3Com 4007, Руководство по внедрению, Страница: 165 / 684

Bridging Implementation Summary 165
You can configure a single path topology purely with cabling. However,
the Spanning Tree Protocol (STP) gives you a way to configure
redundant
cable paths but yet maintain only one active path between two devices.
STP monitors the status of all paths and, if an active path goes down, STP
activates a redundant path and reconfigures the network topology
accordingly. STP operations are fully described in the
IEEE 802.1D MAC
Bridges standard.
For more detailed information about Spanning Tree and the settings in
your modules, see “STP Terms and Concepts” and “STP Bridge and Port
Parameters” later in this chapter.
There are other ways to build redundancy into your network with or
without using STP. Discuss your options with your network designer or
3Com product and service vendor.
Bridging
Implementation
Summary
Your module supports several features that relate to the bridging process
and are therefore organized under the
bridge
menu on the interface.
The following features are covered in this chapter:
■
Compliance with IEEE 802.1D MAC Bridges standard — Modules
comply with the requirements that are outlined in the IEEE 802.1D
Media Access Control (MAC) Bridges standard. Each module:
■
Supports transparent bridging, a form of bridging that listens
promiscuously to every frame that is transmitted
■
Stores each received frame until the frame can be forwarded to
one or more LANs or filtered.
■
Builds one or more address tables (depending on VLAN mode) by
dynamically learning addresses as well as storing manually
configured static addresses. See “MAC Address Table Design” in
this chapter for more information.
■
Ages addresses out of the address table within defined periods of
time if those stations have not transmitted frames or if ports have
been disabled. See “Address Aging” in this chapter for more
information.
■
Can detect loops in the network topology.