IP Addressing in Depth | Network Fundamentals Part 5

Summary

This video script delves into advanced IP networking concepts, focusing on Classless Inter-Domain Routing (CIDR) and Variable Length Subnet Masking (VLSM) for efficient IP address conservation. It explains unicast and broadcast traffic, the significance of network and broadcast addresses, and introduces special addresses like the default gateway and the use of 255.255.255.255 for universal broadcasts. The script also touches on multicasting, the management of IP addresses by organizations like the Internet Assigned Numbers Authority (IANA), and the distinction between public and private IP addresses. It further discusses methods of IP address assignment, including static, DHCP, and APIPA, and concludes with an overview of the IP header and the TCP/IP model.

Takeaways

• 📚 The video continues to build on the concepts introduced in Part 1, focusing on advanced networking topics while still using IPv4.
• 🔍 Variable Length Subnet Mask (VLSM) is introduced as a way to conserve IP addresses by creating subnets of different sizes within a network.
• 🏢 The example of a 172.16.0.0/16 network being broken into smaller subnets like /24 and /30 is used to illustrate how VLSM can be applied in practice.
• 📈 VLSM allows for more efficient use of IP addresses by accommodating networks of varying sizes, including those with minimal hosts like router links.
• 💬 Unicast traffic is explained as traffic between two devices, while broadcast traffic is described as messages sent to all devices in a local network.
• 📡 The special IP address for broadcast traffic is highlighted, with the last IP in a subnet being used for this purpose, and the network address being the opposite, with all host bits set to 0.
• 🔢 The concept of the 'magic number' method is introduced to help calculate network and broadcast addresses in more complex subnetting scenarios.
• 🚀 The importance of the Default Gateway in routing traffic is discussed, emphasizing its role as the first point of contact for devices needing to send traffic outside their local network.
• 🌐 The limitations and downsides of broadcasting are discussed, including the potential for network flooding and the inability of routers to forward broadcast messages.
• 🌐 Multicast is introduced as an alternative to broadcast, allowing devices to opt-in to receive specific types of traffic, with routers able to forward multicast traffic to intended networks.
• 🏷️ The video concludes with a discussion on the management of IP addresses, including the role of the Internet Assigned Numbers Authority (IANA) and the use of RFC 1918 for defining private IP address ranges.

Q & A

What is Classless Inter-Domain Routing (CIDR)?

CIDR is a method used in networking to allocate IP addresses and IP routing. It uses a subnet mask to break a network into smaller, more efficient subnetworks, which helps conserve IP addresses.

What is Variable Length Subnet Mask (VLSM) and how does it help conserve IP addresses?

VLSM is a concept that allows for the creation of subnets of different sizes within the same network. This helps to conserve IP addresses by using only the necessary number of addresses for each subnet, rather than using a fixed subnet size.

How many IP addresses are in a /30 network?

A /30 network uses 30 bits for the network and 2 bits for the host, resulting in 4 IP addresses in each network.

What is the purpose of the broadcast IP address?

The broadcast IP address is used to send a message to all devices within a local network. It is the last IP address in the local network, with all host bits turned on.

Why can't the broadcast IP address be assigned to a device?

The broadcast IP address cannot be assigned to a device because it is a special address used for sending messages to all devices in the local network. Assigning it to a device would interfere with this broadcasting function.

What is the purpose of the network address in an IP network?

The network address is used to identify the network itself. It is the first IP address in the range and is formed when all the host bits are set to 0.

What is the 'magic number' method for determining network and broadcast addresses?

The 'magic number' method is a technique used to quickly determine the network and broadcast addresses in a subnet. It involves working with the subnet mask and the IP address to find the boundaries of the network and the broadcast address.

What is the default gateway and why is it important?

The default gateway is the IP address of the local router. It is important because it is the address that a device sends traffic to when it cannot send the traffic directly to the destination on its own.

Why do routers not forward broadcast messages?

Routers do not forward broadcast messages to prevent flooding the larger network with these messages and to avoid potential loops where broadcast messages are continuously forwarded between routers.

What is multicast and how does it differ from broadcast?

Multicast is a method of sending data to a group of devices that have opted to receive it, using special multicast IP addresses. Unlike broadcast, which sends data to all devices, multicast is more targeted and efficient, and routers can forward multicast traffic to reach the intended networks.

