Interview Questions.

Q1. What Can I Configure Using The Layer Management Entity Interface?

Given below are a few examples of parameters configurable from LME 

Linksets configuration

Link configuration

Route configuration

Timer configuration

Trace Levels

E1/T1 card configuration

Congestion degrees

Other parameters e.G. Call Control configuration parameters, CICs provisioning / unprovisioning etc may be blanketed as in step with the client's requirements

Q2. Data Can Be Stored Permanently In Computer Through What?

Computer facts garage, frequently called storage or reminiscence, refers to pc. Memory can refer to other kinds of fast however temporary storage. ... The CPU continuouslyreads instructions saved there and executes them as required. ... The CPU first off sends more than a few thru an address bus, a number of known as memory address...

Q3. What Is Continuity Test In Ss7 And Why It Is Performed?

COT is an automated diagnostic method executed within the Signaling System 7 (SS7) PublicSwitched Telephone Network (PSTN) among switches to make certain that circuits are in provider and notexperiencing immoderate signal loss. This validation is performed by using sending tones across the bearer channel. Itis carried out on a sampling basis. For example, on 10 percent of the calls.

Q4. How Does Mtp2 Handle Multiple Links ?

MTP2 has a well described interface (inside the shape of useful calls) with the hardware, that's to be ported. This is defined in element, in the MTP2 Porting Guide. 

The more than one SS7 hyperlinks are treated through the hardware in any fashion (polling in spherical robin or some other way/ interrupt pushed) – MTP2 places no limit on this.

MTP2–hardware interface includes a hard and fast of features, that are invoked by means of the hardware as wished :

Whenever the hardware is ready to transmit, it's going to invoke a properly-described MTP2 characteristic.

Whenever the hardware has acquired a signaling unit, it'll invoke any other MTP2 feature.

Q5. Do You Know What Is The Address Of One Node In Isup?

SPC, Signalling factor code.

Q6. Explain Devices That Operate At The Different Layers Of The Osi/tcp/ip Model Clearly Stating Their Functions At The Respective Layers?

Physical layer : all phsical devices like wires, connectors, hubs repeaters,electric signals

Datalink layer : switch ,briges.

Network layer: routers or broutertransport-gateways.

Q7. What Does The Ss7 Signaling Architecture Look Like ?

SS7 messages are exchanged between community factors over 56 or 64 kilobit in line with 2d (kbps) bidirectional channels called signaling hyperlinks. Signaling happens out-of-band on committed channels instead of in-band on voice channels

The Network include three styles of Network Elements

SSP: Signal Switching Points are cellphone exchanges ready with SS7 succesful software program. They are chargeable for originating, terminating or switching calls

STP: Signal Transfer Points are packet switches that obtain and course signaling messages to their right destination

SCP: Signaling Control Point is a database that gives records necessary for advanced name-processing capabilities

Q8. What Are The Layers In A Ss7 Stack ?

The SS7 protocol stack has the subsequent underlying layers.

Message Transfer Part 

The Message Transfer Part (MTP) is divided into 3 tiers. The lowest degree, MTP Level 1, is equal to the OSI Physical Layer. MTP Level 1 defines the physical, electric, and useful traits of the digital signaling hyperlink. Physical interfaces described include E-1 (2048 kb/s; 32 sixty four kb/s channels), DS-1 (1544 kb/s; 24 64kb/s channels), V.35 (64 kb/s), DS-0 (64 kb/s), and DS-0A (56 kb/s).

MTP Level 2 ensures correct end-to-stop transmission of a message throughout a signaling hyperlink. Level 2 implements float control, message sequence validation, and error checking. When an mistakes occurs on a signaling link, the message (or set of messages) is retransmitted. MTP Level 2 is equivalent to the OSI Data Link Layer. 

MTP Level 3 affords message routing between signaling factors inside the SS7 network. MTP Level 3 re-routes visitors away from failed hyperlinks and signaling factors and controls site visitors while congestion occurs. MTP Level 3 is equal to the OSI Network Layer. 

