C-M-G
Series
Manual
© TDT GmbH
Chapter 5: Network Configuration
Seite 91 von 136
Command
Description
Scheduling Method
Round Robin
The incoming requests will be assigned sequentially and regularly
to the individual servers. This procedure is only suitable when all
servers are identically equipped. It cannot however prevent
different utilisation of the individual servers.
Weighted Round Robin
Using this procedure the performance of the individual real
servers will be taken into account. Weaker systems will be
sporadically skipped during the distribution and servers with a
higher weighting may be used more often. Weighting refers to the
„weight” value setting in the real server.
Least-Connection
The allocation of a new connection is carried out on the server,
which has the least number of running connections. Based on the
fact that not all sessions create the same load, it can result in the
overloading of individual servers.
Weighted Least-Connection
With this procedure the running connections are normalised via a
weighting. High performance servers are therefore allocated with
more connections than weaker servers. The weighting refers to
the
„weight” value setting in the real server.
Source Hashing
Using this procedure the jobs are allocated, based on the source
IP address of the individual servers, by looking them up in a static
hash table, which the virtual server creates based on different
criteria. Using “source hashing” can, when the number of
permissible connections (2*Weight) is exceeded, result in the
complete failure of the system.
Destination Hashing
Using this procedure the jobs are allocated, based on the target
IP address of the individual servers, by looking them up in a static
hash table, which the virtual server creates based on different
criteria. Using “destination hashing” can, when the number of
permissible connection (2*Weight) is exceeded, result in the
complete failure of the system.
Locality-Based Least-Connection
Connections that are going in the same IP address direction will
be assigned to the same server, when the server is not
overloaded with connections and is available. Otherwise the
algorithm assigns them to servers with fewer connections and
takes this setting for future assignments.
Forwarding Method
NAT
Using this procedure NAT takes over the control of the individual
real servers. This means that each packet between the client and
server passes through the Loadbalancer. On the way to the
server, the target address of the data packet will be exchanged
with IP of a Backend System. On th way back, the official IP of the
Loadbalancers will be reinstated as the senders address. In the
real servers a default route should be entered on the
Loadbalancers IP.