What are the three special types of IP addresses mentioned in the script?

The three special types of IP addresses mentioned are the broadcast IP, the network address, and the private IP addresses as defined by RFC 1918.

What is the role of the Internet Assigned Numbers Authority (IANA) in managing IP addresses?

IANA is responsible for managing and allocating IP addresses. They give large blocks of addresses to regional internet registries (RIRs), which in turn assign blocks to customers or internet service providers (ISPs), who then allocate addresses to end users.

What is the purpose of RFC 1918 and what private address ranges does it define?

RFC 1918 defines a set of private IP address ranges that can be used within local networks without the need for global uniqueness. The ranges defined are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.

What are the three methods of assigning IP addresses to devices?

The three methods are static IP addressing, where an address is manually configured and does not change; dynamic IP addressing using DHCP, where an address is assigned from a pool by a DHCP server; and Automatic Private IP Addressing (APIPA), where a device assigns itself an address from a reserved range if a DHCP server is not available.

What is the significance of the Time-To-Live (TTL) field in an IP header?

The TTL field in an IP header is used to prevent packets from looping indefinitely in the network. Each time a packet passes through a router, the TTL value is decremented. If the TTL reaches zero, the packet is dropped.

Outlines

00:00

📚 Introduction to Advanced IPv4 Concepts

In this part, we build on what was learned in part one by delving into advanced IPv4 concepts. The focus remains on IPv4, discussing classless inter-domain routing (CIDR) and introducing variable length subnet mask (VLSM) to conserve IP addresses more efficiently. Examples illustrate breaking down networks into smaller subnets, like /24 networks into /30s, and understanding unicast and broadcast traffic.

05:09

🧩 Detailed Breakdown of Network and Broadcast Addresses

This section explains how to calculate network and broadcast addresses using subnet masks. An example with a /24 network is given to illustrate finding these special addresses. The concept of using a /30 network for inter-office links is revisited, highlighting the importance of network and broadcast addresses, and the calculation of usable IP addresses in different network sizes is discussed.

10:14

🔢 Advanced Subnetting and the Magic Number Method

Focusing on a more complex subnetting example, this paragraph introduces the 'magic number' method to simplify subnet calculations. Using a /22 subnet, the process of determining network and broadcast addresses and the number of usable IP addresses is explained. The importance of routers in forwarding traffic and how devices find the router using the default gateway is also discussed.

15:19

🌐 IP Addressing, NAT, and Private vs Public IPs

The difference between public and private IP addresses is covered, including the role of the Internet Assigned Numbers Authority (IANA) and regional internet registries (RIRs). The RFC 1918 standard for private IP spaces is introduced, explaining how NAT (Network Address Translation) allows devices with private addresses to communicate over the internet. The section concludes with a mention of RFCs and their significance.

20:21

⚙️ Static and Dynamic IP Address Assignment

Methods of assigning IP addresses are explored: static assignment, where addresses are manually configured, and dynamic assignment using DHCP servers, which provide IPs from a pool. The less common Automatic Private IP Addressing (APIPA) used by Windows is also explained. The section ends with a brief introduction to IP packet headers, fragmentation, and the time-to-live (TTL) field to prevent infinite loops in routing.

🔍 Understanding IP Packet Headers and Conclusion

An overview of IP packet headers is provided, explaining key fields like source and destination addresses, version, fragment offset, and TTL. The importance of these fields in ensuring proper data delivery and preventing network errors is highlighted. The video concludes with a teaser for the next topic, the TCP/IP model, and encourages viewers to share their thoughts and subscribe for more content.

Keywords

💡Classless Inter-Domain Routing (CIDR)

CIDR is a method for allocating IP addresses and routing that allows for more efficient use of the available address space by using subnet masks to create smaller, more appropriate subnets. In the video, CIDR is discussed as a foundational concept for understanding how networks can be divided into subnets to conserve IP addresses, which is crucial for the theme of network design and optimization.

💡Variable Length Subnet Mask (VLSM)

VLSM is an extension of CIDR that allows for the creation of subnets of varying sizes within the same network. This concept is introduced in the script as a way to further conserve IP addresses by allocating only the necessary number of addresses to each subnet, which is key to the video's discussion on advanced IP address management.

