# 4.7] What is the formula for computing adjusted ring length (ARL)? (Token Ring Physical Layer)

## Description

This article is from the Token Ring
FAQ, by James Messer James@NetworkUptime.com with numerous
contributions by others.

# 4.7] What is the formula for computing adjusted ring length (ARL)? (Token Ring Physical Layer)

The adjusted ring length of a token ring network is the sum of all

cable lengths between wiring closets, minus the shortest cable

between wiring closets. The ARL is used to determine the total

length of the ring, and the maximum lobe distances (see section [4.8]).

This calculation determines the ring length if part of the ring is

removed for troubleshooting. When a cable is removed from a Ring

In/Ring Out port, the loop-back creates a much larger ring than

normal. The ARL calculation defines the largest ring size that can

occur, based on the shortest cable between wiring closets.

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