A washer used to obtain a 'finished' look. Usually used with oval head screws. Split Lock. The most common style of washer used to prevent nuts and bolts from backing out. External Tooth Lock. A washer with external 'teeth' Used to prevent nuts and bolts from backing out. Internal Tooth Lock. A washer with internal 'teeth' Used to prevent nuts and bolts from backing out.
(March 2009). A metropolitan area network (MAN) is a computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.istributed-queue dual-bus (DQDB) refers to the metropolitan area network standard for data communication specified in the IEEE 802.6 standard. With DQDB, networks can extend up to 20 miles (30 km) long and operate at speeds of 34â155 Mbit/s.
Tweet. A WAN (Wide Area Network) is a computer network that covers a broad area and its communication links can traverse across metropolitan, regional or national boundaries. Protocols such as Packet over SONET/SDH, MPLS, ATM and Frame relays are often used for the delivery of circuits that are used in WANs. Multiprotocol Label Switching (MPLS) is a mechanism in high-performance telecommunications networks which directs and carries data from one network node to the next.