udp and cbr internet engineering. 1 contents delivery encode –music or movie is converted to data...
TRANSCRIPT
UDP and CBR
Internet Engineering
2
Internet Engineering
Contents Delivery
Encode – Music or movie is converted to data (compress)
CBR (Constant Bit Rate)– Constant bit assignment method (MPEG2)
– Assign a certain amount of bits VBR (Variable Bit Rate)
– Bit rate is changeable– High bit amount for strong change (moving, color)
Assignment Method (MPEG2)
– Assign a lot of bits for strong change in movement of color
Bit rate ： Number of bits are sent every second [bps (bit per second)].higher bit rate will give more information and better quality of picture or music
3
Internet Engineering
Protocol of transport layer Low reliability, there is no guarantee that packets will be
delivered Suit for delivery of music or movie
Application layerFTP, CBR
HTTP, SMTP
Transport layer TCP UDP
Network layer IP
Physic, data-link layer Ethernet
UDP (User Datagram Protocol)
Sending data
Without considering about network state,UDP sends data according to the request from higher layer
4
Internet Engineering
Hierarchy Architecture
sender receiver
data
data
data
data
data
data
data
data
UDP header
IP header
Ethernet Frame Header Ethernet Frame Header
IP Header
UDP Headeraddition
addition
addition
analysis
analysis
analysis
Communication medium （ LAN Cable ・ Optical Cable ・ Wireless ）
sending receiving
Application layer
Transport layer
Network layer
Physic
Data-link layer
5
Internet Engineering
UDP Packet Configuration
(Notice) Since UDP header is small, In NS header size is considered as 0
Source Port Number
Destination Port Number
PacketLength Checksum
Data
UDP Header
0 31
6
Internet Engineering
CBR/UDP Simulation
Data encoded by CBR
UDP Agent
Network Router
Voice ・ Movie playback
UDP Agent
Network
Parameter
・ Packet size・ Transmission ra
te
7
Internet Engineering
Throughput [Mbps] =
Packet drop rate [%] = ×100
(Total of received packet)×(Packet size(including header)[bytes]
(transmision time)[s]
(Total of dropped packet)
(Total of sent packets)
Experiment 1
0
1
4
5
2 3
CBR/UDP
Bandwidth: Bw(Bottleneck link)
40Mbps40Mbps