N10-009 Networking Concepts

OSI Model

Physical, Data Link, Network, Transport, Session, Presentation, Application (Please Do Not Throw Sausage Pizza Away)

LAN

Local Area Network

Subnet

Stands for subnetwork, a logical or physical subdivision of a larger network

Router

connects 2 or more LANs to internet

Switch

Connects computers in LAN

Firewall

Safeguards computers and networks against unauthorized access

Proxy

Gateway between users and internet

NAS

Network attached storage

SAN

Storage access network

AP

Access Point

IDS

Intrusion Detection System

IPS

Intrusion Prevention System

Load Balancer

Distributes traffic across servers

CDN

Content Delivery Network

QoS

Quality of Service

TTL ( Time to Live)

A mechanism for limiting the lifetime of data on a network or in a system

Network Security List

set of security rules applied to all devices on a subnet

Network Security Group

Set of security rules applied to a group of network devices

Internet Gateway

Allows inbound and outbound connections between private subnets and public networks

Network Address Translation (NAT) gateway

Allows outbound connections from a private subnet to public network services while shielding it from inbound connections from outside.

How does a VPN work?

First, the computer connects to the internet using local DHCP.
Then, the VPN client software creates a virtual NIC (vNIC) on the local computer (endpoint 1).
Then it makes a connection with the VPN server at the office (endpoint 2).
Then it makes a virtual direct cable from the vNIC to the office.

NFV

Network Function Virtualization

VPC

Virtual Private CLoud

SaaS

Software as a Service

IaaS

Infrastructure as a Service

PaaS

Platform as a Service

Direct Connect

On-premises infrastructure connects to a provider’s network, bypassing the public internet

Internet Protocol (IP)

IPv4 and IPv6

Internet Control Message Protocol (ICMP)

Used for ping packets

Transmission Control Protocol (TCP)

Connection oriented, SYN-ACK handshake

User Datagram Protocol (UDP)

Connectionless, best-effort

IPv4 address

32-bit number, consisting of four decimals from 0 to 255 separated by periods. e.g. 192.168.1.1

IPv4 loopback/localhost

127.0.0.1

Automatic Private IP Addressing (APIPA)/link-local

169.254.x.x

Classless Inter-Domain Routing (CIDR)

CIDR IPv4 addresses have a prefix; e.g., “/24“ in “10.150.23.58/24“ denotes a 255.255.255.0 subnet mask

802.11 Standards

for wi-fi communication

802.3 standards

for wired ethernet networks

Transceiver

combined transmitter and receiver of signals

form factor

hardware specifications

TIA/EIA-568A

1. White/green

2. Green

3. White/orange

4. Blue

5. White/blue

6. Orange

7. White/brown

8. Brown

TIA/EIA-568B

1. White/green

2. Orange

3. White/orange

4. Blue

5. White/blue

6. Green

7. White/brown

8. Brown

Single-mode vs. multimode

It is referring to optic fiber and it either allows one or multiple light modes to propagate.

DAC

Direct attach copper

Coaxial

F-type, BNC

BNC

Bayonet Neill-Concelman

Twinaxial/twinax

Has two inner conductors instead of one as in coaxial

Twisted pair

RJ45, (RJ)11

(RJ)11

Registered Jack

STP/UTP

Shielded/Unshielded twisted pair

Fiber optic

SC, ST, LC, FT, MT,RJ

SC

Subscriber Connector

ST

Straight Tip

LC

Local Connector

FC

Fibre Channel

Plenum-rated

Fire Resistant cable; compare with riser-rated, non-plenum rated, and PVC

UTP Categories

CAT1 - up to 1MBps
CAT2 - up to 4Mbps

CAT3 - up to 10Mbps

CAT4 - up to 16Mbps

CAT5 - up to 100Mbps
CAT5e - up to 1Gbps

CAT6 - up to 10Gbps

CAT6a - up to 10Gbps

CAT7 - up to 10Gbps

SFP

Small form-factor pluggable

QSFP

Quad small form-factor pluggable

MPO

Multi-fiber push on

Mesh Topology

A network configuration where every device is interconnected with every other device, providing multiple route for data to travel.

Hybrid Topology

A network topology that combines two or more different network topologies. It can be a combination of bus topology, ring topology and mesh topology

Star/hub and spoke Topology

A network topology type where each individual component is physically linked to a common central node, such as a switch or hub. A star network may comprise either wired or wireless connections. The central node functions as a server, while connected network components are clients, every one of which uses the server as an intermediary.

Spine and Leaf Topology

A two-tier network architecture where leaf switches connect directly to end-user devices, and spine switches form the network's core by interconnecting all leaf switches in a full-mesh pattern

Point to Point Topology

a type of topology that works on the functionality of the sender and receiver. It is the simplest communication between two nodes, in which one is the sender and the other one is the receiver.

3 tier Hierarchical model

Core, Distribution, Access

Collapsed core

Combine core and distribution layers

North-south

Traffic moving between a private network and the outside world

East-west

Traffic moving within an organization’s internal network

RFC1918

IP addresses set aside for private networks

VLSM

Varliable Length Subnet Mask

Classless Inter-Domain Routing (CIDR)

CIDR IPv4 addresses have a prefix; e.g., “/24“ in “10.150.23.58/24“ denotes a 255.255.255.0 subnet mask

IPv4 address classes

• Class A: 0.0.0.0 – 127.255.255.255

• Class B: 128.0.0.0 – 191.255.255.255

• Class C: 192.0.0.0 – 223.255.255.255

• Class D: 224.0.0.0 – 239.255.255.255

• Class E: 240.0.0.0 – 255.255.255.255

SD-WAN

Software-defined wide area network

SDN

Software-defined networking

IaC

Infrastructure as Code

SASE

Secure Access Secure Edge

SSE

Security Service Edge

VXLAN

Virtual Extensible Local Area Network

ZTA

Zero Trust Architecture

DCI

Data center interconnect

GRE

Generic Routing Encapsulation

IPSec

Internet Protocol Security

AH

Authentication Header

ESP

Encapsulating Security Payload

IKE

Internet Key Exchange

Traffic Types

Unicast, Multicast, Anycast