Dell PowerConnect B-RX BigIron RX Series Configuration Guide v02.7.02 - Page 268

7 Configuring forwarding parameters Configuring the device to drop traffic sent to the default IP route address in hardware causes the device to program 32-bit host CAM entries for each destination address using the default route, which could consume the CAM space. To prevent this from happening, you can enable the CAM Default Route Aggregation feature. To do this, enter the following command: BigIron RX(config)# ip dr-aggregate Syntax: ip dr-aggregate Static route tagging Static routes can be configured with a tag value, which can be used to color routes and filter routes during a redistribution process. When tagged static routes are redistributed to OSPF or to a protocol that can carry tag information, they are redistributed with their tag values. To add a tag value to a static route, enter commands such as the following: BigIron RX(config)#ip route 192.122.12.1 255.255.255.0 192.122.1.1 tag 20 Syntax: ip route | / tag The is the route's destination. The is the network mask for the route's destination IP address. Alternatively, you can specify the network mask information by entering a forward slash followed by the number of bits in the network mask. For example, you can enter 192.0.0.0 255.255.255.0 as 192.0.0.0/.24. You can enter multiple static routes for the same destination for load balancing or redundancy. The is the IP address of the next-hop router (gateway) for the route. In addition, the can also be a virtual routing interface (for example. ve 100), or a physical port (for example, ethernet 1/1) that is connected to the next hop router. Enter 0 - 4294967295 for tag . The default is 0, meaning no tag. Configuring load balancing and redundancy using multiple static routes to the same destination You can configure multiple static IP routes to the same destination, for the following benefits: • IP load sharing - If you configure more than one static route to the same destination, and the routes have different next-hop gateways but have the same metrics, the device load balances among the routes using basic round-robin. For example, if you configure two static routes with the same metrics but to different gateways, the device alternates between the two routes. For information about IP load balancing, refer to "Configuring IP load sharing" on page 201. • Backup Routes - If you configure multiple static IP routes to the same destination, but give the routes different next-hop gateways and different metrics, the device will always use the route with the lowest metric. If this route becomes unavailable, the device will fail over to the static route with the next-lowest metric, and so on. NOTE You also can bias the device to select one of the routes by configuring them with different administrative distances. However, make sure you do not give a static route a higher administrative distance than other types of routes, unless you want those other types to be preferred over the static route. For a list of the default administrative distances, refer to "Changing administrative distances" on page 765. 196 BigIron RX Series Configuration Guide 53-1001810-01