Cabletron Systems 9H42X-XX

Bridge Spanning Tree 5-17

Bridging

Changing the Spanning Tree Algorithm Protocol Type

To change the type of protocol used in Spanning Tree:

1. Click the mouse on the appropriate option button: IEEE 802.1, DEC, or None.

2. Click on .

The selected Spanning Tree Algorithm protocol type will be applied to the bridge.

If you selected None, the Spanning Tree Algorithm will be disabled (if it already

was enabled). If STA Protocol Type was changed from None to IEEE 802.1 or DEC,

you must restart the bridge for the newly selected STA protocol to be applied.

Changing Hello Time

If the bridge is the Root Bridge, or is attempting to become the Root, and you

want to change the length of time the bridge waits between sending conﬁguration

BPDUs:

1. Highlight the Hello Time ﬁeld, and type in a new value.

2. Click on .

The IEEE 802.1d speciﬁcation recommends that Hello Time = 2 seconds; the

allowable range is 1 to 10 seconds.

Changing Max Age Time

If the 9H42x-xx module is the Root Bridge or attempting to become the Root, and

you want to change the maximum time that bridge protocol information will be

kept before it is discarded:

1. Highlight the Max Age ﬁeld, and type in a new value.

2. Click on .

The IEEE 802.1d speciﬁcation recommends that Max Age = 20 seconds; the

allowable range is 6 to 40 seconds.

TIP

If your network does not have redundant bridged paths, turning off Spanning Tree can

improve network performance by cutting down on management (BPDU) trafﬁc.

CAUTION

All bridges in a network must use the same Spanning Tree version. Mixing Spanning Tree

Algorithm protocols will cause an unstable network.