Mobile News

In the case of a campaign pushing a message out to a group of subscribers, the service centre interrogates the HLR database to retrieve routing information necessary to forward each SMS-MT message–one per subscriber–and then sends the message to the relevant MSC, transiting other networks if necessary. The MSC then sends the short message to the handset.

In the case of messages sent by subscribers-SMS-MO messages–to the SMS gateway, the mobile handset sends the short message to the MSC. Messages sent by cellco B subscribers will be routed to the appropriate MSC in the network of the SME’s service centre, transiting other networks if necessary via the inter-working function of the MSCs.

Figure draws a parallel between e-mail and SMS infrastructures. It shows how the HLR acts as a domain name service (DNS), which is used by Internet mail servers or relays to chop e-mails into packets that can in turn be handled by routers in the public Internet infrastructure. An MSC acts as a router, effectively routing information across the network.