EXPERIMENT NO.1

AIM:To familiarize with the various basic tools (crimping, krone, etc.) used in establishing a LAN.

CRIMPING TOOL:Crimping is joining two pieces of metal or other malleable material by deforming one or both of them to hold the other. The bend or deformity is called the crimp.

Uses:

A crimping tool is a tool designed to crimp or connect a connector to the end of a cable. For example, network cables and phone cables are created using a crimping tool to connect the RJ-45 and RJ-11 connectors to the end of the cable.

Crimping is most extensively used in metalworking. Crimping is commonly used to join bullets to their cartridge cases, and for rapid but lasting electrical connectors. Because it can be a cold-working technique, crimping can also be used to form a strong bond between the work piece and a non-metallic component. Sometimes, a similar deformity created for reasons other than forming a join may also be called a crimp.

The Crimping Tool for RJ45/RJ12/RJ11 Modular Connectors is made from very high quality of tool steel which ensures high durability at its user end. This Crimping Tool for RJ45/RJ12/RJ11 Modular Connectors is in high demand in the market. Different sizes and designs are easily available in the market. Crimping Tool for RJ45/RJ12/RJ11 Modular Connectors is available at industrial leading prices. This crimping tool for RJ45/12/11 modular connector is with high standard. The driving part is made of high quality tool steel, 40 Crtool bit and 45 steel with quenching procesing.Plactic parts are injected and molded of inflaming fetarding PC,suitable for the site construction of the engineering of various weak electric wiring

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system full functions good practicality adaptable to fit with the operation with different plugs, blocks, modules and distnbution frames of clamping, cutting, shearing and crimping.

How to use crimping tool:

Use the cable stripper to remove two-inches of the outer jacket from the end of the cable.

Untwist and separate the individual conductors.

Arrange the conductors in the desired order.

Trim the ends of the wire evenly to within 1/2-inch of the outer jacket with electrician's scissors.

Insert the conductors into the RJ45 plug. Push the wires into the jack until they reach the end of the slots in the plug. When you are finished, the outer jacket of the cable should at least 1/4-inch inside the opening of the plug.

Insert the RJ45 plug into the die (opening) of the crimping tool. The die is shaped like a jack so it will only fit in the correct position.

Squeeze the handles of the crimping tool together firmly.

Release the handles of the crimping tool and remove the jack.

KRONE TOOL:A punch down tool, also called a punchdown tool or a krone tool (named after the KRONE LSA-PLUS connector), is a small hand tool used by telecommunication and network technicians. It is used for inserting wire into insulation-displacement connectors on punch down blocks, patch panels, keystone modules, and surface mount boxes .

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Most punch down tools is of the impact type, consisting of a handle, an internal spring mechanism, and a removable slotted blade. To use the punch down tool, a wire is pre-positioned into a slotted post, and then the punch down tool is pressed down on top of the wire, over the post. Once the required pressure is reached, the internal spring is triggered, and the blade pushes the wire into the slot, cutting the insulation, and securing the wire. For light-duty use, there are also less expensive punch down tools with fixed blades and no impact mechanism.

To accommodate different connector types, 66, 110, BIX and krone require different blades. Removable blades for 66 or 110 are often double-ended, with one end that only inserts the wire for daisy-chain wiring from post to post, and another end that inserts wire and trims the excess length for termination at a post.[3] The trimming blade cutting edge works against the plastic insulating post. Krone blades require a separate scissor-like

mechanism for trimming the wire.

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EXPERIMENT NO. 2

AIM:To study various topologies for establishing various computer networks.

NETWORK TOPOLOGY:Network topology is the layout pattern of interconnections of the various elements (links, nodes, etc.) of a biological network. Topology can be understood as the shape or structure of a network. This shape does not necessarily correspond to the actual physical design of the devices on the computer network. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring topology.

Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.

A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometric shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.

Topology classification:

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There are two basic categories of network topologies:

Physical topologies

Logical topologies

Physical topology: The physical topology refers to the physical design of a network including the devices, location and cable installation the shape of the cabling layout used to link devices is called the physical topology of the network. This refers to the layout of cabling, the locations of nodes, and the interconnections between the nodes and the cabling. The physical topology of a network is determined by the capabilities of the network access devices and media, the level of control or fault tolerance desired, and the cost associated with cabling or telecommunications circuits. It relates to the core network.

Logical topology: Logical topology refers to how data is actually transferred in a network as opposed to its physical design. The logical topology, in contrast, is the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. A network's logical topology is not necessarily the same as its physical topology. For example, the original twisted pair Ethernet using repeater was a logical bus topology with a physical star topology layout. Token Ring is a logical ring topology, but is wired a physical star from the Unit. It relates to the basic network.

The logical classification of network topologies generally follows the same classifications as those in the physical classifications of network topologies but describes the path that the data takes between nodes being used as opposed to the actual physical connections between nodes. The logical topologies are generally determined by network protocols as opposed to being determined by the physical layout of cables, wires, and network devices or by the flow of the electrical signals, although in many cases the paths that the electrical signals take between nodes may closely match the logical flow of data, hence the convention of using the terms logical topology and signal topology interchangeably.

Logical topologies are often closely associated with Media Access Control methods and protocols. Logical topologies are able to be dynamically reconfigured by special types of equipment such as routers and switches.

The study of network topology recognizes seven basic topologies:

Point-to-point

Bus

Star

Ring

Mesh

Tree

Hybrid

Daisy chain.

POINT TO POINT TOPOLOGY:

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The simplest topology is a permanent link between two endpoints. Switched point-to-point topologies are the basic model of conventional telephony. The value of a permanent point-to-point network is unimpeded communications between the two endpoints. The value of an on-demand point-to-point connection is proportional to the number of potential pairs of subscribers, and has been expressed as Metcalfe's Law.

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BUS TOPOLOGY:It is also known as Horizontal topology. This arrangement is quite popular in Local Area Network (LAN).It is a point to multipoint topology.’ A bus topology consists of a single central cable to which all computers and other devices connect. A bus topology is ‘also known as a bus network. A bus refers to the main physical pathway or central cable where all other devices are connected to it. Like a major motor highway, all traffic flow will be affected if this main “road” is broken. One long cable acts as a ‘backbone’ to link all the devices in the network.

Nodes are connected to bus by taps and drop lines. A drop line is a connection between device and the main bus cable. A tap is a connector that either punctures the sheathing of a cable to create a contact with the metallic core or splice into the main cable to create a contact with core. As a signal travels along the backbone some energy loss takes place and signal becomes weaker and weaker farther it has to travel. Therefore, these are a limit on the number of taps a bus can support and on the distance between those taps.

A network terminator is required at both the ends of the bus to avoid any reflection of signal from the open end, which may lead to wrong signal on the bus.

