Domain 2.1 Flashcards
Describe a hub
“mulit-port repeater”
Everything is half duplex - This becomes an issue at scale.
10/100 Mbit
Describe a bridge
Layer 2
Primarily concerned with connecting different physical networks together.
Basic network device that makes forwarding decisions based on MAC addresses in software.
Most bridges today are used as access points to convert wireless signals into ethernet frames.
Describe a switch
Bridging performed in hardware using ASIC (Application-Specific Integrated Circuit)
Describe an access point
A bridge that extends the wired network onto the wireless network.
layer 2 device.
Describe a cable Modem
Broadband
- Transmits different frequency signals (with different traffic types) over a single transmission medium
Relies on DOCSIS
(data over cable service interface specification)
High speed networking from 4mbits - 250mbits
Gigabit is possible.
data, voice, and video are all carried over this cable
Describe a DSL Modem
ADSL - Asymetric DSL
Downloads are faster than uploads
~10,000 foot distance limatation from the CO (Central Office)
-52Mbit Down -16Mbit up
Describe a Repeater
Device that receives a signal, regenerates it and resends it.
- no forwarding decisions are made
Commonly used to boost copper or fiber connections.
Can be used to convert one network media to another.
Can also be used to extend wireless signals (think of HAM Radio)
Describe the process of converting media
OSI- Layer 1 signal conversion.
- Can be used to extend a copper wire over a long distance, convert it to fiber, and then back to copper for connection with RJ-45.
useful for when switches only have Rj-45, but you want to use fiber between switches
Almost always require power, especially when converting between fiber to copper.
Describe a Layer 3 switch
A layer 2 switch that makes frame forwarding decisions based on MAC addresses, but also has Layer 3 capabilities such as the ability to route packets.
What is a wireless LAN Controller
WLAN Controllers allow for the centralized management of Access points.
-Using controller you can deploy new access points
-Configure and deploy changes to APs that are offsite
-Performance and security monitoring.
-Report on AP usage.
-Usually a proprietary system, where APs will be same make as the controller.
What are some benefits of using load balancers?
-Distribute the load
Multiple servers servicing many users
-Large scale implementations
Web and Database server farms
-Fault tolerance
Server outages do not affect overall availability, and are easier to recover from.
Describe load balancers and the benefit of TCP offload
Configurable load - manage how load is balanced across servers.
TCP Offload -
Reduce the overhead associated with TCP connections as the load balancer performs the TCP handshake and simply passes data back to server
Describe SSL offload
When a client connects to a Load Balancer, the balancer performs the break action and forwards the unencrypted data back to the servers.
Without this feature, the servers would shoulder the burden of encryption/decryption
Describe some other benefits of load balancers
They allow content caching which speeds up common and routine responses
They allow QOS and data prioritization
They allow content switching, which enables application-centric balancing.
Describe Proxies and their uses
They receive and forward request to the internet from clients on the internal network.
Useful for:
-Caching information
-Access Control
- URL filtering
-Content Scanning