💡Subnet Mask

A subnet mask is a 32-bit number that separates the network portion of an IP address from the host portion, determining the size of the network and the number of available host addresses. The script uses the subnet mask to explain how networks can be divided into subnets and how VLSM can be used to create subnets of different sizes.

💡Broadcast Traffic

Broadcast traffic refers to the transmission of data from one device to all other devices on the same network. The video script describes broadcast traffic as a way for a device to send a message to every other device in the local network, such as when a device is looking for a specific resource and doesn't know its location.

💡Broadcast IP

The broadcast IP is a special IP address within a network that is used to send messages to all devices on that network. The script explains that this address is always the last IP in the local network, with all host bits set to 1, and it cannot be assigned to a device.

💡Network Address

The network address is the base address of a network, with all host bits set to 0. It is used to identify the network itself rather than any specific host within it. The script mentions the network address in the context of VLSM and subnetting, emphasizing its importance in identifying the network boundary.

💡Unicast Traffic

Unicast traffic is the transmission of data from one device to a single, specific recipient. The video script contrasts unicast with broadcast traffic, using the analogy of a person in a room having a one-on-one conversation to illustrate the concept of sending data to only one device at a time.

💡Default Gateway

A default gateway is the IP address of the local router that a device sends traffic to when it cannot deliver the traffic to the destination itself. The script explains the default gateway as the 'gateway of last resort,' which is essential for understanding how devices route traffic within and outside their local network.

💡Multicast

Multicast is a method of sending data to a group of devices that have opted to receive it, using a special multicast IP address. The video script introduces multicast as a solution for efficiently sending data to multiple recipients without the need for broadcast or unicast to each individual device.

💡Private IP Addresses

Private IP addresses are a range of IP addresses reserved for use within local networks and are not routable on the public internet. The script discusses private IP addresses in the context of RFC 1918, which defines these ranges and their purpose for conserving the use of public IP addresses.

💡Static IP Address

A static IP address is a manually configured IP address that does not change unless manually reconfigured. The video script describes static IP addresses as being used for devices like routers and servers, where a consistent and unique address is necessary.

💡DHCP Server

A DHCP (Dynamic Host Configuration Protocol) server is a server that dynamically assigns IP addresses to devices on a network from a pool of available addresses. The script explains the role of DHCP in automatically configuring devices with IP addresses, which is essential for understanding the dynamic allocation of IP addresses in networks.

💡APIPA (Automatic Private IP Addressing)

APIPA is a method used by some operating systems, such as Windows, to automatically assign an IP address to a device when a DHCP server is not available. The script mentions APIPA as an alternative to DHCP in cases where a DHCP server fails or is not present, allowing devices to communicate within the same subnet.

💡IP Fragmentation

IP fragmentation is the process of breaking down a large packet into smaller packets to accommodate devices or networks with smaller maximum transmission sizes. The script touches on fragmentation in the context of the IP header, explaining how the fragment offset field is used to reassemble the fragments at the destination.

💡Time-to-Live (TTL)

The TTL field in an IP header is used to prevent packets from looping indefinitely in a network by decrementing its value each time the packet passes through a router. The script explains TTL as a mechanism to ensure that packets do not circulate forever, which is crucial for network stability and performance.

Highlights

Introduction to advanced concepts building on part one, focusing on IPv4.

Explanation of Classless Inter-Domain Routing (CIDR) and its use in conserving IP addresses.

Introduction to Variable Length Subnet Masking (VLSM) for more efficient IP address conservation.

Example of breaking a /16 network into /24 and /30 networks to accommodate various office sizes.

Explanation of network links and the waste of IP addresses with /24 networks for small links.

Detailed example of using /30 networks to minimize wasted IP addresses between routers.

Concept of network and broadcast addresses and their significance in IP addressing.

Explanation of unicast, broadcast, and multicast traffic in networking.

Description of broadcast IP address and its role in sending messages to all devices in a network.

Introduction to the 'magic number' method for calculating network addresses.

Example calculation using a /20 network to determine network and broadcast addresses.

Discussion on the importance of default gateways in directing traffic to routers.

Explanation of special IP address 255.255.255.255 for broadcasting across all networks.

Introduction to the Internet Assigned Numbers Authority (IANA) and its role in managing IP addresses.

Explanation of private and public IP addresses and their uses within and outside local networks.

Brief overview of Network Address Translation (NAT) for connecting private networks to the internet.