It is relatively simple to control traffic flow between DTE’s because the bus permits all stations to receive every transmission .That is a single station “broadcasts” to multiple stations. As a single bus is connecting all the DTE’s any problem on the bus and stop functioning of the entire Network. To avoid such situations many vendors provides by pass switches around every DTE.

ADVANTAGES OF BUS TOPOLOGY:

Easy implementation. New devices can be added to the backbone or to the

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existing nodes.

Failure of a node doesn't affect the entire LAN.

No disruptions to the network when connecting or removing devices.

Network can easily be extended, by adding new devices to the backbone or existing nodes.

Cost of Network is very low as single bus is required to connect all DTE’s.

It is useful when broadcasting is often required on the Network.

DISADVANTAGES OF BUS TOPOLOGY :

If the backbone fails, the entire bus network will be affected.

Network speed decreases when the number of nodes increases.

Troubleshooting is difficult when one of the nodes fails.

There is no security /control on the flow of data, as information transmitted is available to each DTE.

RING TOPOLOGY:The ring topology is named so because of the circular aspect of the data flow. A ring topology consists of all computers and other devices that are connected in a loop. Ring topology is also known as a ring network. A ring network can be found in Local Area Networks. In a ring network each node directly connects to two neighboring nodes. A server may exist in a ring network, but it will not connect to all the nodes in the network. The server, like other nodes, will only communicate to its two neighboring nodes.

In most instance data flow in one direction only with one single station receiving the signal and relaying it to the next station on the ring. It is useful as no bottle neck takes place in it.

In a ring topology each device has a dedicated ‘point to point’ channel configuration, only with the two devices on either side of it. A signal is passed along the ring through token in one direction, from device to device until it reaches its destination.

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Token is a special sequence of bits, which is used for carrying data from one station to another in the ring. Each device in the ring incorporates a repeater. When a device receives a signal into for another device, its repeater regenerates the end passes them further.

DEPENDENCE OF A RING TOPOLOGY :

If one of the nodes fails, the network will fail to function.

ADVANTAGES OF A RING TOPOLOGY :

Troubleshooting is easy when one of the nodes fails.

Repair or remove the failing nodes and the network will continue to function.

A ring is relatively easy to install and reconfigure. As each device is directly linked to its immediate neighbor only. To add or delete a device requires moving only two connectors.

The amount of cabling involved in a ring topology is less in comparison to star, tree and mesh topology and comparable with bus topology.

ASM ring topology data flow is unidirectional it is suitable for using optical fiber as a medium of transmission in ring topology.

DISADVANTAGES OF A RING TOPOLOGY :

Implementation is difficult. Network administrator has to terminate the entire network to install a new node between existing nodes.

A failing node will affect the entire LAN.

Connecting or removing devices is difficult because network administrator needs to terminate the network in order to do it.

Network speed decreases when the number of nodes increases.

Network reconfiguration is going on it makes down the entire network. As it is not possible to shut down a small section of the ring while keeping the majority of it working normally.

Difficult to diagnose faults: The fact that failure of one node will affect all other nodes has serious implication for fault diagnosis. It may be required to examine a

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series of adjacent nodes to determine the faulty one.

STAR TOPOLOGY: In the early days of computer networking, all computers were connected to a centralized mainframe computer. All resources and management of information were centered in this main computer. The idea of a centralized mainframe computer is where the basic concept of a star topology comes from. A star topology consists of a central host which acts as the centre, and all nodes connect to the host. A star topology is also known as star network.

In a star topology the devices are not directly linked to each other, each device has a dedicated point to point link only to a central Hub or primary station .The primary acts as an exchange and any two devices in star network can communicate through this primary only. A star network is found in a Local Area Network setting.

A star network must have a host which acts as the centre. The host can be a server, hub or router. In a star network, every node will not connect to the neighboring nodes. Every node must connect to the host in order to communicate. The host will control the flow of communication in the network. All traffic emanates from hub of the star the central site, which is typically a computer, to control the communication of all other DTEs attached to it .Site is responsible for routing traffic to the other DTEs, it is responsible for fault isolation as well.

DEPENDENCE OF A STAR TOPOLOGY:

If one of the nodes fails, the star network can still function as long as the host is working. If the host fails, the network will fail to function.

ADVANTAGES OF STAR TOPOLOGY:

It is easy to implement. You only add nodes to the host.

The failure of a node does not affect the entire LAN.

There are no disruptions to the network when connecting or removing devices.

The network can be extended by adding new devices to the host or nodes.

Troubleshooting is easy when the host fails. Simply repair or replace the host and the network will continue to function.

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Star topology is useful when a centralized control is required.

DISADVANTAGES OF STAR TOPOLOGY:

If the host fails, the entire LAN will be affected.

Network speed decreases when the number of nodes increases.

Troubleshooting is difficult when one of the nodes fails.

A host must be installed to control the network.

Cost of Network is high as point to point connection from each device to central site is required.

TREE TOPOLOGY:It is also known as hierarchical Topology. The software to control the network is relatively simple and the topology provides a concentration point for control and error detection. The DTE at the root of the tree acts as primary for the Network.

The word tree is appropriate because the Networks often resembles with a inverted tree with branches emanating from the root of the tree and then branches are further divided into subbranches.Traffic flow among DTE’s initiated by DTEs; A distributed aspect is implemented for tree Network by providing methods for subordinates DTEs to directly control the DET’s below them in the hierarchy. This reduces the workload of the central host at site.

ADVANTAGES OF TREE TOPOLOGY:

Addition of a New DTE is very easy.

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More Layers of control and security for Data flow is possible as traffic is controlled at every node.

Failure of any DTE will impact on that branch only and not on rest of the DTE’s which are not in that branch.

Fault diagnosis and removal is easy because of hierarchical structure.

DISADVANTAGES OF TREE TOPOLOGY:

It presents significant bottle-neck problem. (Though in comparison to star Network chances are less as traffic load is distributed at subordinate DTE’s at different branch nodes).

As number of controlling station’s have increased (at each branch node, DTE works as controlling DTE for DTE’s below it), cost of Network is high.

As between any two DTE in tree Network there exists a single path, if any link failure occurs there is no alternate path available.

If root DTE fails then entire Network will not function properly if this DTE is not fully backed up by another computer.

MESH TOPOLOGY:When every device has a dedicated point to point link to every other device, it is known as mesh topology. The term dedicated means that the link carries traffic only between the two devices it connects. To find the number of physical links in a fully connected mesh network with n nodes, we first consider that each node must be connected to every other node.Node1 must be connected to n-1 nodes, node 2 must be connected to n-1 nodes, and finally node n must be connected to n-1 nodes. We need n (n-1) physical links .However .if each physical link allows communication in both directions, we can divide the number of links by 2.In other words, and we can say need n (n-1) /2 duplex mode links.

To accommodate that many links, every device on the network must have n-1 input/output ports to be connected to the other n-1 stations.

