Cisco Systems MGX 8230 Frame Relay-to-ATM Service Interworking

2-24
Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001
Chapter2 Module and Service Descriptions
Frame Relay Service Modules
Frame Relay–to–ATM Direction
EFCI is always set to 0.
ATM–to–Frame Relay Direction
If the EFCI field in the last ATM cell of a segme nt ed f ra me r ec eived is set, then FECN of the Fram e
Relay frame will be set.
PVC Status Management
The management of ATM laye r a n d F R P V C status management c an o perate independently. The PVC
status from the ATM layer is used when determining the status of the FR PVC. However, no direct
actions of mapping LMI A bit to OAM AIS is performed.
Frame Relay-to-ATM Service Interworking
By specifying “service interwo rking” as the channel type when add ing a Frame Relay PVC to an FRSM,
all PVC data is subject to se rv ice interworking translation an d m a pp in g in both the Frame
Relay–to–ATM and ATM–to–Frame Relay directions. Figure2-13 is an illustration of typical SIW
connections.
Figure2-13 BPX 8600 Series Network with SIW Connections
In Figure2-13, an MGX 8230 node on the right has three Frame Relay SIW connections terminating on
an FRSM. Three far-end termination s f or t he s e c on n ect io ns ap pe ar in o th er p arts of Figure 2-13:
•ATM FUNI (framed UNI) port on an FRSM
•ATM UNI port on an RPM
•ATM UNI port on a BPX 8600 series BXM card
In addition to frame-to-cell and DLCI-to-VPI/VCI conversion, SIW maps cell loss priority and
congestion data betw ee n the Frame Relay and ATM form a ts and is FRF.8-compliant. I t pr ov id es full
support for routed and bridged P D Us , t ra nsp ar en t an d tr an slat io n m o de s, an d VP translation.
FRSM
FRSM
RPM
FR UNI
CPE
T1 or E1
T1 or E1
ATM FUNI CPE
ATM UNI CPE
MGX 8850
MGX 8850
BPX 8620 network
PVCs
17909
BPX 8620
B
X
M
T3, E3, OC3
ATM-UNI CPE