What is Computer Networking
Content
What is computer networking
Definition:-A computer network is two or more computers connected together using a telecommunication system for the purpose of communicating and sharing resources
Physical connection
LAN card Cables Networking devices (Hub, Switch , Router )
LOGICAL CONNECTION IP-address Protocol (software)
What’s Network
Types Of Network:• LAN (Local Area Network) • MAN (Metropolitan Area Network) • WAN (Wide Area Network) • Peer To Peer Networking • Server Base Networking -Host (Sender of Information) -Guest (Receiver of Information)
Types Of Network
LAN (Local Area Network)
Network which is include in a single building or room can be defined as LAN
Types Of Network
WAN (Wide Area Network)
Network expanding through cities , countries , continents limit called WAN . which can be connected through phone or modem . it’s also called intranet
Types Of Network
MAN (Metropolitan Area Network)
Sector 1 Sector 2
Network expand through a Single building in city limit is called MAN.
Types Of Network
Peer To Peer Network
In this network both computers have equal rights to share their resources. And both acts as server.
peer-to-peer network
• A pure peer-to-peer network does not have the notion of clients or servers, but only equal peer nodes that simultaneously function as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client-server model where communication is usually to and from a central server.
What are the advantages of peer-to-peer networking? • An important goal in peer-to-peer networks is that all clients provide resources, including bandwidth, storage space, and computing power. Thus, as nodes arrive and demand on the system increases, the total capacity of the system also increases. This is not true of a client-server architecture with a fixed set of servers, in which adding more clients could mean slower data transfer for all users. • The distributed nature of peer-to-peer networks also increases robustness in case of failures by replicating data over multiple peers, and -- in pure P2P systems -- by enabling peers to find the data without relying on a centralized index server. In the latter case, there is no single point of failure in the system.
• When the term peer-to-peer was used to describe the Napster network, it implied that the peer protocol was important, but, in reality, the great achievement of Napster was the empowerment of the peers (i.e., the fringes of the network) in association with a central index, which made it fast and efficient to locate available content. The peer protocol was just a common way to achieve this. Disadvantages of peer to peer? • They are less secure than client-server networks, especially so because the files have to shared and no password is required. • It is more time consuming to maintain the software on individual computers. • Peer-to-peer networks are designed for a small number of users. Network speed and performance starts to deteriorate usually after more than 10 computers are on the network. This makes it difficult to grow the network when the need to add more computers on the network becomes unavoidable.
What are the advantages of peer-to-peer networking?
Types Of Network
Server Base Network
In this network all computers and other shared resources are controlled by centralized server.
Hub (Hybrid Unit Board)
• • • • • • • • • • • • • • It works on layer one (Physical) It has One Collision domain or one way for sending data. It always broadcast. It communicates computers of one network. It’s differentiated by it’s sticker and it’s port (hub link)
Switch
It works on layer two (data link) It has many collision domain. Each port is one collision domain. It broadcasts at first time. It communicates all computers of same network. It’s speed is better than Hub.
Router
It works on layer three (Network) It communicates different network. It has it’s own OS which can be configured by Computer. It has four Modes – User Mode – Privileged Mode – Global Mode – Sub Global Mode. It’s best than all.
•
Repeaters
Repeaters, located within the physical layer of a network, regenerate and propagate signals from one to another. They do not change any information being transmitted, and they cannot filter any information. Repeaters help to extend the distances of networks by boosting weak signals.
Bridges
Bridges are intelligent repeaters. They regenerate transmitted signals, but unlike repeaters, they can also determine destinations.
Hubs
Hubs connect all computer LAN connections into one device. They are nothing more than multiport repeaters. Hubs cannot determine destinations; they merely transmit to every line attached in a half-duplex mode. Routers are a step up from bridges. They are able to route and filter information to different networks. Some routers can automatically detect problems and redirect information around the problem area. These are called "intelligent routers."
Routers
Switches
Switches connect all computer LAN connections, the same as hubs do. The difference is that switches can run in full-duplex mode and are able to direct and filter information to and from specific destinations.
WAN
WAN Infrastructure
As with LANs, there are numerous devices associated with data information flo across a WAN. Together, these devices create the infrastructure of a functiona WAN. These devices include: •Router •ATM Switch •Modem and CSU/DSU •Communication Server •Multiplexer •X.25/Frame Relay Switches
ATM Switches
ATM Switches provide high-speed transfer between both LANs and WANs.
