2.2 - Network Devices Flashcards
Network Interface Card (NIC)
The fundamental network device • Every device on the network has a NIC • Computers, servers, printers, routers, switches, phones, tablets, cameras, etc. • Specific to the network type • Ethernet, WAN, wireless, etc. • Often built-in to the motherboard • Or added as an expansion card • Many options • Single port, multi-port, copper, fiber
Repeater
Receive signal, regenerate, resend • No forwarding decisions to make • Common use • Boost copper or fiber connections • Convert one network media to another • Extend wireless network reach
Hub
“Multi-port repeater”
• Traffic going in one port is repeated to every other port
• Everything is half-duplex
• Becomes less efficient as network speeds increase
• 10 megabit / 100 megabit
• Difficult to find today
Bridge
Imagine a switch with two to four ports
• Makes forwarding decisions in software
• Connects different physical networks
• Can connect different topologies
• Gets around physical network size limitations /
collisions
• Distributes traffic based on MAC address
• A modern bridge is a wireless access point
• Bridges wired Ethernet to wireless
Switches
Bridging done in hardware
• Application-specific integrated circuit (ASIC)
• Forwards traffic based on data link address
• Many ports and features
• The core of an enterprise network
• May provide Power over Ethernet (PoE)
• Multilayer switch - Includes routing functionality
Unmanaged switches
Very few configuration options • Plug and play • Fixed configuration • No VLANs • Very little integration with other devices • No management protocols • Low price point • Simple is less expensive
Managed switches
- VLAN support
- Interconnect with other switches via 802.1Q
- Traffic prioritization
- Voice traffic gets a higher priority
- Redundancy support
- Spanning Tree Protocol (STP)
- External management
- Simple Network Management Protocol (SNMP)
- Port mirroring
- Capture packets
Routers
• Routes traffic between IP subnets
• Makes forwarding decisions based on IP address
• Routers inside of switches sometimes called
“layer 3 switches”
• Often connects diverse network types
• LAN, WAN, copper, fiber
Wireless access point (WAP)
• Not a wireless router • A wireless router is a router and a WAP in a single device • WAP is a bridge • Extends the wired network onto the wireless network • Makes forwarding decisions based on MAC address
Wireless LAN controllers
• Centralized management of WAPs • A single “pane of glass” • Management functions • Deploy new access points • Performance and security monitoring • Configure and deploy changes to all sites • Report on access point use • Usually a proprietary system • The wireless controller is paired with the access points • Can also be cloud-based • Manage the console from anywhere
Firewalls
- Filters traffic by port number
- OSI layer 4 (TCP/UDP)
- Some firewalls can filter through OSI layer 7
- Can encrypt traffic into/out of the network
- Protect your traffic between sites
- Can proxy traffic
- A common security technique
- Most firewalls can be layer 3 devices (routers)
- Usually sits on the ingress/egress of the network
Cable modem
- Broadband
- Transmission across multiple frequencies
- Different traffic types
- Data on the “cable” network
- DOCSIS (Data Over Cable Service Interface Specification)
- High-speed networking
- 4 Mbits/s through 250 Mbits/s are common
- Gigabit speeds are possible
- Multiple services
- Data, voice
DSL modem
• ADSL (Asymmetric Digital Subscriber Line)
• Uses telephone lines
• Download speed is faster than the upload speed
(asymmetric)
• ~10,000 foot limitation from the central office (CO)
• 52 Mbit/s downstream / 16 Mbit/s upstream
are common
• Faster speeds may be possible if closer to the CO
Patch panels
- Combination of punch-down blocks and RJ-45 connectors
- Runs from desks are made once
- Permanently punched down to patch panel
- Patch panel to switch can be easily changed
- No special tools
- Use existing cables
Power over Ethernet
- Power provided on an Ethernet cable
- One wire for both network and electricity
- Phones, cameras, wireless access points
- Useful in difficult-to-power areas
- Power provided at the switch
- Built-in power - Endspans
- In-line power injector - Midspans
