Cabletron Systems SSR-GLX19-02, User Manual

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Chapter 6: Configuring SSR Bridging
76 CoreWatch User’s Manual
6. Click the
Remove
button.
Configuration Expert moves the selected port from the Aging State Disabled list to the
corresponding module in the Aging State Enabled list.
7. Click OK .
Configuration Expert adds the port to those found in the Aging Enabled Ports object,
which is located in the Aging State object.
Setting Up STP on the SSR
The SSR uses the Spanning Tree Protocol (STP) to dynamically discover a loop-free
topology.
STP includes an algorithm that permits bridges to send Bridge Protocol Data Units
(BPDUs). Unless a bridge is a root bridge, it uses the information in a BPDU to perform
the following operations. (A root bridge is a bridge that uses STP to prevent loops by
periodically exchanging topology information with other bridges.)
1. Select a root bridge.
2. Calculate the shortest path from itself to the root bridge.
3. Select a designated bridge.
A designated bridge is the bridge responsible for forwarding frames to a LAN
segment.
4. Select a root port.
A root port is a port that provides the best path from the bridge to the root bridge.
5. Select which ports are included in a spanning tree.
On the SSR, you can enable STP per port. This approach offers flexibility. STP BPDUs that
arrive on ports on which STP is disabled are forwarded only to ports which are part of the
receiving port's VLAN.
You can set up STP on the SSR by performing the following tasks:
Note:
STP is disabled on the SSR by default. If you want the SSR to use STP, you will
need to define the different settings and enable STP.
• Defining STP settings for an SSR bridge.
• Defining STP settings for individual ports.
• Enabling and disabling STP on individual ports.
Separate discussions on these STP tasks follow.