Digital Subscriber Signaling System No

Digital subscriber signaling system No.l (DSS1) is used for signaling between an ISDN (integrated services digital network) subscriber and his local exchange. This chapter is a brief excursion from the description of signaling system No.7 (SS7), which has been the subject of Chapters 7 through 9, and will continue in Chapter 11, with the description of the integrated services digital network user part (ISUP). This order of presentation has been chosen because DSS1 can be discussed without...

Nature of Number NN

000 0001 Subscriber number 000 0011 National number 000 0100 International number Bits BA indicate whether the calling customer allows the presentation of his number to the called party Bits DC indicate whether the calling number was provided by a calling ISDN user, or by the exchange 01 Provided by user, not screened by exchange 01 Provided by user, passed screening by exchange 11 Provided by exchange Par. 8 ChargeNumber. This parameter identifies the charge number of the calling customer. If...

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

Routing Sccp

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

Signaling 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...

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...

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...

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 messages

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...

Global Title Translation

Routing Indicator

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....

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...

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...

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...

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

Isup Messages

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...

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...