Ccitt No 5 Signaling 85 Iscb
Switchblock TC4 TC4 Switchblock Figure 4.3-1 Supervision Signals of CCITT No. 5. a signal on send channel at ISC-A. b signal on receive channel at ISC-A. Signaling Frequencies. Two in-band signaling frequencies are used , 2400 Hz, and 2 is 2600 Hz. There are three signals ,, 2, and a composite signal that contains , and 2. Signaling Circuitry in Trunk Circuits. The functions and circuitry for supervision signaling in the TC4 circuits of analog CCITT No.5 trunks are similar to those discussed in...
Final and Intermediate GT Translations
In the above example, SCCP-E makes a final GT translation, which yields the PC SSN address of destination R800-D. This is possible because an SCCP in a signal transfer point has the necessary data to perform final translations for all destinations in its network, and we have assumed that all entities in Fig. 14.3-4 are in the same network. When the originating and destination ASEs are in different networks, the SCCPs in the originating network have no data to do final GT translations. In this...
Introduction to DSS1
DSS1 is a message-oriented signaling system 1-5 . Literature on DSS1 is usually in terms of signaling between a user and the network. Actually, the signaling takes place between a TE of an ISDN user and the local exchange to which the user's DSL is attached. The DSS1 signaling messages are carried in the D-channel of the DSL, which is the common signaling channel for the TEs on a DSL. Figure 10.1-3 Functional entities in DSS1 and ISUP signaling, a DSS1 primitives, b SS7 primitives. Figure...
Cb Qkv
Figure 6.3-1 CCITT No. 6 Initial address message IAM . Note CCIT No. 6 one-unit messages have the format of ISU. From Rec. Q.258. Courtesy of ITU-T. Table 6.3-1 Coding of heading and signal information fields in CCITT No.6 call-control messages and signals. Table 6.3-1 Coding of heading and signal information fields in CCITT No.6 call-control messages and signals.
M
Figure 3.2-2 Dial-pulse address signals. B break 60 ms . M make 40 ms . I interdigital interval gt 300 ms . presents a path for direct current between points A and B. When the dial after having been rotated by the subscriber spins back to its rest position, DS opens and closes a number of times, producing a string of breaks in the d.c. path. The number of breaks in a string represents the value of the digit one break for value 1, two breaks for value 2, , ten breaks for value 0. The nominal...
Bell System Multifrequency Signaling
This section describes the multi-frequency signaling system that was introduced by the Bell System after the Second World War 1-3 . It is still in use today, mostly in local U.S. networks. A nearly identical signaling system, known as the R1 signaling system 4 and defined by CCITT, is used on international trunk groups in the North American network for example, groups between the U.S. and Canada . Supervision and address signaling are link-by-link. The system can be used on one-way two-wire...
Nature of Number NN 1
000 0001 Subscriber number calling party 000 0011 National number calling party 000 0101 Subscriber number called party 000 0111 National number called party Numbering Plan NP public or private Par.B LATA. This parameter represents the LATA network of the calling party Section 1.1.2 , and consists of three BCD digits. The contents field has the AINDigits format. The NN and NP fields are set to not applicable all zeros . Par. 10 PrimaryCarrier. This parameter specifies the first-choice...
Information Elements 1
The information elements IE in TCAP messages have three fields see Fig. 15.3-1. The tag field indicates the IE type, and the length field indicates the number of octets in the value or contents field. A TCAP IE can be a primitive IE or a constructor IE. The value field of a primitive IE contains the information of the IE. Primitive IEs should not be confused with the primitives that pass information between the SS7 protocols in a node Section 7.3.2 . Figure 15.3-1 Structure of information...
Signaling Route Set Unavailable
Certain combinations of multiple failures in a signaling network can completely disable a route set. Consider two signaling end points, say A and F. When SNM-A determines that its route set to a destination F has become unavailable, it informs its MTP-users by passing MTP-pause indications Fig. 8.7-1 , which include the point code PAD of affected destination F. The users then take the necessary measures. For instance, if signaling point A has a TUP trunk group to F, TUP-A has to take this group...
