Basic Telecom Objective Question TDM, FDM, PSTN - Part 2

Q.11 Find the odd statement out from the following set of statements as far as
         multiplexing is concerned?

A. Multiplexing is used in order to maximize the utilization of shared 
        communication medium.

       B. Multiplexing allows simultaneous transmission of multiple signals 
            across a single communication link

C. TDM, FDM, WDM and XDM are different type of multiplexing 
       techniques.

       D. The process of sharing the common medium (trunk)by sending 
             combine signal from several sources in a predetermined manner 
             is called multiplexing.

Q.12 Amongst statements given below are true as far as PDH goes, 
          which are they?

     A. In North American Multiplexing hierarchy multiplexers are 
          named e1/e2/e3/e4, e4 being the highest order multiplexer.

     B. In North American Multiplexing hierarchy multiplexers are named 
          t1/t2/t3/t4, t4 being the highest order multiplexer.

     C. In Europen Multiplexing hierarchy multiplexers are named e1/e2/e3/e4,
          e4 being the highest order multiplexer.

     D. In Europen Multiplexing hierarchy multiplexers are named t1/t2/t3/t4, t4 
          being the highest order multiplexer.

Q.13 Which amongst the below mentioned switch has following disadvantages 

         Expensive relays, noise due to chattering of relays, limited capacity due to grid.

     
     A. cross bar switch 
     B. strowger switch  
     C. time and space switch 
     D. manual switch  
     E. electronic switch

Q.14 In PSTN,A to D and D to A conversion takes place in ______________

A. etc

B. lic

C. ixc

D. lata

Q.15 When the telephone call is established, resources are reserved ___________

A. Within an exchange

B. on trunk

C. Within an exchange as well as on trunk

D. None

Q.16 __________Signal from exchange to subscriber indicates the progress of the call.

A. Information

B. Control

C. Address

D. Alerting 5.Supervisory

Q.17 In case of channel associated Signaling (CAS), _____

A. Voice and signaling information use the same path

B. Voice and signaling information use separate paths

Q.18 SS7 is ____switched network.

A. Circuit

B. packet

C. message

D. cell

Q.19__________signal is sent as a response to IAM signal in SS7 network.

A. ACM

B. IAM

C. ANM

D. Alert

Q.20 Which of the following equipment(S) is/are installed at customer premises in ISDN technology? Choose the most appropriate answer amongst the following.

A. NT1

B. NT2

C. NT1 and NT2

D. NT1 and NT2 and optionally TA

Answers for Basic Telecom questionnaires’:-  

Question Number	Correct Answer
10	C
11	C
12	A
13	A
14	B
15	C
16	A
17	A
18	B
19	A
20	D

Basic Telecom Objective Part - 1

Basic Telecom Objective type Qustions | PSTN - Network Topology Questions

Q 1.  One amongst the following is not a network technology. Find the option out.

A. PSTN 

B. ATM 

C. SONNET/SDH 

D. BSDN

E. DSL

Q 2. In USA telecom scenario every ixc (inter exchange carrier) puts up a _____ in lata (local transport area)

A.Trunk

B. POP 

C. LEC 

D. None

Q 3. Which of the following statement describes access network of PSTN in the most appropriate manner:-

A. Access Network Connects Access Node (edge of access network) to the individual subscriber.

B. Access Network Consists of trunk/toll exchanges.

C. Access Network is a combination of switching systems

D. Access Network consists of transmission systems connecting switching centers

 Q 4.Which of the following statement is most appropriate in the context of communication protocol?

A. Protocol has syntax, semantics and logical sequencing

B. Protocol consists of rules.

C. Protocol has logical sequencing

D. Protocol has prototypes

Q 5. IP addressing as well as routing based on IP address happens at ______ layer in TCP/IP protocol stack.

A. datalink

B. Transport

C. Application

D. Network

E. Presentation

Q.6 Which one from the following properties of the signal can be change?

A. Amplitude and frequency 

B. Frequency and phase 

C. amplitude and phase 

D. Amplitude, frequency as well as phase

Q.7 What is the equation for SNR?

A. SNR=10log10(Ps/Pn) 

B. SNR=10log2(Ps/Pn) 

C. SNR=2log10(Ps/Pn)

D. SNR=2log2(Ps/Pn)

Q.8 For a signal with frequency range of (0-3) KHZ, what is the minimum sampling frequency required to reproduce the signal according to the sampling theorem

A. 1.3 KHz 

B. 2.6 KHz 

C. 9 KHz 

D. 4.7Khz

Q.9 TV and Radio are entertainment media. Which of the following modulation techniques are used in radio transmission?

A. AM and FM  

B. AM and PM

C. FM and PM 

D. AM,FM and PM

Q.10 In the process of modulation which of the following cannot be digital signal at all

A. Input signal and output signal 

B. Input signal and carrier signal 

C. Output signal and carrier signal 

D. None of the above

Answers for Basic Telecom questionnaires’:-  

Question Number	Correct Answer
1	D
2	B
3	A
4	A
5	D
6	D
7	A
8	B
9	A
10	C

Basic Telecom Objective Question TDM, FDM, PSTN - Part 2

Application Production Server Environment Setup

Application Production Server

Any software application is said to be in production when it is directly dealing with business either in Business to business or business to customer and even for internal business uses. And the application critical or responsible for business operation to work for profitability.