Explanation of dynamic and static IP address assignment methods, including DHCP.

Introduction to automatic private IP addressing (APIPA) used by Windows.

Overview of the IP header fields, including source, destination, version, fragmentation, and TTL.

Introduction to the TCP/IP model and its comparison to the OSI model.

Transcripts

thank you for coming back to part  two we're going to take what you  

learned in part one and build  on it with some more advanced  

concepts we're still going to stick  with ipv4 only throughout this video

at the end of part 1 we talked about classless  inter-domain routing or cider that's where we  

use a subnet mask to break a network into  smaller better sized sub networks this helps  

us to conserve IP addresses we can build on  this by introducing to you a concept called  

variable length subnet mask or vlsm this helps us  to conserve even more IP addresses let's take our  

1 7 to 1600 / 16 network as an example again we  previously spoke about breaking it up into 256  

/ 24 networks we did this because we had several  smaller offices rather than one large one now we  

have 256 IPS in each Network but we also have  links between our offices these are also a kind  

of network they may be very small though with only  a router at each end no printers workstations or  

anything like that if these networks are all  slash 24s we're wasting over 200 IP addresses  

per link what we can do instead is choose one  of our slash 24 networks and break it up even  

further maybe we could break it into slash 30s a  slash 30 network uses 30 bits for the network and  

2 bits for the host that's 4 IP addresses in each  network this allows for our two routers with two  

IPS to spare I'll talk about why we're keeping to  spare a little later on now our original network 1  

7 - 1600 slash 16 has been broken into subnets  of different sizes some are slash twenty fours  

and others are slash 30 and that's all vlsm  is it's creating subnets of different sizes

all the IP addresses that we have spoken about so  far are addresses that are assigned to devices as  

you know these are also called host addresses  often our devices only want to send traffic to  

one other device at a time this is called unicast  traffic you can think of this as being in a room  

full of people and you single one of them out and  you have a conversation with only one person and  

ignore everyone else but that's just common sense  right is in traffic always between two devices  

no not always sometimes the device will want to  send a message to every other device in the local  

network this may happen if it want a particular  resource but it doesn't know where it is it may  

broadcast a message asking who owns this resource  or where can I find this as I've just hinted this  

is called broadcast traffic imagine you're back  in that room full of people and someone gets up  

to the microphone and makes an announcement  they're sending a message to everyone at once  

to broadcast to every device we have a special  IP address I'm sure you won't be surprised to  

find that it's called the broadcast IP so which IP  is the broadcast IP it is the very last IP in the  

local network always the last IP address is the  IP where all host bits are turned on taking the  

172 16 2.0 / 24 network as an example the last  IP is 170 216 to 255 so as this is special you  

can never configure a device with a broadcast  IP and what we're talking about addresses that  

you can't allocate to devices there's another  one and that's called the network address the  

network address is kind of the opposite to the  broadcast address it is when all the host bits  

are set to 0 so 172 16.2 dot 0/24 is a network  address remember just a few minutes ago when we  

said we can use a slash 30 Network between our  offices I said that we would need two addresses  

to spare that's because of the network and the  broadcast addresses a skill you will want to  

develop is working out what these addresses are  in any network as well as how many dresses you  

can actually use let's take an example you have  a device with the IP 1 7 2 16 0 10 / 24 from the  

/ 24 we can see that the first three octet are the  network and the last octet are the host bits if we  

set all host bits to 0 we have 1 7 to 1600 that's  the network address if all the host bits are set  

to 1 we have 1 7 to 16 0 255 that's the broadcast  address 8 host bits mean there is a maximum of 256  

addresses we subtract our two special addresses  and find that we have 254 useable IPS on this  

network now that's not too hard to work out on  a / 24 network but when vlsm enters the picture  

it can get a little more complicated imagine that  a device has an IP of 10.40 2.37 dot 12/20 - this  

is a much more complicated example while you can  sit down and work out all the different ones and  

zeros there's another method that many people  find easier and it's called the magic number  

method we start with our IP address and we work  out the subnet mask a slash 22 has 22 ones so  

we get to a subnet mask of 255 255 - 5 - 0 now  I'll find the octet in the subnet mask that we  

need to work with it's going to be the one that's  got a mixture of ones and zeros so the third octet  

in our case subtract this value from 256 for us  256 - 252 is 4 now we need to know the value of  

