NETWORKING COMPONENTS

ALEX TARABA

LTEC4550.020

20 OCTOBER 2014

COMPONENT #1: HUB

• A hub is a device for connecting multiple Ethernet devices together and making them act as a single network segment. It has multiple input/output (I/O) ports, in which a signal introduced at the input of any port appears at the output of every port except the original incoming. A hub works at the physical layer (layer 1) of the OSI model. Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it detects a collision. In addition to standard 8P8C ("RJ45") ports, some hubs may also come with a BNC and/or Attachment Unit Interface (AUI) connector to allow connection to legacy 10BASE2 or 10BASE5 network segments.

• Some common uses:

• For inserting a protocol analyzer into a network connection, a hub is an alternative to a network tap or port mirroring.[7]

• When a switch is accessible for end users to make connections, for example, in a conference room, an inexperienced or careless user (or saboteur) can bring down the network by connecting two ports together, causing a switching loop. This can be prevented by using a hub, where a loop will break other users on the hub, but not the rest of the network (more precisely, it will break the current collision domain up to the next switch/bridge port). This hazard can also be avoided by using switches that can detect and deal with loops, for example by implementing the spanning tree protocol.[citation needed]

• A hub with a 10BASE2 port can be used to connect devices that only support 10BASE2 to a modern network.

• A hub with an AUI port can be used to connect to a 10BASE5 network.

A cheap inexpensive four port hub could cost as little as $29.99. In today’s market, a larger hub aimed at corporate operation could have as many as 128 ports or more and cost $3,000.00 or more.

COMPONENT #1: HUB OPERATION

• A hub can be compared to a transmitter to a station. Packets of data come in and out of the hub and are then sent to other computers on the network. A hub that only functions as a hub merely passes on the network data.

• If two computers on an Ethernet network try to send out data at the same time, a collision occurs. A data collision is a similar to two cars trying to pass over a one lane bridge at the same time. It simply will not happen. The data that reaches the other end will be garbled and unusable.

COMPONENT #2: SWITCH

• A network switch is a computer networking device that connects devices together on a computer network, by using a form of packet switching to forward data to the destination device. A network switch is considered more advanced than a (repeater) hub because a switch will only forward a message to one or multiple devices that need to receive it, rather than broadcasting the same message out of each of its ports.

• A network switch (also called switching hub, bridging hub, officially MAC bridge) is a multi-port network bridge that processes and forwards data at the data link layer (layer 2) of the OSI model. Switches can also incorporate routing in addition to bridging; these switches are commonly known as layer-3 or multilayer switches. Switches exist for various types of networks including Fibre Channel, Asynchronous Transfer Mode, InfiniBand, Ethernet and others. The first Ethernet switch was introduced by Kalpana in 1990.

• 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 residential 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 physical broadband technology. User devices may also include a telephone interface for Voice over IP (VoIP) protocol.

As seen here, switches look very similar to hubs. A cheap switch can be purchased for $9.99 today. Larger and more expensive ones can be purchased which include 128 or more ports and top out at close to $1,500.00.

COMPONENT #2: SWITCH OPERATION

• How Does a Network Switch Work?: The Basics

• How does a network switch in conjunction with other hardware? For starters, switches are a key component of many business networks. They connect multiple PCs, printers, servers and other hardware. Switches allow you to send information, such as email, and access shared resources, including printers, in a smooth, efficient, and transparent manner.

• How Does a Network Switch Work?: Unmanaged Switches

• An unmanaged network switch works right out of the box. But it's not designed to be configured. Usually, you'll find unmanaged switches in home networking equipment.

• How Does a Network Switch Work?: Managed Switches

• A managed switch gives you greater flexibility because it can be configured. For example, you can monitor a managed network switch and adjust it locally or remotely. This gives you control over network traffic and who has access to the network.

COMPONENT #3: ROUTER

• A router is a networking device, commonly specialized hardware, that forwards data packets between computer networks. This creates an overlay internetwork, as a router is connected to two or more data lines from different networks. When a data packet comes in one of the lines, the router reads the address information in the packet to determine its ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Routers perform the "traffic directing" functions on the Internet. A data packet is typically forwarded from one router to another through the networks that constitute the internetwork until it reaches its destination node.

• Edge router: Also called a Provider Edge router, is placed at the edge of an ISP network. The router uses External BGP to EBGP routers in other ISPs, or a large enterprise Autonomous System.

• Subscriber edge router: Also called a Customer Edge router, is located at the edge of the subscriber's network, it also uses EBGP to its provider's Autonomous System. It is typically used in an (enterprise) organization.

• Inter-provider border router: Interconnecting ISPs, is a BGP router that maintains BGP sessions with other BGP routers in ISP Autonomous Systems.

• Core router: A core router resides within an Autonomous System as a back bone to carry traffic between edge routers.

• Within an ISP: In the ISP's Autonomous System, a router uses internal BGP to communicate with other ISP edge routers, other intranet core routers, or the ISP's intranet provider border routers.

• "Internet backbone:" The Internet no longer has a clearly identifiable backbone, unlike its predecessor networks. See default-free zone (DFZ). The major ISPs' system routers make up what could be considered to be the current Internet backbone core.[14] ISPs operate all four types of the BGP routers described here. An ISP "core" router is used to interconnect its edge and border routers. Core routers may also have specialized functions in virtual private networks based on a combination of BGP and Multi-Protocol Label Switching protocols.

• Port forwarding: Routers are also used for port forwarding between private Internet connected servers.