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TYPES OF MESH TOPOLOGY:

Fully connected : The number of connections in a full mesh = n (n - 1) / 2.

The physical fully connected mesh topology is generally too costly and complex for practical networks, although the topology is used when there are only a small number of nodes to be interconnected.

Partially connected: The type of network topology in which some of the nodes of the network are connected to more than one other node in the network with a point-to-point link – this makes it possible to take advantage of some of the redundancy that is provided by a physical fully connected mesh topology without the expense and complexity required for a connection between every node in the network.

In most practical networks that are based upon the partially connected mesh topology, all of the data that is transmitted between nodes in the network takes the shortest path between nodes, except in the case of a failure or break in one of the links, in which case the data takes an alternative path to the destination. This requires that the nodes of the network possess some type of logical 'routing' algorithm to determine the correct path to use at any particular time.

ADVANTAGES OF MESH TOPOLOGY:

The use of dedicated links assures that each connection can carry its own data load that means no bottleneck problem.

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As every message travels on a dedicated line, only the intended recipient can receives it.

If one link fails the data can be transmitted through alternate path.

Fault identification and fault isolation is easy due to ‘point to point link’. Traffic can be routed through other paths to avoid links with suspected problems.

DISADVANTAGES OF MESH TOPOLOGY:

Cost of Network is very high, as every device is to be connected to every other device amount of cabling and number of I/O ports required very high which in turn leads to high cost.

As every device is to be connected to every other device installation and reconfiguration are difficult.

Bulk of wire requires large space to accommodate it.

Bulk of wires and large number of ports lead to complexity in fault diagnosis.

HYBRID TOPOLOGY:Hybrid networks use a combination of any two or more topologies in such a way that the resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.). For example, a tree network connected to a tree network is still a tree network topology. A hybrid topology is always produced when two different basic network topologies are connected. Two common examples for Hybrid network are: star ring network and star bus network

A Star ring network consists of two or more star topologies connected using a multistation access unit (MAU) as a centralized hub.

A Star Bus network consists of two or more star topologies connected using a bus trunk (the bus trunk serves as the network's backbone).

While grid networks have found popularity in high-performance computing applications, some systems have used genetic algorithms to design custom networks that have the fewest possible hops in between different nodes. Some of the resulting layouts are nearly

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incomprehensible, although they function quite well.

DAISY CHAIN TOPOLOGY:Except for star-based networks, the easiest way to add more computers into a network is by daisy-chaining, or connecting each computer in series to the next. If a message is intended for a computer partway down the line, each system bounces it along in sequence until it reaches the destination. A daisy-chained network can take two basic forms: linear and ring.

A linear topology puts a two-way link between one computer and the next. However, this was expensive in the early days of computing, since each computer (except for the ones at each end) required two receivers and two transmitters.

By connecting the computers at each end, a ring topology can be formed. An advantage of the ring is that the number of transmitters and receivers can be cut in half, since a message will eventually loop all of the way around. When a node sends a message, the message is processed by each computer in the ring. If a computer is not the destination node, it will pass the message to the next node, until the message arrives at its destination. If the message is not accepted by any node on the network, it will travel around the entire ring and return to the sender. This potentially results in a doubling of travel time for data.

EXPERIMENT NO.3

AIM:

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To familiarize with switch, hub, connectors, cables (cabling standards) used in networks.

SWITCH:A switch is a multi-port bridge, meaning that it is an active element working on layer 2 of the OSI model. The switch analyses the frames coming in on its entry ports and filters the data in order to focus solely on the right ports (this is called switching and is used in switched networks). As a result, the switch can act as both a port when filtering and as a hub when handling connections. A switch can be considered a 'smart' hub.  It will actively look at the traffic it receives and based on the destination address it will direct that traffic only to the port needed.  The switch listens to each port at the same time without any interference.  A computer plugged directly into the switch will not receive unnecessary traffic and can transmit to the switch whenever it needs to; this leaves all the bandwidth available to each machine.The switch memorizes the MAC address of each host and which port it resides on.  This is how it can intelligently direct traffic.

A network switch or switching hub is a computer networking device that connects segments. The first Ethernet switch was introduced by Kalpana in 1990.

Network switch. Back view of Atlantis network switch with

Ethernet ports.

Function:

The network switch plays an integral part in most modern Ethernet local area networks (LANs). Mid-to-large sized LANs contain a number of linked managed switches. Small office/home office (SOHO) applications typically use a single switch, or an all-purpose converged device such as a gateway to access small office/home broadband services such as DSL or cable internet. In most of these cases, the end-user device contains a router and components that interface to the particular

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An Ethernet switch operates at the data link layer of the OSI model to create a separate collision domain for each switch port. With 4 computers (e.g., A, B, C, and D) on 4 switch ports, A and B can transfer data back and forth, while C and D also do so simultaneously, and the two conversations will not interfere with one another. In the case of a hub, they would all share the bandwidth and run in half duplex, resulting in collisions, which would then necessitate retransmissions. Using a switch is called micro segmentation. This allows computers to have dedicated bandwidth on point-to-point connections to the network and to therefore run in full duplex without collisions.

Role of switches in networks:

Switches may operate at one or more layers of the OSI model, including data link, network, or transport (i.e., end-to-end). A device that operates simultaneously at more than one of these layers is known as a multilayer switch.

In switches intended for commercial use, built-in or modular interfaces make it possible to connect different types of networks, including Ethernet, Fiber Channel, ATM, 802.11. This connectivity can be at any of the layers mentioned. While Layer 2 functionality is

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adequate for bandwidth-shifting within one technology, interconnecting technologies such as Ethernet and token ring are easier at Layer 3.

Interconnection of different Layer 3 networks is done by routers. If there are any features that characterize "Layer-3 switches" as opposed to general-purpose routers, it tends to be that they are optimized, in larger switches, for high-density Ethernet connectivity.

In some environments where there is a need for a great deal of analysis of network performance and security, switches may be connected between WAN routers as places for analytic modules. Some vendors provide firewall network intrusion detection, and performance analysis modules that can plug into switch ports.

In other cases, the switch is used to create a mirror image of data that can go to an external device. Since most switch port mirroring provides only one mirrored stream, hub scan be useful for fanning out data to several read-only analyzers, such as intrusion detection systems and packet sniffers.

TYPES OF SWITCHES:

Unmanaged   switches — these switches have no configuration interface or options. They are plug_and_play. They are typically the least expensive switches, found in home, SOHO, or small businesses. They can be desktop or rack mounted.

Managed   switches — these switches have one or more methods to modify the operation of the switch. Common management methods include: a command-line interface (CLI) accessed via serial console, telnet or Secure Shell, an embedded Simple Network Management Protocol (SNMP) agent allowing management from a remote console or management station, or a web interface for management from a web browser. Examples of configuration changes that one can do from a managed switch include: enable features such as Spanning Tree Protocol , set port bandwidth, create or modify Virtual LANs (VLANs), etc. Two sub-classes of managed switches are marketed today:

Smart   (or intelligent) switches — these are managed switches with a limited set of management features. Likewise "web-managed" switches are switches which fall in a market niche between unmanaged and managed.

