Results tagged “f5” from Bill Benac

F5 Terminology Cheat Sheet

corporate acronyms.jpgTechnology is a land of overlapping and confusing terminology. I've been involved in plenty of confusing conversations about F5 products as they relate to WCI portal deployments, and I've worked to develop a more precise use of terms. To help a colleague sort out the mishmash, I made this list of objects we commonly discuss. Maybe you'll find it useful too?

In addition to understanding the terms, I think it's helpful to recognize areas of overlap and be careful to avoid confusion. For example, since the VMWare team thinks "virtual servers" run an operating system and the F5 team thinks "virtual servers" represent pathways through their network, I like to say "F5 virtual server" or "VMWare virtual server."

Global Traffic Manager -- GTM (routes requests to the appropriate LTM)
- Wide IPs represent services. An URL is associated with the Wide IP so that users can route through here. Wide IPs can have iRules.
- Pools are configured under Wide IPs.
- Members are assigned within the pools. We create a region1 and a region2 member. These members point to the IP addresses and ports of LTM virtual servers. Normally (but not always) they are given names that match the LTM virtual servers.

Local Traffic Manager -- LTM (routes requests to the appropriate application servers)
- Virtual servers represent services. They have IP addresses and they listen on a port. They can have iRules. When multiple host names are required for the same service, those host names can all alias to the IP of the virtual server (e.g. http://portlets and http://portlets2).
- Pools are configured under virtual servers. One pool can be used by multiple virtual servers, as we do in an environment with the imageserver pool, since we need both HTTP and SSL access to those resources. The customer usually assigns monitors to these, and the monitor applies to every member in the pool.
- Members are assigned within the pools. They are represented by the IP address of the server hosting the service and the port of that service, though the port doesn't have to be the same one used by the virtual server. Customers doesn't usually assign monitors to these, though it could be done.
- Nodes we don't talk about much. These are the IP addresses of the servers that are later combined with ports to be members.

- Wide IP:
- URL:
- Pool of Wide IP: app-portlet
- Members of Pool: port 80, port 80. Member names are app-portlet-reg2-80 and app-portlet-reg3-80

- Virtual Server: Name app-portlet-reg3-80 with IP address and port 80
- Pool of Virtual Server: app-portlet-reg3-80 with monitor
- Members of Pool: and
- Nodes of Members: and

Here is a picture of the LTM's network map view. This shows the virtual servers, their pools, and the members of the pools:


Want to understand F5's LTM in depth, everything from the objects above to session awareness, monitor configuration, iRules, and so forth?  Then I recommend you take "BIG-IP Local Traffic Manager (LTM) Essentials," the free, self-paced, 14 hour training course at You can follow training modules, then log into a cloud-based LTM to do configuration exercises. Even if you're not the person managing the device for your customer, you'll be able to ask for the right things by knowing so much. And you might even know about features your F5 team isn't aware of, and you'll then be able to push them to a new level of ROI from this product.


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