Multi-Tech MultiModem EDGE Reference Manual page 39

<tcpIrt> Initial Retransmission Timeout (IRT)
1....60 This parameter determines the time (in seconds) the TCP/IP stack will wait before starting the
first retransmission of packets during the initial connection establishment phase.
The TCP protocol ensures the retransmission of packets several times at increasing intervals
until some upper limit is reached.
This mechanism prevents packet loss and serious congestion problems.
Parameter is global for the ME and non-volatile. Use of default value is recommended.
If changed the new value takes effect the next time you start an Internet service with AT^SISO.
Default = 3
<tcpMr> Maximum Number of Retransmissions (MR)
1....30 This parameter determines the maximum number of times to retransmit TCP packets while the
service is in connected state. If the service is still connecting (connection setup) another
algorithm applies.
The value set with <tcpMr> will be assumed as default for the <srv-ParmTag> "tcpMR" when a
new service profile is created with AT^SISS. In each service profile, you can set another
"tcpMR" value which has precedence over the global value set with AT^SCFG. Existing service
profiles are not affected when you change the global value via AT^SCFG.
Parameter is global for the ME and non-volatile. Use of default value is recommended.
Default = 10
<tcpOt> Overall TCP Timer for outstanding connections (tcpOT)
1...6000 This parameter specifies the number of seconds to wait before closing a connection if TCP/IP
packets are not acknowledged.
Setting the maximum value is practically equivalent to deactivating the tcpOT mechanism
because the maximum time would never be reached by the TCP/IP stack.
The value set with <tcpOt> will be assumed as default for the <srv-ParmTag> "tcpOT" when a
new service profile is created with AT^SISS. However, in each service profile, you can set
another "tcpOT" value which has precedence over the global value set with AT^SCFG.
Existing service profiles are not affected when you change the global value via AT^SCFG.
Parameter is non-volatile. Use of default value is recommended.
Default = 6000
<tcpSack> Selective Acknowledge (SAck)
This parameter concerns a set of TCP extensions to improve performance and to provide reliable operation. It
defines new TCP options for scaled windows and timestamps, which are designed to provide compatible
interworking with TCPs that do not implement the extensions.
The set of TCP extensions to improve performance is described in RFC 1323. The value set with <tcpSack>
enables or disables the set of TCP extensions.
Parameter is global for the ME. Use of power up value is recommended.
"0" Disable set of TCP extensions.
"1" Enable set of TCP extensions. Default.
<tcpTtcp> Transaction/TCP (T/TCP)
This parameter concerns T/TCP, an extension of TCP to provide a transaction-oriented service.
T/TCP is described in RFC 1644. The value set with <tcpTtcp> enables or disables T/TCP.
Parameter is global for the ME. Use of power up value is recommended.
"0" Disable T/TCP extension. Default.
"1" Enable T/TCP extension.
<tcpWithUrc> URC Mode or Polling Mode for Internet Service Commands
This parameter enables or disables the presentation of the following URCs related to Internet service
commands: "^SISR" URC, "^SISW" URC and "^SIS" URC for parameter <urcCause>=0 (Internet service
events). "^SIS" URCs with <urcCause>=1 or 2 used to indicate incoming Socket connections are always
enabled.
Parameter is global for the ME and non-volatile.
"on" Enable URCs related to Internet service commands.
Throughout the Chapter "Internet Service AT Commands" the mode is also referred to as URC
mode. Default.
"off" Disable URCs related to Internet service commands.
This requires the host application to employ polling techniques when using the Internet service
AT commands: The host application is responsible to retrieve all status information needed to
control an Internet session. The method is referred to as polling mode.
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371G)
Chapter 2 – Configuration Commands
39