Technical & Pricing Information

HSL provide messaging services over the most technically capable and resilient SMS delivery infrastructure in the world. HSL's advantage over its competitors comes from their focus on providing a high quality service that can be depended on by customers, and their focus on the use of SS7 - the telecommunications protocol that provide the most reliable means of SMS delivery.

HSL's SMS Message Delivery Network

In order to reliably deliver SMS messages, Short Message Service Centres (SMSCs) are used to convey messages between mobile users, and between mobile users and applications. HSL utilise a large number of highly reliable SMSC platforms from established mobile operators and also HSL's own carrier grade SS7 SMSCs, located in the UK, as part of the delivery infrastructure for inbound and outbound messaging. Key elements of HSL's infrastructure also include HSL's own SS7 STPs (Signalling Transfer Points), multiple data centre sites (four of which are located in the UK) and high availability links between sites, SMSCs and mobile networks. This infrastructure provides to customers a coverage of over 640 mobile networks worldwide.

Part of HSL's focus on quality and reliability of service includes an ongoing project for interconnecting at the SS7 level with mobile networks in the UK and other countries of the European Union. This project involves HSL, as an operator of their own SS7 network, interconnecting with mobile networks for the sending and receiving of SMS. To date this project has delivered SS7 interconnects to O2, Vodafone, Orange, H3G and T-Mobile in the UK, and over 280 other mobile networks, further strengthening HSL's position as a supplier to customers including wireless service providers and mobile network operators.

HSL's SMSCs (Short Message Service Centres)

HSL's own SMSCs, compliment SMSC connections with established mobile operators and provide exciting service opportunities for HSL and their customers. As with all core messaging software systems operated by HSL, the SMSCs are the result of internal software development by HSL's software engineering team, now part of HSL Mobile Networks (http://www.haysystems.com/mobile-networks/), with development having commenced in 2000. The currently deployed SMSCs located on HSL's SS7 network are connected to mobile networks in the UK and other networks worldwide via the global SS7 network. HSL's SMSC went fully live in October 2004.

HSL's SMSCs comprise integrated HLR (Home Location Register) and MSC (Mobile Switching Centre) capability and have a high degree of functionality for inbound and outbound (MO/MT) SMS. SMSC platforms communicate directly with the SS7 network to provide low latency, highly reliable means of SMS delivery.

Data Centres / POPs

The services operated by HSL are provided using HSL's own server infrastructure located at six geographically separate and independent sites located in Europe. Two of these points of presence (POPs) allow customer access to HSL's network infrastructure. The infrastructure is designed to allow for a failure of a site and for service availability to be unaffected.

Physical Security: Sites operate a strict security policy where site monitoring and access controls are in place. Access to service infrastructure and controls is restricted to qualified and authorised engineers.

Power Supplies: The Edinburgh Gyle (UK) site has dual independent 11kV feeds, backed up by dual battery string Chloride UPS systems and Cummins 1.4 Megawatt and 0.8 Megawatt diesel generator sets which are tested on a monthly basis. The Livingston (UK) site utilises an array of UPS systems and generator backup. All site power systems are engineered to ensure service availability through the longest power outages.

Environmental Control: Fully redundant air handling units provide a constant fresh airflow. The air handling units vary the air temperature in order to match power dissipation.

Traffic Handling: In normal operation all sites dynamically share SMSC connections and load balance customer traffic over all suitable service nodes and SMSCs. In the event of an interruption to connectivity between sites, each site automatically operates independently and handles traffic without any impact to customer service.

Connectivity: Each site utilises different ISPs for providing access to the Internet. Our Livingston (UK) site is served by a protected connection to the serving ISP. Our Edinburgh Gyle (UK) site employs BGP and multiple ISPs to provide a highly resilient Internet connection. The integrity of our own network is further protected by the Livingston and Gyle (UK) sites being directly connected via a 100Mb dedicated connection in addition to a backup connection via the Internet.