TCAP Messages
As shown in Fig. 15.1-2, a TCAP message consists of a TCAP portion, which is processed by TCAP, and a components portion with one or more components, which is passed transparently. There are several TCAP message types. They represent the status of the transaction, as perceived by the sending ASE and TCAP. Unidirectional. This is a message for one-way information transfer. The sender does not expect a response, and the message does not initiate a transaction. Begin. This message initiates a...
Offhook Delay Trigger
Off-hook delay OHD triggers can be assigned to analog or digital ISDN subscriber lines, or private facility trunks, attached to SSP. The trigger is detected when an analog subscriber line goes off hook, a setup message is received from an ISDN line, or a seizure signal has been received on a private facility trunk. The primary criterion for OHD is that the customer is making a call. This can be determined only after the customer's dialed digits have been received. If the customer has dialed a...
Par15 Nature of Connection Indicators Fig 1129 Mandatory MF parameter in IAM
00 No satellite circuit in connection 01 One satellite circuit in connection 10 Two satellite circuits in connection 00 Continuity check not required 01 Continuity check required on this circuit E Echo-control Device Indicator 0 No outgoing half-echo control device included 1 Outgoing half-echo control device included Par.16 Optional Backward Call Indicators Fig. 11.2-9 . Optional parameter in ACM, CPG, and ANM messages. Only bit A is used. A In-band Information Indicator 1 In-band tone or...
Handoff Example
Figure 17.4-l b shows the remote operations for the handoff of mobile station MS from MSC-A to MSC-B 4 . The handoff is done in a sequence of two transactions. Handoff Measurement The first transaction consists of one operation. It is started by MSC-A, with a handoff measurement invoke HOMEAS . This requests MSC-B to measure the signal strengths of the MS on the reverse voice channel of VC-U received in the cells of MSC-B's service area that are adjacent to cell X. The return-result homeas...
TEI Management
The LAPD for point-to-point connections in a terminal Fig. 10.2-1 stores a TEI, and checks the TEI in the address field of received frames to determine whether the frame is intended for it. It also places its TEI in the address fields of its outgoing frames. A terminal is fixed, or portable, depending on the manner in which its TEI value is entered. A fixed TE is intended to be associated with a DSL on a long-term basis, say several years. These terminals have a number of switches whose...
Global Title Translation
A SCCP called party address Par.l can contain various combinations of PC, SSN and or GT. We now explore the reasons for global titles and GT translations. A subsystem in a network is uniquely identified by the combination of the point code PC of its signaling point, and its SSN at that point. If an SCCP message has a PC SSN called party address, the MTPs along the message path then use PC to route the message to its destination signaling point, and the SCCP at this point delivers it to the...
SCMG Interfaces
SCMG has interfaces with the subsystems, the MTP, and the SCCP connectionless control at its signaling point see Fig. 14.1-2. N-Primitives are the interface with the local subsystems and the local MTP. The subsystems pass information to SCMG in N-requests and N-responses, and SCMG passes information to the subsystems in N-indications and reconfirmations. The interface with SCCP connectionless control allows SCMG to send and receive SCCP unitdata messages to from SCMGs in other signaling points....
e
Figure 3.1-1 Signaling for an intraexchangecall. the case, it sends a ringing signal to alert s2, and informs s about the call progress with a ringing-tone. When S2 goes off-hook, an answer signal is generated. The exchange then cuts through sets up a path in its switchblock between the subscriber lines . The conversation starts, and the exchange begins to charge S, for the call. At the end of the call, the subscribers put the handsets back in the cradles of the telephones. The signals...
Rerouting of Messages
In Fig. 8.9-5, signaling links SLy and SL10 have failed simultaneously. Signal transfer point D is therefore no longer able to transfer messages to destination F. SNM-D then alerts the SNMs in all directly connected signaling points such as B and C that it can no longer transfer messages to F, by sending transfer prohibited TFP messages. In these messages, PAD holds the point code of affected destination F. We now examine the actions at signal transfer point B, in response to the TFP message....
