Class
1st Octet
Class A
Number of Hosts
Subnet Mask
Reserved Address
1 - 126
# of bits in
network
8
16.7 million
255.0.0.0
10.0.0.0 - 10.255.255.255
Class B
128 - 191
16
65 thousand
255.255.0.0
172.16.0.0 – 172.31.255.255
Class C
192 - 223
24
254
255.255.255.0
192.168.0.0 – 192.168.255.255
Class D
224 - 239
28
Class E
240-255
Public IPS
How to calculate Network ID? Compare the IP and Subnet Mask one octet at a time, wherever there is a
255 bring down the IP address, and if there is a 0 in the subnet mask bring that down into the Network
ID, or NID.
For Example:
IP- 192.168.30.10
SM- 255.255.255.0
NID- 192.168.30.0
Example 2:
IP- 192.168.40.32
SM- 255.255.255.0
NID- 192.168.40.0
Example 3:
IP- 120.10.40.60
SM- 255.0.0.0
NID- 120.0.0.0
Two computers need to have the same NID’s in order to communicate on the same network.
Example 4: Can these two computers communicate on the same network?
Computer 1: IP- 180.16.32.100 Computer 2: IP- 180.17.19.100
SM- 255.255.0.0
SM- 255.255.0.0
NID- 180.16.0.0
NID- 180.17.0.0
Answer= No, these two computers cannot communicate.
Class
First Address
Last Address
Class A
10.0.0.0
10.255.255.255
Class B
172.16.0.0
172.31.255.255
Class C
192.168.0.0
192.168.255.255
Private IP addresses:
CIDR: Classless Inter Domain Router. Notated by /8 /16 /24 representing the subnet mask for Class A, B
and C IP addresses respectively. For example a Class C subnet mask of 255.255.255.0 will have 8 bits in
each octet that has a 255 in it, so 8+8+8 = 24. A Class B subnet mask of 255.255.0.0 will have 8+8 = 16.
Unicast: One to one communication.
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Public IP: Routable IP Addresses assigned by an ISP.
Private IP: Non-routable IP Addresses.
APIPA: Automatic private IP address self-assigned by a host when DHCP is not available.
o IP address range: 169.254.0.0 – 169.254.255.255 *remember the 169.254 octets for
APIPA. Example, if you ever see an IP address that says 169.254.x.x it means that is an
APIPA address, meaning the computer tried to get an IP address from the DHCP server
but failed to get one, meaning it won’t have internet or even lan access. *Possible
problems could be: Switch is bad, DHCP server is down, NIC card is bad, maybe the cable
is bad, etc.
Multicast: One to many communication

IP address range: 224.0.0.0 – 239.255.255.255
Broadcast (Layer 3): One to everyone communication

IP Address: 192.168.30.255/24. Always the last IP in the range.
Loopback (localhost): IP address that’s already assigned to your machine that represents you. used for a
host to communicate with itself to test connectivity.

IP address range 127.0.0.0 – 127.255.255.255
ARP (Address Resolution Protocol): Translates IP address to Mac address.
Examples:
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192.168.30.0/24 - Network ID (NID)
192.168.30.1-254 – Assignable IP (AIP)
192.168.30.255 – Broadcast IP (BIP), not assignable because it’s used by the computer to
communicate with every computer on the network.
172.30.6.4/16
172.30.0.0 NID
172.30.255.255 BIP
IPV6: Eight blocks, 16 bits each giving you 128 bits total, written in Hex which is 0-9 and A-F.


Prefix: First 64 bits of an IPv6 address, assigned to an organization. The first 48 bits are known as
a Global Routing Prefix, the last 16 bits are the Subnet-ID.
Interface-ID: Last 64 bits of an IPv6 address and is used to identify a unique interface on a host.
Global Unicast Addresses: Publicly routable addresses used to communicate outside of a local network.

