HDLC-Frame Protocol User’s Guide Edition 4 HP 9000 Networking Manufacturing Part Number: Z7487-90005 E0400 © Copyright 2000 Hewlett-Packard Company
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Preface The HDLC.FRAME Protocol Product is used in conjunction with Hewlett-Packard’s Advanced Communications Controller (ACC) product. This manual explains installing the HDLC.FRAME protocol module and configuring the module into the ACC product. Organization This manual contains the following chapters and appendix: Chapter 1 Chapter 1 , “Overview,” presents an overview of the features provided by the HDLC.FRAME Protocol product.
Contents 1. Overview Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Product Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Supported Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Data Rules . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Other Non-E1/T1 interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 E1/T1 interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Receive Completion Status Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4. Protocol Specific Configuration Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Interface Definitions . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Protocol Option Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Predefined Configuration Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 A. Sample Configuration File Terminal Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 B. Using the SS7 Mode Feature Transmitting Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 Receiving Frames . . . . . . . . . . . .
Contents 12
1 Overview 13
Overview Introduction Introduction The HDLC.FRAME Protocol is part of the Advanced Communications Controller (ACC) family of products This manual provides configuration information that is specific to that protocol. There are differences in the use of the HDLC.FRAME protocol, which depend on the type of physical interface in use. The physical interface types fall into one of two categories. These are “E1/T1” and all other types (for example “RS232” or”X.21”).
Overview Supported Devices Supported Devices The HDLC.FRAME protocol implementation may be used to support any protocol which requires HDLC framing conforming to the above published standard at the physical layer. Modes of Operation The HDLC.FRAME implementation supports a single mode of operation: • Two way continuous communication (normal) Data Rules This release of the HDLC.FRAME protocol product is qualified for use at line speeds up to the limit set by the interface card hardware.
Overview Files Provided Files Provided The HDLC.FRAME protocol is provided with all pre-loaded firmware files as part of the ACC Base Software product. The HDLC.FRAME protocol may also be used on the same ACC card as other protocols. For information on installing the ACC product, how to load the relocatable firmware files, and how to start up the ACC Subsystem, refer to the ACC Installation and Configuration Guide.
2 Software Installation Note 17
Software Installation Note Notice Notice This chapter is only included to inform the reader that there are no specific steps or procedures involved in the installation of the Level 1 Framing protocol HDLC.FRAME. When the ACC Base System software is installed, this protocol is included in that installation.
3 Using HDLC.
Using HDLC.FRAME Protocol Introduction Introduction For a complete description of the communications formats and protocol disciplines, the reader is referred to the ISO standard mentioned in the first chapter of this manual. The HDLC.FRAME protocol is a non-polled, bit oriented protocol. Each unit transmitted over a Level 1 link is termed a frame.
Using HDLC.FRAME Protocol Timeout Processing Timeout Processing There are no user-configurable timeouts in use with the HDLC.FRAME protocol. Application Control Requests All HDLC.FRAME terminals must be enabled prior to sending and receiving messages. The activate and deactivate requests have no effect on the HDLC.FRAME protocol.
Using HDLC.FRAME Protocol Link State Indications Link State Indications Non-E1/T1 ACC If the “DSIG” configuration bit is set then the UP/DOWN state of the HDLC.FRAME terminal is dependent on the state of the CTS and DCD signals. When CTS and DCD are both asserted, the HDLC.FRAME terminal is UP. If the “DSIG” configuration bit is clear then the state of the HDLC.FRAME terminal is not dependent on the state of the CTS and DCD signals. In this case the HDLC.FRAME terminal is always UP.
Using HDLC.FRAME Protocol Link State Indications • If the “qdown” option is set then the port is set DOWN whenever the hardware detects a loss of synchronization. It is possible for the hardware to alternately re-establish and lose synchronization extremely rapidly with a poor quality line, making it difficult for higher layer protocols to operate.
Using HDLC.FRAME Protocol Request Specific Processing Request Specific Processing Control Requests All control writes to this protocol share a common format. The first four bytes are defined as a header 15 14 13 12 11 10 9 Control Code 8 7 6 5 4 3 2 1 0 Control Length Packet Length(0) Control Code Defines the action to be taken by this request. Control Length The byte length of the data for this control request. This data immediately follows the header.
Using HDLC.FRAME Protocol Status and Error Messages Status and Error Messages Error conditions and important events are reported to the application program through three kinds of status codes. These are “Transmit completion”, “Unsolicited” and “Receive completion” status codes. The defines for these status codes are located in /usr/include/zcomstatus.h and /usr/include/zx25status.h. Transmit Completion Status Codes Transmit completion status is generated by the protocol on all transmit messages.
Using HDLC.FRAME Protocol Status and Error Messages Non-E1/T1 Interface The following transmit completion status codes may be generated by the HDLC.FRAME protocol on a non-E1/T1 interface. Table 3-1 Non-E1/T1 Interface Transmit Completion Status Codes Transmit Status Code Description IO_OK No error detected. This message was successfully transmitted to the receiving station. IO_DSBL Terminal disabled. Messages cannot be transmitted by a disabled terminal.
Using HDLC.FRAME Protocol Status and Error Messages E1/T1 interface The following transmit completion status codes may be generated by the HDLC.FRAME protocol on an E1/T1 interface. Table 3-2 E1/T1 Interface Transmit Completion Status Codes Transmit Status Code Description IO_OK No error detected. This message was successfully transmitted to the receiving station. IO_DSBL Terminal disabled. Messages cannot be transmitted by a disabled terminal. IO_DOWN Terminal down.
