152 CHAPTER 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
ATM
FRR
FRR
RFC 1433 Encapsulated
VCC
DLCIDLCI
RFC 1490 RFC 1490
