Routing and WAN connections
456
11.17
The rapid spanning tree protocol
BAT54-Rail/F..
Release
7.54
06/08
Configuration with WEBconfig, Telnet or SSH
Under WEBconfig, Telnet or SSH client you will find the WAN RIP table under
the following paths:
11.17The rapid spanning tree
protocol
In networks with many switches and bridges, many physical connections can
exist between two stations that are connected to the network. These redun-
dant data paths are desirable because they can offer alternative paths to the
desired destination in case individual network paths fail. On the other hand,
these multiple connections can also lead to loops or cause network stations
to receive multiple frames. Both occurrences negatively impact free data traf-
fic performance in the network.
The Spanning Tree Protocol (STP) enables an analysis of the network at the
layer 2 level and, as such, offers solutions for intelligent path selection be-
tween two network stations below the routing layer. By discovering redun-
dant paths between network stations, STP builds a unique structure in which
loops and double packets can be avoided. To this end, so-called Bridge Pro-
tocol Data Units (BPDUs) are sent as a multicast to a specific MAC address.
The BPDUs allow redundant paths to be discovered as well as the distance
and the data rate available on this connection. Using these values, the Span-
ning Tree Protocol calculates a priority (also called route or path costs) with
which the various connections are to be treated. The low-priority connections
are disabled and are therefore no longer available for clients. Through the re-
duction of non-redundant connections between the clients, the protocol
builds a tree which unambiguously defines all of the connections that arise
from a central switch (root bridge).
The BPDUs are sent regularly in the network in order to check the availability
of the connections. If a connection fails, then the network analysis is triggered
again; the possible paths and the corresponding priorities are redefined.
After initialization all ports are initially in the "blocking" state in which only BP-
DUs are exchanged. The ports subsequently switch to the states of "listen-
ing" and then "learning" before reaching "forwarding" which allows payload
data to be exchanged via the ports.
Configuration tool Menu/Table
WEBconfig Expert Configuration
 Setup  IP router  RIP  WAN sites
Terminal/Telnet
Setup/IP router/RIP/WAN sites
To Next Page
Loading...
Need help?
General
