Networking Topologies and TCP/IP Protocol
Bus Topology
It just doesn't get much simpler than the physical bus topology when it comes to connecting nodes on a Local Area Network (LAN). The most common implementation of a linear bus topology is IEEE 802.3 Ethernet. All devices in a bus topology are connected to a single cable called the bus, backbone, or ether. The transmission medium has a physical beginning and an end. All connections must be terminated with a resistor to keep data transmissions from being mistaken as network traffic. The terminating resistor must match the impedance of the cable.
One advantage of bus topology is that small networks are fairly easy to set up and does not require specialized networking equipment. It is also fairly inexpensive to set up, since it requires the least amount of cable and equipment. Adding or removing nodes is fairly easy, but moving nodes without affecting neighboring nodes can be difficult.
Troubleshooting media problems on a bus networks can be very tedious, since a break in the backbone will bring down the entire LAN. For this reason, bus topology is not considered one of the more robust network topologies, compared with star or mesh. A loose or missing terminating resistor can also bring down a LAN.
Star Topology
In this topology, all nodes are connected to a central device, usually a hub or a switch. Each connected device has a dedicated, point-to-point connection between the device and the hub. The star network topology is by far the most widely implemented topology in use today.
Star topology networks require more cabling than bus, but the tradeoff comes in the form of a more solid network topology. A break in the network media will only affect a single node, since every node has a dedicated connection to the central device; a hub or switch. This also makes the central device a Single Point of Failure (SPOF). Redundant or failover switches are often used to eliminate the SPOF in a star LAN.
Building a star topology is much more expensive and time consuming than the bus network. The increased costs come in the form of cabling and the central device(s). However, star topologies can be easily expanded to accommodate more nodes and troubleshooting is much easier because connectivity problems are simpler to isolate than a bus network.
Mesh Topology
Perhaps the most redundant, fault-tolerant of all network topologies is the mesh LAN. Each node is connected to every other node for a true point-to-point connection between every device on the network.
A bus is a communication system that connects multiple subsystems within a computer. An average computer system normally consists of several components such as a central processing unit, memory devices, and input/output (I/O) devices. The bus system consists of linking media like wires and connectors, and a bus protocol. Buses can be categorized as serial or parallel and synchronous or asynchronous. The bus lets the different components communicate with each other by allowing information to flow between units and devices.
COMP09022 Network Design BSc COMPUTER NETWORKING COMP09022 ICMPv6 Prepared by B00270675 13-03- 2015 WORD COUNT (0000) TABLE OF CONTENTS TITLE PAGE……………………………………………... 1 TABLE OF CONTENTS………………………………….. 2 INTRODUCTION TO THE REPORT……………………. 3 TABLE OF FEATURES.......................................................4
“The Spanning Tree Protocol (STP) is an older network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.”
... access to what and in which sequence. The router connects the LAN to other networks, which could be the Internet or another corporate network so that the LAN can exchange information with networks external to it. The most common LAN operating systems are Windows, Linux, and Novell. Each of these network operating systems supports TCP/IP as their default networking protocol. Ethernet is the dominant LAN standard at the physical network level, specifying the physical medium to carry signals between computers, access control rules, and a standardized set of bits used to carry data over the system. Originally, Ethernet supported a data transfer rate of 10 megabits per second (Mbps). Newer versions, such as Fast Ethernet and Gigabit Ethernet, support data transfer rates of 100 Mbps and 1 gigabits per second (Gbps), respectively, and are used in network backbones.
Point-to-Point routing system, unlike low-cost competitors that utilize hub-and-spoke system, partnering with larger airlines to provide connecting flights.
The ISA bus, used in 386 and 486 systems, consists of 24 address lines and 16 data lines to transmit data within a computer system. PCI bus a 32-bit bus developed by Intel to extend the local bus of a CPU, and retains the ability to extend 64-bit processors as well, but only transmits at half-duplex. AGP a bus specifically designed for video cardo cards to transfer data from the CPU to video display output devices, however currently replaced by PCI Express in modern day computers. PCI Express bus architecture provides bidirectional transmission of data, allowing data transference and reception of data simultaneously on platform faster than PCI bus. IEEE 1394 bus a high-speed bus that uses serial technology to daisy chain devices, but only can transmit data for short limited distances.
Meanwhile, the advent of early PC’s and the recognition of the value in networking devices together gave rise to Local Area Networks. These LAN’s were developed from a business customer perspective, which placed more emphasis on costs and ease of use over reliability. There were a number of different competing LAN technologies, two of the most common being Token Ring (IBM) and Ethernet (everyone else). The triumph of Ethernet in the marketplace, to the extent where it is included in every PC, game console and some refrigerators, provides a consistent and relatively inexpensive way to build internal networks with relative ease.