Modem (modulator / demodulator)
Modems convert digital and analog signals. At the source, modems convert digital signals to a form suitable for transmission over analog communication facilities (public telephone lines). At the destination, modems convert the signal back to a digital format.
CSU/DSU (Channel Service Unit / Data Service Unit)
CSUs/DSUs are similar to modems, however they send data in digital format across digital telephone loops. They are usually in a physical box, but they may come in two separate units: CSUs or DSUs.
Multiplexers
A Multiplexer combines multiple signals for transmission over a single circuit. This allows for the transfer of various data simultaneously, such as video, sound, text, etc.
Communication Servers
Communication Servers are typically dial in/out servers that allow users to dial in from remote locations and attach to the LAN.
X.25 / Frame Relay Switches
X.25 and Frame Relay Switches connect private data over public data circuits using digital signal. These units are very similar to ATM switches, but the transfe rate of data is not comparable.
OSI Reference Model
• Open Systems Interconnection Reference Model – Standard model for network communications – Allows dissimilar networks to communicate – Defines 7 protocol layers 7 6 5 4 3 2 1
OSI Layers Application Diagram
Presentation Session Transport Network Data Link Physical
Appl icati on P roto co
Transport Protoco
Network Protoco
Application Protocols = FTP , SMTP , TCP etc
Transport Protocols = TCP , UDP Network Protocols = IP , IPX OSI Layers Detail 1. Physical Defines physical means of sending data over network devices Interfaces between network medium and devices Defines optical, electrical and mechanical characteristics 2. Data Link Defines procedures for operating the communication links Frames packets Detects and corrects packets transmit errors 3. Network Determines how data are transferred between network devices Routes packets according to unique network device addresses Provides flow and congestion control to prevent network resource depletion
4. Transport Manages end-to-end message delivery in network Provides reliable and sequential packet delivery through error recovery and flow control mechanisms 5. Session Manages user sessions and dialogues Controls establishment and termination of logic links between users Reports upper layer errors 6. Presentation Manages user sessions and dialogues Controls establishment and termination of logic links between users Reports upper layer errors 7. Application Defines interface-to-user processes for communication and data transfer in network
OSI Layers Detail
OSI Reference Model Data Flow
CLIENT
Data travels down the stack Then up the receiving stack
7 Applicatio n 6 Presentation 5 Session 4 Transport 3 Network 2 Data Link 1 Physical
SERVER
7 Applicatio n 6 Presentation 5 Sessio n 4 Transport 3 Network 2 Data Link 1 Physical
Through the network
As the data passes through each layer on the client information about that layer is added to the data.. This information is stripped off by the corresponding layer on the server.
Hybrid Topology
• A mixture of two or more than two topologies are called hybrid.
Connectivity
IP Address
An IP address (Internet Protocol address) is a unique address that devices use in order to identify and communicate with each other on a computer network IP versions :-The Internet Protocol has two primary versions in use. Each version has its own definition of an IP address. Ip version 4 Ip version 6
1. 2.
IP Addressing An IP address is software address , not a hardware address –the latter is hard coded on a network interface card (NIC) & used for finding host on a local network .IP addressing was designed to allow a host on one network to communicate with a host on a different network ,regardless of the type of LANs the host are participating in.
Bit a bit is one digit, either 1 or 0. Bytes is 8 bits Octet :An octet, made up of 8bits,is just an ordinary 8-bit binary number Network address: this is designation used in routing to send packets to remote network for example 10.0.0.0, 172.168.10.0 & 192.168.10.0 Broadcast address: the address used by application & host to send information to all node on a network is call broadcast address.
