The content of the protocol.

6.3 Description of execution and testing of additional services during the administration by MN.

6.4 Description of execution and testing of additional services during the administration from testing telephone sets.

To learn the principle of organization and administration of signalling system SS7 at the switching node. To consider procedures of administration and inclusion of a new signalling link.

2.1 General information. ITU-T defined signalling system SS7 as the standard for providing operation of telephone exchanges of different manufacturers. SS7 is used by the majority of switching systems with software management all over the world.

Every signalling point (a node of the network) has its own point code (Signalling Point Code – SPC), which uniquely defines this SP inside the SS7 network. The length of SPC is 14 bits, it means that in one network up to 16384 different SPC can exist.

Signalling messages between exchanges A and B are transmitter by Signalling Link. The number of links can vary from one to several. All signalling links between two exchanges are united in Link Set,

The mode of operation, during which a route of voice and signalling channels coincides, is called Associated operation mode.

Assume that we have three exchanges, connected as “any with any”. In this case there are voice and signalling channels between any two exchanges. Voice and signalling networks are independent on each other and signalling messages between exchanges A and B can be transmitted through the exchange C. This operation mode is called qvasi-associated operation mode, and the exchange C – Signalling Transfer Point (STP). This method is used when there are only few voice channels between exchanges A and B and using of a separate signalling channel is not effective. One signalling channel can serve for several destination points.

By means of International 0 and International 1 national networks of the level National 1 are united in the international network SS7.

Inside the local network service providers work on the level National 0 and every exchange inside this network has its unique SPC. Local networks are connected together by means of the signalling network of the level National 1.

2.2 Forming of the database of semi-permanent data. For formation of the database of semi-permanent data at connection organization, served by the signalling system SS7, it is necessary to perform next actions:

2. To describe using ports for communication organization (with E1 trunks). Configuration of ports, channels, and groups of channels is considered in the section about call routing.

3. To enter common data for SS7 operation. For this we use CMG – Signalling – SSN7 – Common Data. This data should be described only once, when SS7 is used for the first time. Parameters:

· Network Indicator defines the level of the SS7 network, on which the exchange works. If it works on the level of a local network the parameter Network Indicator should be equal to 3 (the level National 0). All possible values of this parameters are shown in the table 7.1.

· Congestion Accept, Congestion Discard, Congestion Onset, Congestion Abatement are used for management of overloads in the subsystem of message transfer (2-3 layers according to OSI).

· SSN7 Realization defines the variant of realization of the signalling system SS7. The value of this parameter Russian Realization corresponds to Russian specifications of the signalling system (they are similar to specifications of Ukrainian networks).

3. It is necessary to enter data for signalling points of SS7. Use the menu CMG – Signalling – SS7 – Signalling Point. Parameters:

· SSN7 Signalling Point defines the number of the signalling point. It is inner parameter of the exchange and takes values from 0 to 127. It is important that Signalling Point with the number 0 corresponds to the managed exchange. It means that describing the signalling point 0, we enter data about our own exchange. Signalling points with other numbers correspond to other exchanges of the network, with which signalling links will be described. All exchanges should be described, which we have direct connections by voice or signalling channels to.

· Point Code defined the code of the described signalling point. The point codes for the whole network are defined by the corresponding project organizations. At indication of the point code it is necessary to convert 14-bit code to the decimal form. For example: the code of the exchange is 20-11-3, in binary form 010100-001011-11 should be converted to the decimal form, so we get 5167.

· Point Type defines the type of the signalling point. STP – Signalling Transfer Point, ISUP – ISDN User part; STR and ISUP – combined transfer-end signalling point.

· Link Set 1 and Link set 2 define numbers of link sets of signalling channels, which are necessary to user for transmitting messages to the described signalling point. If for transmitting of signalling messages to the described signalling point only 1 link set is used, then the value of Link Set 2 should equal 0.

· Link Set Alt defines the number of an alternative list set, which can be used for transmitting of signalling messaged to the described signalling point in a case of rejection or overload of main link sets.

· SLS bit has the value only at using both link sets for delivering of signalling messages and manages load sharing between these link sets. The parameter can take values from 0 to 3. Its value defines which one of the least four significant bits of the voice channel identification code (CIC), reserved for setup connection, will be analyzed for the choice of the link set. If the value of analyzed bit is 0, then the first link set will be used, if “-1” – then the second one.

