CCNA Study Notes

Reference [Cisco Blueprint for 200-301](https://learningcontent.cisco.com/documents/200_301_CCNA_v1.0_2.pdf)
I can't recommend enough [David Bombal's Cisco CCNA 200-301 Exam: Complete Course with practical labs ](https://www.udemy.com/course/cisco-ccent-icnd1-100-105-complete-course-sims-and-gns3/)

To Do: Download packet tracer.

If it's your first time to take a Cisco exam, notice the wording **explain/describe/compare/configure.** Think of our current jobs, as IT engineers. 
-How does it fit with your role? Are you ready to begin?

# Network Fundamentals 
[-first let's check Cisco](https://www.cisco.com/c/dam/global/fi_fi/assets/docs/SMB_University_120307_Networking_Fundamentals.pdf)
There's a lot of information out there. 
A lot of this you should know this no matter if your role. It's also just really cool to understand. 

My favorite sentences:
-if 7 Layer OSI Model: **P**lease **D**o **N**ot **T**hrow **S**ausage **P**izza **A**way
**P**hysical **D**ata link **N**etwork **T**ransmission **S**ession **P**resentation **A**pplication 
-**D**on't **S**ome **P**eople **F**ear **B**irthdays?
**D**ata **S**egment **P**acket **F**rame **B**its
## Explain the role and function of network components:
###  Routers 
-how similar/different [great comparison](https://www.geeksforgeeks.org/difference-between-router-and-switch/)
-What makes routers so fast. As strange as it sounds, having more tables is better; RIB/FIB/Adjacency table/CEF. 
[Kevin Wallace is a great reference](https://www.youtube.com/watch?v=dk2YtOoT0w4)
###  L2 and L3 switches 
-What's your role? 
-Who do you interact with? 
-Do you like MAC or IP addresses better? How about frames or packets?
-Evolution in hardware from repeater, to bridge, to switch that can offer hundreds of multi-speed ports. 
-Collision domains(frames colliding) & broadcast domains(send to everyone in group).
-Starting with bridges we can separate collision domains.
-Why broadcast? Because I don't know where to go:runner_tone3:
-let's take a look at the osi model.
-Layer 2 protocols such as CDP(C for Cisco) or LLDP(std.) provide info such as os, interface & IP. They also help reveal the topology in essence. 

###  Next-generation firewalls and IPS 
-Let' check out a Firepower datasheet [Reference](https://www.cisco.com/c/en/us/products/collateral/security/firepower-4100-series/datasheet-c78-742474.html) 
-IPS stands for **Intrusion** Prevention System & IDS stands for Intrusion **detection** system. Ask yourself, where would you place each of these appliances?
-Notice in Firewall datasheet that IPS license can be purchased, and NGFW can even support **deep packet inspection(dpi)** 
###  Access points 
-Ok, have you ever heard of a wireless Access Point(WAP)? What same/different between a WAP and other devices.
-Wifi standards are a vast topic as well.
###  Controllers (Cisco DNA Center and WLC) 
See Cisco's documentation on [Cisco DNA Center](https://www.cisco.com/c/dam/en_us/training-events/product-training/dnac-112/ManagingDeviceSWimages/DNAC112_ManagingDeviceSoftwareImages.pdf)
The keyword is **business intent** and the UI design is broken down between **DESIGN/POLICY/PROVISION/ASSURANCE**
###  Endpoints
-This word gets overused as lot. 
-Could we just say a device connected to the network? Ok, then are a node and a endpoint the same? Try to think it through...
###  Servers
Servers are a type of resource. Resources could be phones, printers, memory, and more...
Let's examine Microsoft Servers [Reference](https://www.microsoft.com/en-us/windows-server) 
-learn the common ports & corresponding applications associated with those ports [REF 1340](https://datatracker.ietf.org/doc/html/rfc1340)

## Describe characteristics of network topology architectures
### 3 tier Vs. 2 tier 
See Cisco [Documentation](https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/campover.html#wp709581). 
It's a lot to digest, but ask yourself which are the advantages / disadvantages of both designed in terms of scale, performance and cost. Is there a reason you would not choose one(special requirements)? 
### Spine-leaf 
Where would you find this, and what's different Vs. other architecture?
Aruba has great [documentation](https://www.arubanetworks.com/faq/what-is-spine-leaf-architecture/#:~:text=A%20spine%2Dleaf%20architecture%20is,in%20a%20full%2Dmesh%20topology.) too
### WAN
The definition I like the best:
"A wide area network(also known as WAN), is a large network of information that is not tied to a single location," says CompTIA 
[Wikipedia link](https://en.wikipedia.org/wiki/Wide_area_network)
Also, get familiar with the term Software Defined WAN or SD WAN.
### Small office/home office (SOHO)
Probably already very familiar with it, but easiest way to understand is to visualize it.
Check out images with a google search might help.
### On-premises and cloud
Let's go over this together
## Compare physical interface and cabling types
RJ45 anyone : [resource](https://www.electronics-notes.com/articles/connectivity/ethernet-ieee-802-3/cables-types-pinout-cat-5-5e-6.php)
Cisco Cable Installation Guide [Link](https://www.cisco.com/en/US/docs/cable/cmts/ubr10012/installation/guide/u10k_cbl.html)
In some network exams like CompTIA Network plus they may expect you to be able to wire a cable, but for CCNA I expect it is enough just to recognize different types such as Crossover Vs Straight-through.
-Twisted pair separate sending/receiving thus separate collision domains.
With most modern devices, the device can automatically recognize the cable type, and handle accordingly.
In real world, you read the manual to device, and do as instructed.
### Single-mode fiber, multimode fiber, copper
Let's check out what a cable manufacturer says.
See ofsoptics.com [link](https://www.ofsoptics.com/single-vs-multimode-fiber/)

