This document provides an overview of networking fundamentals including computer networks, networking models, local and wide area networks, internet protocols, routing, transport protocols, network topologies, transmission methods, broadcast domains, VLANs, switches, routers and other key networking concepts and technologies. It defines common networking terms and provides examples to illustrate networking concepts and designs at both the home/business user and infrastructure levels.

1. Networking Fundamentals
Computer Networks
Andriy Berestovskyy
2017
( ц ) А н д р
і й Б е р е с
т о в с ь к и
й
networking hour
TCP
UDP
NAT
IPsec
IPv4
IPv6
internet
protocolsAH
ESP
authentication
authorization
accounting
encapsulation
security
BGP
OSPF
ICMP
ACLSNAT
tunnel
PPPoE
GRE
ARP
discovery
NDP
OSI
broadcast
multicast
IGMP
PIM
MAC
DHCP
DNS
fragmentation
semihalf
berestovskyy

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

3. Computer Network?
3

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

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

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

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

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

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

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

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

12. 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

13. 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

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

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

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

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

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

19. 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?

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

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

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

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

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

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

26. 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?

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

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

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

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

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

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

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

34. 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?

35. 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

36. 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?

37. 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

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

39. 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?

40. VLAN 2, Broadcast Domain 2VLAN 1, Broadcast Domain 1
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

41. VLAN 2, Broadcast Domain 2VLAN 1, Broadcast Domain 1
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

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

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

44. 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

45. 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