Installation manual

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SIGNAMAX LLC • www.signamax.eu
Network packets are therefore only forwarded between root ports and designated ports,
eliminating any possible network loops.
Once a stable network topology has been established, all bridges listen for Hello BPDUs
(Bridge Protocol Data Units) transmitted from the Root Bridge. If a bridge does not get a
Hello BPDU after a predefined interval (Maximum Age), the bridge assumes that the link
to the Root Bridge is down. This bridge will then initiate negotiations with other bridges to
reconfigure the network to reestablish a valid network topology.
RSTP – RSTP is designed as a general replacement for the slower, legacy STP. RSTP is
also incorporated into MSTP. RSTP achieves much faster reconfiguration (i.e., around 1
to 3 seconds, compared to 30 seconds or more for STP) by reducing the number of state
changes before active ports start learning, predefining an alternate route that can be used
when a node or port fails, and retaining the forwarding database for ports insensitive to
changes in the tree structure when reconfiguration occurs.
MSTP – When using STP or RSTP, it may be difficult to maintain a stable path between all
VLAN members. Frequent changes in the tree structure can easily isolate some of the
group members. MSTP (which is based on RSTP for fast convergence) is designed to
support independent spanning trees based on VLAN groups. Using multiple spanning
trees can provide multiple forwarding paths and enable load balancing. One or more
VLANs can be grouped into a Multiple Spanning Tree Instance (MSTI). MSTP builds a
separate Multiple Spanning Tree (MST) for each instance to maintain connectivity among
each of the assigned VLAN groups. MSTP then builds a Internal Spanning Tree (IST) for
the Region containing all commonly configured MSTP bridges.
x
Designated
Root
Designated
Port
Designated
Bridge
x x
x
Root
Port
x