CCNA 3 Labs and Study Guide - BINARYBB.INFO – @jagalbraith

322 Switching Basics and Intermediate Routing CCNA 3 Labs and Study Guide
Spanning-Tree Recalculation Exercise
Figure 7-5 is the same as Figure 7-3 in the preceding section. However, now the Gigabit Ethernet link
between SWC and SWB has gone down. as indicated by the X. As you did before, circle the root bridge.
On non-root bridges, label root ports with an R, designated ports with a D, and ports that are in the blocking
state with a B. Use the revised IEEE costs to make your determinations. In the space provided after the
topology, draw the logical loop-free spanning-tree topology with the root bridge at the top.
Figure 7-5 Spanning-Tree Recalculation Exercise
None of my costs changed.
I am unaffected.
I lost my best path to
root. My next best path
is through SWD.
Priority: Default
000d.ecdb.4be4
R
Gi0/1
SWA
D
Fa0/1 Gi0/2
D
100 Mbps
B
Fa0/1
Gi0/2
R 1000 Mbps
Gi0/2
D
R
B
Fa0/1
SWC Gi0/1
Gi0/1 SWD
000e.385d.e380
Priority: 36,864
1000 Mbps
1000 Mbps
My path cost to root is now
lower than SWC, therefore my
Gi0/1 is the designated port.
1-58713-171-4
SWD
sl260705aa.eps
05/29/06
ICC
SWC
Priority: 4096
000e.8362.e383
Gi0/1
I have the best BPDU.
D SWB
I am root.
Gi0/2
D Fa0/1
D
1000 Mbps
New Loop-Free Spanning-Tree
Topology After Recalculation
SWB
SWA
100 Mbps
000d.edd3.37a3
Priority: Default
My Gi0/2 has the
lowest cost to root,
therefore it is now
the root port.