A common topic when talking to customers during pre-sales are the differences between load balancing and bonding and which one is best for them. It's true to say that there is no ideal solution to fit all customers and their requirements.
In order to draw conclusion, we must understand how transmissions are made between 2 hosts, the sender and the receiver. Are you ready for the science lesson?
What is a connection?
Commonly refered to as a connection or stream, it is a single data transmission that is established through the Internet between 2 hosts. The TCP/IP protocol contains many types of connection, the most of common of which is TCP.
TCP - Transmission Control Protocol - Establishes a relationship between 2 hosts and provides a reliable connection
UDP - User Datagram Protocol - A fire-and-forget based protocol that offers performance over TCP
Although there are many protocols that make up the TCP/IP protocol suite, most are based on either TCP or UDP.
What is a session?
A session can me made up of multiple transmissions and there are considered two types. Some applications create multiple transmissions or connections of the same type to improve performance, the most common is HTTP.
When requesting a web site, your computer will open up mutliple connections to the web server, hence you will see multiple image relating to the website, appear at the same time.
The second defination of a session are protocols such as VoIP and IPSEC VPN's who use multiple, different types of connection for different purposes. If we take a look at IPSEC, we can see that a UDP connection is first made to establish a security trust between the two hosts or networks, once succeeded a second connection is made to build the encypted tunnel.
How does load balancing help?
When a new connection arrives at the load balancing device, the connection is directed to one of many links using an algorithm specified. For the entirity of this connection, only the bandwidth of one link can be used. In some instances this might be desirable, in some it probably won't. When the next connections arrives at the load balancing device, it is directed to another link, thus incresing overall bandwidth and performance of the network. Moreover, if an application creates multiple connections to the destination server, its possible that in can benefit from increased bandwidth if the load balancing device chooses to route those connections over multiple links.
The drawbacks of load balancing
If a link fails during a transmission
How does bonding help?
Bonding will take each single connection and
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