Computer Networking

Hub

The main part of an optical fiber is a glass fiber (NOT hollow) within another glass fiber of another type of glass. Both types of glass have a different index of refraction; the signal travels through the inner glass fiber.

a. Routers are more expensive than bridges.

b. Routers operate at the first three-layers; bridges operates at the first two layers.

Routers are not designed to provide direct filtering the way the bridges do. A

router needs to search a routing table which is normally longer and more time

consuming than a filtering table.

c. A router needs to decapsulate and encapsulate the frame and change physical

addresses in the frame because the physical addresses in the arriving frame

define the previous node and the current router; they must be changed to the

physical addresses of the current router and the next hop. A bridge does not

change the physical addresses. Changing addresses, and other fields, in the

frame means much unnecessary overhead.

In a controlled access method, the whole available bandwidth belongs to the station that is granted permission either by a central authority or by other stations. In a channelization method, the available bandwidth is divided between the stations. If a station does not have data to send the allocated channel remains idle

It simply tests whether the TCP/IP stack is correctly installed.

2

A hub will repeat an incoming signal through all its ports, except the port where the signal came in.

The advantage of MAC addressing is that there is no attachment cost to devices that connect to the network. Its disadvantage, on the other hand, include easy spoofing due to the broadcast nature of the Ethernet.

gcj

direct connection (EDI) requires each business in the network to operate its own on-site EDI translator computer. Most companies use the service of a value-added network such as VANs that provides communications equipments, software, and skills needed to receive, store, and forward electronic messages that contain EDI transactions set.

the main difference is that indirect connection pass message through the VANs instead of connecting their computers directly to each other.

ping uses the ICMP protocol.

The following ranges are reserved for private addresses:

Class A: 10.0.0.0 - 10.255.255.255
Class B: 172.16.0.0 - 172.31.255.255.
Class C: 192.168.0.0 - 192.168.255.255

Network Portion

Host Portion

A redundant network is one which has some extra capacity, in case certain components fail. It is just like having a spare wheel in your car. You don't need it all the time, but it is there, just in case one of the other wheels fail.

For example, you can have more cable connections between switches or other pieces of equipment than what is absolutely required for the basic working of the network. In this case, if one connection fails, it is possible that data can still be sent over another connection.

You can also has spare switches, spare routers, or spare servers, but that is more expensive, and in some cases complicated to configure. You must weigh the cost of these equipments, against the cost of network downtime.

The protocol field, in the IP header, identifies what kind of data is in the IP packet - the upper-layer protocol. For example, if the code is 6, that means that the data is a TCP segment.

Virtual Circuit is Created. Each circuit is known by its DLCI. i.e. Data Link Connection Identifier.

It is the Intrusion Prevention System that checks the network traffic and tries to provide a defense against malware.

Private spae address blocks are set aside for use in private networks.

Advantages: A company can purchase fewer IP addresses since each machine will not be

statically assigned a fixed address but dynamically assigned an address when it accesses the

Internet. Disadvantages: The software is more elaborate; what if 100 IP addresses are purchased

and the 101st user tries to access the Internet?

Patching a server is the process of applying updates to the software that the server runs on that improve the security of the software, fix bugs in the software, or improve the performance of the software. "Server patching" may refer to applying these "software patches" to the operating system or to other software running on the server, such as web servers, databases and application servers.

The components of NIC are :

buffer

pulse transformers

lan dc/dc converters

lan filters

That's called a "token".

That's called a "token".

That's called a "token".

That's called a "token".

The DHCP server will not issue the addresses ranging from 10.10.4.1 to 10.10.4.5.

bits

Domain name