Identification of MS CMN MSC and VLR
In the U.S., the numbering plan for mobiles is integrated with the PSTN numbering plan Section 1.2.1 . The mobile identification number MIN of a MS consists of a three-digit area code AC , a three-digit exchange code EC , and a four-digit station code. The MINs in this chapter are the counterparts of MINls and MIN2s binary numbers in messages on the RF channels between MS and base station Section 12.4.9 , but are formatted as ten BCD digits. When necessary, an MSC converts MIN to MINI MIN2, or...
SS7 Hierarchy
The parts of SS7 are organized in a four-level hierarchy 1-4 . We say that a higher-level part is a user of services provided by a lower-level part. This arrangement is similar to the seven-layer structure of the open systems interconnection OSI protocols for data communications that have been specified by the International Standards Organization ISO . Several efforts have been made to align the SS7 levels and OSI layers. However, this has been only partially successful. OSI layers 1 and 2...
Info Eva
Source Rec. Q.257. Courtesy of ITU-T. Source Rec. Q.257. Courtesy of ITU-T. Nature of Circuit Indicator N . This indicates whether the connection built up so far includes, or does not include, a satellite trunk N 1, or N 0 . This indicator is used by incoming exchanges. When a call is received with N 1, the exchange avoids routing the call on another satellite trunk. Echo-suppressor Indicator E . This indicates whether the connection built up so far includes, or does not include, an outgoing...
Q931 ISUP Interworking and Mapping
In the example of Figs. 11.3-1 and 11.3-2, interworking between Q.931 signaling and ISUP signaling takes place in local exchanges P and R. These exchanges have to map received Q.931 messages and information elements IE to outgoing ISUP messages and parameters Par. and vice versa. The IEs and Pars, have been described in Sections 10.3.5 and 11.2.4. We now examine the mappings for the call 2 . Mapping of SETUP and 1AM Messages Fig. 11.3-3 . Exchange P receives information elements IE.l mandatory...
Cot
Figure 6.3-3 Signaling sequence for an international call. ISCA receives the test tone, and sends a COT signal. It also cuts through sets up a path between the incoming national trunk and Tt . 3. On receipt of COT, ISCB proceeds with the set-up of the call. It analyzes the IAM, seizes trunk T2, attaches a check-tone generator and detector, and sends an IAM to ISCc. Since this ISC is in the destination country, the called number in the IAM from ISCB is a national number. On receipt of the IAM,...
Transit Network Selection [9
Long-distance calls in the U.S. are handled by an interexchange carrier IXC selected by the calling party Section 3.7.1 . If the caller's local exchange does not have a direct trunk group to an exchange in the IXC network, the IAM sent by the originating exchange includes a transit network selection parameter that identifies the IXC. The contents of the parameter are shown in Fig. 11.9-3 9 . In the U.S., the type of network identification field is set to 010. This means that the identification...
Nxxxxxx
700 number, operator requested
Trunk Blocking and Unblocking
Maintenance personnel or an automatic process in exchanges V and W can block a trunk. Suppose that exchange W needs to test a trunk T in group TG. It then sends a BLO blocking signal for the trunk to exchange V see Table 9.5-1. The latter exchange acknowledges with a BLA blocking acknowledgment signal . The affected trunk T is identified by DPC, OPC, and CIC Fig. 9.1-1 . If trunk T is carrying a call, the call is not interrupted, and exchange W starts the test only after the call has ended....
Identification of GSM Entities
Since GSM systems are deployed in many countries, CCITT and ETSI have standardized the identification of GSM entities according to a numbering plan specified in CCITT Rec. E.212 20 . This plan is different from the CCITT Rec. 163 164 numbering plan for fixed networks. PLMN Identity. A PLMN is uniquely identified by its mobile country code MCC and mobile network code MNC . MCC consists of three digits, of which the first one indicates a world zone 4 The Mid-East and Western Asia The second and...
ISUP Message Format
This section describes the general format of ISUP messages Fig. 11.2-2 . The circuit identification code CIC has 14 bits, and is located in octets 1 and 2. In a Figure 11.2-1 ISUP parameters, a mandatory, fixed-length MF parameters, b mandatory, variable-length MV parameters, c optional OP parameters. network, an ISUP trunk is uniquely identified by the combination of DPC and OPC located in RL see Fig. 7.3-2 , and CIC. In TUP signaling, the four low-order bits of CIC are also used as the...
