HP UX 11.x Operating Systems manual Receiving Frames

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Using the SS7 Mode Feature

Receiving Frames

Receiving Frames

When enabled HDLC.FRAME begins receiving frames from the line. The first frame received is passed to the application. After the first frame has been received, the contents of received frames and the current state of HDLC.FRAME are used to determine whether subsequent frames are passed to the application.

When a LSSU frame is received HDLC.FRAME enters “LSSU receiving mode”.

When a FISU frame is received HDLC.FRAME enters “FISU receiving mode”.

When in “FISU receiving mode”:

Any FISU with the same sequence numbers as the previous frame are discarded and not passed to the application. However the “discard-rate” parameter sets a limit for the maximum number of FISUs to be discarded, with no intervening MSU or LSSU, and with the same sequence numbers. When this limit is reached one FISU is passed to the application, and the discard count is reset.

If an LSSU is received, it is passed to the application and HDLC.FRAME enters “LSSU receiving mode”.

When in “LSSU receiving mode” Any LSSU with the same sequence numbers as the previous frame and the same status byte(s) as the previous LSSU are discarded and not passed to the application. However, the “discard-rate” parameter is processed in the same way as for FISUs in FISU receiving mode above.

If a FISU is received, it is passed to the layer-2 protocol and HDLC.FRAME enters “FISU receiving mode”.

All MSU frames are passed to the application regardless of HDLC.FRAME’s receive mode. The receive mode is unchanged.

LSSU frames may have one or two bytes of status data.

Appendix B

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Contents Edition HDLC-Frame Protocol User’s GuidePage Legal Notices Page Fourth Edition April Release B.03.10 HP-UX Printing HistoryPage Organization PrefacePage Contents Protocol Specific Configuration Using the SS7 Mode Feature Sample Configuration FileContents Overview Introduction Product FeaturesData Rules Supported DevicesModes of Operation Files Provided Software Installation Note Software Installation Note Using HDLC.FRAME Protocol Application Message Headers Application Control Requests Timeout ProcessingNon-E1/T1 ACC Link State IndicationsLink State Indications Control Requests Request Specific ProcessingTransmit Completion Status Codes Status and Error MessagesTransmit Description Status Code Non-E1/T1 InterfaceNon-E1/T1 Interface Transmit Completion Status Codes Iotxurun E1/T1 interfaceE1/T1 Interface Transmit Completion Status Codes IodownUnsolicited Description Status Code Unsolicited Status MessagesZ7340A ACC Interface Z7340A Interface Unsolicited Status CodesOther Non-E1/T1 Interface Unsolicited Status Codes IoalrdydsblIorxbuf Other Non-E1/T1 interfacesE1/T1 Interface Unsolicited Status Codes Iorxorun Receive Completion Status Codes1Receive Description Status Code IobccerrStatus and Error Messages Protocol Specific Configuration Interface Definitions Port Definitions HDLC.FRAME Terminal DefinitionsZLU Terminal Definitions Poll Word Non-E1/T1 HDLC.FRAME Configuration ValuesBadfr Bad frame completion Dsig Go down on loss of signalRTS Control the RTS signal on transmitted frames Select WordAZT Analyzer terminal for transmitted data E1/T1 HDLC.FRAME Configuration ValuesSS7 Enable SS7 processing Fisu Flags Fisu inter-frame flag count SS7 onlyBulk-Rx Received frame group processing SS7 only Predefined Configuration ValuesProtocol Option Word E1/T1 HDLC.FRAME Configuration Values Sample Configuration File LOGICAL-TERM Terminal DefinitionUsing the SS7 Mode Feature Transmitting Frames Receiving Frames Receiving Frames