proc proc - - PDF document

• G. Bianchi, G. Neglia
• G. Bianchi, G. Neglia
• Entire network seen as a pipe

...

Internet

• G. Bianchi, G. Neglia
• !"

#

IP IP IP IP UDP UDP IP proc proc

• $%&'
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• !

!"# "#

• Checksum

Data

• (

all UDP datagram (header + payload)

% ) *

Empty Odd size (bytes) length (bytes) source port destination port

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• which is the only strictly necessary role of a transport protocol
• which may even be disabled for performance

• G. Bianchi, G. Neglia

$%# $%#

• #&

#&

+$ ,&-&.-//0/1% ' 21% $ .-//,3

• +,41%'521%

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%72&8,1% $ $ ) "9: !:7;( 1; ' )

SunOS 4.1.3 had 32767 for max tolerable IP packet transmittable (but 32786 in reception…) – bug fixed only in Solaris 2.2

)*% " +## ,"+-* # # . *##*( << .&/441%=% ./3-

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• # '#

# '#

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(# ) " #*# % # ##

• !"" #$

!""% $

• G. Bianchi, G. Neglia
• #

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• No throttling due to congestion & flow control mechanisms

No retransmission

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• G. Bianchi, G. Neglia

*#+,# *#+,#) )

# # #- * +

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# ' ('#

• Real Time Protocol

(RTP, RFC 3550)

• G. Bianchi, G. Neglia

/ /

• !
• G. Bianchi, G. Neglia

/ / *## *##

Application developer integrates RTP into the application by:

• writing code which creates the RTP

encapsulating packets;

• sends the RTP packets into a UDP

socket interface.

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• G. Bianchi, G. Neglia

16 bit checksum field, obtained by: ,-. (( ,/ ! . $ ,/ ( ,,,,,,0,, !-112133,/$ at destination: ,/ (. (!4 $ efficient implementation RFC 1071

• Data

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• ()
• Zero padding

. + checksum disabled (

• G. Bianchi, G. Neglia

## ##

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