rise Session Border flexibility of this subsequent digits are collect- Controllers implement the transfer method. ed and used as the location playout of "*8" via a TcL to place transfer the call to. script. This is the most common method used for call center transfers today. In SS7 Network Transfer, the There is no direct mapping The originator of an SS7 Network IP-PBX must signal to the to have a SIP message gener- transfer point must send Transfer SS7 network that the call ate a SS7 Transfer Message. SS7 messages, and this should be transferred from The closest solution would requires an expensive one bearer channel to be the use of SIP-I that Signaling Termination Point another. encapsulates the ISUP (STP) and point code. Message that would signal There is no direct mapping the transfer. (ISUP is a type of the signaling used for of SS7 messaging variant.) this in SS7 to SIP. A TBCT is used on PRI lines Cisco SIP solutions for call The capability for a TDM on TDM trunks. In this type centers, such as Cisco Voice trunk or IP Trunk to accept of transfer, a transfer is initi- Portal in combination with the signaling for a TBCT ated on one channel, and the Cisco Voice Gateways and transfer and complete the call is connected until the initiation of a TBCT on a transfer is not well second channel acknowl- TDM trunk; however, there supported. edges receipt of the call and is no standard method to is connected. initiate on a SIP Trunk. This method does provide immediate connectivity; however, it does not allow the media to flow in the most efficient manner from the teleworkers house to the local SBC or voice gateway. As such, a trend is developing to allow for SIP trunking from remote teleworkers, where the SP connects directly to the site of the teleworker and provides an optimal media signaling path. 30 SIP Trunking A third trend that is occurring is the use of more bandwidth resilient codecs for remote teleworkers. Codecs such as internet Low Bandwidth Codec (iLBC) compensate for pack- et loss by having an effective