the third octet in our IP that's 37 in our case  we count by four until we find the numbers that  

are next to the value of the third octet in our IP  that means we want the numbers immediately smaller  

and larger than 37 if we count by four that's 36  and 40 36 is the start of the network that gives  

us the network address 40 is the start of the  next network so we can go back one IP and that  

gives us the broadcast we know there are 10 host  bits that gives us 1,024 IP addresses subtract our  

two special addresses and we have 1022 usable  IPS on this network now that is a lot to take  

in go over it a few times and practice in fact  try a few right now see if you can work out the  

network address the broadcast address and the  number of usable IPs for these networks here we  

know that the router helps to get traffic from one  network to another we also discussed how a device  

knows when to ask the router for help but how do  devices find the router how do they know where  

to send their traffic when they need help when we  configure an IP address on a say a Windows machine  

we will also configure a default gateway this is  the local routers IP address so when a host has no  

way of sending traffic to this destination on its  own it will forward it to the default gateway some  

device is called the default gateway the Gateway  of last resort I kind of like this term because  

it really shows us what this IP address is for if  a host runs out of options to handle their data  

itself as a last resort it sends it to the local  router let's go back to broadcast traffic for a  

moment I said earlier that the last IP address in  the subnet is the broadcast IP it's not the only  

one there's another special IP used for broadcasts  its 255 255 255 255 it's different in that it  

doesn't care what the local subnet is it basically  says I don't care what network you're on send this  

traffic everywhere there are times when this is  useful one case is when a host is starting up and  

it doesn't have an IP address yet we'll get into  this a bit more later but one option is to use a  

special server to give the host an IP address but  the host doesn't know where the server is yet so  

it sends out a broadcast to 255 255 255 255 asking  for an IP so while it's useful there are also some  

downsides to broadcasting around like this routers  are made to forward traffic between networks so  

what would happen if they received a broadcast  well the larger network could get flooded with  

broadcast messages also if a broadcast message  gets forwarded from one router to another router  

it may get stuck in a loop the simple solution to  this is routers never forward broadcast messages  

all IP broadcast messages stay within the local  network that makes us wonder then what if we  

do need to announce something to other parts of  our network an example of this might be a server  

that's sending a video stream several devices in  the network wanted to Union and watch this video  

stream one option is perhaps we could send video  traffic to each device individually that's the  

unicast traffic we discussed before unfortunately  that's inefficient because we would need to  

duplicate this traffic for every single recipient  broadcasting is no good for two reasons first  

not all devices want to receive the stream I mean  what would a printer do with a video stream second  

broadcast don't get passed the router so other  subnets would not be able to receive the traffic  

the way we make this work is with a technology  called multicast multicast uses special IP  

addresses we mentioned this back in the last video  we spoke about Class D these addresses range from  

2 to 4 0 0 0 to 239 255 255 255 we won't get into  much detail here but basically multicast is a way  

for devices to opt-in to receiving certain traffic  the video server sends traffic to a multicast IP  

and other hosts look for traffic sent to that IP  routers also forward multicast so the traffic can  

reach the networks it needs to get to so imagine  you back in that room full of people if all of you  

broke out into small groups and you spoke to your  small group while ignoring everyone else then your  

multi casting this is a lot of information  to take in so see if you got it all we just  

spoke about three different special address types  can you remember what they are and how they work

IP addresses need to be unique if they are  to work properly it's like your home address  

if someone somewhere else in the country has  exactly same address as you your mail might  

end up their place or their mail may end up  at yours so how do we make sure that the IP  

addresses in your network are unique what's to  stop someone else in another company using the  

same addresses that you have IP addresses are  managed by an organization called the internet  

assigned numbers Authority they give large blocks  of addresses to sub organizations around the world  

called regional internet registries each RIR  has a different name the one that we use here  

in Australia is called the asia-pacific network  information center or AP Nick the our IRS then  

assign blocks of RP space either directly to you  if you're a large enough customer or they'll also  

assign blocks to internet providers then ISPs the  internet providers will give some of their space  

to the smaller customers while this process is a  necessity there are some problems we'll face if  

you want to create a new network you may need  to get more IP space and that can really slow  

you down also we use up IP space very quickly as  we have already seen we run into problems when  

we run low on IP addresses so to address these  issues in the mid-1990s a standard called RFC  

