3com 2200 用户手册

The maxT-Req attribute specifies the maximum time value of fddiMACT-Req 
that will be used by any MAC that is configured onto this path. T-Req is the 
value that a MAC bids during the claim process to determine a ring’s 
operational token rotation time, T_Opr. The lowest T-Req bid on the ring 
becomes T_Opr. 

When T_Opr is a low value, the token rotates more quickly, so token latency 
is reduced. However, more of the ring’s available bandwidth is used to 
circulate the token. Higher values of T_Opr use less bandwidth to circulate 
the token, but they increase token latency when the ring is saturated.

To set maxT-Req:

1 From the top level of the Administration Console, enter:

You are prompted for a station, path, and value. The Switch 2200 has one 
station, which appears in brackets.

2 Press [Return].

3 Enter the path (

= primary, 

= secondary).

4 Enter the new minimum time value.

The default value is 165000 microseconds (

µ

s)

See the following example:

Select station [1]:                    

Select path(s) (p,s,|all) [p]:

Station 1 Primary - Enter new value [165000]:

An FDDI MAC uses a token-passing protocol to determine which station has 
control of the physical medium (the ring). The primary purpose of the MAC 
is to deliver frames (packets) to their destination by scheduling and 
performing all data transfers. You can display MAC statistics and configure 
the following parameters:

■

MAC FrameErrorThreshold

■

NotCopiedThreshold

■

Logical Link Control (LLC) service

system
ethernet

➧

fddi
bridge
ip
snmp
analyzer
script
logout

station

➧

path
mac
port

display
tvxLowerBound
tmaxLowerBound

➧

maxTreq