Configuring TCP/IP with SS7

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Purpose

This section describes how to set up communication between a host and an SS7 card using TCP/IP. Redundancy and example configuration traces are also provided.

Before you begin

The host needs to support the TCP/IP protocol. The host communication to the directly-connected SS7 card is similar to that of the Matrix Controller card. The host selects to communicate with the Matrix Controller card or the SS7 card by using a different IP address.

IP Addressing

TCAP messaging can be sent to the Matrix Controller or SS7 Ethernet port. For information on configuring the IP address on the Ethernet port see Host Communication Module in the API Developer’s Guide: Overview.

Configuration

Follow the steps below to create communication between an SS7 card and a host.

Step	Action
1	Establish an Ethernet connection to the Matrix Controller card.
2	Configure the IP addresses. After the system software is successfully loaded to an SS7 card the first time, you must set the IP address and subnet mask of each SS7 card using IP Address Configure or BOOTP server. The cards retain the IP address and subnet mask even if the system software is reloaded or the system is powered down. You can use the IP Address Query message to get the IP address of the SS7 card after it is set. If an SS7 card does not have an IP address set, it attempts to use BOOTP and RARP to find a BOOTP or RARP server which can supply the IP address. If these fail, the card comes up with no IP address, which disables the use of the "local host" connection to the SS7 card.
3	Configure the host connection Using Configuration Type 0x08 in the SS7 SCCP/TCAP Configure message, delete Matrix Controller host connection. Using Configuration Type 0x08 in the SS7 SCCP/TCAP Configure message, add a local host. For SCCP/TCAP applications, you may configure the SS7 local host for each stack/subsystem.
4	Configure redundant SS7 cards (if applicable) See below.

Redundancy Considerations

An SS7 local host should always communicate with the active SS7 card. The messages directly sent to the standby SS7 card will not be processed. You may set up a socket connection from the host to the standby card, but the only messages that go through this connection should be the Poll messages from the SS7 card to the host. In the case of an SS7 card switchover, it is possible that some messages are lost.

Prior to a switchover, you can configure the TCAP User Interface component (0x70) to either "Reset all the TCAP dialogs" or "Keep the TCAP dialogs" based on the nature of the applications. If the lifetime of the TCAP dialogs is long, for example, the dialogs last for a whole call period, the percentage of dialogs being affected during a switchover will be low. The application may choose to keep all of the dialogs after the switchover. If the application keeps all the TCAP dialogs, TCAP and TCAP applications rely on the TCAP dialog timeout feature to eliminate the aged TCAP dialogs.

TCAP application level error handling procedures are used to recover the errors caused by losing messages for the TCAP dialogs. If the lifetime of the TCAP dialogs is short, for example, the dialog is ended after the call is set up, the percentage of affected dialogs could be high. The application may choose to abort all the TCAP dialogs after switchover. In this case, TCAP will automatically initiate a TCAP restart and all the active TCAP dialogs will be aborted after the previous standby card becomes active. The host can then communicate with the new active card directly afterward for the new dialogs.

Example Configuration Traces

The following are examples of various SS7 Host Connection message traces.

Deleting Matrix Controller Host Connection

The following trace of an SS7 SCCP/TCAP Configure message deletes the Matrix Controller host for Stack 0 subsystem 5 so that messages will not be routed to the Matrix Controller host:

00 0f 00 77 00 00 ff 00 01 08 01 00 08 05 02 ff 00

Configuring an SS7 Card-Host Connection

The following trace of an SS7 SCCP/TCAP Configure message adds a local host for Stack 0 subsystem 5 so that messages will be routed to the SS7 local host:

00 0f 00 77 00 00 ff 00 01 08 01 00 08 05 01 fe 00

Querying the Host Connection

The following trace of an SS7 SCCP/TCAP Query message queries the local host for Stack 0 subsystem 5:

00 0c 00 78 00 00 ff 00 01 08 01 01 01 05

Important! These configuration messages are sent to the Matrix Controller card IP address. After the configuration, you may start the TCAP traffic by sending the PPL Event Request to the SS7 card IP address. The CSP will send TCAP PPL event indications to the SS7 local host.

Clear All Dialogs

The following trace of a PPL Event Request message initiates a "TCAP restart" event to clear all dialogs for Stack 0 subsystem 5:

00 11 00 44 00 00 ff 00 01 2a 03 00 05 00 00 70 00 1e 00