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Reply To: CAMEL Phase-1,2,3,4 – ?????

Wallis Dudhnath

CAMEL – Customised Application Enhanced Logic – has
an association with IN – Intelligent Networks.

As IN Services expanded with GSM there was an issue with Roaming.
The use-cases were not standardised and this meant IN Services in the
HPLMN could not be used in the VPLMN. The answer was to use the existing IN
protocols: CS-1 (or variants) and to update it so that HPLMN can be used in the
VLPMN. This led to CAMEL which is basically a Network feature based on CAP V2 (or later versions)
and MAP V3 (or 4, etc..). CAMEL also helps with interoperability. CSPs can interwork gsmSSF, gsmSCF,
gprsSSF, gsmSRF, IP, etc.. from different vendors. Traditional “lock-in” from IN systems is now

At the time of writing CAP V2 is well proven for Roaming PrePaid Voice (telephony) calls.
Data Traffic is now charged using Diameter (DCCA).

CAMEL as a standard that is no longer evolving. The last set of standards was done with
CAMEL Phase4 via 3GPP.


CAP V1: Proof of concept. Several messages were supported
CAP V2: Similar message set that INAP / CS-2 supports. Geared up for Mobility and allows calls to be “teared down” based
on rules set with the PrePaid application
CAP V3: MO-SMS and Volume Based GPRS Charging
CAP V4: Call Party Handling (add / remove callers – move_Legs)
Network-initiated call establishment (InitiateCallAttempt), Interaction with basic optimal routing, Alerting detection point
Mid-call detection point, Change of position detection point, Flexible warning tone and Tone injection and
Enhancement to call forwarding notification

With the rapid growth of the Internet, Web2.0/3.0, SIP, Diameter, etc.. it has reduced the role of CAMEL Phase 4 as a
Multimedia Standard for VHE / OSA (Virtual Home Environment).