IP Terminology
IP version 4 IPv4 uses 32-bit (4 byte) addresses, which limits the address space to 4,294,967,296 (232) possible unique addresses. However, many are reserved for special purposes, such as private networks (~18 million addresses) or multicast addresses (~1 million addresses). This reduces the number of addresses that can be allocated as public Internet addresses, and as the number of addresses available is consumed, an IPv4 address shortage appears to be inevitable in the long run. This limitation has helped stimulate the push towards IPv6, which is currently in the early stages of deployment and is currently the only contender to replace IPv4. • Example: 192.168.1.1
Software (protocol)
Two type of protocol 1. TCP (Transmission control protocol) 2. UDP ( user datagram protocol )
Class A
10.0.0.0--------------(network) ip subnet zero 10.0.0.1---------------1st ip 10.0.0.2 10.0.0.3 TO 10.255.255.254----last ip 10.255.255.255----broadcast Total ip got in class A:- 16,777,216- 2=16,777,214 Total Net got in class A :-127
Class B
172.16.0.0---------------(ip subnet zero) 172.16.0.1----------------1st ip 172.16.0.2 172.16.0.2 TO 172.16.255.254----------last ip 172.16.255.255 --------Broadcast Total ip got in Class B :-65536-2=65534 Total Net got in Class B:- 16385
Class C
• 192.168.10.0 --------(ip subnet zero) 192.168.10.1 ---------1st ip 192.168.10.2 to 192.168.10.254 -----last ip 192.168.10.255 -----Broadcast Total ip got in Class C:- 256-2=254 Total net got in class C:-2097152
Types of Routing
The different types of routing are: • Static routing • Default routing • Dynamic routing
Static Routing
Routes learned by the router when an administrator manually establishes the route. The administrator must manually update this static route entry whenever an internetwork topology change requires an update. Benefits: • There is no overhead on the router CPU. • There is no bandwidth usage between routers • It adds security Disadvantage: •The administrator must really understand the internetwork and how each router is connected to configure routes correctly. • If a network is added to internetwork, the administrator has to add route to it on all routers-by hand
Default Routing
A default route is a special type of static route. A default route is a route to use for situations when the route from a source to a destination is not known or when it is unfeasible for the routing table to store sufficient information about the route.
In the image, Cisco B is configured to forward all frames for which the destination network is not explicitly listed in its routing table to Cisco A.
Dynamic Routing
Routes dynamically learned by the router after an administrator configures a routing protocol that helps determine routes. Unlike static routes, once the network administrator enables dynamic routing, route knowledge is automatically updated by a routing process whenever new topology information is received from the internetwork.
What is Cabling?
• Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.
Unshielded Twisted Pair (UTP) Cable
Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated five categories of wire.
Unshielded Twisted Pair Connector
The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.
Shielded Twisted Pair (STP) Cable
A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference. Shielded twisted pair (STP) is suitable for environments with electrical interference; however, the extra shielding can make the cables quite bulky. Shielded twisted pair is often used on networks using Token Ring topology.
Coaxial Cable
Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers. Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable. The two types of coaxial cabling are thick coaxial and thin coaxial. Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable is popular in school networks, especially linear bus networks. Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. This makes thick coaxial a great choice when running longer lengths in a linear bus network. One disadvantage of thick coaxial is that it does not bend easily and is difficult to install.
Coaxial Cable Connectors
The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters are available for BNC connectors, including a Tconnector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that crimp, rather than screw, onto the cable.
Fiber Optic Cable
Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting. Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install and modify. 10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals Facts about fiber optic cables: Outer insulating jacket is made of Teflon or PVC. Kevlar fiber helps to strengthen the cable and prevent breakage. A plastic coating is used to cushion the fiber center. Center (core) is made of glass or plastic fibers.
Fiber Optic Connector
The most common connector used with fiber optic cable is an ST connector. It is barrel shaped, similar to a BNC connector. A newer connector, the SC, is becoming more popular. It has a squared face and is easier to connect in a confined space.
Fiber optic connector
Ethernet hub
• An Ethernet hub or concentrator is a device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act as a single segment. Hubs work at the physical layer (layer 1) of the OSI model. Hubs are either active or passive. Active hubs repeat the signal received at one port out each of the other ports (but not the original one). The device is thus a form of multiport repeater. Ethernet hubs are also responsible for forwarding a jam signal to all ports if it detects a collision. • Hubs also often come with a BNC and/or AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of low-priced Ethernet switches has largely rendered hubs obsolete but they are still seen in older installations and more specialist applications.
Network switch
• A network switch (or just switch) is a networking device that performs transparent bridging (connection of multiple network segments with forwarding based on MAC addresses) at up to the speed of the hardware. Common hardware includes switches, which can connect at 10,100, or 1000 megabits per second, at half or full duplex. Half duplex means that the device can only send or receive any given time, whereas full duplex can send and receive, at the same time. The use of specially designed expansion also makes it possible to have large numbers of connections utilizing different mediums of networking, including Ethernet, Fibre Channel, ATM, 802.11, to name frequently used technologies.
