Root Path Costs - Hirschmann RS20 Programming Manual

Rapid Spanning Tree

6.1.4 Root Path Costs

Every path that connects two bridges is assigned costs for the transmission
(path costs). The Switch specifies this value based on the transmission
speed (see table
transmission speeds.
Alternatively, the Administrator can specify the path costs. Like the Switch,
the Administrator assigns the higher path costs to paths with lower transmis-
sion speeds. However, since the Administrator can choose this value freely,
he has a tool with which he can give a certain path an advantage among
redundant paths.
The root path costs are the sum of all the individual path costs for all paths
along which a data packet travels between the connected port of a bridge and
the root bridge.
Bridge 1
PC = 200 000
PC = 200 000
Bridge 2
Figure 44: Path costs
Redundanz L2P
Release 5.0 04/09
12). It assigns the higher path costs to paths with lower
PC = 2 000 000
PC
Bridge 3
6.1 The Spanning Tree Protocol
Path costs
Ethernet (100 Mbit/s)
Ethernet (10 Mbit/s)
85