· Pause Timer has the value only for connection in the conversation phase. It defines the delay to the forced disconnection in the case of a signalling channel failure. If during the specified delay the functionality of the signalling channel is recovered, then the connection is not broken. It should be chosen in the range 0..30s.

· Send GRS defines whether the reboot of voice channels at the activation of the signalling point should be performed.

4. For every link set it is necessary to specify the signalling point, with which it directly connects the managed exchange. It can be done via menu CMG – Signalling – SSN7 – Link set. The parameter Link set defined the number of the described link set. The parameter SSN7 Signalling Point defines the number of the signalling point, with which the described link set is directly connected.

5. To describe signalling channels (links). Use the menu CMG – Signalling – SSN7 – Link. Parameters:

· Link defined the number of the described link. Numbers should so from 1 to 127 by order without spaces.

· Module always equals 0. It’s the module where the physical equipment of the node is located.

· Port and Channel define the physical port (with E1 trunk) and the channel in the trunk which is used for organization of the given link.

· CDA defines the number of the CDA card, serving the given signalling channel.

· ECM defines the method of error correction for the given signalling channel (the parameter should be the same for partner exchanges).

- Basic Error Correction is applied on the ground communication lines with propagation time not more than 15 ms.

- Preventive Error Correction is used on main ground or satellite communication lines with propagation time more than 15ms.

· SLC (Signalling Link Code) defines the number of the given link inside the link set. It should be unique inside the link set and coincide by the value with similar parameter at the opposite exchange.

· Additional Flags – defines the quantity of additional flags between signalling units. It usually equals 0.

6. When the forming of the database for SS7 operation will be completed, it is necessary to reboot the subsystem MTP. Use CMG – Signalling – SSN7 – MTP Restart.

Further actions will be connected to the call routing, described in the next laboratory work.

4.2 Prepare the sequence of procedures for execution of managing a new signalling channel.

5.4 Define parameters of administration, if the own Point code is already created at the exchange, convert the Point Code (given by the teacher) to the decimal form.

5.5 For the table Signalling Point enter the record with the corresponding partner exchange (Network indicator: National). The parameter Point Type choose as STP and ISUP.

5.6 Create a Link Set. The parameter SSN7 Signalling point is taken from the stage 5.5, Link set choose by yourself.

5.7 Include links in the link set. Parameters: Link – choose by yourself, Link Set – from the stage 5.6, Module/port/channel should coincide with the chosen channel in the activated equipment on the stage 5.3. Provide using of basic error correction. Parameters SLC and Additional Flags choose by yourself.

5.9. If there exists configure connection at the partner exchange, test the activity of the link.

· To learn algorithms of management of intraswitch and interswitch outgoing calls.

2.1 General points. Subscriber A which wants to establish a telephone connection, picks up the handset on its terminal and begins dialing of subscriber B number. SI2000 system receives these digits and processes them each time the digit comes. As a result, after receiving of one or several digits SI2000 may define the exchange to connect with.

Each TE, with which direct voice channels exist, relate with one or more outgoing destinations (Destination Outgoing) in SI2000 database. Your own TE must relate to local destinations.

Analysis of received digits and defining the destination is called the prefix-analysis. Routing in SI2000 is based on prefix-analysis, i.e. on continuous digit analysis of digits, dialed by a subscriber.

It is required to define a routing method with each adding or deleting of trunk in node configuration. The Routing menu unites commands, using which you can manage the following:

Routing is carried out on the basis of analysis of the first several received digits, which are called the prefix. Prefixes then are to be linked with destination. The latter defines the destination category (routing to the intraswitch ports or to one of outgoing trun, to procedure codes under the subscriber's control for any kind of subscriber service, or to special node services, and so on).

The latter defines the destination category (- routing to the local ports or to some outgoing trunk, to procedure codes that are under subscriber's control, for some service, to special node services and so on).

As for outgoing directions, information on the destination appears to be an interlink between some definite prefix and information on route through which you can reach some destination. Route is a synonym for a group of trunks, which is an interface of node and network. In database, there is a group of outgoing or two-way link facilities defined for each route individually; these groups may be used for handling the given outgoing call. After determination of trunk group number, the system tries to find free trunk in it. Then it defines port & channel number (using the trunk number) for carrying the call.

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