WPCL 2BJ|x ` H   x|@  6'6' X  `  @  <AP IX61E AXX  `  @  <AP IX61E AXI (3202) I (3202)    >ANNEX F A 5(to Recommendation G.771) A 0Proposed candidate protocol suitesă A  ( HThis annex contains the candidate protocol suites currently under consideration for selection as members of the PQ(lcn) family of protocol suites. The description of the individual protocol suites is of varying completeness, but each description is limited to the specification of the lower two or three OSI layers. For a complete protocol suite specification higher layers must be defined, however, the available information is provided here to guide hardware decisions. The completion of the descriptions and the selection is for further study.  X HCandidate protocol suite No. 3 has the widest support, but no candidate protocol suite has yet been subjected to a formal selection process by CCITT. HEach candidate protocol suite is described in the following sections. Following the descriptions is a summary section which contains in TableF.5/G.tmn the the candidate protocol selection attribute values (see AnnexE of this Recommendation). Differences of the values in TableF.5/G.tmn indicate differences in capabilities which may affect the suitability of individual candidates for particular application areas. HSome initial applications are indicated for each candidate protocol suite. However, the range of applications appropriate to these suites has not been thoroughly examined. 1.HCandidate protocol suite No.1 (CPS1) HInitial application: HAlarm surveillance, performance monitoring and configuration control of NEs found in reasonably large numbers in the telecommunications network (e.g., muldex, line transmission terminal). 1.1HOSI layer 1 1.1.1HConfiguration HOne serial bus connects up to 30 nodes. HConfigurations with more than 30 nodes can be realized by a hierarchical structure of several serial buses. HSuch a hierarchical structure is characterized by a high throughput with a low transmission rate per bus. 1.1.2HCommunication environment HThe serial bus configuration shall be used only for inbuilding application. 1.1.3HPhysical connection HOne balanced, screened pair with a maximum length of 500 meters. 1.1.4HElectrical requirements HEach bus interface shall be in accordance with V.11 multipoint interconnections. [1, 3, 14, and 23]. HEach bus shall be terminated by resistors in accordance with [23]. HEach receiver shall present a maximum of one unit load to the bus, as defined in [23]. 1.1.5HLine code HThe line code shall be NRZ (non return to zero). 1.1.6HSpeed HThe bit rate shall be 19.2 kbit/s per second. HThe bit rate tolerance shall be + 1%. 1.1.7HTransmission mode HThe transmission mode shall be half duplex, asynchronous. 1.2HOSI layer 2 HAsynchronous, byte oriented protocol according to [15]. 1.2.1HTransmission frame format HThe transmission frame format shall be in accordance with [15, i]. 1.2.2HLink transmission procedure HThe link transmission procedure shall be in accordance with [15, ii]. HAll standard transmission frames specified in [15] shall be used (frame with variable length, frame with fixed length and single character). HThe operation mode shall be: master/slave, cyclical polling. 1.2.3HAddressing HThe address one to 30 of the 256 possible addresses shall be used for cyclical polling. HThe address 255 shall be used for broadcasting (one message to all nodes). 1.2.4HWindow size _(Ԍ HThe window size is fixed to one. 1.3HHigher layers HUnder study. 2.HCandidate protocol suite No. 2 (CPS 2) HInitial application: HAlarm surveillance, performance monitoring, testing commands, response and configuration control of NEs including crossconnect equipment, can be applied to both NEs found in reasonably large numbers in the telephone network (e.g., muldex, line transmission terminal) and to high capability NEs found in limited numbers in the telecommunications network (e.g., crossconnect). 2.1HOSI layer 1 2.1.1HConfiguration: Bus. 2.1.2HLine speed: 1 Mbit per second. 2.1.3HMedium: Screened pair. 2.1.4HElectrical requirement: V.11 interface with pulse transformer. 2.1.5HLine code: CMI. 2.2HOSI layer 2 2.2.1HFrame format HFrame components: H flag, H destination address 2 octets, H source address 2 octets, H control 1 octet, H LLC data variable length (maximum 512 octets), H frame check sequence CRC 16, H flag. 2.2.2HMedia access control HThe media access control discipline known as carrier sense multiple access is used. 2.2.3HLogical link control layer HAcknowledged connectionless mode protocol specification to be specified in ISO88022/AD2 is used. 2.3HUpper layers HUnder study. 