Any application before going to production server/environment goes out from various environments and levels like development, configuration/testing, SIT, Pre-Production. Once a application reaches to Pre-production or SIT environment, it will move to Production server after completing the user acceptance testing (UAT).



Strategically, Production environment setup can be done in various ways that depends on your requirement like organizational, application, geography, business nature and cost. we are discussing various approach here for production servers.



Standalone Setup

As the name depicts, in this setup application software has only one instance at all time means application logic is available at one place or hosted on one physical server. This approach generally used in small desktop application with low load of user traffic.

Standalone setup can have one hardware machine that can host operating system, database, application server and code logic.

The main disadvantage of this setup is, it does not provide you the facility of high availability and load balance. If the hardware failure occurs, application will not be available to serve.




Clustering Setup

The Cluster is a group of host servers on which your application logic is deployed. In this setup, the whole setup will be visible to client/user as a single or standalone setup where he will have advantages like High Availability and Load Balance.


As a cluster that is group of servers where if any hardware or network failure occurs due to any reason, then user is automatically transferred to other available server in group and the user will use the system as usual and will not face error or downtime during this switch over. This is called High Availability of servers.

How does a cluster work as a set-up point of view ?

• HOT - HOT Setup                     -    Both the Data Center takes traffic simultaneously.

• HOT - COLD Setup                  -    Only one Data Center takes traffic. if HOT DC goes down,                                                            the Cold DC will be manually made active to take the                                                                    traffic. 

• HOT - WARM Setup                 -    One DC takes traffic. if HOT DC goes down, WARM DC                                                             automatically comes up and starts taking traffic.

                              

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How To Resolve Server Hang, Memory Leakage and Out Of Memory Issues

Below are the steps and tips that a production support engineer keep in mind :

• Gather memory leakage data by enabling GC verbose on deployment servers.

• If Application is in JAVA, then you make sure JSP page are with pre-compilation.

• For Web application, Check the deployment descriptor entries.

• HTTP session duration settings, Check for Auto Time out settings.

• Check JDBC Connection Pool Setting like initial and max no of connection with database with no by which it can increase.

• Look for code how developer is handing JDBC connection.

• Optimize Heap Size as per application load.

• High CPU utilization - This is the condition when a process is taking high portion of CPU. You may check that by top command of unix. you may kill it, if that is abnormal and not required to run.

• Monitor Garbage Collection

• Define Separate files for different logs

• Use Application log frameworks like log4j

• Use separate log files for Garbage collection per JVM.

• OS Chunk pool size

• OS Connection backlog buffering

• Use OS performance packs

• Setting OS TCP-IP parameters

• tcp_time_wait_interval

• tcp_conn_req_max_q

Application Production Support Issues Part -1

We are trying to list down all possible reasons that can be the root cause of below issues listed for Application Production Support domain. These are the basics that will be asked in each interview as well as a production support engineer needs to be familiar interact with these issues.


Thread Dump

• On Linux/UNIX system just the below command to get JAVA thread dump

                    $     kill -3   <PID of JVM>

•  In Case IBM WAS server -

            Use DMGR console  >> Troubleshooting >> Select JVM and click core

• Oracle Weblogic Server -

          Using wlsadmin.sh   script   or JSTACK utility  

JAVA Out Of Memory

• Low JAVA Heap Size on server
• Object Slicing too long, like HTTP sessions
• Memory leakage in application code
• Full garbage collection is not happening due to JVM bug.

Server Hang issue 

Various reason can attract the server hang condition that may be called a deadlock condition where system will behave wrong or even does not respond to user queries at all.

• Memory leakage in application code
• Database query is taking long to time to return the output 
• Deadlock Condition
• Network latency
• Out Of Memory Error

_________________________________________________________________________________

IBM WebSphere Introduction

What is IBM WebSphere ?


This is Application server built on Java and provides the Middleware and MQ support in enterprise application development in IT software field. It is large app server in market that is used in Enterprise service bus or service oriented architecture in various organization. It is called as WAS in short.



Below are the some info to remember about WebSphere


WAS Editions

• WAS Network Deployment
• WAS Developers
• WAS Z/OS
• WAS Hypervisor 
• WAS Express
• WAS Base
• WAS Liberty Core

WAS default Ports ?

HTTP /HTTPS     -    9080 / 9443

How To Check WAS Version

Go to profile and bin folder of WAS installation on server box and execute below scripts

$    ./versioninfo.sh




More info at IBM WebSphere Home
_________________________________________________________________________________

Oracle Weblogic Server Starting Status in logs

Different status message When a user starts a weblogic server instance 


1. STARTING

2. STANDBY

3. STARTING

4. ADMIN

5. RESUMING

6. RUNNING



When Weblogic server admin starts the weblogic server from domain home, he may check the status of admin server in AdminServer.log file.