User guide

set tcpip
216 Chapter 2 Command Descriptions
rto_min=30-1000
The TCP maximum retransmission time out (RTO), in milliseconds.
TCP uses progressively larger retransmit values, starting at a minimum
value that is calculated from a sliding window of ACK response round-trip
times that is bounded at the bottom by “rto_min.” So, essentially,
“rto_min” is not necessarily the timeout that will be used as the starting
retransmit timeout, but it is the smallest such value that could be used.
This affects latency, because lowering “rto_min” ensures that retransmits
take place in less time if they occur. By occurring sooner, the network is
able to recover the lost data in less time at the expense of possibly
retransmitting data that is still in-flight or successfully received by the
other side, but unacknowledged due to a “delayed ACK” mechanism or
something similar.
rto_max=1-240
The TCP maximum retransmission time out (RTO), in seconds. When
one side of a TCP connection sends a packet and does not receive an
acknowledgment from the other side within the timeout period, the
sending station retransmits the packet and sets an exponential backoff
timeout. This is done for each successive retransmit until the maximum
retransmission timeout is reached. Then, the TCP connection resets.
tcp_ttl=hops
The initial value of the TCP time-to-live variable, which defines the
maximum number of hops that a packet can survive before being
discarded. The default is 64.
Examples Configure keep-alive options
In this example, the device server TCP component is configured to begin
sending keep-alive probes after a TCP connection has been idle for 10
minutes, send up to 15 probes, and send a probe every 50 seconds.
#> set tcpip keepalive_active=on keepalive_idle=0:10:0 probe_count=15
Configure TCP maximum retransmission timeout value
In this example, the device server TCP component is configured to attempt
to reconnect a dormant connection for up to 100 seconds.
#> set tcpip rto_max=100
See also • "revert" on page 79. The “revert tcpip” option reverts the “set tcpip”
configuration.
• The Digi One and PortServer TS Family User’s Guide’s chapter on
latency tuning.