Practice Set Application Layer
Exercise 1:
If a DNS domain name is voyager.fhda.edu, how many labels are involved here? How many levels
of hierarchy?
3 levels
labels
Exercise 2:
-
voyager
sEad
A fully qualified domain name (FQDN) is a domain name consisting of labels beginning
with the host and going back through each level to the root node.
A partially qualified domain name (PQDN) is a domain name that does not include
all the levels between the host and the root node.
-
The following subtree represents a portion of the Internet Domain Name Space.
root
edu
com
DNS
DNS
PSU
DNS
KSU
CS
PC01
ENG
amazon
sales
H1
google
DNS
PC02
1. Identify the DNS TLD servers. edu com
2. Identify the DNS authoritative servers.PSU KSU amazon google
3. Give the FQDN (full name from bottom to top domain name space levels) of PC01 and
sales PC.
PCOl CSPSUeda sales amazon.com
4. In which server is the IP address of sales.amazon.com stored?
DNSamazon
5. Assume a user of PC01 typed sales.amazon.com. Explain how PC01 gets
sales.amazon.com. (How TCP, HTTP and DNS protocol are used?).
6. How PC01 will get the IP address of that server host? Assume no caching exit.
- Using recursive resolution
- Using iterative resolution
5 first PCOI sendsa DNSquery to thelocalDns server
togot theIpaddressof thehostserver AfteritgetstheIPaddress
thehostserveratport 80after
it initiatesTCPconnection withe
socket
theserveraccepts it it sendstheHTTPrequest intothetop
theserverresponds withthewebpageintothesocket
Recursive resolution
root server
6
2
3
a
DNS.com
Edi
DNSPsu
s
a
localDns
DNSamazon.com
pcol.cs.pj.edu
sales amazon.com
Iterativeresolution
rootserver
DNS.com
É
t
isDNS amazon.com
DIS.PSU.edu
s
2
PCOI.CS.PSU.edu
a
a
sales amazon.com