2000::/3 represents the subnet; this was the originally defined address space.
Unique Local Addresses: FC00::/7 non-publicly routable addresses used to communicate within a local
network.
Link Local addresses: FE80::/10 replacement for Automatic Private IP Addresses (APIPA), every IPv6 host
will have a link local address.
Multicast IPv6: FF00::/8 One to many, packet is sent to many interfaces.
Loopback IPv6: ::1 Used for testing.
Anycast: One to nearest, packet is sent to the nearest interface in terms of routing distance. Replaces
broadcast from IPv4.
Dynamic Host Configuration Protocol (DHCP): is a client/server protocol that automatically provides an
IP host with it’s IP address and other related configuration information such as the subnet mask and
default gateway.

Common DHCP Configurations:
o Scope: is the range of addresses the server can assign
o Exclusion range: The range of addresses the server can NOT assign.
o Lease Time: defines how long an IP address is “owned” by a host before it can be
assigned to another host. Available leases identify how many addresses are still
available from the scope.
o Reservations: allow you to bind a MAC address to a specific IP address.
 Allows DHCP to consistently assign the same IP address to a device without
having to configure a static IP address.
Domain Name Service (DNS): Provides name to IP address resolution for host.
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
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DNS servers can be in your LAN or out on the Internet.
A host is normally assigned a DNS server via DHCP, but it can also be assigned manually.
DNS Name Types
o Host names: identify a specific device in a network.
o Domain names identify a specific network
o Domain name = companyx.lan
o Fully Qualified Domain Name (FQDN): identify a specific device in a specific network.
Domain Keys Identified Mail (DKIM): provides authentication of mail being sent and received to prevent
spam.
Canonical Name (CNAME): resolves an alias to a domain name.
Mail Exchanger (MX): Resolves a name to a mail exchanger (email server)
Virtual Private Network (VPN): Creates a secure tunnel to a private network over the internet. Required
to access resources in a LAN over the internet.
Virtual Local Area Network (VLAN): any network that is partitioned and isolated in a computer network
at the data link layer or by switches.
DSL: DSL is a broadband service that operates over the public switched telephone network (PSTN).
Requirements: DSL modem, DSL Filter/Splitter must be used to prevent noise when connecting a
telephone to a DSL line. Not widely used anymore but may be used in rural areas.
Cable: Uses the DOCSIS (Data Over Cable Service Interface Specification) standard to deliver Internet
over coax.

Described as a FTTN (Fiber to the Node) service.
Fiber: Fiber services like FIOS are FTTP (Fiber to the Premise)

Requirements: ONT (Optical Network Transceiver) converts the fiber cable from the provider to
twisted pair to connect to a router.
Satellite: Widely available and might be the only option for those in rural areas.


Requirements: Satellite dish connected to aa satellite receiver via coax, and a clear view into
space.
Satellite suffers from high latency which makes it unusable for the following services. VOIP,
video streaming, online gaming.
Cellular: cellular Internet has gained usage as coverage has grown quickly.
WISP (Wireless Internet Service Provider): Provides internet to smaller municipalities where cable or
fiber services aren’t available. Providers use wireless access points deployed and at customer sites.
Requires user be within the limited coverage area.
MAN (Metropolitan Area Network): Spread across a single city. Connections between the sites are
often privately owned and managed by the organizations that use them.
CAN (Campus Area Network) spread across a limited geographical distance like a
college/corporate/military campus. It is privately owned and managed.
PAN (Personal Area Network): small networks usually made up of two devices. These devices can be
connected over wired connections (Ethernet or USB) or wireless connections (Wi-Fi, Bluetooth,
Infrared).
WAN (Wide Area Network): When an organization needs to connect their office on one side of the
world to the other, they connect through a WAN.


