Customized Applications for Mobile Network Enhanced Logic (CAMEL):
CAMEL was developed as a standard for mobile intelligence across different vendor equipments for GSM network. What this means is that the end user should be able to roam between different networks (maybe in different countries) and be reachable at the same number and should receive only one bill from the original service provider (Home Operator).
The CAMEL is a network feature and not a supplementary service. It is a tool for the network operator to provide the subscribers with the operator specific services even when roaming in the another network.
The CAMEL protocol supports these mobile-calling operator-provided services: originating and terminating phone calls, charging features, prepaid minute usage, and personal subscriber options such as voice-mail prompts, recorded messages and ringtones.
The CAMEL protocol ensures that if the caller accesses another mobile operator's towers or equipment, his services remain the same as if the caller accessed his own operator's towers or equipment. And, the minutes used and the services rendered will only be billed once by the caller's own operator. This network system applies to GSM operators all over the globe.
The CAMEL protocol does not apply to Emergency Setup. If a mobile user dials 911 while roaming, the CAMEL protocol is disabled. This ensures that the caller is routed to the local emergency response system and not to services in his home calling area.
Applicability of CAMEL procedures:
1. The CAMEL feature is applicable to Mobile Originated and Mobile Terminated Call Related Activities.
2. CAMEL procedures are applicable to all circuit switched basic services without distinction (except Emergency calls).
3. The CAMEL feature is applicable to Supplementary Services Invocation
4. CAMEL procedures are applicable to GPRS sessions and PDP contexts
5. CAMEL procedures are applicable to Mobile Originating/Terminating short message service through both circuit switched and packet switched serving network entities
6. CAMEL procedures are applicable to IP multimedia services (except Emergency calls) to support legacy services
7. CAMEL shall support IPMM sessions which are based on the same charging paradigm as CS/PS calls. 8. This applies most probably to VoIP and Video over IP.
9. CAMEL procedures are applicable to IP multimedia sessions addressed by either E.164 numbers or SIP URLs.
Example of CAMEL procedure:
Take a simple scenario of a voice call being made. When a subscriber starts to make a call, this request is received by the network's Mobile Switching Centre (MSC). The MSC then sends a message that 'queries' the SCP's database. Note that the essential element of any CAMEL solution is a Service Control Point (SCP). This unit effectively hosts a database which holds the instructions needed for an intelligent application.
The SCP processes that query, comes up with an appropriate response and then sends a message back to the MSC telling what action it should take with the subscriber’s request for a specific service. The call is then connected in the most appropriate manner, a process which is transparent to the customer. A very good example of this process in action is short code dialling over a VPN (Virtual Private Network) where the user calls a colleague’s internal extension telephone number but is, in fact, routed to that person’s mobile phone which is roaming abroad.
The main addition in CAMEL phase 2 which phase 1 omitted is support for a Specialised Resource Function (SRF) a component most often found in Voice Response Units (VRUs). For example, when an account balance reaches zero for a pre-paid customer under phase 1, the customer will simply be cut off. With phase 2 thanks to support for SRF, the customer will hear automatically generated messages from the Voice Response Unit warning that the balance is dangerously low before a call and even during the call. Naturally this leads to greater customer satisfaction.