A transit authority wants the DHCP server to assign addresses based on which switch and port a rider Wi-Fi or kiosk attaches to. Which relay feature supplies that location context?
Select an answer to reveal the explanation.
Short Explanation
Option 82 is a sticky note the relay slaps on the DHCP request—‘this came from switch X port Y’—so the server can policy-pick the right pool without guessing.
Full Explanation
DHCP option 82 (Relay Agent Information) lets a relay agent insert circuit-id and remote-id information identifying the attachment point—switch and port context—for a transit authority’s rider Wi-Fi or kiosk. The DHCP server can policy-match that metadata to assign addresses based on location rather than guessing from client MAC alone.
Dynamic ARP Inspection without any DHCP snooping bindings validates ARP, not DHCP location-based assignment. PIM Accept-RP filters on the distribution layer constrain multicast RPs, not DHCP pools. ERSPAN of all DHCP Discover frames to a NetFlow collector may aid visibility but does not itself supply relay location options for server policy.
Exam caveat: option 82 = location context for DHCP policy; mirroring alone is not the assignment feature.
Operational check: enable option 82 on relays, confirm circuit/remote IDs reach the server, map pools to switch/port policies for kiosks, and test a move between ports yields the intended address policy. For civic operations, record the chosen control and the rejected alternatives in the change record so future on-call engineers understand which failure modes were avoided for citizen-facing services. Re-validate after the next platform or policy change.