8 spanning tree – AirLive SNMP-FSH2602MG v2 User Manual

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4. Web Management in SNMP-FSH2602MG v2

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AirLive SNMP-FSH2602MG v2 User’s Manual

4.4.8 Spanning Tree


The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology
for any bridged LAN. Spanning tree allows a network design to include spare (redundant)
links to provide automatic backup paths if an active link fails, without the danger of bridge
loops, or the need for manual enabling/disabling of these backup links. Bridge loops must
be avoided because they result in flooding the network.

Rapid Spanning Tree Protocol (RSTP), which provides for faster spanning tree
convergence after a topology change. STP can take 30 to 50 seconds to respond to a
topology change, RSTP is typically able to respond to changes within a second.

Basic spanning protocol will follow the below rules:
1. Select a root bridge: The root bridge of the spanning tree is the bridge with the

smallest bridge ID. Every bridge has a unique ID and a configurable priority number;
the bridge ID contains both numbers. To compare two bridge IDs, the priority is
compared first. If two bridges have equal priority, then the MAC addresses are
compared. For example, if switches A (MAC=000000001111) and B
(MAC=000000002222) both have a priority of 10, then switch A will be selected as the
root bridge because of smaller MAC address.

2. Determine the least cost paths to the root bridge: The lease cost path is a path from

the device to the root that has minimum cost among all paths from the device to the
root.

3. Disable all other root paths: Any active port that is not a root port or a designated port

is a blocked port.

4. Modification in case of ties: In some sophisticated network, two or more ports on a

single bridge are attached to least-cost paths to the root or two or more bridges on the
same network segment have equal least-cost paths to the root. They are so-called ties,
Spanning tree protocol would break such ties for better usage.



System Configuration

1. You can view spanning tree status about the switch.
2. You can modify RSTP state. After modifying, click “Apply” button to apply your setting.
3. RSTP Mode: Select “Disable”, “802.1d (STP)” or “802.1w (RSTP)”. The default is

“Disabled”.

4. Once selecting 802.1d or 802.1w, you can configure the below setting.

„

Priority: Assign path priority number. The valid value is from 0 to 61440. The

default is 32678.

„

Max Age: When the SNMP-FSH2602MG v2 is the root bridge, the whole LAN

will apply this figure set by this switch as their maximum age time. When a bridge
received a BPDU originated from the root bridge and if the message age
conveyed in the BPDU exceeds the Max. Age of the root bridge, the bridge will

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