• Voice/Data/Fax/Video Processing Routers: Commonly referred to as access servers or gateways, these devices are used to route and process voice, data, video and fax traffic on the Internet. Since 2005, most long-distance phone calls have been processed as IP traffic (VOIP) through a voice gateway. Voice traffic that the traditional cable networks once carried[clarification needed]. Use of access server type routers expanded with the advent of the Internet, first with dial-up access and another resurgence with voice phone service.

A router can be wired or wireless. A cheap router will cost you around $19.99. A larger more expensive router will cost you $999.99+. Prices will not be as expensive as switches, but can come close.

COMPONENT #3: ROUTER OPERATION

• The routers determine where to send information from one computer to another. Routers are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways. A router has two separate, but related, jobs:

• It ensures that information doesn't go where it's not needed. This is crucial for keeping large volumes of data from clogging the connections of "innocent bystanders."

• It makes sure that information does make it to the intended destination.

• In performing these two jobs, a router is extremely useful in dealing with two separate computer networks. It joins the two networks, passing information from one to the other. It also protects the networks from one another, preventing the traffic on one from unnecessarily spilling over to the other. Regardless of how many networks are attached, the basic operation and function of the router remains the same. Since the Internet is one huge network made up of tens of thousands of smaller networks, its use of routers is an absolute necessity.

COMPONENT #4: BRIDGE

• Network bridging is the action taken by network equipment to create an aggregate network from either two or more communication networks, or two or more network segments. Bridging is distinct from routing which allows the networks to communicate independently as separate networks.

• A network bridge is a network device that connects multiple network segments. In the OSI model bridging acts in the first two layers, below the network layer.

• There are four types of network-bridging technologies: simple bridging; multiport bridging; learning, or transparent bridging; and source route bridging.

Costs for network bridges very greatly. A lower priced one can cost as little as $39.99. A more expensive one can cost close to $12,000.00. This is an extreme case as most are around $1,500.00.

COMPONENT #4: BRIDGE OPERATION

• 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.

• 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.

COMPONENT #5: GATEWAY AND OPERATION

• Gateways, also called protocol converters, can operate at any network layer. The activities of a gateway are more complex than that of the router or switch as it communicates using more than one protocol.

• Both the computers of Internet users and the computers that serve pages to users are host nodes, while the nodes that connect the networks in between are gateways. For example, the computers that control traffic between company networks or the computers used by internet service providers (ISPs) to connect users to the internet are gateway nodes.

• In the network for an enterprise, a computer server acting as a gateway node is often also acting as a proxy server and a firewall server. A gateway is often associated with both a router, which knows where to direct a given packet of data that arrives at the gateway, and a switch, which furnishes the actual path in and out of the gateway for a given packet.

Prices for gateways range anywhere from $99.99 to $3,500.00.

COMPONENT #6: FIREWALL

• In computing, a firewall is a network security system that controls the incoming and outgoing network traffic based on applied rule set. A firewall establishes a barrier between a trusted, secure internal network and another network (e.g., the Internet) that is assumed not to be secure and trusted. Firewalls exist both as a software solution and as a hardware appliance. Many hardware-based firewalls also offer other functionality to the internal network they protect, such as acting as a DHCP server for that network.

• Many personal computer operating systems include software-based firewalls to protect against threats from the public Internet. Many routers that pass data between networks contain firewall components and, conversely, many firewalls can perform basic routing functions.

Firewalls can be software and hardware. A cheap software firewall can be free (AVG, Windows, etc.) and more expensive ones can cost up to $199.99 a year for subscriptions. Hardware firewalls can range anywhere from $99.99 to $1,999.99.

COMPONENT #7: WIRELESS AP

• In computer networking, a wireless Access Point (AP) is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards. The AP usually connects to a router (via a wired network) as a standalone device, but it can also be an integral component of the router itself.

• Typical corporate use involves attaching several APs to a wired network and then providing wireless access to the office LAN. The wireless access points are managed by a WLAN Controller which handles automatic adjustments to RF power, channels, authentication, and security. Furthermore, controllers can be combined to form a wireless mobility group to allow inter-controller roaming. The controllers can be part of a mobility domain to allow clients access throughout large or regional office locations. This saves the clients time and administrators overhead because it can automatically re-associate or re-authenticate.

• A hotspot is a common public application of APs, where wireless clients can connect to the Internet without regard for the particular networks to which they have attached for the moment. The concept has become common in large cities, where a combination of coffeehouses, libraries, as well as privately owned open access points, allow clients to stay more or less continuously connected to the Internet, while moving around. A collection of connected hotspots can be referred to as a lily pad network.

• APs are commonly used in home wireless networks. Home networks generally have only one AP to connect all the computers in a home. Most are wireless routers, meaning converged devices that include the AP, a router, and, often, an Ethernet switch. Many also include a broadband modem. In places where most homes have their own AP within range of the neighbors' AP, it's possible for technically savvy people to turn off their encryption and set up a wireless community network, creating an intra-city communication network although this does not negate the requirement for a wired network.

• An AP may also act as the network's arbitrator, negotiating when each nearby client device can transmit. However, the vast majority of currently installed IEEE 802.11 networks do not implement this, using a distributed pseudo-random algorithm called CSMA/CA instead.

Wireless AP are often part of routers in todays world. A cheap one will cost somewhere around $19.99 and a higher end one can cost as much as $1,499.99.

NETWORK DIAGRAM USING ALL MENTIONED DEVICES

This diagram shows how all the devices mentioned here are interconnected to form a corporate network that provides internet to residential areas.