ISDN User Part (ISUP): The ISDN User Part (ISUP) defines the protocol used to set-up, manage, and release trunk circuits that deliver voice and records among terminating line exchanges (e.G., between a calling birthday celebration and a referred to as birthday party). ISUP is used for each ISDN and non-ISDN calls. However, calls that originate and terminate on the equal transfer do not use ISUP signaling. 

Telephone User Part (TUP): In a few parts of the sector (e.G., China, Brazil), the Telephone User Part (TUP) is used to assist basic call setup and tear-down. TUP handles analog circuits most effective. In many nations, ISUP has changed TUP for call management. 

Signaling Connection Control Part (SCCP): SCCP presents connectionless and connection-orientated community offerings and global title translation (GTT) abilities above MTP Level @SCCP is used because the delivery layer for TCAP-primarily based services. 

Transaction Capabilities Applications Part (TCAP): TCAP helps the alternate of non-circuit associated data among packages across the SS7 community the use of the SCCP connectionless provider. Queries and responses despatched among SSPs and SCPs are carried in TCAP messages. For instance, an SSP sends a TCAP question to determine the routing number related to a dialed 800/888 quantity and to to test the non-public identification quantity (PIN) of a calling card person. In mobile networks (IS-forty one and GSM), TCAP includes Mobile Application Part (MAP) messages sent among cellular switches and databases to support person authentication, gadget identification, and roaming. 

Q9. What Standards Does The Ss7 Stack Confirm To ?

The HSS SS7 stack lets in for countrywide variants together with the American National Standards Institute (ANSI) and Bell Communications Research (Bellcore) standards utilized in North America and the European Telecommunications Standards Institute (ETSI) widespread used in Europe. Spanish and British Variants also are supported.

Q10. What Is The Difference Between Mtp3 And Mtp3b?

MTP3 is used for Narrowband signaling and is the traditional TDM based totally transmission system.

On the opposite hand MTP3b is used for Broadband signaling and essentially designed for assisting ATM capabilities on the premise of MTP3.

Q11. How Is Error Handling Implemented ?

All errors are indicated thru an uniform interface. Handling of errors is the responsibility of the gadget control entity. All feasible mistakes that might arise in processing (along with SS7 protocol procedural errors) is numbered and globally defined. All the SS7 protocol processing entity modules maintain a worldwide errors flag (global to a module) which displays closing error encountered within the processing.

Q12. Is Any Global Data Referenced By The Stack Entity? What Are The Implications ?

The database and a few different variables maintained by means of every stack entity are defined as global definitions. This has no implication in OS like Unix, which do now not share memory throughout tasks. However, in case of RTOS (like Vxworks, PSOS) that have a flat reminiscence area, there may be only one replica of this facts irrespective of range of duties or methods started out. E.G. If  times of ISUP are strolling on the identical board they may be regarding the same reproduction of facts.

This might be fixed in future releases of stack – the solution will be as determined inside the Protocol Development framework, which might be one of the following :

Keep international database listed via the instance wide variety of the module.

Define the database as neighborhood to the stack entity and bypass the reference to it with every name of stack and all the way down to all stages. All the database references could be finished with admire to this reference.

Q13. What Is Meant By The Statement - "ss7 Stack Can Work In Both Single-threaded And Multi-threaded Systems"?

The SS7 Stack entities (MTP2, MTP3, ISUP SCCP& TCAP) can be compiled and run as a unmarried thread. This is feasible due to the coding tips which make certain area of expertise of characteristic names and international variables.

In addition, every SS7 Stack Entity can execute as a separate thread. This is viable due to the fact each stack entity is unbiased and does now not percentage any records systems with other stack entities. Communication between  stack entities is through a message based totally interface.

Q14. What Is The Functionality Of The Client Code?

The customer codes parses all the APIs coming to the stack. It bureaucracy an interface among the stack and the user / provider layer.

Q15. What Is Difference Between Osi Layer And Tcp/ip Suite?

In OSI reference version, there are seven layers which are Application layer, Presentation layer, Session layer, Transport layer, Network layer, Datalink Layer, and Physical layer. It is special version for the transfer of data from one vacation spot from other. While the TCP/ IP suite changed into truly compact, it was not as precise.

Q16. Explain How Many Types Tcp/ip Protocol?

