
Spanning Tree
Redundancy L2B
Release 6.0 07/2010
4.6 The Rapid Spanning Tree
Protocol
53
4.6 The Rapid Spanning Tree
Protocol
The RSTP uses the same algorithm for determining the tree structure as
STP. RSTP merely changes parameters, and adds new parameters and
mechanism that speed up the reconfiguration if a link or bridge becomes
inoperable.
The ports play a significant role in this context.
4.6.1 Port roles
RSTP assigns each bridge port one of the following roles
(see fig. 21)
:
X
Root port
This is the port on which a bridge receives data packets with the lowest
path costs from the root bridge.
If there is more than 1 port with the same low path costs, the bridge
identifier determines which port is the root port.
If there is more than 1 port with the same low path costs connected to the
same bridge, the port identifier determines which port is the root port
(see
fig. 17)
.
The root bridge itself does not have a root port.
X
Designated port
The bridge in a network segment that has the lowest root path costs is the
designated bridge. If more than 1 bridge has the same root path costs, the
bridge with the smallest value bridge identifier becomes the designated
bridge. The port on this bridge that connects it to a network segment
leading to the root bridge, is the designated port.
Содержание MACH 1040 Series
Страница 8: ...Key 8 Redundancy Release 6 0 07 2010...
Страница 12: ...Introduction 12 1 2 Overview of Redundancy Protocols Redundancy Release 6 0 07 2010...
Страница 26: ...Ring Redundancy 26 2 2 Example of an MRP Ring Redundancy Release 6 0 07 2010...
Страница 38: ...Multiple Rings 38 3 1 Sub Ring Redundancy Release 6 0 07 2010...
Страница 76: ...Index 76 4 7 Combining RSTP and MRP Redundancy Release 6 0 07 2010...
Страница 78: ......