3.HCandidate protocol suite No. 3 (CPS 3) HInitial application: HAlarm surveillance, performance monitoring, and configuration control of NEs found in reasonably large numbers in the telecommunications network (e.g., muldex, line transmission terminals). 3.1HOSI layer 1 3.1.1HPhysical characteristics 3.1.1.1 Configuration HSerial bus operation in accordance with ISODIS8482 (ring configuration under study). HUse of full or halfduplex operation shall be determined by the administration. 3.1.1.2 Transmission pairs HTwo screened balanced pairs, one pair for each direction of transmission. Note Two administrations have proposed using each of the pairs of halfduplex mode to provide additional bus security without additional wiring. Certain additional requirements relating to bus occupancy may then be necessary for correct operation in this mode. 3.1.1.3 Bus security HWhere additional bus security is required, bus duplication or output driver protection resistors may be considered. Note Where duplicated buses are employed, no deliberate transmission should take place on both buses at the same time, and the functioning of one bus shall not be prejudiced by continuous noise to unintentioned transmissions on the other. 3.1.1.4 Connector HThe administration shall specify the connector type. 3.1.2HElectrical characteristics 3.1.2.1 Static and dynamic characteristics HStatic and dynamic characteristics of each bus connection shall be in accordance with [14]. 3.1.2.2 Bus termination HEach bus end shall be terminated by resistors (120ohms +10%, 0%) in accordance with [14].  k+Ԍ3.1.2.3 Load connection HEach receiver shall present a maximum of one unit load, as defined in [14] to the bus. The number of load connections is limited to 32. 3.1.2.4 Bit rate HThe bit rate shall be 19.2 or 64 kbit/s per second. A bit rate of 128kbit/s per second may be necessary in some applications. The bit rate tolerance shall be + 1%. 3.1.2.5 Turn off time HA transmitting station shall put its generator in the high impedance state within 1ms from the end of the last bit of the final closing flag. Note The need to reduce this time for bit rates above 19.2kbit/s per second is under study. 3.1.2.6 Preamble HFollowing the enabling of the generator an implementation dependant preamble of no more than 4bit times is allowed. No assumption as to the state of the bus during this preamble is allowed. 3.1.3HLine code HThe line code shall be NRZI. HClock extraction by the remaining station is assumed. 3.1.3.1 Principle HEach transition [14] shall represent a zero, and no transition shall represent onebit. 3.1.3.2 Lockin process HFor clock extraction, a lockin sequence of either one octet of zeroes or one or two flags in accordance with [6], shall be sent immediately prior to the beginning of the opening flag of the frame to be transmitted and immediately following the preamble of 3.1.2.6 (if implemented). 3.1.4HExtended mode HWhere an extended mode capability is required (e.g., using a modem) the requirements of 3.1.1 to 3.1.3 shall apply with the following exceptions: 3.1.4.1 Configuration full duplex 3.1.4.2 Connector HThe connector shall conform to [16]. Appropriate signal leads are to be provided for modem control in accordance with CCITT RecommendationV.24 [2, 22]. See TableF.1/6.771. 3.1.4.3 Electrical requirements HData set control leads shall conform to RecommendationV.24 [2, 22]. 3.1.4.4 Line code HNRZ line code shall be employed. A separate clock distribution shall be provided. 3.1.4.5 Speed HThe bit rate shall be 9.6 or 64kbit/s per second. Lower speed, e.g., 1.2, 2.4 and 4.8 kbit/s per second, may be necessary in some applications. 3.2HOSI layer 2 HThe data link protocol is synchronous HDLC type. 3.2.1HHDLC frame structure HThe HDLC frame structure shall conform to [6] (frame structure). 3.2.1.1 Addressing field HThe addressing field shall be one octet. 3.2.1.2 Information field HThe information field in any HDLC frame shall be an integral number of octets. HInformation field octets shall be sent least significant bit first. HMaximum information field lengths of 128 and 256 octets shall be supported. HA maximum information field length of 512 octets may be necessary in some applications. 