Table of Contents

Syntax Description
Usage Guidelines
Examples
Related Commands

add ip route

The add ip route command is used to add runtime static entries to the IP routing table. When the system is rebooted, the parameters will revert to the last saved values. To make permanent changes to the configuration, use the IP Static section.

Syntax Description

destination	A destination option is usually entered in the standard dotted decimal notation for IP addresses. However, values can be entered in hexadecimal as well. Hexadecimal numbers must either be preceded by a "0x" or they must be complete (8 hexadecimal digits, e.g., C6290C00 for 198.41.12.0). If 0.0.0.0 is specified as the destination, then the route being added is to a default router. The mask must also be 0.0.0.0. The default router will be used to route packets when the destination network is not known by the device.
mask	The mask option tells the device how much of the destination address entry should be considered when determining the route for a packet. This field has the same format as the destination field but typically has 255's for the network portion of the address and 0 for the host portion when adding a network route, and all 255's when adding a host route.
gateway | port	The gateway | port option also has the same format as the destination option and usually is the address of another router (gateway) which is responsible for packets being sent to the destination address or network. This field can also be specified as a physical interface of the device you are configuring (e.g., WAN 0:0 or just "0") when the interface is unnumbered. However, the name of a physical interface cannot be used when that interface is configured for Frame Relay operation. This is because the Frame Relay protocol allows multiple IP addresses to be reached over a single physical interface via different PVCs (permanent virtual circuits). See the Frame Relay section for more information. You can also specify a VPN port for the port. See the Tunnel Partner section for more information about VPN ports.
metric	The metric option specifies the distance or cost to the destination. The metric is used by the routing process to determine where packets should be sent. It usually corresponds loosely with the number of hops to the destination. A lower value makes this a "better route." The value entered here must be between 1 and 15 and may correspond to the actual number of hops to the gateway or may be larger to artificially inflate the cost. There are several reasons why you might enter a route with an inflated metric. If there is more than one route to another destination but the route with the shortest number of hops is over a slow WAN link, you might add a route to cause the IP traffic to take the "quicker" route.
Redist=RIP | OSPF1 | OSPF2 | none	If the optional Redist parameter is specified, this route will be redistributed into the specified routing protocol. If you leave this field off or if none is specified, the static route will not be redistributed. Only one routing protocol can be selected for redistributing each static route. If RIP is specified, the static route entry will be redistributed into the RIP routing protocol which means that other routers will be able to choose this device as a way to forward packets to the destination address, depending on the metric and what other routes are available. Routing information received via RIP from other routers will be redistributed out other interfaces where RIP processing is enabled. When routes are rebroadcast in this fashion, the metric for this route is increased by 1, which increases the cost of the route. If OSPF1 or OSPF2 is specified, the static route entry will be redistributed into the OSPF routing protocol. The 1 or 2 refer to the two types of external metrics which may be used in OSPF. The cost of a type 2 route is simply the external cost, regardless of the interior (i.e., within OSPF) cost to reach that router. A type 1 cost is the sum of both the external cost and the internal cost used to reach that router.

Usage Guidelines

Static routes are used to provide information to the device about where IP packets should be sent when the device itself has not been able to determine a correct route for them using dynamic routing information.

In cases where the routing metrics (i.e., the number of routing hops to a destination) are equal between a static route and a dynamic route, Cisco Systems devices will use the dynamic route.

Note   Static routes are more difficult to maintain and are generally not as reliable as dynamically-determined routes. We recommend that you use static routing only when the network does not provide adequate routing information through RIP.

Examples

The first example adds a default route which passes all packets with unknown destinations to WAN 0. This route might be used on a device which has a connection to an Internet Service Provider through WAN 0.

add ip route 0.0.0.0 0.0.0.0 0 1 
 

The next example adds a route to network 198.41.13.0 through the gateway 198.41.9.65. Notice that the metric is 4. That means that if a better dynamic route is found (the metric is less than or equal to 4), this route will not be used. The command also tells the device to include this route in its RIP broadcast. If the device is restarted or the configuration is saved, this route will not be retained.

add ip route 198.41.13.0 255.255.255.0 198.41.9.65 4 redist=RIP
 

Related Commands

Command	Description
configure Frame Relay	Configures Frame Relay parameters for an interface
configure IP	Configures IP parameters for an interface
edit config IP Static	Creates static IP routes
save	Saves the edited configuration
show ip	Shows IP configuration and statistics

Posted: Wed Sep 27 11:11:23 PDT 2000
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