The algorithm of sending TCP keepalive packets changed between HPUX 10 and HPUX 11 (
RFC 1122 - Requirements for Internet Hosts - Communication Layers)
The relevant parameters are:
- tcp_keepalive_interval - Interval for sending keepalive probes
- tcp_ip_notify_interval - R1 for established connection
- tcp_ip_abort_interval - R2 for established connection
The parameter
tcp_keepalive_interval determines the amount of time that TCP waits for an
idle connection with no unacknowledged data before sending keepalive packets.
Default 7200000 ms = 2 hours.
Then send keepalive packets:
tcp_ip_notify_interval (R1)
Default 10000 ms = 10 seconds
UNTIL:
tcp_ip_abort_interval (R2) i
s reached (which is the time that a modem would normally need to re-call for example)
Default 600000 ms = 10 minutes
In other words, the keepalive packets are sent R2/R1 times (in HPUX 10 this was the
tcp_keepstop parameter) which with the default settings, would mean terminate the idle connection in 2 hours 10 minutes.
The HP-UX 10
nettune utility is obsolete functionality in HPUX 11 and has been included instead in the
ndd utility for examining and modifying system-wide transport parameters.
Example:
$ ndd -set [network] [device] [parameter] [value]
$ ndd -set /dev/tcp tcp_keepalive_interval 900000
Use the
"ndd -h <timer_name>" for further information.
Progress does not have specific recommendations - the
tcp_keepalive_interval should be set to as long as an inactive connection is considered to be valid for. These changes will affect all connections, not just Progress.
