Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 1 . Protocols and Architecture 1.1 Protocols Used for communications between entities in a system Must speak the same language Entities User applications e-mail facilities terminals Systems Computer Terminal Remote sensor
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Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 1 Ch1. Protocols and Architecture 1.1 Protocols zUsed for communications between entities.
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Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
1Ch1. Protocols and Architecture
1.1 ProtocolsUsed for communications between entities in a system
Must speak the same language
Entities
User applications
e-mail facilities
terminals
Systems
Computer
Terminal
Remote sensor
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
21.2 Protocol Architecture
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
3 1.3 TCP/IP Protocol Suite
An Internet According to TCP/IP
TCP/IP considers all of the hosts to be connected to this larger logical network rather to their individual physical networks.
Dominant commercial protocol architectureSpecified and extensively used before OSIDeveloped by research funded US Department of DefenseUsed by the Internet
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
4TCP/IP and OSI
TCP/IP and the OSI ModelEncapsulation
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
5TCP/IP Protocol Architecture
Application Layer
Communication between processes or applications
End to end or transport layer (TCP/UDP/…)
End to end transfer of data
May include reliability mechanism (TCP)
Hides detail of underlying network
Internet Layer (IP)
Routing of data
Network Layer Logical interface between end system and network
Physical Layer Transmission medium Signal rate and encoding
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
61.3.2 Network Layer
IP Datagram
variable-length packet (up to 65,536 bytes)
two parts: header(20-60 bytes) and data
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
71.3.3 Addressing
Physical address: local jurisdiction, easy to change.
Internet address: universe jurisdiction, cannot change.
Internet Address
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
8
Class Ranges of Internet Addresses
IP Addresses in Decimal Notation
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
9Nodes with more than one address
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
101.3.4 Subneting
Two Levels of Hierarchy
Three Levels of Hierarchy
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
11Addresses with and without Subnetting
Masking
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
12Example. Find the class, netid and hostid for each address:
Class Netid Hostid
a. 4.23.145.90 A 4 23.145.90
b. 227.34.78.7 D N/A N/A
c. 246.7.3.8 E N/A N/A
d. 129.6.8.4 B 129.6 8.4
e. 198.76.9.23 C 198.76.9 23
Boundary-Level Masking Nonboundary-Level Masking
IP Addr: 45. 23. 21. 8 213. 23. 47. 37
Mask 255.255. 0. 0 255.255.255.240
Subnet addr: 45. 23. 0. 0 213. 23. 47. 32
Bit-wise AND
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
131.3.5 Other Protocols in Network Layer
ARP: find physical address from IP address
RARP: find IP address from physical address.
ICMP: send notification back to the sender
IGMP: identify the hosts that are members of a group.
Unicasting Multicasting Broadcasting
One-to-one one-to-many one-to-all
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
141.3.6 Transport Layer TCP and UDP(User Datagram Protocol)
Port Addresses
IP: host-to-host, deliver a packet from one physical device to another
TCP: port-to-port, (Buffer used by a particular process)
IP addr: 32 bits-- in IP datagram
Port addr: 16 bits—in TCP datagram
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
15UDPUDP Datagram Format
UDP only provides basic functions:port addr, checksum, length.
It does not provide any sequencing or reordering functions, can not soeccify the damaged packet
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
16TCP Segment Format
TCP is a reliable stream transport port-to-port protocol.
TCP generates a virtual circuit between sender and receiver that is active for the duration of a transmission.
connection establishment and connection termination alert.
Sequence number. position of the data in the original data stream.
Header length (HLEN): 4 bits, TCP head length:20—60 bytes
Control(6 bits) :independently.
Window size: size of the sliding window used in ARQ.
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
171.4 Application Layer
1.4.1. Client-Server Model: (many-to-one)Client:a program running on the local machine requesting service from a server. A client program is finite.
Server: a program running on the remote machine provides services to the clients. A server program is infinite.
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
181.4.2 BOOTP and DHCP
Attach to a TCP/IP internet, must know:
Its IP address, its subnet mask, the IP address of a router and the IP address of a name server which stored in a configuration file.
BOOTP: provide information for a diskless or first time boot computer.
DHCP: provide dynamic configuration. Moving, temporary IP addr.
1.4.3 Domain name system(DNS) – map name and address
Generic Domains: first level 7 possible 3-character labels: com, edu, gov, int, mil, net, org. a few more labels have been proposed: arts, firm, info, nom(personal nomenclatures), rec(recreation), store, web.
Country Domains: 2-character country abbreviations.
Inverse Domain: used to map a address to a name.
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
191.4.4 TELNET
Remote Login
Network Virtual Terminal(NVT):universal interface between different OSs.
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
201.4.5 File Transfer Protocol (FTP)Two connections (Date, Control). Which use different strategies and different port numbers.
1.4.6 Trivial File Transfer Protocol (TFTP) – copy files
1.4.7 Simple Mail Transfer Protocol (SMTP)
•User Agent (UA)
•Mail Transfer Agent (MTA)
•Relaying
•Mail gateway
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
21Figure 25-16
The Entire E-mail System
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
22Multipurpose Internet Mail Extensions(MIME)
SMTP: ASCII format
MIME: extend SMTP to non-ASCII
Post Office Protocol (POP) – download mail from server
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
24
PDUs in TCP/IP
Some Protocols in TCP/IP Suite
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture
25Exercise: A site with a given network address and mask. The administration has divided the site into several subnetworks. Choose appropriate subneaddresses, host addresses, and router addresses
(a) (b)
Ya Bao School of Engineering, SBUACS Ch1 Protocol and Architecture