Enterprise Managed   (or fully managed) switches — these have a full set of management features, including CLI, SNMP agent, and web interface. They may have additional features to manipulate configurations, such as the ability to display, modify, backup and restore configurations. Compared with smart switches, enterprise switches have more features that can be customized or optimized, and are generally more expensive than smart switches.

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48-port switch.

Typical switch management features:

Turn particular port range on or off

Link bandwidth and duplex settings

Priority settings for ports

IP Management by IP Clustering.

MAC filtering  and other types of "port security" features which prevent MAC flooding

Use of Spanning Tree Protocol

SNMP  monitoring of device and link health

Port mirroring  (also known as: port monitoring, spanning port, SPAN port, roving analysis port or link mode port)

Link aggregation  (also known as bonding, trunking or teaming)

VLAN settings

802.1X  network access control

IGMP snooping

HUBS:The term ‘hub’ is sometimes used to refer to any piece of network equipment that connects PCs together, but it actually refers to a multi-port repeater. This type of device simply passes on (repeats) all the information it receives, so that all devices connected to its ports receive that information.

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Hubs repeat everything they receive and can be used to extend the network. However, this can result in a lot of unnecessary traffic being sent to all devices on the network. Hubs pass on traffic to the network regardless of the intended destination; the PCs to which the packets are sent use the address information in each packet to work out which packets are meant for them. In a small network repeating is not a problem but for a larger, more heavily used network, another piece of networking equipment (such as a switch) may be required to help reduce the amount of unnecessary traffic being generated.Hubs form the heart of a network, with every separate node of the network connected to the hub through its ports. Anything from a file server to a workstation to a print server can be connected to the hub, making it accessible to every other node of the network.

There are three main points to remember about hubs:1. Many kinds of nodes can be connected to the hub with networking cable.2. All hubs can be uplinked together, either with straight-through cable or cross-over

cable, depending on whether or not the hub has an uplink port.3. Performance will decrease as the number of users is increased.

Types of hubs:1. 10baseT, which will support a speed of 10Mbps; 2. 100baseTX, which supports 100Mbps. A standard 10baseT hub cannot connect

to hardware that runs at 100Mbps unless a switch or hub with auto-sensing capabilities is used between them.

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Many hubs have one or more of the following extra features, which can increase ease of use, efficiency, and expandability:

Auto-sensing or dual-speed 10/100Mbps. Hubs with this feature can support hardware running at both speeds, increasing the length of time you can use your old 10baseT hardware.

Stackable hubs. Hubs with this feature are very expandable, operating as a single hub when stacked together. While standard hubs can only be uplinked through four hubs, a stacked hub is considered a single hub and there is no uplinking required.

SNMP (Simple Network Management Protocol). Hubs that support SNMP allow configuration of the hub from anywhere on the network. This feature can be extremely useful in LANs that span two or more floors, or have more than 50 users.

Function of hub:

Hubs can only communicate in half duplex mode, which means that a computer on the network can only send data when it is not receiving. When a hub receives a packet (chunk) of data (a frame in Ethernet lingo) at one of its ports from a PC on the network, it transmits (repeats) the packet to all of its ports and, thus, to all of the other PCs on the network.  If two or more PCs on the network try to send packets at the same time a collision is said to occur.  When that happens all of the PCs have to go though a routine to resolve the conflict.  The process is prescribed in the Ethernet Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol. 

Two computers can be connected directly together in an Ethernet with a crossover cable.  A crossover cable doesn't have a collision problem.  It hardwires the Ethernet transmitter

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on one computer to the receiver on the other.   The result is a crossover cable doesn't have delays caused by collisions, data can be sent in both directions simultaneously, the maximum available bandwidth is 200 Mbps, 100 Mbps each way, and there are no other PC's with which the bandwidth must be shared.

CONNECTORS:

RJ-45 connector:The RJ-45 connector is commonly used for network cabling and for telephony applications.  It's also used for serial connections in special cases. Although used for a variety of purposes, the RJ-45 connector is probably most commonly used for 10Base-T and 100Base-TX Ethernet connections.

Because only two pairs of wires in the eight-pin RJ-45 connector are used to carry Ethernet signals, and both 10BASE-T and 100BASE-TX use the same pins, a crossover cable made for one will also work with the other. A single pair can be used for pins 3 and 6.

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Pinout for Ethernet:-

Pin #Ethernet 10BASE-T

100BASE-TX

EIA/TIA 568AEIA/TIA 568B or

AT&T 258A

1 Transmit + White with green strip

White with orange stripe

2 Transmit - Green with white stripe or solid green

Orange with white stripe or solid orange

3 Receive + White with orange stripe

White with green stripe

4 N/A Blue with white stripe or solid blue

Blue with white stripe or solid blue

5 N/A White with blue stripe

White with blue stripe

6 Receive - Orange with white stripe or solid orange

Green with white stripe or solid

7 N/A White with brown strip or solid brown

White with brown strip or solid brown

8 N/A Brown with white stripe or solid brown.

Brown with white stripe or solid brown.

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NETWORK CABLES:

Network cables have evolved significantly since the original standard was created in the early 1980s. From the original 10Base2 (Thin Coaxial) cable terminated with BNC connectors to the fiber optic technology we see today the change has been dramatic. For a network to function at its most efficient it is critical for the correct cable to be matched to the type of network being deployed as well as keeping the maximum distance specifications within tolerance.

Types of cables:

Twisted pair cable:

It consists of two insulated copper wires arranged in a regular spiral pattern. A wire pair acts as a single communication link. A number of these pairs are bundled together into a cable by wrapping them in a tough protective sheath. Over longer distances, cables may contain hundreds of pairs. The twisting tends to decrease the crosstalk interference between adjacent pairs in a cable. On long distance links, the twist length typically varies from 5 t0 15 cm.The wires in a pair have thickness of from 0.4 to 0.9 mm.

Crossover Cable - standard Ethernet cables are "straight-thru".  Pin 1 on one end connects to Pin 1 on the far end, Pin2 to Pin2, and so on.  There are only 4 pins that are used, since you only need two wires for transmit, and two for receive. The two pairs used are 1-2, and 3-6.  With a crossover cable, the wires connected to Pins 1-2 on one end are

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"crossed over" and connected to Pins 3-6 on the far end.  The same is done with the wires connected to Pins 3-6 - they are crossed over and connected to Pins 1-2 on the far end.

TIA/EIA 568-A and 568-B Color Schemes (Twisted Pair):

There are two wiring sequences, where the wires and color codes are matched to the RJ-45 pins.  Which of these two wiring pin and coloring standards you need to use will depend mostly on your locale.  For example, Virginia stipulates that 568-A must be used.  Actually, 568-A is more common and is even called "preferred".  Just be aware that you need to check with the building manager before installing cables.

