Questions in: Network & Telecom

dead lock means suppose there is two process process A
depends upon the resources of process B where process B
depends upon the resorses of B.both will be confused and it
wiil be stop forever.This is called delock for relese it
use synchroniz keyword in java

For example,
One process writting data into a file, another process
deleting data from that same file. In this situation both
process cannot be complete. This is called 'Deadlock'

Router: A device that determines the optimal path in which
the data should be fwded. They fwd the pkcts from one
network to the other n/w.
Gateway: Translates the different protocols that are used
on two distinct networks. It performs an application layer
of conversion from one protocol to other.

Router connects two networks.
Gateway starting point of network.

Datalink layer is further divided into two sub layers
1. M.A.C.(Media Access Control)
2. L.L.C.(Logical Link Layer)
Here the packets are converted into frames because to
assign meaning to bit and bytes
Main Responsibilities are
1. Framing
2. Physical Adderessing.
3. Flow Control and
4. Access Control

The data link layer transforms the physical layer(a raw
transmission facility) to a reliable link. It makes
physical layer appear error free to the upper layer.
Specific responsibilities of DLL include
1)Framing
2)physical addressing
3)Flow control
4)Error control
5)Access control

Each IP packet is assigned a checksum, so if the checksums do not match on both receiving and transmitting ends, the data was modified or corrupted.

UTP is unshielded twisted pair cable.
this cable define in catagory
CAT 1,CAT 2,CAT 3,CAT 4,CAT 5,CAT 6,CAT 7
CAT 2 cable use in Telephone Wire.
CAT 5 & Later Catagories use in our LAN.

utp is network cable used rj-45 connector and avilable in
diff. cat. cat1, cat2, cat3, cat4, cat5, cat6, cat7.
cat1 & cat2 used in telephone line.
cat3, cat4, cat5,cat6,cat7 used in networking
cat6 & cat7 provide high bandwidth for communication.
cat means how many twist per inch.
twist reduce e.m.f.
utp cable used for star toplogy.

Fwd Lookup resolves a Hostname to its IP address
Rev Lookup resolves a IP Address to its Hostname

Forware Lookup resolves (converts) FQDN name into IP address
EX: www.allinterview.com into 192.168.5.253
Reverse Lookup resolves (converts)IP Address into FQDN
FQDN = Fully Qualified Domain Name

A firewall is a part of the computer or network which
prevents unauthorized access to it.Firewalls are frequently
used to prevent unauthorized Internet users from accessing
private networks connected to the Internet.It regulates
traffic of the network of different trust levels.
On the other hand,Access Control List refers to rules that
are applied to port numbers or network daemon names that are
available on a host, each with a list of hosts and/or
networks permitted to use the service. Both individual
servers as well as routers can have network ACLs.
This way. ACL are the rules to be implemented for security
while firewall is he complete setup or mechanism.

Firewall provides a permission or destroys for a packet to
enter inside our network from private network .
Acl's which provide rules to control which type of packet
to be destroyed or permitted

If u want be a good network administrator u should under
stand all concepts clearly such as Topologies, Protocols,
Client/server technology.
Here i am giving the commands to trouble shoot the network.
1) ipconfig - this is the command which shows your present
Tcp/IP configuration.
2) ipconfig /all- command which shows your present Tcp/ip
configuration as well as Host name, Physical address, DNS &
DHCP ip addresses and lease duration period.
3) ipconfig /release - if u r using dynamic ip address this
command helps to remove the ip address.
4) ipconfig /renew - this helps to renew the ip address from
DHCP Server.
Trouble shooting steps
1) first Ping your loop back address 127.0.0.1 with
this u can verify u r NIC status.
2)then Ping your own ip address if u r getting reply
3) ping gateway ip address of your network
4)Using NSLOOKUP command verify the dns server ip
address and ping DNS

many ways to acheive the network security?
1. confi. the router & give password for not anybody no
resat the router

1. Change the physical memory dumping settings in advanced
tab in system property .
2. check the your computer Hardware hard disk, RAM, motherboard.

Blue screen error gernally occurs due to hard disk problem,
we can rectify this error my reinsert the bus cable from HD
to mother board,if prolem still persisting use this disk on
onather computer as secondary disk then scan whole disk
from appropiate antivirus then again fit it to target
system,it can work..

Frist of all listen is there any beep comes from from CPU,
if beep comes then problem may be With RAM or Display card
and if no there is no beep then check CMOS Battery,Physical
connectivity and wires of SMPS.

1) Check the power cables is properly inserted or not.

By using netstat command(in linux it works).

netstat -an command used to to find what ports are open on a
machine (both local and remote)

there are many third party tool for capturing the network
traffic.
Example:
Microsoft's Network Monitor

wireshark(ethereal) & tcpdump

Network testing is carried to check the health status and
address the problems fased by the network such as low
bandwidth , delay ,jitter ,congestion etc.
It is carried on nodes facing issue or noded that are
expected to give better results.
checking the hardware requirments.
policys on the node ,ACLs
misconfiguration , and proper allocation of resources are
common task to be handeled.
checking IDS and IPS are also major task

switch is a small hardware device that joins multiple
computers together within one local area network (LAN).
Technically, network switches operate at layer two (Data
Link Layer) of the OSI model

switch is a software based physically harware device in
this communicate same networks, switch is a data
communicate equipment(DCE),Two types of switch available
1.manageable switch 2.un(or)non manageable switch.Switch
every port single collusion domain.ASIC chipset used in
this device in this working 100mbps speed.