3.2.2HAddressing HThe secondary station shall be capable of being assigned any address in the range one to 254. 3.2.2.1 Allstation address HThe address field pattern "11111111" is defined as the allstation address. 3.2.2.2 No station address HThe address field pattern "00000000" is defined as the nostation address. HThe nostation address shall never be assigned to a secondary station. 3.2.2.3 Group address HNot used. 3.2.3HHDLC procedure k+Ԍ HThe HDLC procedure is defined by [7]. 3.2.3.1 Commands and responses HThe following HDLC commands and responses must be supported: H commands: H SNRM: Set Normal Response Mode H DISC: Disconnect, H commands or responses: H I: Information H RR: Receive Ready H RNR: Receive Not Ready H responses: H FRMR: Frame Reject H UA: Unnumbered Acknowledgment H DM: Disconnected Mode 3.2.3.2 Modes HTwo modes are selected: H one operational mode: H Normal Response Mode (NRM) H one nonoperational mode: H Normal Disconnected Mode (NDM) 3.2.4HClass of procedure HThe Unbalanced operation Normal response mode Class (UNC) as defined by ISO7809 shall be implemented. 3.2.4.1 HDLC optional functions HThe following HDLC optional functions shall be implemented: H unnumbered information (option No. 4) H command UI H response UI H data link test (option No. 12) H command TEST H response TEST 3.2.5HOther parameters of OSI layer 2 3.2.5.1 Window size HThe window size is fixed to one. 3.2.5.2 Waitingtime before a repetition HIn the case of noreply or lostreply, the primary station shall provide a waitingtime function. HThe waitingtime before a repetition has to be greater than the duration of the longest frame to be sent by the primary station, added with the responsetime of the secondary station and the duration of the longest frame to be sent by the secondary station. 3.2.5.3 Number of repetitions HIn the situation of 3.2.5.2, the maximum number of repetitions before detecting a noreply or a lostreply condition is fixed to five (six requests). 3.2.5.4 Response time HThe secondary station shall commence the opening flag of its response not later than 5ms after the end of the closing flag of the frame sent from the primary station. (Note: the need to reduce this time for bit rates above 19.2kbit/s is under study). 3.3HHigher layers HUnder study. ITABLE F.1/G.771 P <Pin description of 24pin connector [16]ă  k+Ԍ H Equipment: removable strap to frame ground H Cable: connected to shield H* These circuits are optional for connection to an embedded operations channel or modem and are not used for connections to a multipoint bus HCircuits are grouped by function: ground, data, control and timing. HProvision should be made at each interface point on a multipoint bus for the continuation of the interface to the next network element. HProvision shall be made for the termination of the lines in their characteristic impedance (typically, 120ohms, resistive), should the equipment be at one end of a multipoint bus. HFor further information, see [2, 16, 22, 23]. 4.HCandidate protocol suite No. 4 (CPS 4) HInitial application: HAlarm surveillance, performance monitoring, testing on specific NEs found in limited numbers in the telecommunications network (e.g., muldex, line transmission equipment). 4.1HLayer 1 HElectrical Recommendations V.24, V.28 HConfiguration star HPhysical connection ISO 211 (25 pin) (see Table F.2) HTransmission mode duplex, interface type D HOperating speed 1200, 2400, 4800 and 9600 bits per J(#KK#LL$M second (user option) HShield ground strap to frame (user option) 4.2HLayer 2 HIt is mandatory that the data link layer conform to LAPB as defined in CCITT RecommendationX.25. In addition, provision shall be made for connection between Data Terminal Equipments (OSs and NEs) without an intervening packet switched network. The interface shall conform to [8]. Further detail is provided in the subsection entitled "Equipment type during link setup and reset" below. HThe link layer specification that follows applies to all cases. 