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Computer Networking
Computer networks are collections of computers which are connected together in order to communicate and transfer information. Questions about computer networks, networking protocols, and how to set them up belong here.
18,810 Questions
Which protocol is used to transfer files between Unix and Linux systems?
There are several protocols that could be used, depending on how you wanted to transfer the file. There are, for example:
- FTP - file transfer protocol
- TFTP - trivial file transfer protocol
- NFS - Network file system transfer
- SMTP - via email
- rcp - remote copy protocol
- SFTP - Secure File Transfer Protocol
- scp - secure copy
The easiest way to do this is to convert your subnet mask, 255.255.240.0 to binary. This subnet is a modified class B network.
To find the IP address range
To find the IP address range, you need to compare your IP address and Subnet mask in binary.
Your subnet mask in binary would be:
1111 1111 . 1111 1111 . 1111 0000 . 0000 0000
For reference, your IP in binary would be:
1001 1010 . 0001 0000 . 0011 0100 . 0001 0000
If we match up your IP to the network bits of your subnet, like so:
IP:
1001 1010 . 0001 0000 . 0011 0100 . 0001 0000
Subnet:
1111 1111 . 1111 1111 . 1111 0000 . 0000 0000
..we can match the network bits with the IP address to come up with the base network address to see where your network starts.
1001 1010 . 0001 0000 . 0011 0000 . 0000 0000
When we convert that back to decimal, it becomes:
154.16.48.0
To find the highest addressable IP in our network, we take the above binary IP and change the host bits to 1.
1001 1010 . 0001 0000 . 0011 1111 . 1111 1111
In decimal, that becomes:
154.16.63.255
Your range is 154.16.48.0 to 154.16.63.255. Remember that 0 and 255 are broadcast addresses.
Finding the maximum possible hosts of a given subnet
If you are just looking for the total number of hosts possible and are not concerned with what your IP range will be, you only need to convert your Subnet mask to binary.
Remember that your subnet mask of 255.255.240.0 in binary would be:
1111 1111 . 1111 1111 . 1111 0000 . 0000 0000
Take the host bits (the zeros) and switch them to ones. Convert them from binary to decimal as one large string:
Binary: 1111 1111 1111
Decimal: 4,095
The straight, simple answer to your question is 4,095 hosts. I can't give you a straight answer on subnets, but assuming you're talking about going from a Class B to a modified Class B network, you'd have 15 subnets with 4,095 hosts each. It is more likely that you're going from a Class C (255.255.255.0) to a modified Class B in which you now have, if you will, a negative number of subnets compared to your original network.
Modifying a subnet to accomidate a given number of hosts
If you know you need, for example, 800 hosts, you can change your subnet mask bit by bit. Switching a network bit to a host bit effectively doubles the number of hosts you can have on one network. The default class C network provides 256 hosts (including broadcast). 255.255.254.0 will double the host count to 512 hosts (including broadcast). This also changes the Class C network to a modified Class B network. Switching one more bit will again double the host count to 1024 hosts (including broadcast) with a subnet mask of 255.255.252.0.
Which simple wireless configuration technique can make the network invisible to unauthorized users?
The simple wireless configuration technique that can make the network invisible to unauthorized users are disable SSID broadcasting. This will disable the network from being broadcasted.
On what basis are IP numbers allocated?
If your question is about ip address allocation by isp:
whenever a user connect to the isp's network, from a specified range, its server allocates a dynamic ip address mostly or it can be static. if it is static, then the user will have the same ip address for a very long time (based on the deal). But if it is dynamic then it means it will change after some time or upon reconnect.
now the if your question is about your LAN (at work etc):
a computer again can have a fixed ip address assigned by the administrator or dhcp server can give your PC an ip address upon start. You may retain the same ip address for some days if such permission has been granted by the admin.
IP addresses in LAN are normally not public addresses and therefore the range may not matter as long as it is in the same network segment.
Difference between fdm and tdm?
FDM vs. TDM
TDM (Time Division Multiplexing) and FDM (Frequency Division Multiplexing) are two methods of multiplexing multiple signals into a single carrier. Multiplexing is the process of combining multiple signals into one, in such a manner that each individual signal can be retrieved at the destination. Since multiple signals are occupying the channel, they need to share the resource in some manner. The primary difference between FDM and TDM is how they divide the channel. FDM divides the channel into two or more frequency ranges that do not overlap, while TDM divides and allocates certain time periods to each channel in an alternating manner. Due to this fact, we can say that for TDM, each signal uses all of the bandwidth some of the time, while for FDM, each signal uses a small portion of the bandwidth all of the time.
TDM provides greater flexibility and efficiency, by dynamically allocating more time periods to the signals that need more of the bandwidth, while reducing the time periods to those signals that do not need it. FDM lacks this type of flexibility, as it cannot dynamically change the width of the allocated frequency.
The advantage of FDM over TDM is in latency. Latency is the time it takes for the data to reach its destination. As TDM allocates time periods, only one channel can transmit at a given time, and some data would often be delayed, though it's often only in milliseconds. Since channels in FDM can transmit at any time, their latencies would be much lower compared to TDM. FDM is often used in applications where latency is of utmost priority, such as those that require real-time information.
FDM and TDM are often used in tandem, to create even more channels in a given frequency range. The common practice is to divide the channel with FDM, so that you have a dedicated channel with a smaller frequency range. Each of the FDM channels is then occupied by multiple channels that are multiplexed using TDM. This is what telecoms do to allow a huge number of users to use a certain frequency band.
