Why Terminal Server Solutions in General, and Solutions with
HOB RD VPN in Particular, Should Avoid Using F5 BigIP Load Balancers
The F5 BigIP solution does not provide automatic reconnects in the event
that a user loses his TCP session, e.g., through an unintentional disconnect.
When using the Internet, for example, various technical problems could cause a
user to be disconnected from his TCP session. With F5 BigIP load balancing,
there is a big possibility that this user would be reconnected to a different
server than that on which he had been working before the disconnect took place.
Not only will this user have to start his work from scratch, the old session may
lock some data, preventing the user from starting work again at all without
administrator or help desk intervention.
The F5 BigIP load balancer cannot use the encrypted Terminal
Server Protocols to find out to whom a session belongs, nor can it determine
where a user has a disconnected session. With F5 BigIP, you cannot obtain this
information at all. F5 BigIP load balancing may be a good solution for many
protocols: However, for Terminal Server solutions, other strategies are
required. Properly configured, the HOB load balancing solution, which was
designed especially for the Windows Terminal Server, will reconnect the user to
the previously disconnected session. This superior, patented solution greatly
increases efficiency, as no work is lost, data is not “locked up,” and the user
can pick up exactly where he left off.
F5 BigIP increases latency of the Terminal Server traffic. When a user
works with a terminal server, network latency, not insufficient bandwidth, is
the real problem. Each keystroke and each mouse move has to cross the network
from the client to the server and back to the client before the user sees a
result. The time this roundtrip takes, called network latency, is extremely
critical for user acceptance. As F5 BigIP is another box running software that
has to be traversed, it increases network latency, and this really should be
avoided.
The F5 BigIP cannot measure the really essential data required for proper
load balancing with Windows Terminal Servers. This data can only be queried on
the Windows Terminal Server itself, making it impossible for a box measuring
network traffic to perform proper load balancing. The HOB load balancing module,
however, collects the parameters for load balancing on the Windows Terminal
Server itself.
F5 BigIP means additional hardware and software components, i.e.,
additional points of failure and sources of bugs. With HOB’s load balancing
solution, only Microsoft and HOB components are needed, making troubleshooting
that much easier.
HOB offers simple load balancing at no extra charge. If enhanced load
balancing is required, this is available at a additional cost, in combination
with Kaspersky anti-virus software for checking RDP local drive mapping. Of
course, the Kaspersky anti-virus software has to be purchased separately. This
server module, called HOB Enhanced Terminal Services, is well worth its price,
as it provides an extra degree of security, stability and performance that helps
ensure user acceptance, thereby increasing efficiency.
