EtherWAN EX24000, User Manual

Page: 96 / 239

Setting the MAX Age, Forward Delay and Hello Timer
To navigate to the STP/Ring Global Configuration page:
1. Click on the + next to STP/Ring .
2. Click on Global Configuration .
The Network Diameter
The Diameter of a network depends on the type of topology your network uses. In a ring
topology, the Network Diameter is the total number of switches in a network minus the
Root Bridge. In a star topology, the Network Diameter is the maximum number of hops
to get from Root Bridge to the switch that is the most hops away. the In the RSTP
protocol, the
Max Age parameter is used as a hop count limit on how far the Spanning
Tree protocol packet can propagate throughout the network topology, therefore, it must
be configured with a value that is greater than the network diameter.
Relationship between Max Age, Forward Delay and Hello Time
The following rules must be followed when setting the Max Age , Forward Delay and
Hello Timer :

Max Age >= 2 × (Hello Time + 1.0 second)

2 × (Forward Delay – 1.0 second) >= Max Age
To change the Max Age , Forward Delay and Hello Timer (see Figure 42 ):
1. Enter the Max Age in the text box to the right of Max Age (6..40 sec) label.
2. Enter the Hello Time in the text box to the right of the Hello Time (1..10 sec)
label.
3. Enter the Forward Delay in the text box to the right of the Forward Delay (4..30
sec) label.
4. Click on the Update Setting button.
5. Save the configuration (see the Save Configuration Page )
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EX24000 Switch Users Guide