NetMedia iViewHD-2M - Manual (Page 22)

See iViewHD Services and Protocols section for more details about the protocols and how to use
them.
Change TCP Keep-Alive
You can enable and change various parameters which control iViewHDʼs keep-alive mechanism. The
keep-alive mechanism will terminate network connections if a computer is not reachable for a period
of time. The parameters which can be changed here are global and effect all iViewHD TCP/IP
protocols/services (i.e. HTTP).
Normally TCP/IP connections are maintained indefinitely. This means that intermediate computers
and routers can go down and come back up and TCP/IP will not care. This can cause problems in
certain cases when a computer connected to iViewHD goes down. iViewHD will maintain the connec-
tion to its service for the computer because it has no way of knowing the computer has been shut
down. Because a connection is still maintained for a particular service, iViewHD will not allow other
computers to connect to that service.
To remedy this problem you can enable TCP Keep-Alive. You can fine tune the keep-alive mechanism
by altering various parameters:
• Idle Time - specifies the amount of time in seconds to wait before sending a probe packet to de-
termine if the other end is still active. The default value of 7200 is 2 hours.
• Retry Interval - specifies the amount of time in seconds between successive probe packets.
The default is 9 seconds.
• Retry Count - specifies the number of times probe packets will be retried before the connection
is terminated. The default value is 75 times.
Set Extra Port
All iViewHD services can be accessed at their default port numbers. The extra port value is a number
which is added to the default port number which allows iViewHD to also be accessed at a different
port number. For example, by default iViewHDʼs web pages can be accessed at port 80. The default
extra port value of 47000 allows iViewHD to also be accessed at port 47080. If you need to disable
this feature, just set the extra port value to 0.
The extra port value can be used, for example, in a NAT router to forward TCP/IP data in a certain
port range to a iViewHD. You could set port 47080 to be forwarded to a iViewHD on the local network
while the NAT routerʼs web page was externally accessible as port 80. This is also useful in cases
where some ISPs block port 80. In this case, iViewHD would be externally accessed on port 47080
while still being internally accessed on port 80.
iViewHD Userʼs Manual
22 © 2009 NetMedia, Inc.