NETWORKING COMPONENTSAN OVERVIEW OF COMMONLY USED HARDWARE

Christopher Johnson

LTEC 4550

Hub

Ethernet Hub (shown) Link multiple hosts to single central point Can be used to share single network

connection, for example, or multiple USB devices sharing a single USB port over a USB hub

Broadcasts network traffic to all connected hosts

Operates at OSI Layer 1 Serves as signal

repeater, boosting strength of broadcastmessages

How it works - Hub

Single Ethernet port. This could be a network port in a cubicle on an Ethernet-wired corporate network, for example

Ethernet hub8-port ethernet hub. Supports source device plus up to 7 additional devices

Laptop with Ethernet interface.

Desktop with Ethernet NIC.

Desktop with Ethernet NIC.

Switch

Ethernet switch (shown) Connects multiple devices to central point Can be used to build small

peer-to-peer network Communicates on OSI

Layer 2 Usually contains software to build routing

table Directs traffic on network to proper hosts –

doesn’t broadcast traffic to all devices like a hub

How it works - Switch

Desktop with Ethernet NIC.

Desktop with Ethernet NIC.

Ethernet switch8-port Ethernet switch. Connect up to 8 devices on a peer-to-peer network

Laptop with Ethernet interface.

Desktop with Ethernet NIC.

Desktop with Ethernet NIC.

Router

Router (wireless router shown) Acts as a connector between

two different networks Directs traffic from nodes on

one network to the correctnode on the second network

Communicates on OSI Layer 3 Directs traffic on network to proper hosts –

uses IP addresses to route packets

How it works - Router

Laptop with WiFi network adapter

Desktop with Ethernet NIC.

Wireless Router5-port Ethernet router plus Wireless router. Connect up to 5 wired devices plus up more than 200 wireless devices

Desktop with Ethernet NIC.

Desktop with Ethernet NIC.

XBOX 360 with WiFi network adapter.

From Internet (through

ISP)

Bridge

Networking Bridge Acts as a connector between two different network

segments Builds forwarding database

containing list of nodes on each segment

Communicates on OSI Layer 2 Uses hardware-based MAC addresses to direct

traffic Filters network traffic (frames)

Forwards to different network segment when destination address is not on local segment

Drops frames if destination address is on same segment as source

How it works - Bridge

Network Segment 1

Node A

Node B

Node C

Node D

Node E

Node F

Network Segment 2

Ethernet BridgeConnects Network Segment 1 to Network Segment 2. Let’s assume, on a newly implemented network, Node A sends a packet to Node E. First, the frame containing the packet would travel to the bridge. A record for Node A address would be added to the bridge’s address table. Then, the frame would be broadcast to Nodes D, E and F. Node D and F would ignore the frame, while E would respond back to the bridge. The address for Node E is recorded, and then Nodes A and E may communicate through the bridge, across their different network segments.

Gateway

Gateway – node at the edge of a network Serves as a point of entry from one

network to another Capble of joining two networks built

on different protocols Commonly combined with firewalls

due to their position at the edge of a given network

Can communicate on any OSI layer Can be implemented either by hardware or

software Routers are a special type of gateway PCs can be configured to be a gateway

How it works - Gateway

Home Network

Node A

Node B

Node C

Wireless Router

-- OR --

From Internet (through

ISP)

GatewayServes as a point of entry from one network to another. In this case, the home network is connected to the Internet through either a wireless router or another PC which is configured as a router.

A gateway can thus be implemented either by hardware (with the router) or software (with the specially configured PC)

Desktop with two Ethernet NICs.One NIC is connected to internal network, and other is connected to external network.

Firewall

Firewall (hardware firewall shown) Device which permits or denies network connections

based on rules (i.e. restricted portsor source addresses

Can be either hardware orsoftware based

Provides security to nodes behind it Many routers contain basic firewall functionality

Hardware Firewalls Work on first 4 layers of OSI model

Software Firewalls Most operating systems contain basic firewall

functionality Operates at Application Layer of OSI model

How it works - Firewall

Home Network

Node A

Node B

Node C

Hardware Firewall

From Internet (through

ISP)

FirewallFilters network traffic coming in to the network from external source. Hardware firewalls operate on the first 4 layers OSI layers, blocking content based on MAC addresses or IP addresses, or based on type of content and destination port on protected computers.

Can also be implemented on application layer of OSI by software-based firewall. Software firewalls block traffic based on IP address or MAC address or content.

Wireless Access Point

Wireless Access Point (wireless router shown) Device which broadcasts traffic from one

network to another or between connected nodes on the same network

Utilizes wireless signal to configure the network connections, making networkseasy to set up and maintain

Provides routing functionality May also contain firewall functionality to

control flow of traffic and content throughoutand between local networks and WANs.

Works on Layer 3 of OSI model

How it works – Wireless Access Point

From Internet (through

ISP)

Wireless Access PointConnects multiple devices to a single connection to another network.

Commonly used in homes to set up wireless networks servicing multiple consumer devices.

Also used in public places providing temporary internet access to a variable number of customers.

Wireless

Access

Point

Belkin RouterWireless G+ MIMO

• Easy setup through web interface

• Configure router to handle DHCP connections

• Set WPA encryption• Can configure to restrict

access to specific MAC addresses

• Built-in firewall• Port forwarding and other

virtual server functions• Can manually configure

DNS settings

Laptop PCs with WiFi NICs.

Range of Prices for Hardware

Device Price Range

Hub (gigabit Ethernet, 8 port) $80 - $160

Switch (gigabit Ethernet, 24 port)

$440 - $500

Router $200 - $800

Bridge $80 - $200

Gateway $150 - 300

Firewall $129 - $300

Wireless AP $100 - $800

These prices represent products with mid-range capabilities. Since there is such a vast number of products on the market, with a wide range of capabilities, the products priced here would be suitable for medium size offices or small school environments.

Networking components – a sample setup using all components we’ve discussed

From Internet (through

ISP)

GatewayMotorola cable modem serves as a gateway between home sample network and the Internet

Network Attached Storage (NAS) DevicesContains shared documents and media content. Router/

Wireless AP/FirewallContains software-based firewall. We will configure this to protect the wireless network

FirewallHardware firewall will be used to secure traffic to wired network

ServerConfigured to manage resources on wired network

Switch

BridgeConnecting wireless and wired networks

Workstation A

Workstation B

HubNAS

drives share

connection to

switch

Network connected to Internet through gateway. Wireless network connects to Wireless AP/Router. Wired network connects to switch, then to firewall, then to gateway. NAS devices connect to hub and then to switch for access on wired network. Bridge connects wired and wireless networks.