A route domain is a configuration object that isolates network traffic for a particular application on the network.

Because route domains segment network traffic, you can assign the same IP address or subnet to multiple nodes on a network, provided that each instance of the IP address resides in a separate routing domain.

Using the route domains feature of the BIG-IP system, you can provide hosting service for multiple customers by isolating each type of application traffic within a defined address space on the network.

With route domains, you can also use duplicate IP addresses on the network, provided that each of the duplicate addresses resides in a separate route domain and is isolated on the network through a separate VLAN. For example, if you are processing traffic for two different customers, you can create two separate route domains. The same node address (such as 10.0.10.1) can reside in each route domain, in the same pool or in different pools, and you can assign a different monitor to each of the two corresponding pool members.

This illustration shows two route domain objects on a BIG-IP system, where each route domain corresponds to a separate customer, and thus resides in its own partition. Within each partition, the customer created the network objects and local traffic objects required for that customer's application (AppA or AppB).

Sample partitions with route domains

A route domain ID is a unique numerical identifier for a route domain. You can assign objects with IP addresses (such as self IP addresses, virtual addresses, pool members, and gateway addresses) to a route domain by appending the %ID to the IP address.

The format required for specifying a route domain ID in an object’s IP address is A.B.C.D%ID, where ID is the ID of the relevant route domain. For example, both the local traffic node object 10.10.10.30%2 and the pool member 10.10.10.30%2:80 pertain to route domain 2.

The BIG-IP system includes a default route domain with an ID of 0. If you do not explicitly create any route domains, all routes on the system pertain to route domain 0.

You can create a parent-child relationship between two route domains, and configure strict isolation, to control the extent to which the BIG-IP system can forward traffic from one route domain to another.

The route domains feature includes the concept of default route domains, to minimize the need for you to specify the %ID notation. When you designate a route domain as the default route domain in a partition, any BIG-IP system objects in that partition that do not include the %ID notation in their IP addresses are automatically associated with the default route domain.

You can assign one or more VLANs, VLAN groups, or tunnels to a route domain. The VLANs, VLAN groups, or tunnels that you assign to a route domain are those pertaining to the particular traffic that you want to isolate in that route domain. Each VLAN, VLAN group, or tunnel can be a member of one route domain only.

When you assign a VLAN group to a route domain, the BIG-IP system automatically assigns the VLAN group members to the route domain.

Please note the following facts:

• If you delete a VLAN group from the system, the VLAN group members remain assigned to the route domain.
• If a VLAN is assigned to a non-default route domain and you delete that route domain, the BIG-IP system automatically assigns the VLAN to the default route domain for that partition.
• When you create VLANs, VLAN groups, and tunnels, the BIG-IP system automatically assigns them to the default route domain of the current partition. You can change this assignment when you create other route domains in the partition.

For each route domain that you configure, you can enable one or more dynamic routing protocols, as well as the network protocol Bidirectional Forwarding Detection (BFD). Use of dynamic routing and BFD for route domain 0 or any other route domain is optional.

When you configure more than one route domain on the BIG-IP system, the traffic from one particular route domain can potentially consume an inordinate amount of BIG-IP system resource. To prevent this, you can define the amount of BIG-IP system resource that traffic for each route domain can consume.

You do this by assigning a different throughput limit to each route domain. This throughput limit is defined in a bandwidth controller policy. For example, for route domain 1, you can assign a static bandwidth controller policy that specifies a throughput limit of 10 Gbps, while for route domain 2, you can assign a static bandwidth controller policy that specifies a throughput limit of 20 Gbps. When you assign a different bandwidth controller policy to each route domain, traffic for one route domain does not cross the boundary into another route domain on the system.

1. On the Main tab, click Network > Route Domains. The Route Domain List screen opens.
2. Click Create. The New Route Domain screen opens.
3. In the Name field, type a name for the route domain. This name must be unique within the administrative partition in which the route domain resides.
4. In the ID field, type an ID number for the route domain. This ID must be unique on the BIG-IP system; that is, no other route domain on the system can have this ID.
5. In the Description field, type a description of the route domain. For example: This route domain applies to traffic for application MyApp.
6. For the Strict Isolation setting, select the Enabled check box to restrict traffic in this route domain from crossing into another route domain.
7. For the Parent Name setting, retain the default value.
8. For the VLANs setting, from the Available list, select a VLAN name and move it to the Members list. Select the VLAN that processes the application traffic relevant to this route domain. Configuring this setting ensures that the BIG-IP system immediately associates any self IP addresses pertaining to the selected VLANs with this route domain.
9. For the Dynamic Routing Protocols setting, from the Available list, select one or more protocol names and move them to the Enabled list. You can enable any number of listed protocols for this route domain.
10. From the Bandwidth Controller list, select a static bandwidth control policy to enforce a throughput limit on traffic for this route domain.
11. From the Partition Default Route Domain list, select either Another route domain (0) is the Partition Default Route Domain or Make this route domain the Partition Default Route Domain. This setting does not appear if the current administrative partition is partition Common. When you configure this setting, either route domain 0 or this route domain becomes the default route domain for the current administrative partition.
12. Click Finished. The system displays a list of route domains on the BIG-IP system.