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Manual Chapter: The Physical Network
Manual Chapter
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The components that make up Global Traffic Manager can be divided into two categories: logical network components and physical networks components. Logical network components are abstractions of network resources, such as virtual servers. Physical network components have a direct correlation with one or more physical entities on the network. This chapter deals with the physical components of Global Traffic Manager, and describes how to use Global Traffic Manager to define the following physical network components that make up your network:
A data center defines the servers and links that share the same subnet on the network. All resources on your network, whether physical or logical, are associated in some way with a data center. Global Traffic Manager consolidates the paths and metrics data collected from servers, virtual servers, and links into the data center, and uses that data to conduct load balancing operations.
For example, the fictional company SiteRequest has a network operation center in New York, which contains two subnets: and Because there are two subnets, the IT team needs to create two data centers: New York 1 and New York 2, within Global Traffic Manager.
On the opposite side of the country, SiteRequest has three operational centers, but they all share the same subnet of Therefore, the IT team needs to create only a single data center: West Coast.
When you create a data center, it is enabled by default. You can disable a data center manually, which allows you to temporarily remove it from global traffic management load balancing operations; for example, during a maintenance period. When the maintenance period ends, you can re-enable the data center.
The resources associated with a data center are available only when the data center is also available, based on the metrics collected by Global Traffic Manager.
A server defines a specific physical system on the network. Within Global Traffic Manager, servers are not only physical entities that you can configure and modify as needed; servers also contain the virtual servers that are the ultimate destinations of name resolution requests. When you configure a server on Global Traffic Manager, unless the server is either a Global Traffic Manager system or a Link Controller system, the server must contain at least one virtual server.
BIG-IP systems
A BIG-IP® system can be a Global Traffic Manager system, a Local Traffic Manager system, a Link Controller system, or a VIPRION® system.
Third-party load balancing systems
A third-party load balancing system is any system, other than a BIG-IP system, that supports and manages virtual servers on the network.
Third-party host servers
A third-party host system is any server on the network that does not support virtual servers.
Global Traffic Manager systems are load balancing servers that are part of your physical network. First, configure the settings of Global Traffic Manager itself. Next, add other Global Traffic Manager systems to the configuration.
If Global Traffic Manager that you are configuring has multiple links (that is, multiple network devices that connect it to the Internet), you can add the self IP addresses of these devices to the system. After you configure these systems, the agents and other utilities, such as the big3d agent, can gather and analyze network traffic path and metrics information.
After you configure the additional servers and links, you can synchronize the settings of a specific Global Traffic Manager to other Global Traffic Managers on the physical network.
Important: You must use a self IP address when you define Global Traffic Manager. You cannot use the management IP address.
Local Traffic Manager systems are load balancing servers that manage virtual servers on the network. There are two standard configurations for Local Traffic Manager:
Regardless of whether Local Traffic Manager shares the same hardware as Global Traffic Manager, you should ensure that you have the following information available before you define the system.
Note: When you define Local Traffic Manager, you must use a self IP address. You cannot use a management IP address.
The IP address and service name or port number of each virtual server managed by Local Traffic Manager, unless you want to use auto-configuration to discover the virtual servers on the Local Traffic Manager system
Note: If your installation of Global Traffic Manager resides on the same system as a Local Traffic Manager system, you define only one BIG-IP server. This server entry represents both Global Traffic Manager and Local Traffic Manager modules.
In addition to BIG-IP systems, Global Traffic Manager can interact with other load balancing servers to determine availability and performance metrics for load balancing connection requests.
Alteon® Ace Director
Cisco® CSS
Cisco® LocalDirector v2
Cisco® LoadDirector v3
Cisco® SLB
Foundry® ServerIron
Note: If your network uses a load balancing server that is not found on this list, you can use the Generic Load Balancer option.
Another server type that you might include as part of your network is a host. A host is an individual network resource, such as web page or a database, that is not a part of the BIG-IP product family and does not provide load balancing capabilities for the resources it supports.
Sun® Oracle® Solaris
Windows® 2000 Server
Note that you can monitor a Windows Vista® Enterprise Edition-based server using a Windows 2000 Server-based computer.
Windows® NT 4.0
Each server that you add to Global Traffic Manager, whether it is a BIG-IP system, a third-party load balancing server, or a host server, has a variety of monitors available. You can assign these monitors to track specific data, and use that data to determine load balancing or other actions.
When you set thresholds for availability, Global Traffic Manager can detect when a managed server is low on resources, and redirect the traffic to another server. Setting limits can help eliminate any negative impact on a server's performance of tasks that may be time critical, require high bandwidth, or put high demand on system resources. The system resources vary depending on the monitors you assign to the server.
When you configure a server, you can set limits for specific elements depending upon whether the server is part of the BIG-IP product family, such as Local Traffic Manager, or another server type. If the server is part of the BIG-IP product family, you can base thresholds on:
If a server meets or exceeds its limits, both the server and the virtual servers it manages are marked as unavailable for load balancing. You can quickly review the availability of any of your servers or virtual servers on the Statistics screens.
If a pool meets or exceeds its limits, both the pool and the pool members it manages are marked as unavailable for load balancing. You can quickly review the availability of any of your pools or pool members on the Statistics screens.
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 specific IP address and port number that points to a resource on the 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.
A link defines a physical connection to the Internet that is associated with one or more routers on the network. Global Traffic Manager tracks the performance of links, which in turn can dictate the overall availability of a given pool, data center, wide IP, or distributed application.
To configure the links that you want Global Traffic Manager to load balance, you add a link entry, and then associate one or more routers with that entry. You can also configure monitors to check certain metrics associated with a link, and modify how the system load balances network traffic across links.
After you configure a link, you can assign monitors that track specific data to the link. The system can use this data to manage global traffic.
You can configure how the system manages and distributes traffic for a given link on the properties screen for the link, using these settings:
Ratio Weighting
If you have links of varying bandwidth sizes, and you want to load balance the traffic to the controller based on a ratio, you can select the Ratio option from the Weighting list. You use this configuration to avoid oversaturating a smaller link with too much traffic.
Price Weighting
If you pay varying fees for the bandwidth usage associated with the links, you can select the Price (Dynamic Ratio) option from the Weighting list. You use this configuration to direct traffic over the least expensive link first and to avoid the costs associated with exceeding a prepaid bandwidth.
Duplex Billing
If your ISP provider uses duplex billing, you can configure the Duplex Billing setting so that the statistics and billing report screens accurately reflect the bandwidth usage for the link.
Important: You can use either the Ratio or Price (Dynamic Ratio) weighting option to load balance the traffic through all of your links. You must use the same weighting option for all links.
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