Axel AX3000 80WMS, Руководство пользователя

Страница: 128 / 136

Appendix
120
AX3000 Model 80WMS - User's Manual
between 1024 and 3072. For each session a range of 8 TCP ports is given:
session 1 = (x...x+7), session 2
= (x+8…x+15)... When a connection is
established the next port of the associated range is used. After 8 connections,
the same TCP port of a range is re-used.
The main benefit of this method is that if the AX3000 is suddenly powered off
(power cut for example), at the next boot time, the connections are immediately
accepted by the server. (i.e. the sessions are hooked on different sockets
because the TCP ports are different). However this does create ‘phantom’
sessions, as the initial sessions are still active from the server’s perspective, and
must be killed by the server.
This can be done with the ‘keepalive’ process, manually killing or rebooting.
In some situations it may be beneficial to have always the same TCP port for an
AX3000 resource (to avoid phantom sessions or to identify connections). This is
the fixed port assignment. With this method the AX3000 resources are always:
- session 1 = 1024,
- net1 = 1035, net2 = 1036,
- usb1 = 1037, ... ,usb4 = 1040
e) The 'Nagle's Algorithm' Parameter
The Nagle's Algorithm controls behavior of the output network dataflow of a
TCP/IP device. This algorithm allows the number of datagrams sent by the
AX3000 to decrease. However a certain latency may be noticeable due to the
caching of data before transmission.
This algorithm is disabled to prioritize performance. However some operating
systems require this function to be enabled.
f) The 'Keepalive' Parameter
The keepalive is a mechanism that allows the AX3000 to regularly check its
TCP/IP connection status.
In event of network incident, the AX3000 is able to detect this incident and to
close the related TCP/IP connections. This mechanism is also useful when DSL
connections are used (the AX3000 IP address is reset on time per day).
By default the keepalive function is disabled.