4.2.1HEquipment type during link setup and reset HWhen a packet switched network is used to connect the NE and OS, they each are designated "Data Terminal Equipment" (DTE) and the network acts as a "Data CircuitTerminating Equipment" (DCE). When a dedicated or dialup link is provided, other means must be used to supply the DCE role. HAt level 1, the modems will provide the DCE interface, supplying bit synch. HAt the link level, the procedures specified in [8] are followed. The NE or OS must be able to start the setup or reset of the link (a DCE function in CCITT RecommendationX.25) as well as to respond to a start from the connecting equipment (a DTE function in CCITT RecommendationX.25). In addition, provision must be made for assignment of the A/B addresses. This mandatory option is to be fieldsettable and stored in nonvolatile memory. Equipment which meets this requirement is compatible with connection to either a DCE or remote DTE. 4.2.2HWindow HModulo 8 operation shall be used. The window for unacknowledged frames is to be optional between 1 and 7 frames. Typical values are 7 and 2. 4.2.3HUser information HThe user information is to be arranged in an integral number of octets. HThe maximum length of the user information shall be user settable, consistent with the range of values for the N1 parameter as shown in Table F.3. Maximum information field lengths that shall be supported are 131 and 259 octets with 515 octets optional. These values provide for three packet header octets and maximum length of packet data units of 128, and 256 and 512 octets respectively. 4.2.4HOther frame parameters HCertain other frame parameters shall be set by the user to be consistent with the bit rate, frame size and characteristics of the connecting network. The NE design should be sufficiently flexible to accommodate parameter sets for diverse networks, both as order options and later reconfigurations. The range of parameters is shown in TableF.3. These options, like those of the physical layer, are to be set at installation, changeable by the user, and non volatile. 4.3HOther layers HNo layer 3 is planned for this suite. HLayers 47 are under study. 5.HCandidate protocol suite No. 5 (CPS 5) HInitial application: HAll management of high capability NEs found in limited numbers in the telecommunications network (e.g., digital crossconnect). HLayer 1 HElectrical Recommendations V.24, V.28 HConfiguration star HPhysical connection ISO 2110 (25 pin) k+Ԍ (see Table F.2) HTransmission mode duplex, interface type D HOperating speed 1200, 2400, 4800 and 9600 bits per second (user option) HShield Ground strap to frame (user option) 5.2HLayer 2 HIt is mandatory that the data link layer conform to LAPB as defined in CCITT RecommendationX.25. In addition, provision shall be made for connection between Data Terminal Equipments (OSs and NEs) without an intervening packet switched network. The interface shall conform to [8]. Further detail is provided in the subsection entitled "Equipment type during link setup and reset" below. HThe link layer specification that follow applies to all cases. 5.2.1HEquipment type during link setup and reset HWhen a packet switched network is used to connect the NE and OS, they each are designated "Data Terminal Equipment" (DTE) and the network acts as a "Data CircuitTerminating Equipment" (DCE). When a dedicated or dialup link is provided, other means must be used to supply the DCE role. HAt level 1, the modems will provide the DCE interface, supplying bit synch. HAt the link level, the procedures specified in [8] are followed. The NE or OS must be able to start the setup or reset of the link (a DCE function in CCITT RecommendationX.25) as well as to respond to a start from the connecting equipment (a DTE function in CCITT RecommendationX.25). In addition, provision must be made for assignment of the A/B addresses. This mandatory option is to be fieldsettable and stored in nonvolatile memory. Equipment which meets this requirement is compatible with connection to either a DCE or remote DTE. 5.2.2HWindow HModulo 8 operation shall be used. The window for unacknowledged frames is to be optional between 1 and 7 frames. Typical values are 7 and 2. 5.2.3HUser information HThe user information is to be arranged in an integral number of octets. In other words, the data is to be structured in 8 bit bytes. HThe maximum length of the user information shall be user settable, consistent with the range of values for the N1 parameter as shown in TableF.3. Maximum information field lengths that shall be supported are 131 and 259 octets with 515 octets optional. These values provide for three packet header octets and maximum length of packet data units of 128, 256 and 512 octets, respectively. 