ahmedabad the cg roadbased illegal international telephone exchange racket based on session initiation protocol sip a popular internet telephony protocol using cloudbased services is the firstofitskind in the country a team of ahmedabad crime branch and the department of telecom dot officials have now unearthed a racket that has serious security implications the kingpin of the racket identified only as sheriyar hails from dhaka in bangladesh cops said he facilitated the establishment of exchanges some of which routed a huge number of international calls from the residents of pakistan india and bangladesh a lookout notice has been issued for sheriyar who according to cops is now based in dubai besides these calls have also caused a huge loss to the telecom companies we could get the call data records of only about 1098 sip lines one line can host 1000 calls at a time said the officer the initial target was to unravel the details of 2700 calls in all the analysis could reveal more information these 43 lakh calls might be the tip of the iceberg the racket was unearthed after officers received an input that a sarkhej resident tabrez kataria was operating the illegal telephone exchange katarias exchange converted voip voice over internet protocol calls to gsm global system for mobile communication calls for countries where internet telephony is regulated kataria with the help of a keralabased man used an sip line to provide this illegal service to their main operator in the gulf later it was determined that a dubai resident rafiq babu was among the accomplices further investigation exposed the rackets links to sheriyar who police say has connections in a uae telecom company investigators have deduced that he provided calling cards to some labourers working in the uae and other gulf countries as for the 43 lakh calls checking the details of all those conversations is humanly impossible said a police officer these calls which could not be recorded may have been used to run extortion or hawala rackets said the officer worse they could relate to operations which pose a threat to the countrys internal security the officer added we have a strong apprehension that the hawala mafia used this exchange while explaining the sipbased voip call rerouting the official said sip doesnt work alone during voip calls several other protocols work along with it to ensure voice data reaches its destination the session description protocol sdp is one such protocol sip connects with ip endpoints to share signalling details whereas sdp sends sessionrelated information to assist participants in joining or receiving session details it transmits three sorts of data session description time description and media description the officer explained sdp does not transfer this information session descriptions are instead supplied as a payload in sip communications before being sent over the network speech data is encoded using codecs which convert audio impulses into binary data many codecs are used for this purpose he added