Two varieties of tcp/ip protocol is  types tcp/ipv4 & tcp/ipv6.Tcp/ipv4 it's miles 32 bit now a days it's far used. Tcp/ipv6 it's far 128 bits it is advancd era.

Q17. What Is The Difference Between Sccp And Mtp3?

In MTP3 The routing label info like Servive indicator ,servive network kind ,OPC and DPC details are aviable.The SCCP is the Transport layer for Tcap Based programs.The SCCP Placed over the MTP3 layer.

Q18. What Are 4 Parameters Between Node A And Node B, To Bring A Pcm Link Up Between Them?

The 4 parameters between node A and node B, to carry aPCM link up among them are

DPC(Destination Point Code) and OWNSP

Signaling Link set.

Network ID(NAT0 & NAT1)

PCM channel on which link is developing.

Q19. What Is The Full Form Of D-hyperlink?

Complete shape of D-link is diagonal link . This link certainly used to attach the STP pairs inside the same network .

Q20. Can Multiple Instances Of The Same Stack Entity Run On One Processor ?

This relies upon upon the running device.

In OS like Solaris, Windows NT etc., where each instance / execution of the stack entity has its personal records vicinity, this is possible. 

In RTOS like VxWorks and so on., the global variables are mapped to a hard and fast place in memory (flat reminiscence shape). Hence, multiple times of the stack entity get admission to the identical statistics place for globals, main to conflict. 

Q21. What Are The Performance Requirements That The Hss Ss7stack Has Been Designed To Meet?

The protocol stack (and every constituent entity) might be so designed which will allow porting at the goal platform with minimal real-time overload at the client’s thread of control (calling software). This means that on every occasion viable, the stack code ought to be accomplished inside the stack’s thread of manipulate.

Keeping in mind the strong time and reminiscence constraints in telecom structures, the stack design and code could be evolved for optimum time and reminiscence performance.

Wherever messages need to be exchanged across entities, stack architecture may be so designed for you to minimize the bandwidth requirement.

Q22. What Does Porting The Stack Onto A System Involve?

Porting the stack onto a machine involves the following :

Porting the OS calls

Porting error handler & printing of trace messages

Porting System Management Entity 

Porting redundancy

Porting the OS calls is depending on the Operating System & involves :

Memory control

Timer management

IPC mechanism between stack entities / stack entity & service consumer

Porting error handler is dependent on the User’s System & is primarily based on how the mistakes are to be said.

Porting the printing is depending on the User’s System & is based on how / where the trace messages are to be displayed.

Porting System Management Entity entails developing an User Interface (GUI / other) for handling the stack entities using the Layer Management APIs (Provisioning, Statistics, Controlling Error Reporting and Traces and many others.). 

SS7 stack may be ported unto any consumer platform 

Q23. What Are The Different Links In A Ss7 Network?

There are 6 hyperlinks

A-Access link

B-Bridge link

C-Crossover link

D-Diagonal link

E-Extended hyperlink

F-Fully Associated link.

Q24. What Is The Difference Between Iam And Sam?

IAM(Initial Address Message)includes the information requried for setup call.For a primary call it's far a first message send to Destination.SAM(next address message)precisely it is overlap calls deal with.SAM message needs to be sent in the scenario when assume a subscriber dialed a variety of 9321353536.SSP send the IAM message to there vacation spot with out reading the 35353@I.E originating SSP seems 9321 and sends the IAM message to their respective Destination.And SAM to be send with relaxation dialed digit.

Q25. What Is Global Title Translation?

A worldwide name is an address (e.G., a dialed 800 variety, calling card number, or cellular subscriber identification range) that is translated through SCCP into a destination point code and subsystem wide variety. A subsystem variety uniquely identifies an software at the vacation spot signaling factor.

Q26. Why Are Cd And Dvd Media Better Than Floppy Disks?

Floopy Disc store information Less than 200MB CD,DVD's are morethan 200MBCD-700MBDVD-four.3to 8.5GB.

Q27. Explain The Booting Process Of A General Computer?

Computer is powered on -> Power On Self Test (POST) is doneto take a look at all the hardware -> BIOS (detects the gadgets like,tough-disk, sets the date and time and many others.) -> MBR (locates thefirst place of boot-loader and begins booting theboot-loader) -> boot-loader (locates the OS and startsloading the OS).

