5.1.1 LANs and WANs
Network Types Overview
| Type | Full Name | Scope | Key Details |
|---|---|---|---|
| LAN | Local Area Network | Single site; nodes within ~1-2 km | Connected by cabling and switches; owned/managed by the organization. Based on IEEE 802.3 (Ethernet). |
| WLAN | Wireless LAN | Same as LAN | Uses radios/antennas. Based on IEEE 802.11 (Wi-Fi). Complements wired Ethernet on the same network. |
| WAN | Wide Area Network | Multiple geographic locations | Spans cities, countries, or globally (e.g. the Internet). Uses cabling/equipment leased from an ISP to link LAN sites. |
| MAN | Metropolitan Area Network | City or municipality | Larger than a LAN, smaller than a WAN. Multiple connected networks within the same metro area. |
| PAN | Personal Area Network | A few meters | Connects personal devices wirelessly (e.g. Bluetooth earbuds, smartwatches, phones). Growing with IoT. |
| SAN | Storage Area Network | Dedicated storage network | Dedicated network for storage devices; block-level access; consolidated storage; high-speed (Fibre Channel or iSCSI). |
Ethernet Standards (IEEE 802.3)
Ethernet standards follow the naming format xBASE-Y, where x = nominal data rate and Y = cable type.
| Standard | Speed | Cable | Notes |
|---|---|---|---|
| 100BASE-T | 100 Mbps | Copper twisted pair | Fast Ethernet |
| 1000BASE-T | 1 Gbps | Copper twisted pair | Gigabit Ethernet; mainstream LAN standard |
| 10GBASE-T | 10 Gbps | Copper twisted pair | High-speed; used in backbones and high-demand links |
Most LANs use copper cabling (electrical signaling). Fiber optic cabling (light pulses) is used for LAN backbones or special high-speed segments.
SAN Key Characteristics
- Dedicated network: independent of the LAN to prevent storage traffic from interfering with normal network operations.
- Block-level access: data transferred as raw blocks with no file system structure, enabling efficient transfers and flexible storage management.
- Consolidated storage: multiple storage types (RAID arrays, tape drives) joined together as centralized resources for servers.
- High speed: typically uses Fibre Channel or iSCSI connections.
Key Terms
- IEEE 802.3
- The set of standards governing Ethernet on wired LANs, using the xBASE-Y naming format.
- IEEE 802.11 (Wi-Fi)
- The set of standards governing wireless LAN communications.
- ISP (Internet Service Provider)
- A company that provides access to the Internet or leases WAN cabling/equipment to connect enterprise LAN sites.
- IoT (Internet of Things)
- The growing ecosystem of everyday objects with embedded digital/network functionality, driving expanded PAN use.
- Fibre Channel
- A high-speed networking technology commonly used in SANs for connecting servers to storage devices.
- iSCSI (Internet Small Computer System Interface)
- A protocol that enables block-level storage access over standard IP networks, used as a lower-cost alternative to Fibre Channel in SANs.