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22 FSU User Manual 61200.130L1-1
Chapter 4. Applications
In all cases, the FSU is transparent to the XID (exchange identifica-
tion) negotiation between any two network devices.
The FSU uses LLC protocol (mode 2) to transport SDLC informa-
tion frames. This protocol ensures a reliable link across frame
relay, providing protection from frame loss and excessive delays.
The encapsulation method uses the RFC 1490 format. See Table
4-A for an example of how to configure the FSU for this applica-
tion.
3270 Controller
FEP Host
SDLC
SDLC
SDLC
PU Address = C1
DTE1
DTE2
DTE1
DTE2
DLCI=17 DLCI=120
FSU
Remote End Host End
FSU
RFC1490/LLC2
UNI
NN
UNI
PU Address = C0
PU Address = C0
PU Address = C0
3270 Controller
FRAME RELAY
Figure 4-1
SNA /SDLC with Local Spoofing