NetComm IP DSLAM NCT480 - Manual (Page 86)

NCT480 IP DSLAM User Guide YML856 Rev3
86 www.netcomm.com.au
Spanning Tree Protocol
The spanning tree protocol allows you to configure the STP parameters on network Ethernet interface.
Spanning-Tree Protocol is a link management protocol that provides path redundancy while preventing
undesirable loops in the network. For an Ethernet network to function properly, only one active path can exist
between two stations. Multiple active paths between stations cause loops in the network. If a loop exists in
the network topology, the potential exists for duplication of messages. When loops occur, some switches see
stations appear on both sides of the switch. This condition confuses the forwarding algorithm and allows
duplicate frames to be forwarded.
To provide path redundancy to prevent undesirable loops, Spanning-Tree Protocol defines a tree that spans
all switches in an extended network. Spanning-Tree Protocol forces certain redundant data paths into a
standby (blocked) state. If one network segment in the Spanning-Tree Protocol becomes unreachable, or if
Spanning-Tree Protocol costs change, the spanning-tree algorithm reconfigures the spanning-tree topology
and reestablishes the link by activating the standby path.
STP is a technology that allows bridges to communicate with each other to discover physical loops in
the network. The protocol then specifies an algorithm that bridges can use to create a loop-free logical
topology. In other words, STP creates a tree structure of loop-free leaves and branches that spans the
entire Layer 2 network.
Figure 6- Spanning Tree Protocol Setting Dialog
Refer to Table 6-5 Spanning Tree Protocol Dialog Description