Definition:-A computer network is two or more computers connected together using a telecommunication system for the purpose of communicating and sharing resources
Physical connection
LAN card Cables Networking devices (Hub, Switch , Router )
LOGICAL CONNECTION IP-address Protocol (software)
What’s Network
Types Of Network:• LAN (Local Area Network) • MAN (Metropolitan Area Network) • WAN (Wide Area Network) • Peer To Peer Networking • Server Base Networking -Host (Sender of Information) -Guest (Receiver of Information)
Types Of Network
LAN (Local Area Network)
Network which is include in a single building or room can be defined as LAN
Types Of Network
WAN (Wide Area Network)
Network expanding through cities , countries , continents limit called WAN . which can be connected through phone or modem . it’s also called intranet
Types Of Network
MAN (Metropolitan Area Network)
Sector 1 Sector 2
Network expand through a Single building in city limit is called MAN.
Types Of Network
Peer To Peer Network
In this network both computers have equal rights to share their resources. And both acts as server.
peer-to-peer network
• A pure peer-to-peer network does not have the notion of clients or servers, but only equal peer nodes that simultaneously function as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client-server model where communication is usually to and from a central server.
What are the advantages of peer-to-peer networking? • An important goal in peer-to-peer networks is that all clients provide resources, including bandwidth, storage space, and computing power. Thus, as nodes arrive and demand on the system increases, the total capacity of the system also increases. This is not true of a client-server architecture with a fixed set of servers, in which adding more clients could mean slower data transfer for all users. • The distributed nature of peer-to-peer networks also increases robustness in case of failures by replicating data over multiple peers, and -- in pure P2P systems -- by enabling peers to find the data without relying on a centralized index server. In the latter case, there is no single point of failure in the system.
• When the term peer-to-peer was used to describe the Napster network, it implied that the peer protocol was important, but, in reality, the great achievement of Napster was the empowerment of the peers (i.e., the fringes of the network) in association with a central index, which made it fast and efficient to locate available content. The peer protocol was just a common way to achieve this. Disadvantages of peer to peer? • They are less secure than client-server networks, especially so because the files have to shared and no password is required. • It is more time consuming to maintain the software on individual computers. • Peer-to-peer networks are designed for a small number of users. Network speed and performance starts to deteriorate usually after more than 10 computers are on the network. This makes it difficult to grow the network when the need to add more computers on the network becomes unavoidable.
What are the advantages of peer-to-peer networking?
Types Of Network
Server Base Network
In this network all computers and other shared resources are controlled by centralized server.
Hub (Hybrid Unit Board)
• • • • • • • • • • • • • • It works on layer one (Physical) It has One Collision domain or one way for sending data. It always broadcast. It communicates computers of one network. It’s differentiated by it’s sticker and it’s port (hub link)
Switch
It works on layer two (data link) It has many collision domain. Each port is one collision domain. It broadcasts at first time. It communicates all computers of same network. It’s speed is better than Hub.
Router
It works on layer three (Network) It communicates different network. It has it’s own OS which can be configured by Computer. It has four Modes – User Mode – Privileged Mode – Global Mode – Sub Global Mode. It’s best than all.
•
Repeaters
Repeaters, located within the physical layer of a network, regenerate and propagate signals from one to another. They do not change any information being transmitted, and they cannot filter any information. Repeaters help to extend the distances of networks by boosting weak signals.
Bridges
Bridges are intelligent repeaters. They regenerate transmitted signals, but unlike repeaters, they can also determine destinations.
Hubs
Hubs connect all computer LAN connections into one device. They are nothing more than multiport repeaters. Hubs cannot determine destinations; they merely transmit to every line attached in a half-duplex mode. Routers are a step up from bridges. They are able to route and filter information to different networks. Some routers can automatically detect problems and redirect information around the problem area. These are called "intelligent routers."
Routers
Switches
Switches connect all computer LAN connections, the same as hubs do. The difference is that switches can run in full-duplex mode and are able to direct and filter information to and from specific destinations.
WAN
WAN Infrastructure
As with LANs, there are numerous devices associated with data information flo across a WAN. Together, these devices create the infrastructure of a functiona WAN. These devices include: •Router •ATM Switch •Modem and CSU/DSU •Communication Server •Multiplexer •X.25/Frame Relay Switches
ATM Switches
ATM Switches provide high-speed transfer between both LANs and WANs.
