER ODULES
Figure 138 FRF.8 Transparent Encapsulation Mode
DLCI
FRR
RFC 1490
Figure 139 Translation Encapsulation Mode
DLCI
FRR
RFC 1490
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 switch 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.
, P , A
ORTS AND PPLICATIONS
VCC
A TM
RFC 1433 Encapsulated
VCC
A TM Router with FRR IWF
A TM
Translation
DLCI
FRR
RFC 1490
RFC 1483