Chapter 3 - Network hardware devices Flashcards
Repeater
- A network device that generates a weak signal to its original strength
- To boost signals in coaxial cable, twisted pair and fiber optic cable
- OSI layer 1 physical
Hub
• A hub is a central connection where all network cables are connected
• Packet transmitted from one node to all nodes connected to the hub
• OSI layer 1 physical
• Do not interpret data
- Unaware of source and destination addresses
• Reduces excessive data transmission
Switch
• filters the network traffic
• create a sub network from a large network
• Provide/extend network capacity with the ability to increase the network bandwidth
• Switch also can decide how to filter and forward LAN traffic
• Uses special hardware components:
- Can read multiple ports simultaneously
- Establish multiple and simultaneous forwarding paths
• Uses MAC address/IP address
• Quicker than routers for internal communication
• OSI layer 2 & 3 data link, Network layer.
Firewall
- It is a network device that is used to help keep a network secure
- To control the incoming and outgoing by analysing the data packets and determining whether it should be allowed the packets through to the network.
- OSI :Data link layer, network layer, transport layer and application layer
Attenuation
Loss of signal strength
Advantages of Repeater
- Extend the distance of a network
* Does not increase the network traffic
Disadvantages of Repeater
- A network can only include limited number of repeaters
* Create network collision
Advantages of Hub
- Cheap, simple and readily available
- Easy to deploy and maintain
- Can connect media operating at different speeds
Disadvantages of Hub
• Introduces network collisions • Cannot filter information passing through them - All packets transmit to all segments • Wastes bandwidth • Creates lots of unnecessary traffic
Stand Alone Hub
• Simple type - A number of port configurations • Include: - Uplink port • Designed for: - Smaller LANs
Stackable Hubs
- Can be physically connected and stacked (rack system)
- Allows data signals to pass from hub to hub
- Built-in management capabilities
- Flexible solution for LANs that are expected to grow in size
Network Collision
• A section of a network where data packets collide with one another
- When being sent on a shared a medium
Bridges
• physical + data link layer
• LAN devices that connects two or more LAN segments
- Filtering network data transmissions
• Used to divide the network into smaller segments
- Reduces the chance of collisions
• Can improve overall LAN performance
- Controlling the network traffic
• Can be configured in redundant pairs
- For fault tolerance
• Only one bridge in the pair can be active
- Causes loop otherwise
Advantages of Bridge
• Limits network collision
• Extend the network distances
- By boosting the signal
• Can filter packets
Disadvantages of Bridge
- More expensive than a repeater
- More difficult to configure
- Creates a more complex network design
Advantages of Switches
- Limit network collision
- Can segment the network into multiple segments
- Support intelligent network capabilities
- Smarter than a Hub
- Less latency
Disadvantages of Switches
- More expensive
* Complex and difficult to configure
Switch Implementation
• Encompass: - Department-level - Workgroup LAN ~ Connectivity • Distribution layer switches: - Interconnect access layer switches • Core layer switches: - Interconnect distribution layer switches - Provide access to centralized network services
VLAN Switches
• Virtual networks/Virtual LANs: - When switches form logical networks from a larger network • Permits the packets to only flow between designated nodes • Filter: - Network-to-network broadcast traffic - Collision traffic from other VLANs • Provides flexibility • Available as: - Layer 1 - Layer 2 - Layer 3 - Layer 4 ~ VLAN switches
Routers
• A network device that navigate packets access large Network such as the internet using the most efficient route
• Broadcast WiFi signals
• Routers route the data packets across WAN
• OSI layer 3 network
• Connect networks to one another:
- Direct packets to their destinations based on IP addresses
• Establish a path (for network communication)
• Performing network address translation
• Improve network security
- Filtering broadcasts
- Providing access list filtering
• Provide scalability
