Network
Network: Interconnected Things
Types of Networks
LAN: Local Area Network
- Small groups of systems (tens to hundreds)
- 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.
- I:
- A: