CALCULATING RING LENGTH
Page C-7
C.3 MULTIPLE WIRING CLOSET NETWORKS
In multiple wiring closet applications, both external trunk cable
length and lobe cable length must be considered in the overall drive
distance for a passive ring. Use the UTP Cable Length
Worksheet, Multiple Wiring Closet form toward the end of this
section to determine the cable lengths that can be used in multiple
wiring closet token ring applications. Choose the column that
matches your ring speed and complete the worksheet as follows:
1.
Determine your Actual Longest Lobe length, by combining:
TCU port to patch panel
feet
Wiring closet to wall plate
+ feet
Wall plate to station
+ feet
Longest Lobe Length
2.
Since we are trying to establish a budget for Type 1 STP trunk
cabling, the UTP Lobe Length for your network (Actual
Longest Lobe) must be converted to an Equivalent Type 1
Lobe Length using a conversion factor of 2.54 for networks
operating at 4 Mbit/s or by 2.91 for 16 Mbit/s.
3.
Multiply the Actual Longest Lobe by the conversion factor.
Actual Longest Lobe x (2.54 or 2.91) =
Equivalent Type 1 Lobe Length
4.
Refer to the table at the bottom of the worksheet to find the
Internal Trunk Length for each Wiring Closet (WC) in the
multiple closet configuration. Add these values to find the total
Combined Trunk Length:
WC-1 + WC-2 + WC-n = Combined Trunk Length