2. Explain snmp protocol? How is snmp work with NMS and EMS?

SNMP is based on the manager/agent model consisting of an
SNMP manager, an SNMP agent, a database of management
information, managed SNMP devices and the network protocol.
The SNMP manager provides the interface between the human
network manager and the management system. The SNMP agent
provides the interface between the manager and the physical
device(s) being managed.
The SNMP manager and agent use an SNMP Management
Information Base (MIB) and a relatively small set of
commands to exchange information. The SNMP MIB is organized
in a tree structure with individual variables, such as
point status or description, being represented as leaves on
the branches. A long numeric tag or object identifier (OID)
is used to distinguish each variable uniquely in the MIB
and in SNMP messages.

SNMP uses five basic messages (GET, GET-NEXT, GET-RESPONSE,
SET, and TRAP) to communicate between the SNMP manager and
the SNMP agent. The GET and GET-NEXT messages allow the
manager to request information for a specific variable.

The agent, upon receiving a GET or GET-NEXT message, will
issue a GET-RESPONSE message to the SNMP manager with
either the information requested or an error indication as
to why the request cannot be processed. A SET message
allows the SNMP manager to request a change be made to the
value of a specific variable in the case of an alarm remote
that will operate a relay. The SNMP agent will then respond
with a GET-RESPONSE message indicating the change has been
made or an error indication as to why the change cannot be
made. The SNMP TRAP message allows the agent to
spontaneously inform the SNMP manager of an "important"
event.

3. Explain RRC States in Umts?

There are four RRC states present in UMTS .
1.CELL_DCH STATE
2.CELL_FACH STATE
3.CELL_PCH STSTE
4.URA_PCH STATE

WHEN MOBILE IS MOVING FROM IDLE MODE TO DEDICATED MODE AND
DATA TRANMISSION IS OF LARGE AMOUNT OF DATA THEN CELL_DCH
STATE COMES IN TO PICTURE .

IF DATA TRANSMISSION IS OF SMALL AMOUT OF DATA THEN
CELL_FACH STATE WILL COME IN TO PICTURE

WHEN MOBILE IS MOVING FROM ONE CELL TO ANOTHER CELL IT
SHOULD PERFORM HANDOVER THEN MOBILE RRC STATE WILL BE IN
CELL_PCH STATE.

URA MEANS UTRAN REGISTRATION AREA

THE AREA COVERED BY ONE RNC IS KNOWN AS URA

SO WHEN MOBILE IS MOVING FROM URA AREA TO ANOTHER URA AREA
THEN LOCATION UPDATION SHOULD PERFORM THEN MOBLIE RRC STATE
COMES TO URA_PCH STATE .


THESE ARE THE FOUR RRC STATES PRESENT IN UMTS NETWORK

4. Explain Crankback?

Crankback is a mechanism used by ATM networks when a
connection setup request is blocked because a node along a
selected path cannot accept the request. In this case, the
path is rolled back to an intermediate node, which attempts
to discover another path to the final destination

5. Explain whats the purpose of GSM DEVISE AND WHAT IS GPRS?

GSM stands for Global System for Mobile Communications. GSM devices are used to make voice calls through a circuit switched networks. GPRS is General Packet Radio Services an aditional feature for data surfing on mobile.

6. In GSM we use MSRN for routing but what parameter is used in the CDMA for routing?

In Gsm We use routing number towards the calling subscriber
and tldn towards the calling subscriber , but in cdma the
subcriber will not be allocated any routing number for the
internal routing, i..e.. for the itra cell or intra msc
routing there will be no token issued, but for the inter
msc there will be token only towards called party.

7. What is TTCN-3?

TTCN-3 (Testing and Test Control Notation version 3) is a strongly typed test scripting language used in conformance testing of communicating systems and a specification of test infrastructure interfaces that glue abstract test scripts with concrete communication environments. TTCN-3 has been developed by ETSI and its predecessor is TTCN-2. Despite sharing same fundamental concepts, TTCN-2 and TTCN-3 are essentially two different languages, the latter having simpler syntax and standardized adapter interfaces. TTCN-3 scripts can be combined with ASN.1 type definitions. ASN.1 is natively supported by major TTCN-3 tool vendors.

8. Did mobile moves from cell DCH to Cell FACH State if so What information will pass between Cell FACH and Cell Dch states?

yes it is possible to move from cell Fach to cell Dch ,
when the mobile have low rate of data flow then it will be in
Cell Fach mode if it wants to transfer of large amount of
internet data and wants to move on to voice call then the
mobile will pass the information from cell Fach to Cell Dch.

9. What is protocol testing. whether you have used any tool in telecom testing?

Protocol testing means to test the functionality of the
node(piece of software) which should compliance to some
standard message flow. For this one should take a
tester(Testing Unit) which should send standard messages to
the node(Item under test). Above all tester mentioned are
good but according to me K1297-G20(Tektronics)is the best
tester.
Advantages
1) Many standard Protocol are supported by this tester
2) One can add just new protocol supports easily
3) With introduction of G-20 its interface is really good,
one can easily learn.

Disadvantages
1) Load can't be tested with this, as this tester is windows
based with low processing capabilities
2) It is little bit costly as it give license per link per
protocol base
3) Support too have some issues