Preferred - TIA/EIA 568-A  Optional - TIA/EIA 568-B (comes from the old AT&T standard, 258A) 

Rj45 receptacle-not plug.

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Ethernet Send/Receive Pairs 2 and 3 positions are reversed.  However - in both cases:

Pair 2 = White/Orange and Orange

Pair 3 = White/Green and Green

The colors schemes are listed below with traditional nomenclature of Base/Stripe, where the Base coat color is listed first, followed by the Stripe color.  For example, White/Blue means the insulated sheath base color is white (not paint - the actual material is white), with stripes or dashes of the secondary color, Blue, painted on.

Types of twisted pair cables:

Unshielded Twisted Pair: It is ordinary telephone wire. Office buildings, by universal practice, are prewired with excess unshielded twisted pair, more than is needed for simple telephone support. In UTP two insulated color coded copper wires are twisted around each other to decrease crosstalk or electromagnetic induction between wire pairs and does not include any foil or branding as insulator to protect against interference.

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Shielded Twisted Pair: The twisted pair is shielded with a metallic braid or sheathing that reduces interference. This STP provides better performance at higher data rates.STP is made up of copper wires that are twisted together and offers a protective sheathing around the copper wire. The pairs are covered in a foil or braided mesh as well as outer PVC jacket which prevent electromagnetic noise and Crosstalk.

Coaxial cable:

Coaxial cables are a type of cable that is used by cable TV and that is common for data communications. Taking a round cross-section of the cable, one would find a single center solid wire symmetrically surrounded by a braided or foil conductor. Between the center wire and foil is a insulating dielectric. This dialectric has a large affect on the fundamental characteristics of the cable. In this lab, we show the how the permittivity and permeability of the dialectric contributes to the cable's inductance and capacitance. Also, the Data is transmitted through the center wire, while the outer braided layer serves as a line to ground. Both of these conductors are parallel and share the same axis. This is why the wire is called coaxial! The impedance of coaxial cables depends on the dialectric material and the radii of each conducting material 

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In this lab we used a RG-580/U coaxial cable. This is just one of many types of cables that are used today to transmit data. The dialectric of the RG-580/U was made of polyethylene. The radius of our cable's inner copper wire was .42mm and there was 2.208mm of polyethylene between the inner wire and outer mesh conductors.

Optical Fiber Cable:

It is a thin, medium capable of guiding an optical ray. It has cylindrical shape and consists of three concentric sections: the core, the cladding and the jacket. The core is the inner section and consists of one or more very thin fibers of glass or plastic; core has diameter in the range of 8 to 50 micrometer. Each fiber is surrounded by its own cladding, a glass or plastic coating that has optical properties different from those of the core and a diameter of 125 micrometer. The interface between core and cladding acts as a reflector to confine light that would otherwise escape the core. The outermost layer, surrounding one or a bundle of cladded fibres, is the jacket. The jacket is composed of plastic and other material layered to protect against moisture, abrasion, crushing and other environmental dangers.

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Fiber optic cable functions as a "light guide," guiding the light introduced at one end of the cable through to the other end. The light source can either be a light-emitting diode (LED) or laser.

There are three types of fiber optic cable commonly used: single mode, multimode and plastic optical fiber (POF).

Single Mode cable is a single stand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission.  Single Mode Fiber with a relatively narrow diameter, through which only one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width.

sMulti-Mode cable Multimode fiber gives you high bandwidth at high speeds (10 to 100MBS - Gigabit to 275m to 2km) over medium distances. Light waves are dispersed into numerous paths, or modes, as they travel through the cable's core typically 850 or 1300nm. Typical multimode fiber core diameters are 50, 62.5, and 100 micrometers. However, in long cable runs (greater than 3000 feet [914.4 meters), multiple paths of light can cause signal distortion at the receiving end, resulting in an unclear and incomplete data transmission .

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ANSI TIA/EIA 568-B2   -   Twisted Pair Categories of Cable Standards:

In the mid 1980s, the Electronic Industries Association (EIA) developed a standard called TIA/EIA-568-A.  The higher the standard, the more twists per inch the pairs have, and the better the quality of the jack (RJ-45).

ANSI/EIA (American National Standards Institute/Electronic Industries Association) Standard 568 is one of several standards that specify "categories" (the singular is commonly referred to as "CAT") of twisted pair cabling systems (wires, junctions, and connectors) in terms of the data rates that they can sustain.

ANSI Category

Maximum data rate Usual application

CAT 1 Up to 1 Mbps (1 MHz )analog voice (POTS)Integrated Services Digital Network Basic Rate Interface in ISDN Doorbell wiring

CAT 2 4 Mbps Mainly used in the IBM Cabling System for Token Ring networks

CAT 3 16 Mbps Voice and data on 10BASE-T Ethernet

CAT 4 20 MbpsUsed in 16 Mbps Token RingOtherwise not used much

CAT 5100 Mbps1000 Mbps (4 pair)

100 Mbps TPDDI155 Mbps ATM

CAT 5E(ISO Class D)   100 Mbps TPDDI

155 Mbps ATM

CAT 6(ISO Class E)

Up to 400 MHz Super-fast broadband applications (proposed standard).  Used with GigE (1000 Mbps or 1 Gbps)

CAT 7(ISO Class F)

600-700 MHz Even faster broadband applications (proposed standard)

CAT 5 CABLE:

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Cat-5 cable, sometimes called Ethernet cable, is short for Category 5 cable, a current industry standard for network and telephone wiring. Cat-5 cable is unshielded wire containing four pairs of 24-gauge twisted copper pairs, terminating in an RJ-45 jack.

The outer sheath of Cat-5 cable can come in many colors, with bright blue being quite common. Inside, the twisted pairs are also sheathed in plastic with a standard color scheme: Solid orange, blue, green and brown wires twisted around mates that are white and striped with a solid color. The twisted pairs inside a Cat-5 cable reduce interference and crosstalk, and should be left twisted except at the termination point. Some experts recommend untwisting only ½ inch (12.7 mm) of the pairs to strip and make connections. Cat-5 cable can be purchased off a spool in varying lengths, or bought pre-cut to standard lengths with RJ-45 jacks already attached.

Cat-5 cable replaces Cat-3 cable, which could only carry data at speeds up to 10 megabits per second (mbps), while Cat-5 cable supports data speeds of 100 mbps or more. A Cat-5e is enhanced Cat-5 cable that supports 1000 mbps or gigabit Ethernet, or it can be used with 100 Base-T networks for long-distance runs of 1150 feet (350 meters). This type of Cat-5 cable meets a specific standard referred to as "EIA/TIA 568A-5," which should be stamped on the outer sheath.