Modem (modulator / demodulator)
Modems convert digital and analog signals. At the source, modems convert digital signals to a form suitable for transmission over analog communication facilities (public telephone lines). At the destination, modems convert the signal back to a digital format.
CSU/DSU (Channel Service Unit / Data Service Unit)
CSUs/DSUs are similar to modems, however they send data in digital format across digital telephone loops. They are usually in a physical box, but they may come in two separate units: CSUs or DSUs.
Multiplexers
A Multiplexer combines multiple signals for transmission over a single circuit. This allows for the transfer of various data simultaneously, such as video, sound, text, etc.
Communication Servers
Communication Servers are typically dial in/out servers that allow users to dial in from remote locations and attach to the LAN.
X.25 / Frame Relay Switches
X.25 and Frame Relay Switches connect private data over public data circuits using digital signal. These units are very similar to ATM switches, but the transfe rate of data is not comparable.
OSI Reference Model
• Open Systems Interconnection Reference Model – Standard model for network communications – Allows dissimilar networks to communicate – Defines 7 protocol layers 7 6 5 4 3 2 1
OSI Layers Application Diagram
Presentation Session Transport Network Data Link Physical
Appl icati on P roto co
Transport Protoco
Network Protoco
Application Protocols = FTP , SMTP , TCP etc
Transport Protocols = TCP , UDP Network Protocols = IP , IPX OSI Layers Detail 1. Physical Defines physical means of sending data over network devices Interfaces between network medium and devices Defines optical, electrical and mechanical characteristics 2. Data Link Defines procedures for operating the communication links Frames packets Detects and corrects packets transmit errors 3. Network Determines how data are transferred between network devices Routes packets according to unique network device addresses Provides flow and congestion control to prevent network resource depletion
4. Transport Manages end-to-end message delivery in network Provides reliable and sequential packet delivery through error recovery and flow control mechanisms 5. Session Manages user sessions and dialogues Controls establishment and termination of logic links between users Reports upper layer errors 6. Presentation Manages user sessions and dialogues Controls establishment and termination of logic links between users Reports upper layer errors 7. Application Defines interface-to-user processes for communication and data transfer in network
OSI Layers Detail
OSI Reference Model Data Flow
CLIENT
Data travels down the stack Then up the receiving stack
7 Applicatio n 6 Presentation 5 Session 4 Transport 3 Network 2 Data Link 1 Physical
SERVER
7 Applicatio n 6 Presentation 5 Sessio n 4 Transport 3 Network 2 Data Link 1 Physical
Through the network
As the data passes through each layer on the client information about that layer is added to the data.. This information is stripped off by the corresponding layer on the server.
Hybrid Topology
• A mixture of two or more than two topologies are called hybrid.
Connectivity
IP Address
An IP address (Internet Protocol address) is a unique address that devices use in order to identify and communicate with each other on a computer network IP versions :-The Internet Protocol has two primary versions in use. Each version has its own definition of an IP address. Ip version 4 Ip version 6
1. 2.
IP Addressing An IP address is software address , not a hardware address –the latter is hard coded on a network interface card (NIC) & used for finding host on a local network .IP addressing was designed to allow a host on one network to communicate with a host on a different network ,regardless of the type of LANs the host are participating in.
Bit a bit is one digit, either 1 or 0. Bytes is 8 bits Octet :An octet, made up of 8bits,is just an ordinary 8-bit binary number Network address: this is designation used in routing to send packets to remote network for example 10.0.0.0, 172.168.10.0 & 192.168.10.0 Broadcast address: the address used by application & host to send information to all node on a network is call broadcast address.
