Copyright © 2010 NEXCOM International Co., Ltd. All Rights Reserved.
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Appendix C: Bypass Specifications
NSA 3111 User Manual
NSA 3111 provides LAN bypass functionality to ensure that data can still
pass through the device, even when it is powered off. This feature helps
ensure the continuous flow of data through the device in the event of a
hardware failure. For network security appliances deployed at the gate-
way, for example, it is crucial that they provide LAN bypass functionality to
ensure that hardware failure on these appliances will not bring down the
entire network.
A
ppendix
C: B
ypAss
s
peCifiCAtions
BTCR - Bypass Timer Configuration Register = 0XF2
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R
X
X
X
X
W
W
W
Bit 7: Timer Expired
0 - Timer has not expired
1 - Timer has expired
Bit [2:0]: Timer Value
000 - 0 second
001 - 1 second
010 - 2 second
011 - 4 second
100 - 8 second
101 - 16 second
110 - 32 second
111 - 64 second
Bypass Control Function
BCSR - Bypass Control Status Register = 0XF3
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
W
W
R/W
R/W
R/W
R/W
R/W
R/W
Bit [7:6]: Bypass Mode
00 - Ignore, no action taken
01 - Force enable
10 - Force disable
11 - Timer enable
Bit [5:0]: Segment Control Bit
Bit 0: Segment 1 (facing the front panel, the leftmost is the 1st Bypass)
Bit 1: Segment 2 (facing the front panel, the second from the left is the
2nd Bypass)
Bit 2: Segment 3 (facing the front panel, the third from the left is the 3rd
Bypass)
Bit 3: Segment 4 (facing the front panel, the fourth from the left is the 4th
Bypass)