Among Cat-5 cables, there are three different configurations for pinouts, or wiring of the RJ-45 connectors. Various network devices utilize one of the three types of pinouts. The three pinouts are referred to as straight through, crossover and roll-over.

The Cat-5 cable that runs from a computer to a switch will be a straight through cable, for example. If two PCs or two switches are connected, the Cat-5 crossover cable would be used. Finally, a Cat-5 roll-over cable will connect a PC to a router.

EXPERIMENT NO.4

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AIM: To familiarize with routers and bridges.

NETWORK ROUTERS:A router is used to route data packets between two networks. It reads the information in each packet to tell where it is going. If it is destined for an immediate network it has access to, it will strip the outer packet, readdress the packet to the proper Ethernet address, and transmit it on that network. If it is destined for another network and must be sent to another router, it will re-package the outer packet to be received by the next router and send it to the next router.

A router is often a full-fledged computer system with multiple network cards and its own operating system. A router:

Link networks using different network identities. Transmit only the data needed by the final destination across the LAN.

Working of routers: Routing occurs at the network layer of the OSI model. They can connect networks with different architectures such as Token Ring and Ethernet. Although they can transform information at the data link level, routers cannot transform information from one data format such as TCP/IP to another such as IPX/SPX. Routers do not send broadcast packets or corrupted packets. If the routing table does not indicate the proper address of a packet, the packet is discarded.

A router stores and forwards data packets—each of which contains a destination and source network address—from one LAN or WAN to another. Routers are "smarter" than bridges, because they find the best route for all the data sent to them by the previous router or the end station of the LAN.

Routers operate on the third layer of the OSI Model, the Network-Control Layer.  Rather than passing packets based on the Media Access Control (MAC) Layer addresses (as bridges do), a router examines the packet's data structure and determines whether or not

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to forward it. This determination is made based on the network information within the packet.

Once the router determines where the packet should be sent, it finds the fastest route to send the data to its destination. The router also has to send this data in the most appropriate format for transferring information. That means it may repackage or break the data into smaller pieces than the receiving destinations can handle.

A router is an intelligent packet sorter, which can look at the ultimate destination for a packet and analyze the best way to get it there. A router provides the information on how to get from one place to another, and this information is added to the packet header. This makes it a much more powerful device for use with complex networks, including the Internet. In fact, the Internet itself could be described as a network of routers.

Routers don't have a bridge's ability to learn addresses, so they have to do more data processing than bridges do. Routers also have to be aware of the network protocols they serve and often have more complex installation and configuration requirements.

BRIDGES:A bridge is a hardware device for linking two networks that work with the same protocol. Like a repeater, a bridge has just two ports and is used to connect two groups of computers. Unlike a repeater, which works at the physical level, a bridge works at the logical level (on layer 2 in the OSI model), which means that it can filter frames so that it only lets past data whose destination address corresponds to a machine located on the other side of the bridge.

The bridge is used to segment a network, holding back the frames intended for the local area network while transmitting those meant for other networks. This reduces traffic (and especially collisions) on all networks, and increases the level of privacy, as information intended for one network cannot be listened to on the other end.

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On the other hand, the filtering carried out by the bridge can cause a slight delay when going from one network to another, and this is why bridges must be carefully placed within a network.

ConceptA bridge has two connections to two distinct networks. When the bridge receives a frame on one of its interfaces, it analyses the MAC address of both the sender and recipient. If a bridge doesn't recognize the sender, it stores its address in a table in order to "remember" which side of the network the sender was on. This way, the bridge can find out if the sender and receiver are found on the same side or opposite sides of the bridge. If it's the former, the bridge ignores the message; if it's the latter, the bridge sends the frame along to the other network.

Working of a bridge: A bridge works at the data link layer of the OSI model, meaning that it

operates using the physical addresses of the machines.

In reality, the bridge is linked to several local area networks, called segments. The bridge creates a function table with the machines' addresses and the segments they belong to, and "listens" to the data running through the segments. .

They can distinguish between local and remote data, so data traveling from one workstation to another in the same segment doesn't have to cross the bridge.

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Bridges operate on MAC-Layer addresses. They're protocol independent, so they transfer data between workstations without having to understand the protocol. That means they require little or no configuration.

When data is transmitted, the bridge checks the function table for the segment the sending and receiving computers belong to (using their physical address, called the MAC address, and not their IP address). If they belong to the same segment, the bridge does nothing; otherwise, it switches the data over to the destination computer's segment.

A bridge connects two LAN segments into one larger continuous LAN. Unlike routers, every bridge builds an internal list of addresses of the attached network devices on both sides of it. When a bridge sees a packet, it checks the packet's address against its internal list. If the destination address is on the opposite segment or if the bridge doesn't have the address logged, the bridge forwards the information.

A bridge reads the outermost section of data on the data packet, to tell where the message is going.

It reduces the traffic on other network segments, since it does not send all packets. Bridges can be programmed to reject packets from particular networks.

To determine the network segment a MAC address belongs to, bridges use one of:

Transparent Bridging - They build a table of addresses (bridging table) as they receive packets. If the address is not in the bridging table, the packet is forwarded to all segments other than the one it came from. This type of bridge is used on Ethernet networks.

Source route bridging - The source computer provides path information inside the packet. This is used on Token Ring networks.

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EXPERIMENT NO.5

AIM: To use some basic commands like ping, trace-root, ipconfig for troubleshooting network related problems. PING COMMAND:

The Internet Ping command bounces a small packet off a domain or IP address to test network communications, and then tells how long the packet took to make the round trip. The Ping command is one of the most commonly used utilities on the Internet by both people and automated programs for conducting the most basic network test: can your computer reach another computer on the network, and if so how long does it take?

How Ping was invented. The original PING command stood for "Packet Internet Groper", and was a package of diagnostic utilities used by DARPA personnel to test the performance of the ARPANET. However, the modern Internet Ping command refers to a program was written by Mike Muuss in December, 1983, which has since become one of the most versatile and widely used diagnostic tools on the Internet. Muuss named his program after the sonar sounds used for echo-location by submarines and bats.

How Ping works . Ping operates by sending Internet Control Message Protocol (ICMP) echo request packets to the target host and waiting for an ICMP response, which then sends an ECHO_REPLY packet in return. The IP address 127.0.0.1 is set by convention to always indicate your own computer. Therefore, a ping to that address will always ping yourself and the delay should be very short. This provides the most basic test of your local communications. The results of the test are printed in the form of a statistical summary of the response packets received, including the minimum, maximum, and the mean round-trip times, and sometimes the standard deviation of the mean.

How to use Ping . You can use the Ping command to perform several useful Internet network diagnostic tests, such as the following:

Access . You can use Ping to see if you can reach another computer. If you can't ping a site at all, but you can ping other sites, then it's a pretty good sign that your Internet network is fine and that site is down. On the other hand, if you can't ping any site, then likely your entire network connection is down -- try rebooting.

