Lec33) Overview of TCP/IP Architecture and Service

Application Layer

• Consist of process that use the NW(Network)
• Porvides progamming interface used for building a program
• Protocols used are http, telnet, ftp, smtp, ssh
• Addresses are string based URIs (URL, URN)

 

Transport Layer

• Provides host to host communication 
• Protocols used are TCP ,UDP , RAW
• 16 bits Port numbers are used for addressing

 

Internet Layer

• Break data into fragments small enough for transmission via link layer
• Routing data across internet
• Protocols used are IP, ICMP , IGMP
• IPv4 and IPv6 are used for addressing

 

Link Layer / Physical Layer

• Place packets on the NW medium and receiving packets off the NW medium
• Protocols used are Ethernet , Token ring , FDDI, ISDN, SONET , ATM 
• 48 bit Mac address are used for addressing

 

Addressing on the Application Layer

A host on the Internet can be uniquely identified by a Fully Qualified Domain Name (FQDN), having 2 parts

A mapping of these hostnames with their corresponding IP addresses is kept in a hierarchical decentralized database and the service that performs a look up is called DNS/BIND

the organization can add suffixes and prefixes to its domain name to define its resources

 

Addressing on the TCP Layer

the transport layer address are called port numbers. A 16bits integer used to identify a specific process to which a network message is to be forwareded when it arrives at a host.

 

private ip address (ipv4)

firewalls translates private ip address to public IP address using a process called network address translation(nat)

 

Addressing on the Physical Layer

the 48bit addresses used on the physical layer are called mac address

 

ssh connection established

there are other connection that can be checked by using xinetd..? 

Everything is turned off by default. If you go inside and change the option to yes, it can work. Then, just like tcp 22 is used for ssh, daytime and chargen also work on a specific port.