Newbie Q - main/standby server access to TS16 Realport ports

Dear forum,
I have got a TS16 for evaluation, I have an application involving about 300 COM ports on dual servers. They will be modem and radio devices, some with RTS Toggle required. One of the servers is usually Main, connecting to ports. The other is Standby and will not be connected.

On failure of Main, the Standby will take over and must force a grab of the ports to talk with the devices. It must break through any existing connection the old Main had.

Is this possible with RealPort, and how would I configure it. I am not sure that Port Sharing is right in this case. Maybe there is an API call to break through?

Thanks for the help,


Yes, configuring for failover is possible using these products.

You can use port sharing or implement a timeout to have the PortServer close the primary connection after it is idle:

Thanks for that. I have tried it with:

set tcp active=on
set tcp keepalive_idle=00:00:10
set tcp probe_cnt=5
set tcp probe_interval=10
(And reboot)
And got a 12 minute timeout (time between unplugging old server from LAN and new one taking over and getting the port).

This was slow, so to get shorter:
Set tcpip rto_max=10
Set tcpip keepalive_byte=on
With these settings I get a 1.5 to 2 minute port takeover.

I did try enabling port sharing (2 conn, shared control, 6000ms t/out), but the takeover time did not improve. I guess I don’t fancy this mode either, because of the potential failure mode.

So, can I get any shorter port takeover?

(I’ve had a weekend of doing changeover tests, so forgive any config bloopers in trying to get this going!)


A timeout value of 50 seconds is the minimum:

#> set tcpip keepalive_active=on keepalive_idle=00:00:10 probe_cnt=5 probe_interval=10 rto_max=5

will make the unit lose the tcp socket connection after about 50 seconds of idle/inactivity, thus another connection could take over the port.

Not sure why there would be a delay for a shared connection, it should connect right away. Perhaps the RealPort host is having some affect. What O.S./version are you running?

Hi again,

Yes thanks, I think I’m seeing about 50s, independent of additional application delays.

Lots of quick questions but I think I’m nearly there!

  1. Both hosts for my test are XP Pro, although the intended application will be 2003 Server. There will be about 12 TS16 in this system (and another separate system!), are there any issues with this number of ports supported?

  2. I have retried enabling multiple connections to a port. Is the web interface supposed to report No Active Connections when the port is used in this way?

  3. The first time I tried to get a second connection (with Hyperterminal), it was unable to connect. On subsequent connections it was fine, and the changeover speed was limited only by the application.

  4. I am nervous of attempting RTS Toggle on ports used in this shared way - is this an acceptable way of using it? (Please confirm I need to use the registry setting for RTS toggle, as in KB item 859).

  5. Will setting the multiple port connection timeout prevent the ‘dormant’ server from causing problems, even if it has the port open and is not reading it (set sharing range=1 clients=2 control=shared timeout=60 wrpolicy=all).

  6. By the way, will the keep-alive setting on the port’s Advanced Tab in Device Manager have any effect? As far as I can see, I’ll get a load of messages to the Event Viewer but the time to disconnect will not shorten.

  7. My present driver and firmware versions:

Model: PortServer TS 16 Rack
POST: 82000685_F 08/03/2005
Firmware: Version 82000684_R2 12/12/2005
PortServer 15/11/2004

Do you recommend that I upgrade it to POST '685_G, Firmware '684_R3, and PortServer '2164_T ( 12/9/05) ?

Thanks for all your help and best regards,


Message was edited by: biblet

Steve, I think you’re going to want to submit an online support request with all the information in your last post. Here is a link to the request form:

OK, have done.