FoxGate S6424-S2C2 series User Manual

STP Configuration
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configuration BPDU in response.
 If a path becomes faulty, the root port on this path will no longer receive new
configuration BPDUs and the old configuration BPDUs will be discarded due to
timeout. In this case, the device will generate a configuration BPDU with itself as the
root and sends out the BPDU. This triggers a new spanning tree calculation process
so that a new path is established to restore the network connectivity.
However, the newly calculated configuration BPDU will not be propagated throughout the
network immediately, so the old root ports and designated ports that have not detected the
topology change continue forwarding data along the old path. If the new root port and
designated port begin to forward data as soon as they are elected, a temporary loop may
occur.
3) STP timers
 STP calculations need three important timing parameters: forward delay, hello time,
and max age.
 Forward delay is the delay time for device state transition. A path failure will cause
re-calculation of the spanning tree, and the spanning tree structure will change
accordingly. However, the new configuration BPDU as the calculation result cannot be
propagated throughout the network immediately. If the newly elected root port and
designated ports start to forward data right away, a temporary loop is likely to occur.
For this reason, as a mechanism for state transition in STP, a newly elected root port
or designated port requires twice the forward delay time before transitioning to the
forwarding state, when the new configuration BPDU has been propagated throughout
the network.
 Hello time is the time interval at which a device sends hello packets to the surrounding
devices to ensure that the paths are fault-free.
 Max age is a parameter used to determine whether a configuration BPDU held by the
device has expired. A configuration BPDU beyond the max age will be discarded.
21.3 Implement RSTP on Ethernet Switch
The Ethernet Switch implements the Rapid Spanning Tree Protocol (RSTP), i.e., the
enhancement of STP. The Forward Delay for the root ports and designated ports to enter
forwarding state is greatly reduced in certain conditions, thereby shortening the time period
for stabilizing the network topology.
To achieve the rapid transition of the root port state, the following requirement should be
met: The old root port on this switch has stopped data forwarding and the designated port in

FoxGate S6424-S2C2 series Specifications

General

Brand	FoxGate
Model	S6424-S2C2 series
Category	Switch
Language	English