3Com CoreBuilder 3500, Implementation Manual, Page: 105 / 592

FDDI Paths 105
Effects and Consequences
When you set the tvxLowerBound attribute, consider the following:
■
By adjusting the tvxLowerBound value, you specify how quickly the
ring recovers from an error. The lower that you set this value, the
faster the network reacts to problems, but the ring may reinitialize
when there is no problem. The recommended value for
tvxLowerBound
is
2500
microseconds.
■
The higher that you set the tvxLowerBound value, the less chance of
frequent reinitializations, but the network takes longer to recover from
errors. The recommended value for tvxLowerBound
is
2500
microseconds.
Setting
tmaxLowerBound
The tmaxLowerBound attribute specifies the minimum time value of
fddiMAC T-Max that any MAC that is configured on this path uses. This
value specifies the boundary for how high T-Req (the requested token
rotation time) can be set.
Setting maxT-Req The maxT-Req attribute specifies the maximum time value of
fddiMACT-Req that any MAC that is configured onto this path uses. 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.
Effects and Consequences
When you set the maxT-req, consider the following:
■
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.