- Reducing the performance penalty associated with broadcast traffic
• Can be installed at the edge or border of a LAN
• Maintains a routing table
• Hop:
- Connection between routers (between source and destination)
• Broadcasting a WIFI signal (access point)
• Assigning IP address to hosts using DHCP)
Advantages of Router
- Limits network collision
- Connect networks using different media
- Determine the best path to reach another network
Disadvantages of Router
- More expensive than a modem
* Difficult to configure
Gateways
• Hardware/Software/Combination of both:
- Provides:
~ Protocol translation
~ Connectivity between two systems
• Use different protocols to communicate
• Above OSI layer 3
• Examples:
- Connecting a LAN to a mainframe computer
- Connecting a LAN e-mail system to external e-mail providers
- Connecting a non IP network to the Internet
Network Interface card
• Also known as:
- Network host adapter
- Network expansion card
- Network adapter card
• Send and receive a digital signal
• Fits into one of the motherboard slots inside a PC:
- Provides a way for the PC to connect to the network media
• A driver must be installed
• Contains:
- Physical ID called MAC (Media Access Code) address
~ Six-byte hexadecimal number
Network Backbones
• Combination of:
- Hardware
- Media
- Protocols
- Architecture
~ Form the high-speed communications links between two networks
• Network backbone access layer:
- Distribution layer & core layer are combined
- When required for interconnectivity
• Backbone Fault Tolerance and Load Balancing
- Requires the implementation of:
~ Duplicate distribution layer switches
~ Duplicate core layer switches
~ Redundant cabling to establish extra paths
Fault Tolerance
• Provides the ability to continue transmitting data
- If a backbone device or data path fails
Load balancing
• Provides the ability to transmit data across multiple paths simultaneously to the same destination
Rack Mounted Backbone Hardware
• Provides a common location
• Chassis-based Backbone Hardware:
- Provides a metal frame with basic circuitry
- Devices:
~ Blades have different functions
- Provides a common power source and cooling capabilities
LAN PROTOCOLS
• Define ways in which data can be:
- Packaged
- Access a network medium
- Transported
- Reassembled at the destination
• Rules that specify how services and devices exchange information
- Communication Protocols
~ Allows us to send and receive information from remote data sources
~ Building blocks for information exchange
~ Example: Internet Protocol
Internet Protocol
• Provides an addressing scheme (unique identification)
- For networks and nodes
• Allows network devices to be located anywhere in the world (to exchange information)
IP Addressing
• Common implementation: - IPv4 ~ Comprised of a 32-bit binary address, divided into four 8-bit octets • Represented in: - Numeric dotted decimal form - Binary form • Uses subnet masking - Separates the network portion of the IP address from the node portion ~ 32-bit combination of binary digits • Similar to a street address
Internet Protocol : Class A
• Addresses range from 1 to 126 in the first octet
• Default subnet mask:
- 255.0.0.0.
• 1.0.0.1 to 126.255.255.254
• Used for large networks
• Supports 16 million hosts on each of 127 networks
Internet Protocol : Class B
• Addresses range from 128 to 191 in the first octet
• Default subnet mask:
- 255.255.0.0.
• 128.1.0.1 to 191.255.255.254
• Used for medium networks
• Supports 65000 hosts on each of 16000 networks
Internet Protocol : Class C
• Address range from 192 to 223 in the first octet
• Default subnet mask:
- 255.255.255.0.
• 192.0.1.1 to 223.255.254.254
• Used for home networks
• Supports 254 hosts on each of 2 million networks
Internet Protocol : Class D
- Used for multicasts
* Addresses range from 224 to 239 in the first octet
Internet Protocol : Class E
- Used in broadcast transmissions
* First octet ranges from 240 to 255
Manual IP Address Assignment
- Static IP address (fixed)
* Requires manual configuration with an IP address
Automatic IP Address Assignment
- Achieved with Dynamic Host Configuration Protocol (DHCP)
* Configuration takes place on a DHCP server
Loopback address
• Reserved IP address of the network interface card
• Used to test if:
- An IP address is configured for the NIC
- The network card is functioning normally
- Loop back address:
~ 127.0.01
