(HTTP Load Balancing is only available in OctaGate Switch Enterprise Edition)
Improve site performance by spreading load over multiple servers
Avoid site downtime through server failover
Combine Load Balancing and SSL Encryption on one machine
Load Balancing is a method of improving site performance and site up time by
distributing the load of a site over several servers. At $950 OctaGate Switch is
an extremely competetively priced Load Balancing product.
HTTP Load Balancing
OctaGate Switch offers HTTP Load Balancing, which will let you speed up your web applications by
simply adding another server to your site. OctaGate Switch will determine which server
currently has the lightest load, and new connections will be forwarded to that
server. Several load balanced servers are called a load balanced cluster, or
simply a cluster.
OctaGate Switch is an extremely cost
effective method of improving performance of a web
application or web site that's
running slowly. For instance, if you have to choose between a complete re-write
of a system, or simply adding a few more servers, the
choice is easy to make!
If one server suddenly dies, OctaGate Switch will stop redirecting to
it and instead favor the servers that are still working. Once
the server is working again, OctaGate Switch will again include it in the cluster. This
can radically improve your site uptime, because even if a server dies, the site
stays active and responsive but with less capacity.
OctaGate Switch will frequently (currently every 10 seconds) poll all load balancing
servers to verify if they are online or offline. This means that a failed server
will be detected within, on average, 5 seconds.
Connection Persistence - User Session
Once a user has connected to your site, he has a persistent session. This
means that OctaGate Switch will redirected him to the
same server for the duration of his visit - so server side persistence will work
just as it did before.
The most important features of HTTP Load Balancing are:
Speed up slow web application by adding more hardware and let OctaGate
Switch divide the load between the servers
Failover broken servers to servers that are still working
Currently OctaGate Switch supports two main methods for Session identification;
IP Number based session identification
Browser cookie based session identification
IP Number based session identification means that the IP number of the
incoming request is used to identify the user and the session. If you have a
number of users behind a NAT router that method will break down. This is because
they will all appear to have the same IP number.
Instead you can use browser cookie base session identification. This means
that OctaGate Switch will add a cookie to the communication between the server
and the browsers. This cookie will be used to identify the user throughout the
session. This method requires that cookies are enabled on all browsing
computers, though, otherwise it will not work.
For internet applications and external web sites, we recommend that you use
IP number based session identification, because you can't guarantee that all
users have cookies enabled. For intranets and extranets you may use browser
cookie based session identification, just make sure that all browsers accept
Which you prefer will depend on your network topology though - do you use NAT
routers or not?
Balance By Server Capacity
Many Load Balancing solutions don't take the server capacity into account.
This means that if you add a new server that is two times faster than your old
server, the old server will still get as many requests as the new server. In
that situation, it's better do simply remove the old server completely. OctaGate
Switch will instead make sure that the new server get two times as many connections /
requests as the old server. This means that the old server will actually help
instead of hinder the site. The choice for which server a new connection is
forwarded to is based on up to date information about the servers current load.
This also means that old hardware will get a new lease on life, because OctaGate Switch will make sure that they all work to the top of their capacity.
You typically only need one cluster for your site, but OctaGate Switch can easily
handle multiple clusters.