...ipment. This problem would cause headaches when one network was not in synch with the others. Centralized manageability would increase the stability of the network system.
A switch can be used to make various connections. Ethernet, Token Ring, and various other types of packet switched network segments together to form a heterogeneous network operating at OSI Layer 2.
The project team has identified several issues with the current network infrastructure. The first is the availability and cost of token ring hardware. Ethernet is the dominant network topology and is included on many devices at no cost. Equipment with token ring interfaces can be found but are much more expensive. Another problem is that the current hardware is about 10 years old and is experiencing increased maintenance costs. Another problem is that the majority of the existing cable plant does not meet minimal category 5 standards.
Spanning tree protocol is a protocol that prevents loops that are not wanted in a network. In order for a network to work properly it has to have only one active path between two network stations. If there are multiple active paths between stations loops can and will occur. When loops occur, there can sometimes be duplicate messages in the network. The loops are created by the network and if the devices that connect the network segments are all configured to forward, they will continuously forward frames into an endless network loop. If there are enough loops going then a frame will not reach its destination. The reason duplicate messages occur is because sometimes switches will see situations appear on both sides of it. When this occurs that is when spanning tree protocol comes in. In order to shut down the loops bridges and switches exchange BPDU messages with other bridges and switches to detect loops and then remove them by shutting down selected bridge interfaces. BPDU is short for bridge protocol data unit. Bridge protocol data units are part of the spanning tree protocol and they help describe and identify the parts of a switch port. The bridge protocol data unit allows switches to obtain information about each other. All the switches gather information from each other by exchanging data messages. In order for them to exchange messages they have to elect a root switch for the topology. The root switch has to be unique. The way they elect they have to have a unique switch for every local area network segment. To exchange messages they have to remove all loops by putting them in a backup state. Now to talk about states there is 5 different states. Two of the five states do not participate in frame forwarding. Frame forwarding is what the three main states do. The three main states are listening, learning, and forwarding. The other 2 are blocking state and disabled state. When you enable the spanning tree protocol the network goes through the blocking state and then the listening state and learning state are enabled after being turned on. If the protocol is properly configured the ports are stabilized to the forwarding or blocking state. The blocking state does not participate in the frame forwarding. It removes frames that are received from the attached segment. It also discards frames from another port for forwarding.
Local Area Network as defined in our textbook is a “group of computers located in the same general area,” (Fitzgerald & Dennis, 2012. p13). LANs is a type of network usually implemented within an office, school or home environment where group of computers are located in proximity with each other or in a small geographic area. Thus, client computers are interconnected through a switch to access another network, server, then to a router that access the internet. LANs uses hardware such as Ethernet cables, network cards, wireless access points, switches and routers.
LANs systems can be defined and connected in many different ways. This is the reason for the standardization for every one can have a common ground to start from. “The LANs described Herein are distinguished from other types of data networks in that they are optimized for a moderate size geographic area such as a single office building, warehouse, or a campus. The IEEE 802 LAN is a shared medium peer-to-peer communications network that broadcasts information for all stations to receive. As a consequence, it does not inherently provide privacy. The LAN enables stations to communicate directly using a common physical medium on a point-to-point basis without any intermediate switching node being required. There is always need for an access sublayer in order to arbitrate to access to the shared medium. The network is generally owned, used, and operated by a single organization. This is in contrast to Wide Area Networks (WANs) that interconnect communication facilities in different parts of a country or are used as a public utility. These LANs are also different from networks, such as backplane buses, that are optimized for the interconnection of devices on a desk top or components within a single piece of equipment.”(IEEE 802 Standard 1990) That is the standard definition for LANs by Institute of Electrical and Electronics Engineer committee 802. They are the committee used to set the standard in workmanship and operations for technicians that set-up and perform maintenance on LANs systems. And through all the technical words what they are trying to say is a LAN is a small area network that distributes information among computer in a small work environment unlike WANs that distribute information across global areas.
TCP/IP is a network model which enables the communication across the Internet. The most fundamental protocol on which the Internet is built. This is made up of the 2 common networking protocols, TCP, for Transmission Control Protocol, and IP, for Internet Protocol. TCP maintains and handles packet flow linking the systems and IP protocol has the ability to handle the routing of packets. However The TCP/IP stack consists of 5 layers first being application layer, the transport layer, then the network layer, the link layer and finally the physical layer. The assignment focuses on the three middle layers and is divided into five parts. Firstly explaining how the TCP and UDP the most vital protocols needed to deliver and communicate.
Bus topology refers to a local area network (LAN) arrangement where each node or device is connected to a main cable or link called a bus. A bus network is simple yet very reliable. Since nodes themselves are not relied upon for communication, the failure of a single node is not problematic for the rest of the network. For a major issue to occur, there must be a problem with the bus itself.