Passive optical network (PON) is a single-fiber bidirectional optical access network with what structure?

Question

Options

• AChain type
• BRing type
• CTree type
• DMesh type

• A
  16% (8)
• B
  4% (2)
• C
  73% (37)
• D
  8% (4)

Explanation

A PON uses a tree (branching) structure because a single fiber from the central office connects to a passive optical splitter, which then fans out to multiple end users - visually and functionally resembling a tree trunk splitting into branches. This architecture allows one upstream fiber to serve many subscribers without active switching equipment in the field.

• Chain (A) is wrong because chain/bus topologies connect nodes in series along a single line, meaning all traffic must pass through intermediate nodes - PON splitters don't work this way.
• Ring (B) is wrong because ring topologies loop back to the origin for redundancy; PON has no such loop - signals flow one-way outward from the splitter.
• Mesh (D) is wrong because mesh topologies have multiple redundant paths between nodes, requiring active switching - PON is passive (no active electronics in the distribution network) and doesn't support this complexity.

Memory tip: Think "PON = Point-to-multiPoint = Tree." The optical splitter is the "trunk," and each subscriber line is a "branch" - a passive tree that needs no power in the field.

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