tcp/ip protocol

Question 1

why communication protocols necessary for communication over the network?

Answer 1

ensures successful transmission and reception of messages btwn client and server

(context: LAN) protocols needed to route data frm LAN to internet vice versa

(context: RELIABLE communication protocol) protocols can incl error detection & correction to enable communication to take place more readily

Question 2

what are the 4 network layers

Answer 2

application layer
transport layer
internet layer
network link layer

Question 3

application layer

Answer 3

application handles data acc to relevant application protocols (eg. HTTPS DNS)

Question 4

transport layer

Answer 4

data arrives at comp & uses DESTINATION PORT NUM to decide which app/service data is to be transmitted to (COMP TO APP)

Question 5

internet layer

Answer 5

data is transmitted frm COMP TO COMP by identifying source/DESTINATION IP ADDRESS

Question 6

network link layer

Answer 6

MAC ADDRESS is used to transmit data OVER PHYSICAL MEDIUM (eg cables / internet is transmitted thru em waves tht travel thru air / converting data frm bits/bytes to str, encoding/decoding)

Question 7

problem with IPv4 address + soln using IPv6

Answer 7

only hv abt 4bil addresses avail, running out of avail IP addresses

:. IPv6 also deployed (used tgt w IPv4)
IPv6 represented in 8grps of 4 hex char (16bits) :. provides 16^(8x4) = 16^32 = 3.4x10^38 possible addresses

Question 8

private IP address

Answer 8

(random) users unable to connect to remote server w private IP address, req public IP of server to connect

Question 9

routing protocols (internet layer)

Answer 9

router stores a mapping of destination addresses to gateway addresses in the routing table. it chks the destination address of incoming data packets against the routing table to decide which address to route the data packet to

Question 10

DNS protocol

Answer 10

after checking local cache for existing record, client requests DNS lookup through DNS resolver which then sends request to DNS root server
which redirects resolver to TLD (top level domain) name server
which directs resolver to authoritative DNS server which returns IP address of its web server
resolver returns IP address of web server to client

Question 11

purpose of DNS protocol

Answer 11

associate domain names w ip addressess
enable client to access server using domain names instead of ip addresses