Using HDLC.FRAME Protocol Status and Error Messages Unsolicited Status Messages The unsolicited status messages (mrq.mrqcode = = ZCOM_MRQCODE_STATUS) are used to inform the application program of events which occur affecting communications with the remote station. The status code “No error detected” is used to inform the application that the remote station is communicating normally. This could occur when an terminal has been enabled, or after an error condition has been cleared.
Using HDLC.FRAME Protocol Status and Error Messages Table 3-3 Z7340A Interface Unsolicited Status Codes Unsolicited Status Code Description IO_ALRDY_DSBL A disable request is received, while HDLC.FRAME is already disabled. No action is taken. IO_RX_BUF Either the port or the card as a whole is running low on free buffers. Some tuning of the ACC configurable parameters may be required. Refer to the section on “TTGEN” in the ACC Utilities Reference Guide.
Using HDLC.FRAME Protocol Status and Error Messages E1/T1 interface The following unsolicited status codes may be received by an application program from the HDLC.FRAME protocol on an E1/T1 interface. Table 3-5 E1/T1 Interface Unsolicited Status Codes Unsolicited Status Code Description IO_OK No error detected. Normal communications have been established or resumed. IO_DSBL Terminal Disabled IO_TX_TMOUT Cable or local modem fault. The physical connection to the remote device has been lost.
Using HDLC.FRAME Protocol Status and Error Messages Receive Completion Status Codes1 If the BADFR bit is not set in the configuration, all messages received by the application from HDLC.FRAME will have a status code of zero. Received messages that have errors will not be returned by the protocol. See Chapter 4 , “Protocol Specific Configuration.” If the BADFR bit is set, all messages, regardless of whether or not they have errors, are received by the application from HDLC.FRAME.
Using HDLC.
4 Protocol Specific Configuration 33
Protocol Specific Configuration Introduction Introduction This chapter provides specific information on preparing the network configuration file when HDLC.FRAME is to be used. The parts of the network configuration file relevant to HDLC.FRAME are: • Interface definitions • Port definitions • Terminal definitions Interface Definitions Any card with HDLC.FRAME terminals configured, must have an interface definition line in the network configuration file.
Protocol Specific Configuration Port Definitions Port Definitions The ports used must be defined as operating in SDLC mode. They may be defined with either an external (modem supplied) clock, or an internal (Card supplied) clock. With an external clock, the speed is for documentation purposes only, and is not used by the ZCOM system. The clock multiplier should be x1, and the encoding mode may be NRZ or NRZI.
Protocol Specific Configuration Terminal Definitions Terminal Definitions Only one HDLC.FRAME terminal may be configured on each port (or in the case of an E1/T1 interface, on each subchannel). The only exception to this rule is that two Protocol Analyzer terminals (one for transmitted and one for received data) may also be configured on a subchannel.
Protocol Specific Configuration Terminal Definitions name A description of the HDLC.FRAME terminal, preferably including a reference to the location of the remote end of the link. This field is used in some ZMNTR displays. It may also be accessed programmatically from the Logical Terminal table using the “zinfo()” library function. An example Level 1 terminal definition line follows: Term 120 1:6 HDLC.
Protocol Specific Configuration Non-E1/T1 HDLC.FRAME Configuration Values Non-E1/T1 HDLC.FRAME Configuration Values Poll Word 15 14 13 12 11 Reserved (0) AZR AZT 0 10 9 8 7 6 5 4 3 2 1 0 CWEN RSIG DSIG RTS Reserved (0) All reserved bit positions must be filled with zeros (0). AZR - (Z7340A only) Analyzer terminal for received data Enables this terminal for monitoring frames received on the port.
Protocol Specific Configuration Non-E1/T1 HDLC.FRAME Configuration Values DSIG - Go down on loss of signal If set to one (1), this bit will cause the HDLC.FRAME terminal’s status to be changed to DOWN when the CTS or DCD signal is lost. At the same time, an unsolicited status message is delivered to the receiving application. The RSIG option has no effect in this case. If this bit is set to zero (0), then the HDLC.FRAME terminal continues to operate whatever the state of the CTS and DCD signals.
Protocol Specific Configuration E1/T1 HDLC.FRAME Configuration Values E1/T1 HDLC.FRAME Configuration Values Poll Word 15 14 13 12 11 10 9 8 7 6 0 0 AZR AZT 0 0 0 SS7 FISU Flags 5 4 3 2 1 0 All reserved bit positions must be filled with zeros (0). FISU Flags - FISU inter-frame flag count (SS7 only) Sets the number of flag octets to be inserted between transmitted FISU frames. The flags reduce the frequency of FISU transmission. Recommended value - 6.
Protocol Specific Configuration E1/T1 HDLC.FRAME Configuration Values Select Word 15 14 13 12 11 10 9 8 Bulk-Rx 7 6 5 4 3 2 1 0 Discard-rate Discard-rate - Received FISU or LSSU frames to discard (SS7 only) This determines how many FISU or LSSU frames are received and discarded before one is passed up to the receiving application. The actual number of frames discarded is obtained by multiplying this parameter by sixteen (16). Recommended value - 200.
Protocol Specific Configuration E1/T1 HDLC.
A Sample Configuration File 43
Sample Configuration File Terminal Definition Terminal Definition The file shown is an example of the configuration of HDLC.FRAME protocol devices.
B Using the SS7 Mode Feature 45
Using the SS7 Mode Feature Transmitting Frames Transmitting Frames When enabled HDLC.FRAME begins sending flags. The application can then send a MSU, LSSU or FISU to HDLC.FRAME for transmission. Note that an LSSU may have one or two bytes of status information. Following the transmission of the frame, HDLC.FRAME enters one of two states.
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”.
Using the SS7 Mode Feature Receiving Frames 48 Appendix B
