Introduction

The Point Code and CIC Translation (PCT) feature allows the EAGLE to change the destination point code (DPC) and originating point code (OPC) of an MTP-routed MSU to previously configured values. This functionality allows external networks to continue using the old point codes by emulating and mapping them to the new real point codes within the networks. The feature can also be used to change the circuit identifier code (CIC) for the MSU.

24-bit ITU-N point codes, spare point codes, and private point codes are not supported by PCT entries.

Network nodes can send and receive traffic to and from the emulated point code (EPC) without knowing the real point code that is being emulated by the emulated point code. This ability allows the real point code to be changed transparently from the rest of the network, which can continue using the emulated point code to route traffic.

For each incoming MTP-routed MSU, a DPC lookup is performed if the PCT feature is applied either by using the global setting defined by the chg-stpopts command or using the setting for the incoming linkset defined by the chg-lsopts command. If a translation is found during the DPC lookup, then the DPC of the MSU is replaced by the real point code as the MSU is received by the EAGLE. If the matching translation also contains provisioning for CIC translations, then the CIC of the MSU is changed to the value from the real CIC range.

For each incoming MTP-routed MSU, a DPC lookup and an OPC lookup are performed. If a translation is found during the DPC lookup, then the DPC of the MSU is replaced by the real point code as the MSU is received by the EAGLE. If a real CIC was provisioned in the translation, then the CIC of the MSU is changed to the value from the real CIC range.

If no matching translation is found during the DPC lookup, the OPC lookup is performed. If a translation is found during the OPC lookup, then the OPC of the MSU is replaced by the emulated point code as the MSU leaves the EAGLE. If the matching translation also contains provisioning for CIC translations, then the CIC of the MSU is changed to the value from the emulated CIC range. The OPC lookup is also performed on MTP-routed MSUs which are processed by the service module after feature processing has completed but before the service module sends the MSUs to an outbound LIM for routing. The OPC lookup is performed only on MSUs whose OPC is not the EAGLE's point code, a capability point code, or a secondary point code.

If no matching translation is found during the DPC lookup, the OPC lookup is performed. If a translation is found during the OPC lookup, then the OPC of the MSU is replaced by the emulated point code as the MSU leaves the EAGLE. If an emulated CIC was provisioned in the translation, then the CIC of the MSU is changed to the value from the emulated CIC range. The OPC lookup is also performed on SCCP MSUs after the GTT feature processing has completed but before the service module sends the MSUs to an outbound LIM for routing. The OPC lookup is performed only on MSUs whose OPC is not the EAGLE's point code, a capability point code, or a secondary point code.

To provision the PCT feature, these procedures must be performed.

• Changing the Point Code and CIC Translation Quantity - Used to enable the number of PCT entries that the EAGLE can contain. The EAGLE can contain a maximum of 1000 PCT entries.
• Adding a Point Code and CIC Translation Entry - Used to add a PCT entry to the database.
• Configuring the Point Code and CIC Translation STP Option - Used to configure a system-wide option for controlling the behavior of the PCT feature. This option has three values.
  • on – The PCT feature is applied to all MSUs.
  • off – The PCT feature is not applied to any MSUs. This is the default value for this option.
  • lset – The PCT feature is applied to incoming MSUs or outgoing MSUs on a linkset whose PCT option value is on.
• Configuring the Point Code and CIC Translation Linkset Option - Used to configure the PCT value for a specific linkset when the system-wide option is set to lset. This option has two values.
  • on – The PCT feature is applied to incoming MSUs or outgoing MSUs on a linkset.
  • off – The PCT feature is not applied to incoming MSUs or outgoing MSUs on a linkset. This is the default value for this option.
• Removing a Point Code and CIC Translation Entry - used to remove a PCT entry from the database.