In the GPON network, which one of the following descriptions is correct?

Question

Options

• ADifferent T-CONTs are identified by Port-ID
• BDifferent GEM-PORTs are identified by Alloc-ID
• CDifferent ONUs are identified by Port-ID
• DDifferent ONUs are identified by ONU ID

• A
  9% (2)
• B
  4% (1)
• C
  9% (2)
• D
  78% (18)

Explanation

In GPON, each ONU on a PON segment is assigned a unique ONU ID (ranging from 0–253) by the OLT during the activation/ranging process, making option D correct. Option A is wrong because T-CONTs (Transmission Containers) are identified by Alloc-ID, not Port-ID - Alloc-IDs are what the OLT uses to grant upstream bandwidth slots to each T-CONT. Option B reverses the mapping: GEM-PORTs are identified by Port-ID (also called GEM Port ID), not Alloc-ID - Port-IDs label the logical traffic-carrying channels within the GEM framing layer. Option C incorrectly assigns Port-ID to ONUs; Port-ID belongs to GEM ports, not to the ONU device itself.

Memory tip: Match the name to the identifier - ONU gets an ONU ID, GEM Port gets a Port-ID, and T-CONT gets an Alloc-ID (think "Alloc" = allocation of upstream bandwidth).

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