What is RTP/UDP ?

Answer 1

RTP is a protocol used for carrying multimedia application traffic, including audio and video, over an IP network. RTP packets have a 40-byte header and typically a 20 to 150 payload. RTP protocol travels over UDP. Given the size of the IP/UDP/RTP header combination, it is inefficient to transmit those small payloads using an uncompressed header. RTPC is a technology that helps RTP run more efficiently, especially over lower-speed links, by compressing the RTP/UDP/IP header from 40 bytes to 2 to 5 bytes. This is especially beneficial for smaller packets (such as IP voice traffic) on slower links, where RTP header compression can reduce overhead and transmission delay significantly.

UDP:



Description:
Protocol suite:TCP/IP.
Type:Connectionless transport protocol.
IP Protocol:17.
Ports:Well known port numbers.
Related protocols:UDP-Lite, Lightweight User Datagram Protocol.
SNMP MIBs: iso.org.dod.internet.mgmt.mib-2.udp (1.3.6.1.2.1.7).
iso.org.dod.internet.mgmt.mib-2.udpMIB (1.3.6.1.2.1.50).



The User Datagram Protocol offers only a minimal transport service -- non-guaranteed datagram delivery -- and gives applications direct access to the datagram service of the IP layer. UDP is used by applications that do not require the level of service of TCP or that wish to use communications services (e.g., multicast or broadcast delivery) not available from TCP.

UDP is almost a null protocol; the only services it provides over IP are checksumming of data and multiplexing by port number. Therefore, an application program running over UDP must deal directly with end-to-end communication problems that a connection-oriented protocol would have handled -- e.g., retransmission for reliable delivery, packetization and reassembly, flow control, congestion avoidance, etc., when these are required. The fairly complex coupling between IP and TCP will be mirrored in the coupling between UDP and many applications using UDP.


MAC header IP header UDP header Data :::

UDP header:
0001020304050607 0809101112131415 1617181920212223 2425262728293031
Source Port Destination Port
Length Checksum
Data :::

Source Port. 16 bits.
The port number of the sender. Cleared to zero if not used.

Destination Port. 16 bits.
The port this packet is addressed to.

Length. 16 bits.
The length in bytes of the UDP header and the encapsulated data. The minimum value for this field is 8.

Checksum. 16 bits.
Computed as the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded as needed with zero bytes at the end to make a multiple of two bytes. If the checksum is cleared to zero, then checksuming is disabled. If the computed checksum is zero, then this field must be set to 0xFFFF.

When transported by IPv4, the pseudo header contains the following fields:
0001020304050607 0809101112131415 1617181920212223 2425262728293031
Source IPv4 address
Destination IPv4 address
0 Protocol Total length

The checksum is not optional when transported by IPv6. In this case, the pseudo header contains the following fields:
0001020304050607 0809101112131415 1617181920212223 2425262728293031
Source IPv6 address :::
Destination IPv6 address :::
Upper layer packet length
0 Next header

Data. Variable length.

Answer 2

RTP is Real Time Protocol that let you stream media files for playing on your screen and speaker.

UDP is User Datagram Protocol it has a technical status parallel to the TCP in TCP/IP; so rightfully it can be said UDP/IP, it dispenses the round trip confirmation mechanism in TCP for speed. RTP, most IMsgers, NFS, bootup SFTP, games use it for speed.