An engineer is configuring a CUBE for interoperability with a SIP Service Provider.
What are three different ways Mid-Call Re-Invites function to assure smooth interoperability of supplementary services? (Choose three.)
Click on the arrows to vote for the correct answer
A. B. C. D. E. F.BDF.
CUBE ( Cisco Unified Border Element) is a device that provides control and security at the edge of a VoIP network. It can act as a border element between different VoIP networks or between a VoIP network and a PSTN (Public Switched Telephone Network) service provider. One of the key functions of CUBE is to enable interoperability between different SIP implementations.
Mid-call re-invite is a SIP mechanism that allows for modification of the existing call parameters during a call, without terminating the call. This is important for providing supplementary services, such as call transfer, call hold, call waiting, and conferencing. Here are the explanations of the three ways Mid-Call Re-Invites function to assure smooth interoperability of supplementary services:
A. Converts a delayed offer to an early offer: In some SIP implementations, the offer for the media stream is delayed until the connection is established. This is known as a delayed offer. However, some devices require the media stream offer to be included in the initial SIP INVITE message, known as an early offer. Mid-call re-invite can convert a delayed offer to an early offer during an ongoing call, which enables the devices to interoperate seamlessly.
E. Provides support for media flow-around in early offer forced call flows: Media flow-around is a mechanism where the media stream bypasses the SIP network and is directly exchanged between the endpoints. This is useful when the SIP network is unable to handle the media stream due to NAT (Network Address Translation) or firewall issues. Early offer forced call flows require the media stream offer to be included in the initial SIP INVITE message. Mid-call re-invite can provide support for media flow-around in such scenarios.
F. Provides early offer to delay offer codec change in 200 OK message: When two SIP devices establish a call, they negotiate the codec to be used for the media stream. However, during an ongoing call, one of the devices may want to change the codec due to network conditions or user preferences. Mid-call re-invite can provide an early offer to delay offer codec change in the 200 OK message, which enables seamless codec changes during an ongoing call without terminating the call.
B, C, and D are incorrect answers: B. Blocks all mid-call signaling for specific SIP trunk: Blocking mid-call signaling for a specific SIP trunk will prevent supplementary services from being provided during an ongoing call, which will lead to interoperability issues. C. Disables codec re-negotiation in the middle of a call: Disabling codec re-negotiation during an ongoing call will prevent codec changes, which may be necessary for providing high-quality voice calls. D. Allows pass-through of mid-call signaling on media change: Allowing pass-through of mid-call signaling on media change may cause issues if the devices have different interpretations of the signaling.