IP Terminology
IP version 4 IPv4 uses 32-bit (4 byte) addresses, which limits the address space to 4,294,967,296 (232) possible unique addresses. However, many are reserved for special purposes, such as private networks (~18 million addresses) or multicast addresses (~1 million addresses). This reduces the number of addresses that can be allocated as public Internet addresses, and as the number of addresses available is consumed, an IPv4 address shortage appears to be inevitable in the long run. This limitation has helped stimulate the push towards IPv6, which is currently in the early stages of deployment and is currently the only contender to replace IPv4. • Example: 192.168.1.1
Software (protocol)
Two type of protocol 1. TCP (Transmission control protocol) 2. UDP ( user datagram protocol )
Class A
10.0.0.0--------------(network) ip subnet zero 10.0.0.1---------------1st ip 10.0.0.2 10.0.0.3 TO 10.255.255.254----last ip 10.255.255.255----broadcast Total ip got in class A:- 16,777,216- 2=16,777,214 Total Net got in class A :-127
Class B
172.16.0.0---------------(ip subnet zero) 172.16.0.1----------------1st ip 172.16.0.2 172.16.0.2 TO 172.16.255.254----------last ip 172.16.255.255 --------Broadcast Total ip got in Class B :-65536-2=65534 Total Net got in Class B:- 16385
Class C
• 192.168.10.0 --------(ip subnet zero) 192.168.10.1 ---------1st ip 192.168.10.2 to 192.168.10.254 -----last ip 192.168.10.255 -----Broadcast Total ip got in Class C:- 256-2=254 Total net got in class C:-2097152
Types of Routing
The different types of routing are: • Static routing • Default routing • Dynamic routing
Static Routing
Routes learned by the router when an administrator manually establishes the route. The administrator must manually update this static route entry whenever an internetwork topology change requires an update. Benefits: • There is no overhead on the router CPU. • There is no bandwidth usage between routers • It adds security Disadvantage: •The administrator must really understand the internetwork and how each router is connected to configure routes correctly. • If a network is added to internetwork, the administrator has to add route to it on all routers-by hand
Default Routing
A default route is a special type of static route. A default route is a route to use for situations when the route from a source to a destination is not known or when it is unfeasible for the routing table to store sufficient information about the route.
In the image, Cisco B is configured to forward all frames for which the destination network is not explicitly listed in its routing table to Cisco A.
Dynamic Routing
Routes dynamically learned by the router after an administrator configures a routing protocol that helps determine routes. Unlike static routes, once the network administrator enables dynamic routing, route knowledge is automatically updated by a routing process whenever new topology information is received from the internetwork.
What is Cabling?
• Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.
Unshielded Twisted Pair (UTP) Cable
Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated five categories of wire.
Unshielded Twisted Pair Connector
The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.
Shielded Twisted Pair (STP) Cable
A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference. Shielded twisted pair (STP) is suitable for environments with electrical interference; however, the extra shielding can make the cables quite bulky. Shielded twisted pair is often used on networks using Token Ring topology.
Coaxial Cable
Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers. Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable. The two types of coaxial cabling are thick coaxial and thin coaxial. Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable is popular in school networks, especially linear bus networks. Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. This makes thick coaxial a great choice when running longer lengths in a linear bus network. One disadvantage of thick coaxial is that it does not bend easily and is difficult to install.
Coaxial Cable Connectors
The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters are available for BNC connectors, including a Tconnector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that crimp, rather than screw, onto the cable.
Fiber Optic Cable
Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting. Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install and modify. 10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals Facts about fiber optic cables: Outer insulating jacket is made of Teflon or PVC. Kevlar fiber helps to strengthen the cable and prevent breakage. A plastic coating is used to cushion the fiber center. Center (core) is made of glass or plastic fibers.
Fiber Optic Connector
The most common connector used with fiber optic cable is an ST connector. It is barrel shaped, similar to a BNC connector. A newer connector, the SC, is becoming more popular. It has a squared face and is easier to connect in a confined space.
Fiber optic connector
Ethernet hub
• An Ethernet hub or concentrator is a device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act as a single segment. Hubs work at the physical layer (layer 1) of the OSI model. Hubs are either active or passive. Active hubs repeat the signal received at one port out each of the other ports (but not the original one). The device is thus a form of multiport repeater. Ethernet hubs are also responsible for forwarding a jam signal to all ports if it detects a collision. • Hubs also often come with a BNC and/or AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of low-priced Ethernet switches has largely rendered hubs obsolete but they are still seen in older installations and more specialist applications.
Network switch
• A network switch (or just switch) is a networking device that performs transparent bridging (connection of multiple network segments with forwarding based on MAC addresses) at up to the speed of the hardware. Common hardware includes switches, which can connect at 10,100, or 1000 megabits per second, at half or full duplex. Half duplex means that the device can only send or receive any given time, whereas full duplex can send and receive, at the same time. The use of specially designed expansion also makes it possible to have large numbers of connections utilizing different mediums of networking, including Ethernet, Fibre Channel, ATM, 802.11, to name frequently used technologies.
