Slide 1

Transcript Slide 1

Internet Technology
NETW 902
Tutorial 6
Mohamed Esam
1
Curriculum
• First 3 Chapters
• Chapter 4: from the chapter start (page 255) up to
(page 372)
• Chapter 5: from page 491 to 554
2
Main Points for Problems
1.
2.
3.
4.
5.
6.
7.
8.
9.
ALOHA
Slotted ALOHA
CSMA/CD
Token Ring, Token BUS & Ring Types. (last Tutorial)
BUS Segments
WLAN
FDDI
Spanning Tree
Performance of (Aloha, CSMA & Token Ring)
10.
11.
12.
13.
14.
15.
SONET/SDH
ATM
Virtual Connections
ISDN
Dial up
DSL
Ch’s 1&2
Till page: 200
Ex.1:
LAN-Inter working
& Spanning Tree
Ex.2:
MAC protocols
Performance
Ch’s 3
Till page: 255
Ex.3:
IP Addressing, ATM
& Access Networks
3
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Internet Arch. & IP Addressing.
ARP
MTU
Routing Functions
Forwarding
Routing Principles
Distance Vector Algor.
Link State Algor.
Path Vector Algor.
Routing in Internet.
Internet Routing Protocols
ARQ
UDP
TCP
QoS
Some of Ch’s 4&5
Till page: 554
Ex.4:
Distance Vector &
Link State Routing
Ex.5:
TCP
4
ARP (Automatic Resolution Protocol)
5
10.10.10.1
In Star Network
PC1
PC2
Send data to
10.10.10.3
Internet
Data
10.10.10.3
PC3
Switch
Router
10.10.10.2
My MAC is 3B
MAC
IP
Port
8A
10.10.10.0
_
1F
1
2A
2
3B
10.10.10.3
3
7D
4
2C
5
Who has IP
10.10.10.3, reply
With MAC
Address to
MAC:8A
IP:10.10.10.0
PC4
10.10.10.4
PC5
10.10.10.5
• Switch is the responsible device in the network for ARP.
• It’s done one time after connection and then updated
regularly
6
MTU (Maximum Transmission Unit)
• Sender doesn’t send larger than MTU of the used
Technology.
• Routers may divide the payload into smaller data units
while forwarding.
Tech.
MTU
IPv4
(Bytes)
65535
Eth.2
1500
FDDI
4352
7
Dynamic Routing
Update Routing Table periodically
8
I- Distance Vector Algorithm
• Bellman Ford Algorithm.
7
N2
8
N3
N4
6
1
N5
5
N6
4
2
N6 is the Destination
N7
N1
3
Link ID
9
N6 is the Destination
7
N2
Assumes whole links
have the same cost (=1).
So Total path cost = number of hops.
In case of same cost select randomly.
N3
8
N4
6
1
5
N5
N6
4
Not Unique Solution
2
N7
Distance
(No. of hops)
Link No.
N1
N1
Steps/nodes
0
1
-1
-1
N2
∞
∞
-1
-1
∞
∞
N3
3
N4
N5
N6
N7
-1
∞
-1
∞
-1
∞
D
0
-1
∞
1
1
-1
∞
5
1
D
0
2
1
D
0
D
0
D
0
D
0
10
7
N2
N6 is the Destination
N3
8
N4
6
1
5
N5
N6
4
2
N7
Distance
(No. of hops)
Link No.
3
N1
N1
Steps/nodes
0
N2
Shorter than (4, 2)
N3
N4
N5
N6
N7
∞
∞
-1
-1
∞
∞
-1
∞
-1
∞
-1
∞
D
0
-1
∞
1
-1
-1
1
1
-1
∞
5
1
D
0
2
1
2
3
2
6
2
1
1
8
2
5
1
D
0
2
1
D
0
D
0
D
0
11
7
N2
N6 is the Destination
N3
8
N4
6
1
5
N5
N6
4
2
N7
Shorter than (7,3)
3
N1
N1
Steps/nodes
0
N2
Shorter than (4, 2)
N3
N4
N5
N6
N7
∞
∞
-1
-1
∞
∞
-1
∞
-1
∞
-1
∞
D
0
-1
∞
1
-1
-1
1
1
-1
∞
5
1
D
0
2
1
2
3
2
6
2
1
1
8
2
5
1
D
0
2
1
3
3
2
6
2
1
1
8
2
5
1
D
0
2
1
D
0
12
• Repeat with All destinations  Get the routing Table
• N7 to All Destinations
13
• Count to infinity Problem:
14
Exerc.4 Part 1 Dynamic Routing
15
Q2-a
16
Q2-b
17
Q2-C
18
Q3-a
19
Q3-b
20
Q3-c
• Looping (Count to Infinity)
21
Q3-d
22
23
II- Link State Algorithm
1.
2.
Discover the neighbours:
Measure the cost to each
neighbour
Flooding: Send Link State
packet to all routers saying the
new information; includes:
3.
•
•
•
•
4.
Echo (Round Trip) packet
Sender ID
Packet Sequence No. (32 bits)
Packet age (TTL)
List of neighbours and
corresponding Cost.
Compute shortest path to all
routers using Dijkstra
algorithm.
24
Part 2- Exerc.4
2
4
B
C
1
1
1
6
2
4
B
1
D
1
1
1
6
12
A
1
A
5
Cost
3
D
1
12
4
E
C
3
1
4
E
5
Link ID
25
AIf Duplicate Messages are not avoided
2
4
B
C
1
1
1
6
A
5
3
C
1
D
1
12
1
2
4
B
1
1
6
3
D
1
12
4
E
A
1
4
E
26
B- Link State Database
From
To
Link
Cost
A
B
1
1
A
E
5
1
B
C
2
4
C
D
3
1
C
E
6
1
E
D
4
12
2
B
4
C
1
1
1
6
3
D
1
12
A
1
4
E
5
Cost
Link ID
27
C• Using Time Stamps (Synchronized routers)
• Using Seq. Number:
– 32 bits address to avoid Wrap around problem.
– Incremented with every new message
28
D- Apply Dijkstra
2
4
B
C
1
1
1
6
3
D
1
12
1
A
5
Cost
4
E
Link ID
Step
B
C
D
E
0
∞
1/A
∞
∞
∞
1
∞
∞
1/A
29
D- Apply Dijkstra
Doesn’t Send to the Source Node (A)
2
4
B
C
1
1
1
6
3
D
1
12
1
A
5
Cost
4
E
Link ID
Step
B
C
D
E
0
∞
1/A
2
1/A*
5/B
∞
∞
∞
∞
1
∞
∞
1/A
1/A
30
D- Apply Dijkstra
2
4
B
C
1
1
1
6
3
D
1
12
1
A
5
Cost
4
E
Link ID
Step
B
C
D
E
0
∞
1/A
1/A
2
1/A*
5/B
∞
∞
∞
∞
1
∞
∞
3
1/A*
5/B 2/E
13/E
1/A*
1/A
31
D- Apply Dijkstra
2
4
B
C
1
1
1
6
3
D
1
12
1
A
5
Cost
4
E
Link ID
Step
B
C
D
E
0
∞
1/A
1/A
2
1/A*
5/B
∞
∞
∞
∞
1
∞
∞
3
1/A*
5/B 2/E
13/E
1/A*
4
1/A*
2/E*
13/E 3/C
1/A*
1/A
32
D- Node A Routing Table
Dest.
Link No.
Cost
Next Hop
A
_
0
_
B
1
1
B
C
5
2
E
D
5
3
E
E
5
1
E
33