Enterasys Matrix N Standalone Series, Руководство по настройке, Страница: 430 / 1372

Spanning Tree Configuration Summary
Spanning Tree Features
6-2 Matrix NSA Series Configuration Guide
only if the forwarding link goes down. MSTP assigns each VLAN present on the network to a
particular Spanning Tree instance, allowing each switch port to be in a distinct state for each such
instance: blocking for one Spanning Tree while forwarding for another. Thus, traffic associated
with one set of VLANs can traverse a particular inter-switch link, while traffic associated with
another set of VLANs can be blocked on that link. If VLANs are assigned to Spanning Trees wisely,
no inter-switch link will be completely idle, maximizing network utilization.
For details on creating Spanning Tree instances, refer to Section 6.2.1.12 .
For details on mapping Spanning Tree instances to VLANs, refer to Section 6.2.1.15 .
6.1.2 Spanning Tree Features
The Matrix Series device meets the requirements of the Spanning Tree Protocols by performing the
following functions:
•
Creating a single Spanning Tree from any arrangement of switching or bridging elements.
•
Compensating automatically for the failure, removal, or addition of any device in an active data
path.
•
Achieving port changes in short time intervals, which establishes a stable active topology
quickly with minimal network disturbance.
•
Using a minimum amount of communications bandwidth to accomplish the operation of the
Spanning Tree Protocol.
•
Reconfiguring the active topology in a manner that is transparent to stations transmitting and
receiving data packets.
•
Managing the topology in a consistent and reproducible manner through the use of Spanning
Tree Protocol parameters.
6.1.3 Loop Protect
The Loop Protect feature prevents or short circuits loop formation in a network with redundant
paths by requiring ports to receive type 2 BPDUs (RSTP/MSTP) on point-to-point inter-switch
links (ISLs) before their states are allowed to become forwarding. Further, if a BPDU timeout
occurs on a port, its state becomes listening until a BPDU is received.
NOTE:
MSTP and RSTP are fully compatible and interoperable with each other and
with legacy STP 802.1D.