Time & distance . You can use the Ping command to determine how long it takes to bounce a packet off of another site, which tells you it’s Internet distance in network terms. For example, a website hosted on your neighbor's computer next door with a different Internet service provider might go through more routers and be farther away in network distance than a site on the other side of the ocean with a direct connection to the Internet backbone.

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If a site seems slow, you can compare ping distances to other Internet sites to determine whether it is the site, the network, or your system that is slow.

Domains IP address . You can use the Ping command to probe either a domain name or an IP address. If you ping a domain name, it helpfully displays the corresponding IP address in the response.

You can run the ping command on a Windows computer by opening an MSDOS window and then typing "ping" followed by the domain name or IP address of the computer you wish to ping.

Syntax:

Ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS][-r count] [-s count] [[-j host-list] | [-k host-list]][-w timeout] destination-list

Options:-t Pings the specified host until stopped.

To see statistics and continue - type Control-Break;To stop - press Ctrl + C.

-a Resolve addresses to hostnames.-n count Number of echo requests to send.-l size Send buffer size.-f Set Don't Fragment flag in packet.-i TTL Time To Live.-v TOS Type Of Service.-r count   Record route for count hops.-s count Timestamp for count hops.-j host-list Loose source route along host-list.-k host-list Strict source route along host-list.-w timeout Timeout in milliseconds to wait for each

reply.

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The following example illustrates how to send two pings, each 1,450 bytes in size, to IP address 131.107.8.1C:\>ping -n 2 -l 1450 131.107.8.1Pinging 131.107.8.1 with 1450 bytes of data:

Reply from 131.107.8.1: bytes=1450 time<10ms TTL=32Reply from 131.107.8.1: bytes=1450 time<10ms TTL=32

Ping statistics for 131.107.8.1: Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),Approximate roundtrip times in milliseconds: Minimum = 0ms, Maximum = 10ms, Average = 2ms

By default, ping waits 4,000 milliseconds (4 seconds) for each response to be returned before displaying the "Request Timed Out" message. If the remote system being pinged is across a high-delay link, responses may take longer to be returned.

A response of "Destination net unreachable" means there was no route to the destination. You need to check the routing table on the router listed in the "Reply from" address in the

"Destination net unreachable" message.

A response of "Request timed out" means that there was no response to the ping in the default time period (1 second). You can check for the following:

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A router is down.

To check the routers in the path between the source and the destination, use the tracert command.

The destination host is down.

Physically verify that the host is running or check connectivity through another protocol.

There is no route back to your computer.

If the host is running, you can check for a return route by viewing the default gateway and local routing table on the destination host.

The latency of the response is more than one second.

Use the -w option on the ping command to increase the time-out. For example, to allow responses within 5 seconds, use ping -w 5000.

Increase or Decrease the Time Interval between Packets:

By default ping waits for 1 second before sending the next packet. You can increase or decrease this using option -i as shown below.

Increase Ping Time Interval:

Example: Wait for 5 seconds before sending the next packet.

$ ping -i 5 IP

Decrease Ping Time Interval:

Example: Wait 0.1 seconds before sending the next packet.

# ping -i 0.1 IP

Note: Only super user can specify interval less than 0.2 seconds. If not, you’ll get the following error message.

$ ping -i 0.1 127.0.0.1PING 0 (127.0.0.1) 56(84) bytes of data.

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Audible ping: Give beep when the peer is reachable:

This option is useful for sysadmin during troubleshooting. There is no need for you to look at the ping output after each and every change. You can continue working with your changes, and when the remote machine become reachable you’ll hear the beep automatically.

$ ping -a IP

Find out the IP address:

You can identify the ip-address using the host name as shown below.

$ ping -c 1 google.comPING google.com (74.125.67.100) 56(84) bytes of data.64 bytes from gw-in-f100.google.com (74.125.67.100): icmp_seq=1 ttl=43 time=287 ms

--- google.com ping statistics ---1 packets transmitted, 1 received, 0% packet loss, time 0msrtt min/avg/max/mdev = 287.903/287.903/287.903/0.000 ms

Print Only Ping Command Summary Statistics:

Use option -q to view only the ping statistics summary as shown below.

$ ping -c 5 -q 127.0.0.1PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.

--- 127.0.0.1 ping statistics ---5 packets transmitted, 5 received, 0% packet loss, time 3998msrtt min/avg/max/mdev = 0.047/0.053/0.061/0.009 m

IPCONFIG COMMAND:

ipconfig is a command line utility available on all versions of Microsoft Windows starting with Windows NT. ipconfig is designed to be run from the Windows command prompt. This utility allows you to get the IP address information of a Windows computer. It also allows some control over active TCP/IP connections. ipconfig is an alternative to the older 'winipcfg' utility.

Syntax:

ipconfig [/all] [/renew [Adapter]] [/release [Adapter]] [/flushdns] [/displaydns] [/registerdns] [/showclassid Adapter] [/setclassid Adapter [ClassID]]

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Parameters:

/all: Displays the full TCP/IP configuration for all adapters. Without this parameter, ipconfig displays only the IP address, subnet mask, and default gateway values for each adapter. Adapters can represent physical interfaces, such as installed network adapters, or logical interfaces, such as dial-up connections.

/renew [Adapter]: Renews DHCP configuration for all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.

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/release [Adapter]: Sends a DHCPRELEASE message to the DHCP server to release the current DHCP configuration and discard the IP address configuration for either all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter disables TCP/IP for adapters configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.

/flushdns: Flushes and resets the contents of the DNS client resolver cache. During DNS troubleshooting, you can use this procedure to discard negative cache entries from the cache, as well as any other entries that have been added dynamically.

/displaydns : Displays the contents of the DNS client resolver cache, which includes both entries preloaded from the local Hosts file and any recently obtained resource records for name queries resolved by the computer. The DNS Client service uses this information to resolve frequently queried names quickly, before querying its configured DNS servers.

/registerdns: Initiates manual dynamic registration for the DNS names and IP addresses that are configured at a computer. You can use this parameter to troubleshoot a failed DNS name registration or resolve a dynamic update problem between a client and the DNS server without rebooting the client computer.

/showclassid Adapter: Displays the DHCP class ID for a specified adapter. To see the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place of Adapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically.

/setclassid Adapter [ClassID]: Configures the DHCP class ID for a specified adapter. To set the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place of Adapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically.

/?: Displays help at the command prompt.

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TRACEROUTE COMMAND:

The traceroute command traces the network path of Internet routers that packets take as th ey are forwarded from your computer to a destination address. The "length" of the network connection is indicated by the number of Internet routers in the traceroute path.

Traceroutes can be useful to diagnose slow network connections. For example, if you can usually reach an Internet site but it is slow today, then a traceroute to that site should show you one or more hops with either long times or marked with "*" indicating the time was really long.

