For the BIG-IP®
Global Traffic Manager system to operate effectively, you need to define the components that make up the segments of your network. These components include physical components, such as data centers and servers, as well as logical components, such as wide IPs, addresses, and pools. By defining these components, you essentially build a network map that Global Traffic Manager can use to direct Domain Name System (DNS) traffic to the best available resource.
After this basic configuration is complete, Global Traffic Manager has
enough information available to begin directing DNS traffic. You can increase the systems capabilities by adding additional network components.
Several components that you can configure on Global Traffic Manager
system have a direct correlation to a physical location or device on the network. These components include:
Data centers are the top level of your physical network setup. You must
configure one data center for each physical location in your global network. When you create a data center in Global Traffic Manager, you define the servers (Global Traffic Manager systems, Local Traffic Manager systems, Link Controller systems, hosts, and routers) that reside at that location.
A data center can contain any type of server. For example, one data center
can contain a Global Traffic Manager system and a host, while another might contain two Global Traffic Manager systems and eight Local Traffic Manager systems.
is a physical device on which you can configure one or more virtual servers. The servers that you define can include both BIG-IP systems and third-party servers, such as Local Traffic Manager systems and systems running Microsoft®
is a logical representation of a physical device (router) that connects your network to the Internet. You can assign multiple links to each data center by logically attaching links to a collection of servers in order to manage access to your data sources. Configuring links is optional, although they are very useful when determining resource availability.
Servers, excluding Global Traffic Manager systems and Link Controller
systems, contain at least one virtual server. A virtual server
, in the context of Global Traffic Manager, is a combination of an IP address and a port number that points to a resource that provides access to an application or data source on your network. In the case of host servers, this IP address and port number likely point to the resource itself. With load balancing systems, such as Local Traffic Manager, these virtual servers are often proxies that allow the load balancing server to manage the resource request across a multitude of resources. Virtual servers are the ultimate destination for connection requests.
In addition to the physical components of your network, Global Traffic
Manager also handles DNS traffic over logical components. Logical network components
consist of network elements that may not represent a physical location or device. These components include:
To communicate with the rest of your network, you must configure Global
Traffic Manager so that it can correctly identify the resolution requests for which it is responsible. A listener
is an object that monitors the network for DNS queries, and thus is critical for global traffic management. The listener instructs the system to monitor the network traffic destined for a specific IP address.
In most installations, when you define a listener for Global Traffic Manager,
you use the IP address of Global Traffic Manager; however, there are many different ways you can configure listeners so that the system handles DNS traffic correctly.
is a collection of virtual servers that can reside on multiple network servers. When you define the virtual servers to which Global Traffic Manager directs DNS traffic, you combine those virtual servers into pools. You can then configure Global Traffic Manager to direct traffic to a specific virtual server within a pool, using a specific load balancing method.
You can apply a different set of options to the same resources as a virtual
server. When you add a virtual server to a pool, it becomes a pool member to which you can apply monitors, iRules®
, and other configuration options.
One of the most common logical components you create in Global Traffic
Manager is a wide IP. A wide IP
maps a fully-qualified domain name to one or more pools of virtual servers that host the domains content.
When an LDNS requests a connection to a specific domain name, the wide
IP definition specifies which pools of virtual servers are eligible to answer the request, and which load balancing modes to use in choosing a pool. Global Traffic Manager then load balances the request across the virtual servers within that pool to resolve the request.
A distributed application
is a collection of one or more wide IPs, data centers, and links that serve as a single application to a web site visitor. A distributed application is the highest-level component that Global Traffic Manager supports. You can configure Global Traffic Manager so that the availability of distributed applications is dependent on a specific data center, link, or server. For example, if the New York data center goes offline, this information causes the wide IP and its corresponding distributed application to become unavailable. Consequently, the system does not send resolution requests to any of the distributed application resources, until the entire application becomes available again.