Usually uses private IP addresses and devices can directly communicate with each other.
e.g., home, office space
WAN: Wide Area Network
Generally covers larges geographic area.
Connects different LANs together and typically uses public IP addresses for routing.
Contains many LANs (hundreds to thousands)
e.g., the entire campus network
Internet:
Refers to large numbers of small networks combined together to form a larger one.
Not owned by a single organization.
Most commonly used to refer to global World Wide Web, email, etc.
Example: A home network
A Wireless Access Point (WAP) may be connected to a cable modem, which is then connected to your ISP.
Computers, smartphones, TVs, et cetera all go through a WAP.
Example: A Brief and Not That Great Summary of the Internet
Made by DARPA in the 1960s.
Used for email/bulletin.
Collection of universities in California and Utah.
Expanded to US and globally.
1990s: Web browser and server invented (World Wide Web)
Now we have streaming and IoT.
Network Components
Network Interface Card (NIC): Parts of computers and other connected systems which allow digital communications.
There are different NICs for wired and wireless communication.
Each NIC has a unique MAC address that identifies it on the local network.
Switch: Connects multiple network devices inside a single LAN.
e.g., one switch per household may connect to one router
Router: Routes traffic between LANs and WANs
Large core routers serve as the backbone of the internet.
Generally used for WANs.
Switch v. Router: Switches has lots of points, routers have less.
Example: A WAN
Multiple houses may have switches that all connect to a neighborhood switch, which then connects to a router, which may connect to routers of tons of other providers (AT&T, Verizon, etc.)
Wired v.s. Wireless
All the below is in general.
Wired
Wireless
Faster
Slower
Less bandwidth
More bandwidth
More Reliable
Less Reliable
Costlier
Cheaper
Harder to Eavesdrop / Interfere
Easier to Eavesdrop / Interfere
Harder Maintenance / Install
Easier Maintenance / Install
Harder to Join (Less Flexible)
Easier to Join (More Flexible)
Remember: All wireless networks lead to a wired network eventually!
Network Security Devices
Firewall: Blocks network traffic based IP, ports, protocols, and rules.
Network-Based: Blocks traffic coming into the network.
Host-Based: Blocks traffic on the endpoint computer.
Intrusion Detection System (IDS): Monitors traffic and alerts security of possible intrusion attempts.
Rule-Based: Detects previously-discovered threats for rules which have been created.
Anomaly-Based: Detects new threats based on behavior.
(Also can be network or host-based.)
Defense in Depth: Many organization use network and host-based security, for additional layers of security.
Firewall v.s. IDS:
Firewalls sit “in line” to block traffic.
IDSs (usually) only observe traffic.
Example:
Q: What are the components, network setup, and ??? for a home security camera?
A:
Components:
Camera
Motion Detector
Connection to servers
Network Setup:
WAP -> Modem -> ISP -> Server
Server -> Cell Tower -> Phone (strong generalization)
Information:
C: Video footage should be encrypted and only accessible by you.