F5 GTM Topologies Load Balancing

Topologies are a way to load balance to a specific pool dependent on were the traffic comes from or is going.


This requires a topology record for the GTM, so that it knows how to handle DNS requests. This is made up of 3 parts. the Request Source, the Destination Source and Weight.




The reuqest source defines where the DNS request came from. the can use 

A continent

A country (based on the ISO 3166 top-level domain codes)

An IP subnet (CIDR definition)

An Internet Service Provider (ISP)

A custom region

The destination defines the resource to which the GTM will direct the DNS request too.

A continent
A country (based on the ISO 3166 top-level domain codes)
A data center
An IP subnet (CDIR definition)
An Internet Service Provider (ISP)
A pool of virtual servers
A custom region

The last element of a topology record, called the topology score or weight, allows the Global Traffic Manager to evaluate the best resolution option for a DNS request. In the event that a name resolution request matches more than one topology record, the Global Traffic Manager uses the record with the highest weight attribute to determine which statement it uses to load balance the request

To set up a topology record

On the Main tab of the navigation pane, expand Global Traffic and then click Topology.
The main screen for topologies opens.
Click the Create button.
The New Record screen opens.
To create a request source statement, use the request resource settings:
Select an origin type from the corresponding list.
Select an operator, either is or is not.
Define the criteria for the request source statement. For example, if the statement focuses on a country, a list appears from which you select the country. If the statement focuses on an IP subnet, a box appears that allows you to define that subnet.
To create a destination statement, use the destination settings:
Select a destination type from the corresponding list.
Select an operator, either is or is not.
Define the criteria for the destination statement. For example, if the statement focuses on a country, a list would appear from which you select the country. If the statement focuses on an IP subnet, a box appears that allows you to define that subnet.
In the Weight box, specify the priority this record has over topology records.
Click the Create button to save the new topology.

Using topology load balancing in a wide IP

You can use the Topology load balancing mode to distribute traffic among the pools in a wide IP. To do this, you must have at least two pools configured in the wide IP. With topology load balancing, you send name resolution requests to specific data centers or other resources based on the origin of the request.

To configure a wide IP to use topology load balancing

On the Main tab of the navigation pane, expand Global Traffic and then click Wide IPs.
The Wide IPs screen opens.
Click the name of the wide IP for which you want to assign topology-based load balancing.
The properties screen for the wide IP opens.
On the menu bar, click Pools.
The pools screen opens. This screen contains a list of the pools currently assigned to the wide IP.
From the Load Balancing Method list, select Topology.
Click the Update button to save your changes.

Repeat this process for each wide IP as needed.