Technical data

17
Bridging and Routing Operation
The router can operate as a bridge, as a router, or as both (sometimes called a brouter).
• The router will operate as a router for network protocols that are enabled for routing (IP or IPX).
• The router will operate as a bridge for protocols that are not supported for routing.
• Routing takes precedence over bridging; i.e., when routing is active, the router uses the packet’s protocol
address information to route the packet.
• If the protocol is not supported, the router will use the MAC address information to forward the packet.
Operation of the router is influenced by routing and bridging controls and filters set during router configuration as
well as automatic spoofing and filtering performed by the router. For example, general IP or IPX routing, and
routing or bridging from specific remote routers are controls set during the configuration process.
Spoofing and filtering, which minimize the number of packets that flow across the WAN, are performed
automatically by the router. For example, RIP routing packets and certain NetBEUI packets are spoofed even if
only bridging is enabled.
Bridging and Routing Configuration Settings
The router can be configured to perform general routing and bridging while allowing you to set specific controls.
One remote router is designated as the outbound default bridging destination. All outbound bridging traffic, with
an unknown destination, is sent to the default bridging destination. Bridging from specific remote routers can be
controlled by enabling/disabling bridging from individual remote routers.
Routing is performed to all remote routers entered into the remote router database. All routing can be enabled/
disabled with a system-wide control.
The following charts describe the operational characteristics of the router, based on configuration settings.
IP/IPX Routing ON Bridging To/From Remote Router OFF
Data Packets Carried IP (TCP, UDP), IPX
Operational
Characteristics
Basic IP, IPX connectivity
Typical Usage When only IP/IPX traffic is to be routed and all other traffic is to be
ignored. For IP, used for Internet access.
Note:
This is the most easily controlled configuration.