EXP Computer S200 用户手册

104 

Bridging

Local termination or “spoofing” of LLC protocol means that acknowledgments to 
information frames and certain supervisory frames are handled locally by the 
spoofer. The spoofer, the LT software in a PathBuilder S200 series switch, ensures 
the acknowledged information frames are reliably delivered to the destination peer 
spoofer and that any flow control issues are handled appropriately. Because of local 
acknowledgment, spoofing of LLC frames may enhance network performance and 
allows for reliable Token Ring to Token Ring connectivity.

This table describes the types of frames Local Termination spoofs:

The maximum number of sessions you can spoof at one time is 64. If you reach the 
maximum number of sessions, Local Termination does not establish additional 
spoofing sessions, nor does it source route bridge the additional sessions.

Local Termination runs a subset of LLC2 protocol between spoofers to ensure that 
frame traffic reliably passes from one edge point node to another edge point node in 
your network. The subset protocol uses separate timers and retry counts that can be 
set greater than the LLC protocol timers.

LLC2 LT supports intermediate Token Ring networks between spoofers. For 
example, Figure 53 shows Local Termination running in the edge point nodes of this 
network to provide “spoofing” across multiple Token Rings.

All Specifically Routed LLC frames, such as I frames and Supervisory frames

• Route Explorer frames, such as ARE or STE

• Internally matched frames coming in from the LAN port

• Frames generated by LSS/LLC in the bridge going out to the LAN port

• WAN to WAN frames

PB 
LT

X.25

End
Station

Spoofing

Intermediate Ring

PB
LT

FEP

#1

PB

BN

PB

BN

FEP

#2

LT enabled with MAC 
Address of FEP #1 and 
SAP value being used.

LT enabled with MAC

Address of FEP #2 and

SAP value being used.