1918 was released if you're not familiar with  RFC's their standards that describe how certain  

internet technologies work I'll include a link  to one of them if you're interested but be warned  

they're very detailed and sometimes quite complex  so don't feel obligated to hub have a read anyway  

this particular RFC says that some IP spaces are  now reserved for private use you can use these  

IPS in any way that you see fit within your local  network all other IP s these are the ones that are  

assigned to you or to the ISP are called public  IPs remember these IPS the ones you see on your  

screen here you will see them a lot in your daily  life but there's something interesting about these  

addresses they are not allowed on the internet  why well this prevents us from overlapping with  

any other company that is using the same addresses  it also conserves IP addresses as we don't need  

to use so many public IP addresses anymore but  if they're not allowed on the internet how do  

you get access to the Internet even with private  addressing you still use some public addressing  

at the very least your internet provider will  give you one public address let's say you have  

a device in your network with the IP 170 to  1601 when it sends a message to the Internet  

the internet router will alter this message to  use a public IP address this is a process called  

NAT or network address translation it's a topic  all of its own so I won't go into any more detail  

on this right now we'll cover that in another  video some other time let me propose the simple  

question which RFC defines private addresses  which private address ranges does it define

we'll now take a moment to talk about how devices  get addresses there are two main ways and one less  

common way first you can login to a device and  configure an address this is called a static  

address as it doesn't change unless you manually  reconfigure it when you assign an IP address this  

way you need to choose the address and you need  to make sure it's unique if two devices end up  

with the same address will have an IP conflict  which causes us all sorts of problems you will  

commonly use this method for devices like routers  and some servers devices whose addresses should  

never change the second method is to set addresses  dynamically with a DHCP server a dhcp server has  

a pool of IP addresses available to it when  a device starts up it broadcasts a message  

around the local network to find the DHCP server  the server then gives it an IP address from its  

pool the server makes sure that it doesn't give  the same IP address to more than one device also  

there's no guarantee that the device will get  the same IP address each time that's part of  

what makes this process dynamic this is good news  for workstations laptops phones and tablets these  

are devices that may be mobile and will need  to get a new address whenever they move to a  

new network there's also a lot of these devices  so it's an easier method than logging into every  

single device and configuring them manually  now the third method it's a little unusual  

it's called automatic private IP addressing and as  far as I can tell only Windows uses it the basic  

idea is you don't statically set an IP address on  this machine the workstation starts and sends a  

broadcast message to find a DHCP server however it  doesn't find one this is when ap IP a let me did I  

get that correct apipa yep that's right now that  is when apipa kicks in it picks a random IP from  

the 169.254 dot 0 0 / 16 space and assigns that  to the workstation this kinda has its uses perhaps  

on a small network if the DHCP server fails then  devices can still reach each other they won't know  

what the default gateway should be so they won't  be able to reach other networks on the internet  

but at least they can reach each other personally  I would not recommend relying on this method

when we looked at the OSI model we learned how  extra headers are added to the data before it is  

sent this adds information needed for delivery  is like writing an address on an envelope IP is  

no exception to this it adds the header that you  see here not all the details that you will see  

will make a lot of sense right now we'll cover  a few of the fields but we won't get into a lot  

of detail for now the two important parts that you  need to know are the source and destination fields  

and they're pretty self-explanatory the version  field is also easy it's either for ipv4 or ipv6  

now this is where it gets interesting sometimes a  packet is too large for a particular device so the  

device will break the packet into smaller packets  and send each of them individually this is called  

fragmentation so this field here the fragment  offset tracks the order of these fragments so  

they can be reassembled in the right order at  the destination but sometimes we decide we want  

to prevent fragmentation altogether and we can  do that by using the flags field he's another  

interesting one remember earlier I said that  broadcast could go round and round and round  

in the circles if routers didn't stop them well  the same could happen to other kinds of traffic so  

to deal with is we have this time-to-live field  the device sending the packet sets a value in  

this field every time the packet passes through a  router the TTL value is lowered by one if it gets  

all the way to zero the packet is dropped this  is how we prevent a packet from looping forever  

if there is some sort of error in the network  next up we're going to look at the tcp/ip model  

this is somewhat like the OSI model but it has  a bit of a different approach let me know what  

you thought of this video in the comments and  subscribe if you don't want to miss anything new