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SCP: Secure copy command of SSH
SNMP: Simple Network Management Protocol, a network protocol used to manage TCP/IP networks. This
protocol provides functions that enable you to access the data object whose definitions are located in the MIB.
S-NAT: Network Address Translation for a source IP address.
SSH: Secure Shell Protocol
Two-armed: Two Ethernet interfaces are used for in and outbound traffic, one connected to the network side
and one to the farm side.
UTC: Universal Time Coordinated
VIP: Virtual IP Address: The IP address of a service defined on the LoadMaster.
VS: Virtual Service: An entry on the LoadMaster over which a service being hosted in the server farm can be
reached.
WUI: Web User Interface used to perform LoadMaster administration via a web browser.
B. Overview of the LoadMaster
1. Load Balancing and it’s Benefits
As the Internet and networking based Applications evolve and become more sophisticated, they also become
more complicated and unwieldy for those who operate these services and applications. Consequently, the
following issues become key in providing users with the Quality of Service they expect and require:
Scalability of server machines – as the demand on services and applications grows, it is no longer
sufficient to simply upgrade the hardware that hosts these units. Sooner or later, physical limits of
hardware upgradeability are reached. Furthermore, users are not willing to accept the downtime that
accompanies such upgrades.
High availability of services and applications – as Internet based networking is used for mission critical
applications such as banking, B2B and voice over IP, the availability of services can easily determine
the success or failure of a business.
Greater flexibility – as the number and diversity of Internet services and applications increases, it
becomes imperative for network managers to have an environment in which they can trivially “juggle”
their resources around on demand, without endangering the robustness of the environment.
Improved performance – mission critical services and applications require deterministic response
times. The competition is only a click away.
The Solution . . .
Load Balancers are highly robust network devices, and have the effect of making several server machines
appear as one. Thus, a network service can be distributed across an array of physical machines – sometimes
referred to as a server or application farm. The Load Balancer channels requests to a network service using a
variety of intelligent scheduling methods. This has several benefits, which is why load balancing has become a
successful and widely employed technique in recent years:
Scalability of server machines – can be achieved by simply adding server machines to the farm as
demand for services increases. Upfront investments in server capacity, which may go unused, can be
avoided.
