CCNAv3.3 103
CCNAv3.3 103
CCNAv3.3 103
LAN WAN
Objectives
operate at each layer of the OSI model and how packets flow through each device as they go through the layers of the OSI model.
Define LAN, WAN, MAN, and SAN Explain VPNs and their advantages Describe the differences between intranets
and extranets
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Bandwidth
Table of Content
1 2 3 4 5 LAN-WAN
BASIC LAN DEVICES DATA FLOW THROUGH LANs NETWORKING TERMINOLOGY BANDWIDTH
LAN benefits Avoid duplication of equipment and resources Allow user in the department quickly
Some common WAN technologies are: Modems Digital Subscriber Line (DSL) Frame Relay Integrated Services Digital Network (ISDN) T1 (1.544 Mbps), E1 (2.048 Mbps)
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Networking Devices
Equipment that connects to a network segment is called a device These devices are broken into two classifications
End user devicesIncludes computers, printers, scanners Network devicesIncludes devices that connect the end-user devices to allow them to communicate
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Network Devices
Physical topologies
Define the actual layout of the wire (media)
Logical topologies
Define how the media is accessed by the hosts
Physical Topologies
Extended Star Hierarchical
Bus
Ring
Star
Mesh
Single backbone All hosts directly connected to backbone Each end of the bus must be properly terminated
All devices connected to a central point Center of star is usually a hub or a switch
Connects individual star topologies together. At the center of the star is a hub or a switch. Extends the length and size of the network.
Like the extended star except a computer controls traffic (not a hub or a switch).
Each host has its own connection to every other host. Used in situations where communication must not be interrupted.
Logical Topologies
Broadcast
Token Passing
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Each host on the LAN sends its data (or broadcasts its data) to every other host. First-come, first-serve.
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Access to media is controlled by an electronic token. Possession of the token gives the host the right to pass data to its destination.
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Technologies
Ethernet
FDDI
Token Ring
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Token Ring
Token Passing
Technology: FDDI
FDDI
Token Passing
Technology: Ethernet
Ethernet
Broadcast
Hosts
Computer
NIC
Printer
Server
Ethernet Line
Token Ring
Serial Line
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FDDI Ring
Responsibility:
Transmission of an unstructured bit stream over a physical link between end systems.
Concerned:
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Responsibility:
Provides for the reliable transfer of data cross a physical link.
Concerned:
Frames. Physical address (HW or MAC): Flat. Error and flow control. Segment.
Keeps traffic local by filtering traffic based on physical addresses. Layer 2 device.
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Responsibility:
Connection and path selection between two end system across networks.
Concerned:
Packets. Logical address: Hierarchical.
Networks and Hosts addressing.
Path determination:
The process of evaluating a packets destination IP address so that the router can decide which port to send out the packet.
Packet switching:
The router re-encapsulates the packet in the protocol needed for the specified port and then switches the packet out that port.
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Encapsulation
Encapsulation: Example
NETWORKING TERMINOLOGY
Wireless bridge technologies that send signals across public areas can also be used to create a MAN. A MAN usually consists of two or more LANs in a common geographic area. Typically, a service provider is used to connect two or more LAN sites using private communication lines or optical services. A MAN can also be created using wireless bridge technology by beaming signals across public areas.
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A storage-area network (SAN) is a dedicated, high-performance network used to move data between servers and storage resources; because it is a separate, dedicated network, it avoids any traffic conflict between clients and servers SAN technology allows high-speed server-tostorage, storage-to-storage, or server-to-server connectivity; this method uses a separate network infrastructure that relieves any problems associated with existing network connectivity
Benefits of VPNs
A VPN is a service that offers secure, reliable connectivity over a shared public network infrastructure such as the Internet. VPNs maintain the same security and management policies as a private network. The use of a VPN is the most cost-effective way to establish a point-to-point connection between remote users and an enterprise network.
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Benefits of VPNs
Benefits of VPNs
Intranet Web servers differ from public Web servers in that the public must have the proper permissions and passwords to access the intranet of an organization. Intranets are designed to permit users who have access privileges to the internal LAN of the organization. Within an intranet, Web servers are installed in the network. Browser technology is used as the common front end to access information on servers such as financial, graphical, or text-based data.
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BANDWIDTH
Bandwidth
Bandwidth is defined as the amount of information that can flow through a network connection in a given period of time.
Importance of Bandwidth
Importance of Bandwidth
Bandwidth is finite. Regardless of the media used to build a network, there are limits on the network capacity to carry information. Bandwidth is limited by the laws of physics and by the technologies used to place information on the media. Bandwidth is not free. It is possible to buy equipment for a LAN that will provide nearly unlimited bandwidth over a long period of time. For WAN connections, it is usually necessary to buy bandwidth from a service provider. In either case, individual users and businesses can save a lot of money if they understand bandwidth and how the demand will change over time.
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Importance of Bandwidth
Bandwidth is an important factor that is used to analyze network performance, design new networks, and understand the Internet. A networking professional must understand the tremendous impact of bandwidth and throughput on network performance and design. The demand for bandwidth continues to grow. As soon as new network technologies and infrastructures are built to provide greater bandwidth, new applications are created to take advantage of the greater capacity.
Measurement
In digital systems, the basic unit of bandwidth is bits per second (bps) Bandwidth is the measure of how many bits of information can flow from one place to another in a given amount of time Although bandwidth can be described in bps, a larger unit of measurement is generally used Network bandwidth is typically described as thousands of bits per second (kbps), millions of bits per second (Mbps), billions of bits per second (Gbps), and trillions of bits per second (Tbps)
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Measurement
Measurement
Although the terms bandwidth and speed are often used interchangeably, they are not exactly the same thing
For example, a T3 connection at 45 Mbps operates at a higher speed than a T1 connection at 1.544 Mbps. However, if only a small amount of their data-carrying capacity is being used, each of these connection types will carry data at roughly the same speed
Limitations
Bandwidth varies depending upon the type of media as well as the LAN and WAN technologies used The physics of the media account for some of the difference; signals travel through twistedpair copper wire, coaxial cable, optical fiber, and air The physical differences in the ways signals travel result in fundamental limitations on the information-carrying capacity of a given medium
Limitations
However, the actual bandwidth of a network is determined by a combination of the physical media and the technologies chosen for signaling and detecting network signals
Throughput
Throughput refers to actual measured bandwidth, at a specific time of day, using specific Internet routes, and while a specific set of data is transmitted on the network. Unfortunately, for many reasons, throughput is often far less than the maximum possible digital bandwidth of the medium that is being used.
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Throughput
The following are some of the factors that determine throughput:
Internetworking devices Type of data being transferred Network topology Number of users on the network User computer Server computer Power conditions
Throughput Variables
The answers to problems like these are not always easy to find, but one place to start is with a simple data transfer calculation.
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Q&A