LANs (local area networks)
LANs (local area networks) are networks that connect computers and resources together in a building or buildings close together.
The components used by LANs can be divided into cabling standards, hardware and protocols.
Examples of cabling standards used on LANs are:
• Cat 3, 4 and 5 cables
• IBM Type 1¬9 cabling standards
• EIA568A and 568B
• Ethernet cabling standards: IEEE 802.3 (10Base5), IEEE 802.3a (10Base2), IEEE 802.3i (10BaseT)
• Unshielded Twisted Pair (UTP)
• Shielded Twisted Pair (STP)
• Connectors: RJ45, RJ11, Hermaphroditic connectors, RS¬232, DB¬25,
MANs (Metropolitan Area Networks)
Metropolitan Area Networks (MANs) are networks that connect LANs together within a city.
The main criteria for a MAN is that the connection between LANs is through a local exchange carrier (the local phone company).
The protocols that are used for MANs are quite different from LANs except for ATM which can be used for both under certain conditions.
Examples of MAN protocols are:
• RS¬232, V¬35
• X.25 (56kbps), PADs
• Frame Relay (up to 45 Mbps), FRADs
• Asynchronous Transfer Mode (ATM)
• ISDN (Integrated Services Digital Network) PRI and BRI
• Dedicated T¬1 lines (1.544 Mbps) and Fractional T¬1
• T¬3 (45 Mbps) and OC¬3 lines (155 Mbps)
• ADSL (Asymmetrical Digital Subscriber Line) ¬ up to 8 Mbps
• xDSL (many different types of Digital Subscriber Lines)
WANs (Wide Area Networks)
Wide Area Networks (WANs) connect LANs together between cities.
The main difference between a MAN and a WAN is that the WAN uses Long Distance Carriers.
Otherwise the same protocols and equipment are used as a MAN.