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C
HAPTER
4: C
ONFIGURING
P
ATH
B
UILDER
S330/S310 M
ODULES
, P
ORTS
,
AND
A
PPLICATIONS
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: 1
6...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
A TM
FRR
FRR
RFC 1433 Encapsulated
VCC
DLCI
DLCI
RFC 1490
RFC 1490