Cisco Cisco Aironet 350 Wireless Bridge Guía Para Resolver Problemas
Components Used
This document is not restricted to specific software and hardware versions.
Conventions
Refer to Cisco Technical Tips Conventions for more information on document conventions.
Equal−Cost Load Balancing
Load balancing is a concept that allows a router to take advantage of multiple best paths (routes) to a given
destination. When a router learns multiple routes to a specific network −− via static routes or through routing
protocols −− it installs the route with the lowest administrative distance in the routing table. If the router
receives and installs multiple paths with the same administrative distance and cost to a destination, load
balancing will occur. In this design, the router will see each wireless bridge link as a separate, equal−cost link
to the destination.
destination. When a router learns multiple routes to a specific network −− via static routes or through routing
protocols −− it installs the route with the lowest administrative distance in the routing table. If the router
receives and installs multiple paths with the same administrative distance and cost to a destination, load
balancing will occur. In this design, the router will see each wireless bridge link as a separate, equal−cost link
to the destination.
Note: The use of equal−cost load balancing and the routing protocols mentioned in this article are a
Cisco−supported means of aggregating Cisco Aironet bridges for additional throughput between sites or as a
redundant failover wireless bridge link.
Cisco−supported means of aggregating Cisco Aironet bridges for additional throughput between sites or as a
redundant failover wireless bridge link.
Routing Protocols
If your design requires failover capabilities, the use of a routing protocol is required. A routing protocol is a
mechanism to communicate paths between routers and can automate the removal of routes from the routing
table, which is required for failover capabilities. Paths can be derived either statically or dynamically through
the use of routing protocols such as Routing Information Protocol (RIP), Interior Gateway Routing Protocol
(IGRP), Enhanced IGRP, and Open Shortest Path First (OSPF). The use of dynamic routes for load balancing
over equal−cost wireless bridge routes is highly recommended because it is the only means available for
automatic failover. In a static configuration, if one bridge fails, the Ethernet port of the other bridge will still
be active and packets will be lost until the problem is resolved. Therefore, the use of floating static routes will
not work for failover purposes.
mechanism to communicate paths between routers and can automate the removal of routes from the routing
table, which is required for failover capabilities. Paths can be derived either statically or dynamically through
the use of routing protocols such as Routing Information Protocol (RIP), Interior Gateway Routing Protocol
(IGRP), Enhanced IGRP, and Open Shortest Path First (OSPF). The use of dynamic routes for load balancing
over equal−cost wireless bridge routes is highly recommended because it is the only means available for
automatic failover. In a static configuration, if one bridge fails, the Ethernet port of the other bridge will still
be active and packets will be lost until the problem is resolved. Therefore, the use of floating static routes will
not work for failover purposes.
With routing protocols there is a tradeoff between fast convergence and increased traffic needs. Large
amounts of data traffic between sites can delay or prevent communication between routing protocol
neighbors. This condition can cause one or more of the equal−cost routes to be removed temporarily from the
routing table, resulting in inefficient use of the three bridge links.
amounts of data traffic between sites can delay or prevent communication between routing protocol
neighbors. This condition can cause one or more of the equal−cost routes to be removed temporarily from the
routing table, resulting in inefficient use of the three bridge links.
The design presented here was tested and documented using Enhanced IGRP as the routing protocol.
However, RIP, OSPF, and IGRP could also be used. The network environment, traffic load and routing
protocol tuning requirements will be unique to your situation. Select and configure your routing protocol
accordingly.
However, RIP, OSPF, and IGRP could also be used. The network environment, traffic load and routing
protocol tuning requirements will be unique to your situation. Select and configure your routing protocol
accordingly.
Switching Paths
The active forwarding algorithm determines the path that a packet follows while inside a router. These are
also referred to as switching algorithms or switching paths. High−end platforms have typically more powerful
forwarding algorithms available than low−end platforms, but often they are not active by default. Some
forwarding algorithms are implemented in hardware, some are implemented in software, and some are
implemented in both, but the objective is always the same −− to send packets out as fast as possible.
also referred to as switching algorithms or switching paths. High−end platforms have typically more powerful
forwarding algorithms available than low−end platforms, but often they are not active by default. Some
forwarding algorithms are implemented in hardware, some are implemented in software, and some are
implemented in both, but the objective is always the same −− to send packets out as fast as possible.