Convergence In A Simple Topology - Dell PowerConnect B-FCXs Configuration Manual

8
Configuring STP related features
FIGURE 38
Recall that Switch 200 sent the agreed flag to Port4/Switch 60 and not to Port1/Switch 100 (the
port that connects Switch 100 to Switch 200). Therefore, Port1/Switch 100 does not go into
forwarding state instantly. It waits until two instances of the forward delay timer expires on the port
before it goes into forwarding state.
At this point the handshake between the Switch 60 and Switch 200 is complete.
The remaining bridges (Switch 300 and Switch 400) may have to go through the reroot handshake
if a new Root port needs to be assigned.

Convergence in a simple topology

The examples in this section illustrate how 802.1W convergence occurs in a simple Layer 2
topology at start-up.
NOTE
The remaining examples assume that the appropriate handshake mechanisms occur as port roles
and states change.
Convergence at start up
In Figure
connections between Port3/Switch 2 and Port3/Switch 3.
244
Handshake completed after election of new root port
Switch 100
Proposing
Switch 200
Port2
Proposing
Port2
Switch 300
39, two bridges Switch 2 and Switch 3 are powered up. There are point-to-point
Designated
Port2
Root port
Port1
Port1
Alternate port
Port4
Root port
Port3
Proposing
Port3
Switch 400
PowerConnect B-Series FCX Configuration Guide
Port2
port
Switch 60
Port4
Designated port
53-1002266-01