### Connections (Ethernet shared media and point-to-point)
maybe check out diagrams on google again
### Concepts of PoE
Power over Ethernet to power your devices 
See [wikipedia](https://en.wikipedia.org/wiki/Power_over_Ethernet) 

### Identify interface and cable issues (collisions, errors, mismatch duplex, and/or speed)
Cables handled by end users have a habit of getting damaged. There are tools to validate cables. See [link](https://www.galvinpower.org/best-network-cable-testers/#:~:text=A%20network%20cable%20tester%20is,and%20other%20related%20work%20fields.).
Simply put, collisions are when packets are sent out at same time, well, you can guess the rest. 
Let's stop and ask ourselves, where would you expect to see collisions? (Discussion topic)

For ***Mismatch duplex*** see [here](https://community.cisco.com/legacyfs/online/legacy/2/1/9/64912-Speed%20and%20Duplex%20Matrix.pdf). 
Try to imagine a busy parent trying to tell a young child a million things to do at once. 
### Compare TCP to UDP
Ok, lets look online. [Here](https://www.lifesize.com/en/blog/tcp-vs-udp/#:~:text=TCP%20is%20a%20connection%2Doriented,is%20only%20possible%20with%20TCP.) is just one comparison.
I find the easiest way to remember, is try to think of the application, or what is the traffic used for. If it's time sensitive data like live video or voice, it's UDP. 
Also, let's ask ourselves is UDP reliable? ⇒No, by itself, UDP is not reliable, but the features in upper layers can ask again for missing data. 

### Configure and verify IPv4 addressing and subnetting

How to configure an IPv4 address on a Cisco switch? See [Here](https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350-series-managed-switches/smb5557-configure-the-internet-protocol-ip-address-settings-on-a-swi.html)

How to subnet. It takes a little memorization of this. [RFC 1878](https://www.ietf.org/rfc/rfc1878.txt)
But let's discuss together. There are a lot of tricks.
When I first learned, I usually tried to recall from memory and write down as much as I could everyday for a month. 
There are a lot of tricks we will talk about.
### Describe the need for private IPv4 addressing
-Because we keep creating more devices to connect to the internet? 
 Let's look at that RFC 1878 again. Is there any upper limit?
 Ok, do you see the problem now?
 By the way, what do you think about this ***loopback Address***, 127.0.0.1? Great idea, right? ⇒　maybe not?
[Here](https://www.freecodecamp.org/news/subnet-cheat-sheet-24-subnet-mask-30-26-27-29-and-other-ip-address-cidr-network-references/) is another good cheat sheet with explanation.
You should also know what an ***[APIPA Address](https://ja.wikipedia.org/wiki/APIPA)*** is. If you see it, it means your not getting out of your LAN; you are relying on layer 2 networking.

Start quizzing yourself with this wonderful test tool prepared by someone who genuinely wants to make you a better network engineer: [davidbombal.com/subnet-quiz/](davidbombal.com/subnet-quiz/)

### Configure and verify IPv6 addressing and prefix
See [here](https://study-ccna.com/how-to-configure-ipv6/) for example
### Describe IPv6 address types examples and IPv4 equivalents [here](https://www.ripe.net/participate/member-support/lir-basics/ipv6_reference_card.pdf)
###### Unicast (global, unique local, and link local)
###### Anycast
###### Multicast


###### Modified EUI 64
-
###***To be Continued***

### Verify IP parameters for Client OS (Windows, Mac OS, Linux)
### Describe wireless principles
###### Nonoverlapping Wi-Fi channels
###### SSID
###### RF
###### Encryption
### Explain virtualization fundamentals (server virtualization, containers, and VRFs)
### Describe switching concepts
###### MAC learning and aging
###### Frame switching
###### Frame flooding
###### MAC address table
Interesting fact: MAC addresses were developed after IP addressing so messages could get from A to B to C.