IBM 8239 Token-Ring Stackable Hub, Руководство по установке и эксплуатации

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MIB II
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Remote Monitoring (RMON)
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RMON 2
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Enterprise Communications Analysis Module (ECAM)
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IBM Token Ring Surrogate MIB and Surrogate Trap MIB
Cable Types and Distances
This section gives information about supported cable types and maximum cable
distances.
Ports
Table 1-1 shows the types of cable and maximum distances supported for port
cabling.
Table 1-1. Port Cabling
Cable Type 4-Mbps Ring Speed 16-Mbps Ring Speed
UTP, ScTP, or FTP Cat 3 250 m (820 ft) 100 m (328 ft)
UTP, ScTP, or FTP Cat 4 425 m (1394 ft) 210 m (689 ft)
UTP, ScTP, or FTP Cat 5 425 m (1394 ft) 225 m (738 ft)
STP or STP-A 750 m (2460 ft) 375 m (1230 ft)
Stack Unit Cabling
You can install up to eight 8239s in a stack, using any combination of 8239 Model
1s and 8239 Model 2s in the stack. Use standard TIA/EIA/ANSI 568A or ISO/IEC
11801 Category 5 cable for your stack.
Determining Maximum Cable Length
Each of the 8239s in a stack can be up to 25m (82 ft) apart without regard to the
total distance among all 8239s in the stack. If distances over 25m are required,
they are supported provided that the sum of all of the stack cable lengths minus the
length of the shortest stack cable does not exceed 210 M (689 ft). For example,
four 8239s have the following stack cables connecting them to form a stack:
Cable 1 connects stack unit 1 to stack unit 2 1 m
Cable 2 connects stack unit 2 to stack unit 3 25 m
Cable 3 connects stack unit 3 to stack unit 4 25 m
Cable 4 connects stack unit 4 to stack unit 1 150 m
To see if this configuration is allowable, use this formula:
(Total length of stack cables) - (length of shortest cable)
<
210 m
Substituting the values in the example in this formula:
1 + 75 + 90 + 150 - 1 = 200
Because 200 m is less than 210 m, this configuration is allowable. In this case,
even though there are lengths of cable that are greater than 25 m, the configuration
is still acceptable because the total distance is less than 210 m.
Attention: To prevent ring disruptions, be sure you connect Stack-In and Stack-Out
cables at both ends.
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8239 Setup and User’s Guide