Summary:
1. FDM divides the channel into multiple, but smaller frequency ranges to accommodate more users, while TDM divides a channel by allocating a time period for each channel.
2. TDM provides much better flexibility compared to FDM.
3. FDM proves much better latency compared to TDM.
4. TDM and FDM can be used in tandem.
E3
A wideband digital circuit with standardized operating characteristics that operate at a rate of 34.368 Mbps. This standard is widely used in Europe for intercarrier communications as the rough equivalent of a DS3
Channelized
A transmission option for subscribers of symmetrical services. Channelized service allows a subscriber to assign one device (such as a PC) to a DS0 channel, resulting in many devices being able to transmit and receive simultaneously at 64 kbps.
Example of application used by the UDP and TCP?
UDP: DNS, TFTP, DHCP...
TCP: SMTP, HTTP, HTTPS, DNS, FTP, SHH, Telnet...
How ISDN PRI equals 2.048 mbps?
As we know that voice signal is of frequency 3.3 Khz,and as per the Nyquist Rate or PCM quantization rate for transmission we required signal of >=2f(here 'f' is GIF [3.3]=4).and each sample of data is a byte. DS0: provides one 64kbps channel.E1: 32 DS0 or 32 channels with 64kbps
Also we know that voice signal frame consisits of 32 bytes .Hence value of an E1 will be
=2x4Khzx8bitsx32slots
=2.048Mbps
What a router can do and a hub can not do?
Routers create a private virtual session for each connection, they do not broadcast your connection to all computers, they optimize network traffic.
What is a DHCP sever used for?
A DHCP server will assign IP addresses, and other network parameters, automatically, to computers who ask for it. In Windows, if you select that you want the computer to get an IP address automatically, it will try to get the IP address (and other parameters) from a DHCP server.
The idea is to reduce the amount of configuration required for each computer, especially in larger networks.
What is mode in optical fiber?
mode means path, the way in which light travel, in the fiber means angle in multi mode fiber light can travel in more then one angle so it is called multi mode fiber.
but in single mode fiber there is dedicated path or single path through which light beam/source can travel.
It's difficult to say from here without more information, but the things I'd look at are:
Are the two machines the same - does the slower machine have less memory, slower hard drive, slower processor or different software? Are the files being transferred to the main drive of the computer - for example, FAT is much slower than NTFS so if download to a FAT formatted memory stick, it will be a lot slower. Are both PCs connected in the same way? (if one is wireless connected and the other using a cable, the wireless will be a lot slower).
Are there any errors being reported for the Ethernet connection on the PC?
What router ports are commonly used for LAN connections?
the router as ports commonly used for lan cannection is (Ethernet)
Which osi model break data into smaller pieces?
The Transport layer breaks the application data into segments, or smaller pieces for transport across the network.
Which protocol is associated with Industrial Control System functional networks?
Inter-Control Center communications Protocol (ICCP)
What is the basic difference between ISDN and ADSN connection?
With ISDN you can implement ASDN. ISDN is a way of transmitting digital signals on a network - fiber or analog copper. It allows "virtual circuits" to be configured and bandwidth reduced or raised as needed. This is controlled by signalling messages that goes on a dedicated part of the lines.
ASDN is a way of coding signals on a copper wire - where the signals can be ISDN lines.
ISDN is the core network technology in the GSM mobile network, which allows this to set up phone connections, and keep these connected as you call while you move around.
Why use the more than one subnet in one ip address?
You don't use more than one subnet in one single IP address. The IP address indicates what subnet you are in and a client may belong to only one subnet at a time.
An IP address range may indicate the presence of more than one subnet, however. This is done to split up a larger network into multiple smaller networks.
The IPv6 specification allows routers to ignore Flow Labels and also
allows for the possibility that IPv6 datagrams may carry flow setup
information in their options. Unknown Flow Labels may also occur if a
router crashes and loses its state. During a recovery period, the
router will receive datagrams with Flow Labels it does not know, but
this is arguably not an error, but rather a part of the recovery period.
Finally, if the controversial suggestion that each TCP connection be
assigned a separate Flow Label is adopted, it may be necessary to
manage Flow Labels using an LRU cache (to avoid Flow Label cache
overflow in routers), in which case an active but infrequently used
flow's state may have been intentionally discarded. In any case, it is
clear that treating this situation as an error and, say dropping the
datagram and sending an ICMP message, is inappropriate. Indeed, it
seems likely that in most cases, simply forwarding the datagram as
one would a datagram with a zero Flow Label would give better
service to the flow than dropping the datagram.
Can MIME standard replaces SMTP?
Yes, using various TCP/IP protocols along with MIME can significantly increase network stability. This is why most industry standards use MIME instead of the former standard, SMTP
What are the minimum requirements user identification and authentication systems must support?
User identification and authentication systems must support the minimum requirements of ?
What would you use a 2 port Ethernet switch for?
An individual can use a 2 port ethernet switch (or one with more than two) if he or she wants to add a network connection without having to add another cable drop.
Garbage printing is when a printer prints "garbage" that is unreadable. It may be due to corrupted data sent to the printer, or a driver fault, or even a sticking roller or blocked print-head, etc.
Is the internet be descrided as a circuit switched network or packet switched network?
The Internet is packet switched, meaning each individual packet is routed from the source to the destination separately, and possibly through different paths.
An example of a circuit-switched network would be the telephone network, where a connection from one end to the other is created and maintained until the call is disconnected.
