Networking Fundamentals
● > Computer Networks
● Networking Models
● Local Networks
● Internet
● IPv4 Routing
● Transport Protocols
2

Computer network — telecommunications network
which allows nodes to share resources
— Wikipedia
4

Computer Network
5
Host A
Host B
Host C
Server
Host?
Computer
Network

Host computer — consumer of communication services
— RFC 1122
6
RFC?

Request for Comments — principal technical
and standards-setting documents for the Internet
— Wikipedia
7RFC 1. Host Software. 1969

Ethernet Cable
Networking: Home User View
8
Internet
Ethernet
DSLWireless
Devices?

Ethernet Cable
Networking: Business User View
9
Company
Network
Wireless
Devices?

Computer Network Design
10
Host A
?
Host B
Host C
Server
How?

Computer Network Size
11
Host A
?
Host B
Host C
Server
Distance

Local Area Network (LAN) interconnects hosts within a limited area
and has its network equipment and interconnects locally managed.
Metropolitan Area Network (MAN) interconnects several local area
networks by bridging them with backbone lines.
Wide Area Network (WAN) covers a larger geographic distance, also
generally involves leased telecommunication circuits or Internet.
— Wikipedia
12

Krakusa 11, 1st floor
Local Area Network
13
Krakusa 11, 2nd floor Krakusa 11, 3rd floor
How?
Interconnects hosts within a limited area and has its network
equipment and interconnects locally managed

Backbone, CracowKrakusa 11, Cracow
Metropolitan Area Network
14
Wadowicka 8a, Cracow
How?
Interconnects several local area networks
by bridging them with backbone lines

WroclawCracow
Wide Area Network
15
Leased Line
or Internet
How?
Covers a larger geographic distance, also generally involves leased
telecommunication circuits or Internet

Ethernet is Everywhere
Ethernet — family of networking technologies
commonly used in LAN, MAN and WAN
— Wikipedia
16
Other
technologies?

Computer Network Design
17
Host A
?
Host B
Host C
Server
How?

Computer Network Topology
18
Host A
?
Host B
Host C
Server
Topology

Network Topologies
Point-to-Point — communications between two endpoints.
Bus — nodes are directly connected to a common link called a bus.
Star — central hub with a point-to-point connections.
— Wikipedia
19
Other
topologies?

Point-to-Point Network Topology
20
Examples?
Communication between two endpoints

Point-to-Point Topology Example
21
Host A
Host B
Host C
Server
Pros/Cons?
LAN/WAN?

Bus Network Topology
22
Examples?
Nodes are directly connected to a common link called a bus

Bus Topology Example
23
Host A
Host B
Host C
Server
Pros/Cons?
10Base2 Ethernet
over Coaxial cable
LAN/WAN?
BNC
T-Connector

Central hub with a point-to-point connections
Star Network Topology
24
Central Hub
Examples?

Star Topology Example: Repeater
25
Host A
Host B
Host C
Server
Repeater Hub
10Base-T Ethernet
over a Twisted Pair
Pros/Cons?

Star Topology Example: Switch
26
Host A
Host B
Host C
Server
Switch
Pros/Cons?
10GBase-T Ethernet
over a Twisted Pair
Does it
scale?

Unicast Transmission
27
Host A
Host B
Host C
Server
S
A
S
A
B
C
B
C

Unicast — one-to-one transmission from one point
in the network to another point
— Wikipedia
28
Examples?

Multicast Transmission
29
Host A
Host B
Host C
Server
M
A
M
A
M
A

Multicast — information is addressed to a
group of destination computers simultaneously
— Wikipedia
30
Examples?

Broadcast Transmission
31
Host A
Host B
Host C
Server
F
A
F
A
F
A
F
A

Broadcasting — method of transferring a message
to all recipients simultaneously
— Wikipedia
32
Examples?
All?

Broadcast Domain
Broadcast Domain
33
Host A
Host B
Host C
Server
F
A
F
A
F
A
F
A

Broadcast domain — computer network in which all nodes can
reach each other by broadcast at the data link layer
— Wikipedia
34
All?
Does it
scale?

Broadcast Domain
Broadcast Storm
35
Host A
Host B
Host C
Server
F
A
B
C
F
A
B
C
F
A
F
A
Solutions?
F
C
F
C

LAN 2, Broadcast Domain 2LAN 1, Broadcast Domain 1
Splitting Broadcast Domain
36
Host A
Host B
Host C
Server
F
A
F
A
F
C
F
C
Host
A — C?

LAN 2, Broadcast Domain 2LAN 1, Broadcast Domain 1
Connecting Broadcast Domains
37
Host A
Host B
Host C
Server
R
A
S
R
Device?
Two
switches?
R
A
S
R

VLAN — any broadcast domain that is partitioned
at the data link layer (OSI layer 2)
— Wikipedia
38

VLAN 2, Broadcast Domain 2VLAN 1, Broadcast Domain 1
Virtual LANs
39
Host A
Host B
Host C
Server
R
A
S
R
R
A
S
R
Two links?

VLAN Trunk
40
Host A
Host B
Host C
Server
R
A
S
R
R
A
S
R
R
C
B
R
B
R
R
C
How to
distinct?Trunk
Interface

VLAN Tags
41
Host A
Host B
Host C
Server
R
A
S
R
R
A
S
R
R
C
B
R
B
R
R
C
Still two
devices?
R
C
R
A
What adds
tags?
Virtual
Interface

VLAN 2VLAN 1
Multilayer Switch
42
Host A
Host B
Host C
Server
R
A
S
R
R
C
B
R Virtual
Interfaces

Icons
43
Router
Switch
Access Point
Wireless Router
Repeater Hub Multilayer Switch

Computer Networks Checklist
1. Host?
2. RFC?
3. LAN?
4. WAN?
5. Network topologies?
6. Unicast, multicast, broadcast transmissions?
7. Broadcast domain?
8. VLAN?
9. VLAN trunk?
10. Multilayer switch?
44

References
1. Kevin Wallace. CCNP Routing and Switching ROUTE 300-101 Official Cert Guide. Cisco Press, 2014
2. David Hucaby. CCNP Routing and Switching SWITCH 300-115 Official Cert Guide. Cisco Press, 2014
3. RFC 1122. Requirements for Internet Hosts — Communication Layers.
4. IANA Protocol Numbers: http://www.iana.org/assignments/protocol-numbers
45

Networking Fundamentals: Computer Network Basics