Learning by Doing: CISCO Certified Network ... - SCN Research

Intermediate STP
Objective:
To be able to understand STP states, cost parameters, root bridges, priorities, ports and
port fast mode.
Tools and Materials:
(4) switches
(4) cross over cables
(2) straight through cables
(2) console cables
(2) workstations
Lab Design:
Background:
In the last lab we learned about basic STP construction. We learned Spanningtree
frames called bridge protocol data units (BPDU’s) are sent and received by all
switches in the network at regular intervals (usually every 2 seconds) and are used to
determine the spanning tree topology. STP is implemented on switches, by default, for
VLANs 1-64. This means all you have to do is plug in your redundant backbone into any
available port. There are five states for every switch port:
1. Blocking—port does not participate in frame-forwarding; port does not
learn new addresses
2. Listening—same as blocking, but switch is actively trying to bring the port
into the forwarding state; the port does not learn new addresses
3. Learning—port does not participate in frame-forwarding; port does learn
new addresses; the switch is trying to change the port to frame-forwarding
4. Forwarding—port does participate in frame forwarding; port does learn
new addresses
5. Disabled—port is removed from operation; administrative intervention is
required to enable the port
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