week7 final
TRANSCRIPT
LAN Design Issues
Media; Topology; Protocol;
Addressing; Naming;
Example networking application.
Recap
IP addressingIP Address192.168.15.2 (decimal)
11000000 10101000 00001111 00000010 (binary)
Subnet Mask:255.255.255.0 (decimal)
11111111 11111111 11111111 00000000 (binary)
IP Address192.168.15.2 (decimal)
11000000 10101000 00001111 00000010 (binary)
Subnet Mask:255.255.255.0 (decimal)
11111111 11111111 11111111 00000000 (binary)
Network part Host part
IP addressing (network/ broadcast)
.1
.254
192.168.15.0/24
For our example:
192.168.15.255 -> broadcast address;
Packet sent to broadcast address
.1
.254
A packet sent to broadcast address will be received by all nodes.
Range: 192.168.15.0 to 192.168.15.255;
Two addresses are reserved in every network1) host bits all zeros (for representing the network)
2) host bits all ones (for the broadcast address)
Example application
We assumed that a student (in the niit.edu.pk LAN) wanted to access NUST-SEECS website hosted at www.niit.edu.pk
WWWP
C
In the last lecture, we assumed a greatly simplified
model of the LAN of NUST-SEECS
Network’s domain name: niit.edu.pk
DNS Client/Server Exchange
WWW
DNS
Request
Tell me the IP address of www.niit.edu.pk?
WWW
DNSReply
The IP address of www.niit.edu.pk is 202.125.157.196
DNS Client/Server Exchange
The IP address of www.niit.edu.pk is 202.125.157.196
ARP Client/Server Exchange
WWW
DNS
Request
Any one knows the MAC (physical) address of 202.125.157.196 ?
Request
WWW
DNS
Reply
The MAC address of 202.125.157.196 is 12:34:aa:bb:cc:dd
ARP Client/Server Exchange
The MAC address of 202.125.157.196 is 12:34:aa:bb:cc:dd
Layered Communications
GET / HTML/1.1
Source MAC address | Destination MAC address 23:34:aa:bb:cc:dd | 12:34:aa:bb:cc:dd
FCSPayload
Payload
Source Port | Destination Port> 1024 | 80
Payload
Payload
Source IP | Destination IP 202.125.157.150 | 202.125.157.196
Payload
Application data
TCP Segment
MAC Frame
IP Packet
HTTP High-level Exchange
WWW
DNS
Send me the index.html page for the host www.niit.edu.pk
using HTTP version 1.1
Request
Send me the index.html page for the host www.niit.edu.pk
using HTTP version 1.1
WWW
DNS
Reply
The index.html page in the wwwroot directory configured for the www.niit.edu.pk webserver
is sent back to the browser for display
HTTP Client/Server Exchange
Internetworking
Today’s
lecture
Encapsulation/ layered communication;
Hierarchical addressing;
Interconnecting multiple networks;
Layered Communication
GET / HTML/1.1
Source MAC address | Destination MAC address 23:34:aa:bb:cc:dd | 12:34:aa:bb:cc:dd
FCSPayload
Payload
Source Port | Destination Port> 1024 | 80
Payload
Payload
Source IP | Destination IP 202.125.157.150 | 202.125.157.196
Payload
Application layer
Transport layer
Link layer
Internet layer
TCP/IP model
Application
Transport
Network
Data Link
Destination Host (Same LAN)
Bits
Bridges/ Switches
Repeater/ Hub
Source Host
Application
Transport
Network
Data Link
Bits
Networking devices (same LAN)
Device used in a single LAN: hub, bridge, switch
Application
Transport
Network
Data Link
Destination Host (Different network)
Bits
Routers/ Gateway
Source Host
Application
Transport
Network
Data Link
Bits
Internetworking devices (different LAN)
Course to be tested
Every thing we have studied in the classroom.
Topics covered in the assignment will not be
tested in this exam.
Details of material discussed in class (that is in
your textbook) may be tested.
Material from your textbook that was not covered
in the class at all will not be tested
Mid sessional format
3 Sections
a) Multiple choice questions
(30 marks)
b) Fill in the blanks
(30 marks)
c) Questions requiring short answers
(40 marks)
Types of questions:
d) Requiring lower-order skills
(memorization
and comprehension)
e) Requiring higher-order skills
(analyzing and
applying)
Lecture’s
Summary
a) We studied the
TCP/ IP layering model
b) We discussed basic networking device types:
1) hubs/ repeaters
; 2) bridges/ switches
;
3) routers.
c) We studied that
routers are necessary for
internetworking.
d) We discussed details of the
mid-semester exam.
???Questions/
Confusions?
Credits/ Acknowledgement can be found
at the course website:
http://tinyurl.com/5hb8pp