The alternative carrier market - hosted, IP-based services
Deployment notes
GroomerII can be used to gateway SS7 from a carrier switch onto an IP network running SIP and backhaul traffic to a remotely hosted, IP-based application platform. GroomerII also offers an added advantage, with some unique functionality.
Many alternative carriers are adopting a ‘cap and grow’ strategy, which means investment in existing circuit switched infrastructure is frozen and new CAPEX is focused on IP-based equipment purchases. New IP platforms overlay the existing architecture and will ultimately, over time, replace it.
In parallel with this approach, ILECs/CLECs in North America, for example, are subscribing to hosted, service delivery platforms, provided by a third party. This can be more cost-effective and, of course, shifts the cost from a CAPEX line to an OPEX line.
To achieve the service delivery, carriers need a cost-effective connection to the remote platform. The traditional method of doing this is to lease an ISDN line all the way back to the platform location. SS7 inter-machine trunks (IMTs) are less expensive than PRIs for this purpose, however, a gateway to IP at the remote end is still needed.
These approaches are undoubtedly expensive. An alternative is to use an SS7-to-SIP gateway. The CLEC effectively has SS7 capability ‘for free’ on their Class IV/V switch and if they connect via a gateway, SIP backhaul to the remote platform becomes an attractive option. Using SIP to the far end, over an IP network, is more cost-attractive.
The argument also holds true for communications equipment suppliers who provide service platforms to carriers and service providers. Suppliers such as these, systems integrators and solution providers, all have a need for SS7-to-SIP gateways in their portfolio – to satisfy the needs of their target customers.
In some territories, particularly in South America and the Pacific Rim, it is very likely that SS7 is all that would be offered by the local carrier. Fixed and mobile telcos have native SS7 capability as it forms the backbone of their networks, but in order to provide ISDN connection to a gateway (into an IP-based platform) they’d have to install an expensive upgrade (hardware and software) for their CO switches. As SS7 is readily available to them, SS7-to-SIP gateways are the obvious choice.
GroomerII, therefore, enables carriers to cost-effectively subscribe to hosted, IP-based services under a controlled investment strategy that involves migration to an all VoIP network. Crucially, however, this strategy can be realised at a pace to match their spending plans.
See figures 1 and 2 for examples of alternative deployments.
Figure 1 – Expensive, leased line connection to application platform
Figure 2 – Cost-effective, SS7-to-SIP gateway to hosted, IP-based service platform
GroomerII’s added advantage
Figure 2 also illustrates unique functionality provided by GroomerII. As shown, a call to a fixed line subscriber is unanswered, and the call is intended to be forwarded to voicemail (call forward no answer).
At point 1 (as labelled in the diagram), GroomerII inserts the original called number, which it extracts from the incoming SS7 IAM, into the outgoing SIP INVITE, within a diversion header. At point 2, this essential information is presented to the IP platform within the inbound SIP message.
Critically, the application needs this information to be able to correctly route the call. Point 3 illustrates the voice message having been successfully routed to the correct IP mailbox address.
