Networked Graphics Building Networked Virtual Environments and Networked Games Chapter 3: Overview of the Internet

THE INTERNET

Application Transport Network Link Physical DHCP, DIS, DNS, FTP, HTTP, IMAP, RTP, SMTP, SSH, Telnet TCP, UDP, RSVP IP, ICMP, IGMP Ethernet, , ADSL copper wires, fibre-optic cable, radio waves

Message Segment Packet Frame Application Data Transpo rt Header Network Header Link Header Link Footer

TRANSPORT LAYER

Bits Source PortDestination Port 32-63LengthChecksum 64+Data

Transport Network Link Transport Network Link Application Source Port = Port1 Destination Port = Port2 Destination Port = Port3

Transport Network Link Transport Network Link Application Source Port = 1901 Destination Port = narok ( ) seychelles ( ) Destination Port = Source Port = 1220

Transport Network Link Application Msg i Msg i-2Msg i-1… Data Heade r Buffer Segment

Bits Source PortDestination Port 32-63Sequence Number 64-95Acknowledgement Number Data Offset Not Used FlagsReceive Window ChecksumUrgent Pointer Options (Optional) , 224+, etc. Data

Transport Data Heade r Send Buffer Receive Buffer Byte Expected Received Data Sent Data Start Byte Start Byte + MSS Sequence Number = Start Byte Acknowledgement Number = Byte Expected Unsent Data

Header Sequence Number = M Transport Send Buffer Acknow- ledged Last Acknowledged = M Next Sequence Number = N Unsent To Send Data Transport Receive Buffer Received Expected = N Just Received Transport Send Buffer Acknowledged Last Acknowledged = N Unsent Header Acknowledgement Number = N

Transport Network Link Transport Network Link Application Source Port = 1995 Destination Port = narok ( ) seychelles ( ) Destination Port = Source Port = 1234

Seq # = 100 Data Host AHost B Seq # = 200 Data Seq # = 300 Data Ack # = 200 Data Ack # = 200 Data Seq # = 200 Data Ack # = 400 Data

Seq # = 100 Data Seq # = 200 Data Ack # = 200 Data Seq # = 200 Data Timeout Host AHost B

Seq # = 100 Data Seq # = 200 Data Seq # = 300 Data Ack # = 200 Data Ack # = 400 Data Ack # = 300 Data Host AHost B

SYN Seq # = N SYN, ACK Ack # = N+1,Seq # = M ACK Ack # = M+1,Seq # = N+1 Host AHost B

FIN ACK FIN ACK Wait, then close Host AHost B

Time Rate (bytes/s) 10K 20K 30K

NETWORK LAYER

Router Route Table IP Packet

Bits VersionHeader Length Type of Service Total Length 32-63Identification Flags Fragment Offset 64-95Time to LiveProtocolHeader Checksum Data Offset Not Used FlagsReceive Window Source Address Destination Address Options (Optional) Bits VersionHeader Length Type of Service Total Length 32-63Identification Flags Fragment Offset 64-95Time to LiveProtocolHeader Checksum Source Address Destination Address Options (Optional) , 224+, etc. Data

Bits TypeCodeChecksum IDSequence

LINK AND PHYSICAL LAYER

Bits VersionHeader Length Type of Service Total Length 32-63Identification Flags Fragment Offset 64-95Time to LiveProtocolHeader Checksum Data Offset Not Used FlagsReceive Window Bits Destination MAC Address … 32-63… Destination MAC AddressSource MAC Address … 64-95…Source MAC Address EtherTypeData … …CRC Checksum

OTHER NETWORK FACILITIES

SUMMARY