Which of the following protocols is widely used for setting up and tearing down multimedia
communication sessions such as voice and video calls over the Internet (VoIP)?
A.
ICMP
B.
UDP
C.
SIP
D.
LDAP
Explanation:
Session Initiation Protocol (SIP), designed by Henning Schulzrinne and Mark Handley in 1996, is a
signaling protocol, widely used for setting
up and tearing down multimedia communication sessions such as voice and video calls over the
Internet (VoIP). Other feasible application
examples include video conferencing, streaming multimedia distribution, instant messaging,
presence information and online games. The
protocol can be used for creating, modifying, and terminating two-party (unicast) or multiparty
(multicast) sessions consisting of one or several
media streams. The modification can involve changing addresses or ports, inviting more participants,
adding or deleting media streams, etc.
The SIP protocol is a TCP/IP-based Application Layer protocol. Within the OSI model, it is sometimes
placed in the session layer. SIP is
designed to be independent of the underlying transport layer; it can run on TCP, UDP, or SCTP. It is a
text-based protocol, sharing many
elements of the Hypertext Transfer Protocol (HTTP), upon which it is based, allowing for easy
inspection by administrators. SIP clients typically
use TCP or UDP (typically on port 5060 and/or 5061) to connect to SIP servers and other SIP
endpoints.
Answer D is incorrect. Lightweight Directory Access Protocol (LDAP) is a protocol used to query and
modify information stored within
directory services.Answer A is incorrect. Internet Control Message Protocol (ICMP) is an integral part of IP. It is used to
report an error in datagram
processing. The Internet Protocol (IP) is used for host-to-host datagram service in a network. The
network is configured with connecting
devices called gateways. When an error occurs in datagram processing, gateways or destination
hosts report the error to the source hosts
through the ICMP protocol. The ICMP messages are sent in various situations, such as when a
datagram cannot reach its destination, when
the gateway cannot direct the host to send traffic on a shorter route, when the gateway does not
have the buffering capacity, etc.
Answer B is incorrect. User Datagram Protocol (UDP) is often used for one-to-many
communications, using broadcast or multicast IP
datagrams. Microsoft networking uses UDP for logon, browsing, and name resolution. UDP is a
connectionless and unreliable communication
protocol. It does not guarantee delivery, or verify sequencing for any datagram. UDP provides faster
transportation of data between TCP/IP
hosts than TCP.