Q28. If There Is No Rlc In Response To Rel What Will The Intermediate Switch Will Do?

After timeout intermediate transfer will launch the decision.

Q29. What Can The Ss7 Network And Protocol Be Used For?

The SS7 community and protocol can be used for: 

primary name setup, management, and tear down 

wireless services together with personal communications offerings (PCS), wi-fi roaming, and cell subscriber authentication 

local wide variety portability (LNP) 

toll-loose (800/888) and toll (900) wireline offerings 

enhanced call features such as name forwarding, calling birthday party name/quantity show, and three-manner calling 

efficient and relaxed international telecommunications 

Q30. What Are The Different Functionalities Of Mtp3 Layer?

Message Transfer Part degree three (MTP3) is the network layer inthe SS7 protocol stack. It routes SS7 signalling messages topublic network nodes by means of Destination Point Codes,and to the suitable signalling entity within a node bymeans of a Service Info Octet. MTP3 is unique as a part of the SS7 protocol and is also known as a part of theB-ICI interface for ATM. MTP3 sits among MTP2 and the userparts (ISUP, TUP, SCCP and TCAP) of the SS7 protocol stack.B-ISUP is an Application Layer protocol run over MTP3.

Q31. How Many Links Are Possible Between 2 Ss7 Links?

Two links are feasible between 2 ss7 hyperlinks.

High Speed Links (HSL).

Low Speed Links (LSL).

Q32. What Is File Fragmentation In Disks?

Some times called 'file machine growing older'is the inability of a report gadget to lay out related information sequentially (contiguously), an inherent phenomenon in storage-backed record systems that permit in-area amendment of their contents. It is a special case of data fragmentation.

Q33. On A 64bit Processor, Do Checksums And Crcs Calculation In The Stack Get Impacted ?

All the checksums calculated in SS7 (i.E. CRC in MTP2) are 16-bit CRC. They will not be suffering from a sixty four-bit processor.

All the stack entities operates on following basic kinds : 

U8bit

U16bit

U32bit

S8bit

S16bit

S32bit 

(where U is for unsigned and S for Signed)   These definitions are described in a header report & can be changed if wished. 

Q34. What Is The Functionality Of The System Management Entity?

The SS7 stack includes a primitive System Management entity. The functionality of machine control entity includes the subsequent: 

Provisioning, initialization and protection of SS7 stack entities.

Debug and hint management of SS7 stack entities.

Solicited and periodic information collection/reporting.

Redundancy management of SS7 stack entities.

Q35. What Is Meant By 'redundancy Management'?

Redundancy control if carried out shall suggest the following

SS7 stack shall have two working states ONLINE and STANDBY.

An interface shall be furnished for redundancy facts updation.

A mechanism will be supplied to signify to the device control entity for triggering the redundancy records updation to all of the redundant components.

System management entity shall have the manage for changing the state of the SS7 stack.

Compile time flag to govern the inclusion/exclusion of redundancy functions will be supplied. 

Q36. What Is Ss7?

Common Channel Signaling System No. 7 (i.E., SS7 or C7) is a worldwide wellknown for telecommunications defined with the aid of the International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T). The preferred defines the techniques and protocol by way of which network factors within the public switched smartphone network (PSTN) alternate information over a virtual signaling network to effect wi-fi (cellular) and wireline call setup, routing and manipulate. 

Q37. Is Any System Requirement Functionality Assumed From An External Db?

Database maintained via every stack entity is neighborhood to it and has were given no outside dependency. The database maintained via every entity has were given a static component (that's initialized by provisioning) and a dynamic component (which is updat5ed at run-time by the stack entity).

The interface of each stack entity with its database module is a properly defined practical interface (study/write/access/adjust). If there is a want to use an outside database, this purposeful interface has to be ported.

Q38. What Compiler Do We Use For Ss7 ?

The SS7 improvement environment is Solaris, with GNU C (gcc) compiler.

We also compile our supply code the usage of the subsequent compilers, earlier than a release :

Microtek MCC68K compiler

Borland C compiler

If a purchaser is making plans to apply a extraordinary compiler than the above, the source code can be compiled using that compiler before the discharge.