DRAG DROP
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Explanation/Reference:
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Cisco 642-437 Exam
Explanation:
The Real-Time Transport Protocol (RTP) is an Internet protocol standard that specifies a way for programsto manage the real-time transmission of multimedia data over either unicast or multicast network services.RTP is commonly used in Internet telephony applications. RTP does not in itself guarantee real-timedelivery of multimedia data; it does, however, provide the wherewithal to manage the data as it arrives tobest effect. RTP combines its data transport with a control protocol (RTCP), which makes it possible tomonitor data delivery for large multicast networks. When protocols are used in conjunction, RTP isoriginated and received on even port numbers and the associated RTCP communication uses the nexthigher odd port number. Monitoring allows the receiver to detect if there is any packet loss and tocompensate The Secure Real-time Transport Protocol (or SRTP) defines a profile of RTP (Real-timeTransport Protocol), intended to provide encryption, message authentication and integrity, and replayprotection to the RTP data in both unicast and multicast applications. Since RTP is closely related to RTCP(Real Time Control Protocol) which can be used to control the RTP session, SRTP also has a sisterprotocol, called Secure RTCP (or SRTCP); SRTCP provides the same security-related features to RTCP,as the ones provided by SRTP to RTP. Utilization of SRTP or SRTCP is optional to the utilization of RTP orRTCP; but even if SRTP/SRTCP are used, all provided features (such as encryption and authentication) areoptional and can be separately enabled or disabled. The only exception is the message authenticationfeature which is indispensably required when using SRTCP.
On slow links, it may be advantageous to compress the IP/UDP/RTP headers using Compressed RTP(cRTP). If you use cRTP then the 40 bytes of overhead incurred by the IP/UDP/RTP headers can typicallybe compressed down to 2 to 4 bytes (2 bytes when no UDP checksums are sent, and 4 bytes whenchecksums are sent). Enabling compression on both ends of a low-bandwidth serial link can greatly reducethe network overhead if it carries a lot of RTP traffic. cRTP is supported on serial lines using Frame Relay,HDLC, or PPP encapsulation. It is also supported over ISDN interfaces. CRTP should not be used on linksgreater than 2 Mbps.
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Cisco 642-437 Exam