The internet is a public WAN that anyone can get access to.
Site-to-Site connections are used by large organizations to connect their different locations over
private WAN links.
SAN (Storage Area Network): Specifically built to store data. The network consists of high-speed fiber
links and large storage servers.
Crimper: Used to terminate RJ45 and RJ11 heads to twisted-pair cables.
Cable Stripper: used to strip the jacket of a cable.
Wireless Analyzer: Application for your desktop or mobile phone that can analyze the type and
strengths of wireless networks. Useful to understand where to place access points.
Toner Probe: Used to identify the other end of a twisted-pair cable. Tone generator sends a signal
through the known end of the cable. The probe is used to locate the other end of the cable.
Punch Down Tool: used to terminate twisted-pair to a 110 or 66 block.
Cable Tester: a simple tool that is used to test twisted pair terminations. One end of the cable is plugged
into the main unit and the other end to the remote. Lights should go off in sequence on both ends.
Loopback Plug: used to test if a network port can communicate to itself. These are available for copper
and fiber interfaces.
Network Cables
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Transmission Speeds
o Copper cables: achieve speeds of up to 40 Gigabits
o Fiber cables: achieve speeds above 100 Gigabits
Transmission Distance
o Copper Cables: can reach distances of 1,100 meters (3,609 feet)
o Fiber Cables: can reach distances of 40 kilometers (25 miles)
Attenuation: is the loss of signal strength in networking cables or connections. Usually occurs
due to using a cable that’s too long, usually copper cables. Fiber doesn’t suffer from it as much.
Noise Immunity
o EMI (Electro Magnetic Interference) is a condition when signals from a device or cable
leak out and disrupt signals of another device or cable.
o Copper cables are highly susceptible to interference.
 Use shielded cables to protect against EMI.
o Fiber cables are NOT susceptible to EMI since it is not copper.
Twisted Pair cables: Consist of eight wires that are twisted into four pairs. This is the most used
networking cable in homes and offices.
o Twisted Pair Types
 STP (Shielded Twisted Pair): Has shielding to protect against EMI.
 Direct-burial cable: a special type of electrical wiring or cable that is
designed to be buried in a trench underground.

UTP (Unshielded Twisted Pair): Does NOT have shielding to protect against EMI.
Twisted Pair Categories
Category
Cat 5
Cat 5e
Speed
100 Mbps
1,000 Mbps / 1 Gbps
Distance
100 meters
100 meters
Note
Used in older networks
More twist per foot allows it
handle disturbances to achieve
faster speeds.
Cat 6
10,000 Mbps / 10 Gbps
1,000 Mbps / 1 Gbps
55 meters
100 meters
Cat 6a
10,000 Mbps / 10Gbps
100 meters
Includes a piece of plastic to
separate the 4 wire pairs
which minimizes crosstalk
Thicker wires to carry a more
powerful signal for longer
distance.

Coaxial Cable: is a round cable often used for cable and satellite television connections. It’s thick
outer jacket makes it ideal for outdoor use.
o RG-6 is the most common type of coax cable.
o Advantages:
 Shielding protects against EMI
 Long transmission distance (1100 meters)
 More affordable than fiber optic cables
o Disadvantages:
 More expensive than twisted pair cable
 Copper core can snap if mishandled.



BNC Connector: Secure locking connector commonly used in the old bus and ring networks.
F Connector: Twisting hand screw commonly found on cable modems
Fiber Optic Cable:
o Advantages:
 Not susceptible to EMI
 Longest transmission distance up to 40km
 Fastest speeds up to 255 Tbps
o Disadvantages:
 Most expensive cable
 Most difficult to install.
 Difficult to troubleshoot issues.
 Expensive tools needed for installation and troubleshooting.
 Can’t easily repair cables in the field.
o Fiber Connectors: (Just need to know that ST, LT SC and Dual LC are fiber connections)
 ST Connector: Straight Tip Connector
 BNC style connector from the late 1980s and 1990s
 Used in SMF (Single Mode Fiber) installations.
 LC Connector: LC (Little Connector)
 Snaps-in style connector
 Small form-factor connector
 Used in SMF and MMF (Multi Mode Fiber) installations.
 SC Connector: Standard Connector/Subscriber Connector/Square Connector
 Dual LC Connector: Dual LC, snaps-in style connector. Small Form Factor
connector, used in SMF and MMF installations.
Network Cable Specs
SATA Versions



SATA 1: 1.5 Gbps / 150 MB/s
SATA 2: 3 Gbps / 300 MB/s
SATA 3: 6 Gbps / 600 MB/s