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
