Distributed Queue Dual Bus (DQDB), defined by IEEE 802.6, is a standard primarily intended for which type of network?

Difficulty: Easy

LAN
MAN
WAN
Wireless LAN
LAN and MAN

Correct Answer: MAN

Explanation:

Introduction / Context:
DQDB (Distributed Queue Dual Bus) was developed to support metropolitan-scale networks with shared medium access and quality of service considerations across city-wide areas.

Given Data / Assumptions:

Standard: IEEE 802.6.
Topology: dual unidirectional buses.
Scope: metropolitan coverage.

Concept / Approach:
MANs bridge the gap between LAN (local building/campus) and WAN (long haul). DQDB’s dual-bus design and distributed queueing aim to coordinate access across multiple nodes over metropolitan distances.

Step-by-Step Solution:

1) Recognize IEEE 802 family mappings: 802.3 (LAN Ethernet), 802.11 (WLAN), 802.6 (MAN DQDB).2) Match DQDB to MAN characteristics (scale, access method).3) Select the MAN option accordingly.

Verification / Alternative check:
Historical references consistently list DQDB under metropolitan technologies, not LAN/WAN categories.

Why Other Options Are Wrong:

LAN and Wireless LAN target smaller geographic areas.WAN spans much larger, carrier-grade distances and technologies (e.g., MPLS, SDH), distinct from DQDB's MAN scope.“LAN and MAN” conflates scopes; DQDB is specifically a MAN standard.

Common Pitfalls:
Assuming any IEEE 802 technology is LAN-only; overlooking the MAN category.

Distributed Queue Dual Bus (DQDB), defined by IEEE 802.6, is a standard primarily intended for which type of network?

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