5.2.4HOther frame parameters HCertain other frame parameters shall be set by the user to be consistent with the bit rate, frame size and characteristics of the connecting network. The NE design should be sufficiently flexible to accommodate parameter sets for diverse networks, both as order options and later reconfigurations. The range of parameters is shown in TableF.3. These options, like those of the physical layer, are to be set at installation, changeable by the user, and non volatile. 5.3HLayer 3 HIt is mandatory that the Packet Layer conform to CCITT RecommendationX.25. In addition the packet layer must provide for connection of Data Terminal Equipment (OSs and NEs) without an intervening packet network; the required interface for this purpose conforms to ISO 8208. In addition, the provisions of ISO 8878 shall apply. HThe attributes which must be supported are summarized in TableF.4. Note in particular that this table shows the different attributes needed to support PVCs (the X.25/PVC procedures) and SVCs (the X.25/SVC procedures). 5.2.1HEquipment type during restart HWhen the packet level X.25 interface is used, automatic selection of the DCE/DTE role during restart is required, as specified in ISO8208. 5.3.2HOther features and parameters HThe Packet Layer attributes are summarized in Table F.4. 5.HUpper layers HUnder study. ITABLE F.2/G.771 P DISO 2110 pin descriptionă H Equipment: removable strap to frame ground H Cable: connected to shield Hs Additional interchange circuits required for switched service Ht Additional interchange circuits required for synchronous channel k+Ԍ Hx Basic interchange circuits, all systems H= Circuit DA (CCITT 113) is not used in OS/NE interfaces HDuplex, interface type D. HCircuits are grouped by function: ground, data, control and timing. HFor further information, see [2, 3, 5, 19]. ITABLE F.3/G.771 P ALAPB data link layer attributesă  ITABLE F.4/G.771ă P BX.25 packet layer attributesă  6.HCandidate protocol suite No. 8 (CPS 8) HInitial application: HAlarm surveillance, performance monitoring and configuration control of NEs found in reasonably large numbers in the telecommunications network (e.g., muldex, line transmission terminal). Interface characteristics 6.1HGeneral characteristics H Network topology: "loop" (a variety of a ring chain configuration) k+ƌ HH© Serial data transmission  `  H Masterslave principle H Maximum number of slaves: 30   H Transmission medium: one balanced screened pair (with the possibility of providing bypasses of faulty sections of the "loop" and slaves)   H Maximum connection length between two connected slaves: 1000m 6.2HLayer 1 of the ISOOSI reference model (physical layer) H Electrical characteristics in accordance with RecommendationsV.11 and V.24 [1, 2, 21] H Transmission method: asynchronous H Mode of operation of the slave: duplex H Transmission rate: < 19200 bits per second 6.3HFurther layers are under study XDTABLE F.5/G.771 XK X5Candidate protocol selection attribute valuesă    Attribute  CPS 1  CPS 2  CPS 3  CPS 4  CPS 5  CPS 6   Layer 1                 configuration  B  B  B,R*  S  S  R   No. of ports per         configuration  M  VL  M  M  M  M   physical medium  SP  SP  SP  SP  SP  SP   transmission mode  ASHD  SFD SHD,FD  SFD  SFD  ASHD   operating speed  19200 1000000  19200  1200  1200 < 19200      64000      (bits per second)   128000  9600  9600    communication         distance  M  M  M(L)  M(L)  M(L)  M   communication         environment  IB  IB  IB(OB)  IB(OB)  IB(OB)  IB   availability*  X  X  X  X  X  X   Layer 2                 data link connection  CO  CL  CO  CO  CO  CO   data link initiator  M  AP  M  AP  AP  M   data link address         size  M  VL  VL  S  S  *   receipt confirmation  Y  Y  Y  Y  Y  Y   max. frame size  S  M  S,M  S,M  S,M  S   max. frame frequency         per port  H  H  H  H  H  M   max. frame transmit         delay  M  S  M  S,M  S,M  S   error detection  P+CS8  CRC16  CRC16  CRC16  CRC16  CRC   hamming distance  4        error recovery  R  R  R  R  R  R   Layer 3                 LCN network size      VL    routing      Y    (un) packing      Y    connections      P,SW    priority      Y    Higher layers*          * Under study. XFREFERENCESă  k+Ԍ 0ICCITT\APIX\DOC\061E6.TXS 00ICCITT\APIX\DOC\061E6.TXS 0