SDP Content Headers

CD.

Connection info is optional field in SDP whether Media attributes decide the codec and media type for that call.

SDP (Session Description Protocol) is a protocol used in VoIP (Voice over Internet Protocol) communications to describe the media sessions between endpoints. SIP (Session Initiation Protocol) is used to initiate and manage the VoIP sessions between the endpoints. SIP messages such as INVITE, ACK, BYE, and others are used to initiate, manage and terminate a VoIP call. The SIP INVITE message is used to initiate a VoIP call and carries important information about the session.

The SDP content headers that can be found in a SIP INVITE message are:

1. Media Attributes (D): The media attributes header in SDP describes the media types, codecs, and other media-related parameters. This header provides the necessary information about the media to be used during the session. The media attributes header in SDP is a required field in the SIP INVITE message.

2. Connection Info (C): The Connection Info header in SDP describes the network connectivity information for the media stream. It includes information about the IP address and port number for the media stream. This header provides information about the network connectivity to be used for the media stream. The Connection Info header in SDP is a required field in the SIP INVITE message.

The other options in the answer choices are not SDP content headers that can be found in a SIP INVITE message.

1. Expires (A): The Expires header in SIP is used to indicate the expiration time of a SIP message. It is not an SDP content header.

2. Contact (B): The Contact header in SIP is used to identify the endpoint that initiated the SIP message. It is not an SDP content header.

3. Allow (E): The Allow header in SIP is used to indicate the methods supported by the endpoint. It is not an SDP content header.

4. CSeq (F): The CSeq header in SIP is used to indicate the sequence number of the SIP message. It is not an SDP content header.