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show voice port - Tecnológico de Costa Rica

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Using the Spanning-Tree Protocol 8 - 13<br />

Setting the Hello Message Interval Time (Hello_Time)<br />

The hello_time option is used to set the interval time, in seconds,<br />

between the transmission of configuration messages. This value is only<br />

used if the local bridge becomes the spanning tree root bridge. If not,<br />

the value in received configuration messages transmitted from the root<br />

bridge is used.<br />

If the interval time is set too high, the infrastructure will respond slowly<br />

in resolving any conflict problems. However, if set too low, the infrastructure<br />

will be crow<strong>de</strong>d with hello message traffic. The interval time<br />

values range between 1 and 10 with a <strong>de</strong>fault value of 2.<br />

Setting the Forwarding Delay Time (Forward_Delay)<br />

The forward_<strong>de</strong>lay option is used to set the <strong>de</strong>lay time, in seconds, that<br />

the <strong>port</strong>s will spend in the listening and learning states. This value is<br />

only used if the local bridge becomes the spanning tree root bridge. If<br />

not, the value in received configuration messages transmitted from the<br />

root bridge is used.<br />

This option is also the timeout period used to age learned addresses<br />

whenever the spanning tree topology is changed. The value should be at<br />

least twice the transit time of a packet sent from one end of the infrastructure<br />

to the other. This allows for news of a topology change to<br />

reach all no<strong>de</strong>s and allows all <strong>port</strong>s to be blocked before new <strong>port</strong>s enter<br />

the forwarding state.<br />

If the interval time is set too low, then temporary loops could be formed.<br />

However, if set too high, it will take longer for the infrastructure to<br />

become active after a spanning tree topology change has been ma<strong>de</strong>. The<br />

<strong>de</strong>lay time values range between 4 and 30 with a <strong>de</strong>fault value of 15.<br />

Setting the Receive Hello Message Timeout (Msg_age_timeout)<br />

The msg_age_timeout option is used to set the timeout period, in seconds,<br />

a blocked or root <strong>port</strong> watches for configuration messages from<br />

the infrastructure’s <strong>de</strong>signated <strong>port</strong>. This value is only used if the local<br />

bridge becomes the spanning tree bridge. If not, the value received in<br />

configuration messages transmitted from the root bridge is used.<br />

Each time a configuration message is received, the timer is started. If<br />

the timer expires, the root bridge is assumed to have failed and the spanning<br />

tree infrastructure will be reconfigured.

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