Allied Telesis AT-WR4500 - Manual (Page 78)

78 AT-WR4500 Series - IEEE 802.11abgh Outdoor Wireless Routers
RouterOS v3 Configuration and User Guide
Quick Setup Guide
To put interface ether1 and ether2 in a bridge.
Add a bridge interface, called MyBridge:
/interface bridge add name="MyBridge" disabled=no
Add ether1 and ether2 to MyBridge interface:
/interface bridge port add interface=ether1 bridge=MyBridge
/interface bridge port add interface=ether2 bridge=MyBridge
Specifications
Packages required: system
License required: Level3
Submenu level: /interface bridge
Standards and Technologies:
IEEE801.1D
Hardware usage: Not significant
Related Topics
•
IP Addresses and ARP
•
EoIP
Description
Ethernet-like networks (Ethernet, Ethernet over IP, IEEE802.11 in ap-bridge or bridge mode, WDS,
VLAN) can be connected together using MAC bridges. The bridge feature allows the interconnection of
hosts connected to separate LANs (using EoIP, geographically distributed networks can be bridged as well
if any kind of IP network interconnection exists between them) as if they were attached to a single LAN.
As bridges are transparent, they do not appear in traceroute list, and no utility can make a distinction
between a host working in one LAN and a host working in another LAN if these LANs are bridged
(depending on the way the LANs are interconnected, latency and data rate between hosts may vary).
Network loops may emerge (intentionally or not) in complex topologies. Without any special treatment,
loops would prevent network from functioning normally, as they would lead to avalanche-like packet
multiplication. Each bridge runs an algorithm which calculates how the loop can be prevented. STP allows
bridges to communicate with each other, so they can negotiate a loop free topology. All other alternative
connections that would otherwise form loops, are put to standby, so that should the main connection fail,
another connection could take its place. This algorithm exchange configuration messages (BPDU - Bridge
Protocol Data Unit) periodically, so that all bridges would be updated with the newest information about
changes in network topology. STP selects root bridge which is responosible for network reconfiguration,
such as blocking and opening ports of the other bridges. The root bridge is the bridge with lowest bridge
ID.
Additional Resources
http://www.ieee802.org/1/pages/802.1D.html
http://en.wikipedia.org/wiki/IEEE_802.1D
http://ebtables.sourceforge.net/
4.5.2
Bridge Interface Setup
Submenu level: /interface bridge
Description
To combine a number of networks into one bridge, a bridge interface should be created (later, all the
desired interfaces should be set up as its ports). One MAC address will be assigned to all the bridged
interfaces (the smallest MAC address will be chosen automatically).