Info Tqf
Source. Rec. Q. 441. Courtesy of ITU-T. Source. Rec. Q. 441. Courtesy of ITU-T. The group I forward signals represent the digits of the called party number. Group II signals indicate the category of the calling party, and group III signals, which are used in some national networks only, represent the digits of the calling party's number. In R2 and CCITT-R2 signaling, the incoming exchange controls the signaling sequence. A group A signal requests a particular next forward signal, or indicates...
General Request Message GRQ
This backward message requests actions and or information from a preceding exchange in the connection. The message format Fig. 9.2-5 consists of one octet of indicators, each of which represents a request for a particular action or information item parameter Indicator Requested Action or Parameter D Malicious call identification F Inclusion of outgoing echo controller To request a particular action or information item, the corresponding indicator bit is set to 1.
Examples of SCMG Procedures
Subsystem Status Test This test is performed as a part of other procedures. In Fig. 14.3-1, when SCMG-A has received a subsystem-prohibited message for R800-C, it periodically audits the status of the subsystem, by sending subsystem-status-test messages. If SCMG-C determines that R800-C is inservice again, it responds with a subsystem-allowed message. Otherwise it does not respond. Broadcast Procedure. This procedure is used when a status change occurs in a subsystem that has a number of...
SABME DISC DM and UA Frames
These unnumbered frames Table 10.2-1 are used to start and end multiframe acknowledged operation on a point-to-point data link connection. For example, when the network-layer function identified by SAPI 0 at an exchange needs to initiate multiframe acknowledged operation on a DSL connection identified by say, TEI 5, SAPI 0, it passes a set automatic balanced mode extended SABME frame to the LAPD-E for the connection, which then initializes its N S and N R counters to 0, and transfers the frame...
Abc
O Exchange Cuts Through O Exchange Releases Connection Figure 4.1 -1 Interexchange signaling. called number. Exchange A sends the digits, and then cuts through sets up a path in its switchblock between the subscriber line of S, and T . When exchange B has received the complete called number, it seizes an available trunk T2 to destination exchange C, and sends a seizure signal on the trunk. Exchange C responds with a wink signal, after which exchange B sends the digits of the called number, and...
TUP Support of Digital Connectivity
For this service, the path between the calling and called digital subscriber lines has to be completely digital 64 kb s in both directions . This requires that all exchanges in the connection have digital switchblocks, and that all trunks are digital trunks. These connections also require TUP signaling all the way. When a call originates on a pre-ISDN digital subscriber line, the originating exchange selects a digital outgoing TUP trunk to a next exchange that has a digital switchblock, and...
MTP2 Structure
The main parts of MTP2 are shown in Fig. 8.3-1. Link control LC controls the other functional units of MTP2. In the first place, it coordinates the transfer of signal units. LC also monitors the operation of the signaling link. It communicates with its MTP3, accepting link status commands C , and reporting link status information with indications I . Finally, LC communicates with the LC at the distant end of the signaling link, using link status signal units. The MTP3 in a signaling point...
Mtp2a
FIBb 0, FSNb 25 FIBC 0, FSNC 26 BIBa 0, BSNa 24 FIBd 0, FSNd 27 FIBf 0, FSNf 28 FIBg 0, FSNg 29 BIBe 0, BSNe 26 BIBh 1, BSNh 26 FIBj 1, FSNj 27 BIB, 1, BSN, 26 FIBk 1, FSNk 28 FIB, - 1, FSN, 29 FIB 1. FSN_ 30 FIBb 0, FSNb 25 FIBC 0, FSNC 26 BIBa 0, BSNa 24 FIBd 0, FSNd 27 FIBf 0, FSNf 28 FIBg 0, FSNg 29 BIBe 0, BSNe 26 BIBh 1, BSNh 26 FIBj 1, FSNj 27 BIB, 1, BSN, 26 FIBk 1, FSNk 28 FIB, - 1, FSN, 29 FIB 1. FSN_ 30 Figure 8.4-2 Example of basic error correction of MSUs sent by MTP2-A. A MSU is...