Specifications

Functions
RS2-4R
Release 1.0 03/04
4.4 Spanning Tree Algorithm
109
D Designated port
The port that connects the designated bridge to a network segment
that leads away from the root bridge.
Each network segment in which there is no further RSTP bridge is
connected to exactly one designated port. This designated port then
functions as an (edge port) at the same time. Characteristic of an edge
port is the fact that it does not receive any RST BPDUs (Rapid
Spanning Tree Bridge Protocol Data Unit).
Link speed
Recommended
value
Recommended range Range
<=100 Kb/s 200 000 000* 20 000 000-200 000 000 -200 000 000
1 Mb/s 20 000 000* 2 000 000-200 000 000 -200 000 000
10 Mb/s 2 000 000* 200 000-20 000 000 1-200 000 000
100 Mb/s 200 000* 20 000-2 000 000 1-200 000 000
1 Gb/s 20 000 2 000-200 000 1-200 000 000
10 Gb/s 2 000 200-20 000 1-200 000 000
100 Gb/s 200 20-2 000 1-200 000 000
1 Tb/s 20 2-200 1-200 000 000
10 Tb/s 2 1-20 1-200 000 000
Table 7: Recommended path costs according to the data rate
(see “Root path costs” on page 103)
* Bridges conformant to IEEE Std 802.1D, 1998 Edition, i.e., that support
only 16 bit values for Path Cost, should use 65 535 as the Path Cost for
these link speeds when used in conjunction with Bridges that support 32
bit Path Cost values.