Plain-language definition
The question an SMSC asks the HLR: where is this subscriber right now?
Technical definition
MAP SendRoutingInfoForSM returns the IMSI and the serving MSC/SGSN (or IP-SM-GW) address for MT delivery; home routing answers it with the home SMSC or firewall address instead.
Why it matters
SRI-SM results are used for routing, MNP resolution and, in firewalls, to detect home-routing bypass and mismatched delivery paths.
Last reviewed 2026-09-12 by the Guardivia QoS Engineering Team. Product facts on this page describe current capabilities; items marked “where supported”, “optional”, “integration” or “consultancy” are confirmed per deployment.