Tracert Command Syntax:

tracert [-d] [-h MaxHops] [-w TimeOut] [-4] [-6] target [/?]

-d = this option prevents tracert from resolving IP addresses to hostnames, often resulting in much faster results.

-h MaxHops = this tracert option specifies the maximum number of hops in the search for the target. If you do not specify MaxHops, and target has not been found by 30 hops, tracert will stop looking.

-w TimeOut = you can specify the time, in milliseconds, to allow each reply before timeout using this tracert option.

-4 = this option forces tracert to use IPv4 only.

-6 = this option forces tracert to use IPv6 only.

target = this is the destination, either an IP address or hostname.

[/?] = Use the help switch with the tracert command to show detailed help about the command's several options.

Traceroute operating systems:

On a Windows computer, you can run a traceroute in an MSDOS or Command window by typing "tracert" followed by the domain name, for example as in "tracert www.yahoo.com" shown in the picture below. For windows users, the command is tracert. For Macintosh OS X users, its traceroute.

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In this example we will trace the hops from a computer to yahoo.com:

C:\WINDOWS>tracert yahoo.com Tracing route to yahoo.com [66.218.71.198] over a maximum of 30 hops:

  1 <1 ms <1 ms <1 ms 208.170.243.1   2 44 ms 14 ms 18 ms sl-gw15-rly-6-0-1.sprintlink.net [144.232.246.165]   3 31 ms 25 ms 13 ms sl-bb22-rly-1-0.sprintlink.net [144.232.25.232]   4 21 ms 17 ms 17 ms sl-st20-ash-15-1.sprintlink.net [144.232.20.106]   5 15 ms 17 ms 19 ms so-0-0-0.edge1.Washington1.Level3.net [209.244.219.169]   6 16 ms 17 ms 15 ms so-5-0-0.gar1.Washington1.Level3.net [209.244.11.9]   7 82 ms 82 ms 82 ms so-3-0-0.mp2.SanJose1.Level3.net [64.159.1.130]   8 87 ms 87 ms 83 ms gige10-0.ipcolo3.SanJose1.Level3.net [64.159.2.41]   9 87 ms 84 ms 93 ms unknown.Level3.net [64.152.69.30]  10 90 ms 88 ms 92 ms w1.rc.vip.scd.yahoo.com [66.218.71.198]

Trace complete.

Understanding the output:

The first line is the command we typed: tracert yahoo.com.

The next line shows the traceroute program acquiring the ip address from the domain. "Maximum of 30 hops" is how many routers the packet will go through before giving up trying to find the host.

The next lines show each server the packets traveled through to get to the destination yahoo.com. These show both the IP address and domain name of the actual servers that the packets passed through.

Interpreting the results:

Traceroutes allow you to see the path your packets take over the Internet. Sometimes, they will also allow you to "see" how your information traveled over the world: in above example our information passed from our computer to servers in Washington DC then through servers in San Jose before reaching its destination (yahoo.com).

Traceroutes can show where there is a break in your connection. This allows us to determine exactly where our packets are being dropped or lost. Dropped or lost packets on a traceroute will usually show as asterisks (*).

How to Use the Traceroute Command:

Traceroute is a command which can show you the path a packet of information takes from your computer to one you specify. It will list all the routers it passes through until it reaches its destination, or fails to and is discarded. In addition to this, it will tell you how long each 'hop' from router to router takes.

Enter the word tracert, followed by a space, then the domain name.

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The following is a successful traceroute from a home computer in New Zealand to mediacollege.com:

Firstly it tells you that it's tracing the route to mediacollege.com, tells you the IP address of that domain, and what the maximum number of hops will be before it times out.

Next it gives information about each router it passes through on the way to its destination.

1 is the internet gateway on the network this traceroute was done from (an ADSL modem in this case)2 is the ISP the origin computer is connected to (xtra.co.nz)3 is also in the xtra network4 timed out5 - 9 are all routers on the global-gateway.net.nz network (the domain that is the internet gateway out of New Zealand)10 - 14 are all gnaps.net in the USA (a telecom supplier in the USA)15 - 17 are on the nac network (Net Access Corporation, an ISP in the New York area)18 is a router on the network mediacollege.com is hosted onand finally, line 19 is the computer mediacollege.com is hosted on (sol.yourhost.co.nz)Each of the 3 columns is a response from that router, and how long it took (each hop is tested 3 times). For example, in line 2, the first try took 240ms (240 milliseconds), the second took 421 ms, and the third took 70ms.

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Tracert Command Examples: tracert 192.168.1.1

In the above example, the tracert command is used to show the path from the networked computer on which the tracert command is being executed to a network device, in this case a router on a local network, that's assigned the 192.168.1.1 IP address. The result displayed on screen will look something like this:

Tracing route to 192.168.1.1 over a maximum of 30 hops

1 <1 ms <1 ms <1 ms 192.168.1.254 2 <1 ms <1 ms <1 ms 192.168.1.1

Trace complete.

In this example, you can see that tracert found a network device using the IP address of 192.168.1.254 followed by the destination, 192.168.1.1, the router.

tracert www.google.com

Using the tracert command as shown above, we're asking tracert to show us the path from the local computer all the way to the network device with the hostname www.google.com.

Tracing route to www.l.google.com [209.85.225.104]over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 10.1.0.1 2 35 ms 19 ms 29 ms 98.245.140.1 3 11 ms 27 ms 9 ms te-0-3.dnv.comcast.net [68.85.105.201] ... 13 81 ms 76 ms 75 ms 209.85.241.37 14 84 ms 91 ms 87 ms 209.85.248.102 15 76 ms 112 ms 76 ms iy-f104.1e100.net [209.85.225.104]

Trace complete.

In this example we can see that tracert identified fifteen network devices including our router at 10.1.0.1 and all the way through to the target of www.google.com which we now know uses the public IP address of 209.85.225.104.

tracert -d www.yahoo.com

In this example, the path to a website www.yahoo.com is requested but now resolving hostnames are prevented by using the -d option.

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Tracing route to any-fp.wa1.b.yahoo.com [209.191.122.70]over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 10.1.0.1 2 29 ms 23 ms 20 ms 98.245.140.1 3 9 ms 16 ms 14 ms 68.85.105.201 ... 13 98 ms 77 ms 79 ms 209.191.78.131 14 80 ms 88 ms 89 ms 68.142.193.11 15 77 ms 79 ms 78 ms 209.191.122.70

Trace complete.

In this example we can see that tracert again identified fifteen network devices including our router at 10.1.0.1 and all the way through to the target of www.yahoo.com which we can assume uses the public IP address of 209.191.122.70.

Tracert Command Availability:

The tracert command is available from within the Command Prompt in all Windows operating systems including Windows 7, Windows Vista, Windows XP, and older versions of Windows as well.

Tracert Related Commands:

The tracert command is often used with other networking related Command Prompt commands like ping, ipconfig, netstat, nslookup, and others.

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