Multicast Explained in 5 Minutes | CCIE Journey for Week 6-12-2020

Summary

In this video, the creator shares progress on their CCIE journey, focusing on multicast, QoS, and IP services like NTP, NAT, and redundancy protocols. Despite a sick child, family priorities took precedence, but steady study progress was made. The video explains multicast in under five minutes, describing how it efficiently manages network traffic through IGMP and PIM protocols. The creator reflects on using resources like CBT Nuggets and is halfway through their CCIE Encore textbook, targeting a slower, more thorough approach to ensure success on the first exam attempt.

Takeaways

• 👨‍👦 The speaker prioritized family last week due to a sick child, showing the importance of balancing family and study.
• 📚 The speaker is halfway through the Encore textbook, progressing steadily in their CCIE journey.
• 🎥 Their study method involves watching CBT Nuggets videos for a high-level understanding, followed by reading textbooks and practicing with exams.
• 💻 This week, the focus was on multicast, QoS, and IP services like NTP, first hop redundancy protocols, and NAT.
• 📖 Last week, the speaker completed topics on IP routing, including EIGRP, OSPF, and BGP, building on their previous knowledge.
• 🌐 The speaker explained that multicast solves the issue of bandwidth overload by allowing multiple receivers to subscribe to one stream, as opposed to unicast or broadcast methods.
• 🔁 Multicast uses IGMP for Layer 2 communication between the router and endpoints and PIM for Layer 3 routing decisions.
• 🔗 PIM helps routers find the most efficient paths for multicast streams, and techniques like rendezvous points are used to optimize the process.
• 🖧 IGMP snooping helps switches efficiently deliver multicast traffic only to the intended receivers, preventing unnecessary bandwidth usage.
• 🏫 The speaker highly recommends CBT Nuggets and the Encore course for deep dives into multicast, configuration, and labs, while noting their own CCIE exam preparation timeline may need adjusting.

Q & A

What progress has the speaker made in their CCIE journey?

The speaker is about halfway through the Encore textbook and has been watching CBT Nuggets to supplement their study. They've focused on multicast, QoS, and IP services such as NTP, first hop redundancy protocols, and NAT.

Why didn't the speaker record a video last week?

The speaker had a sick child and prioritized taking care of their family, putting family first over studying and recording.

What is the speaker's method for preparing for the CCIE exam?

The speaker's method involves watching CBT Nuggets for high-level understanding, then digging into the details with the textbook, followed by practice exams before taking the final exam.

How does multicast solve the issue of multiple sessions in a network?

Multicast allows the server to send one stream of data into the network, and devices can subscribe to that stream. This reduces the number of individual sessions the server has to manage, compared to unicast.

What role does IGMP play in multicast routing?

IGMP (Internet Group Management Protocol) occurs at Layer 2 and allows a receiver to inform the router that it wants to subscribe to a multicast stream.

What is PIM, and how does it assist in multicast?

PIM (Protocol Independent Multicast) occurs at Layer 3 and helps routers find the most efficient path to the server for multicast streams. There are various modes of PIM, such as sparse mode, dense mode, and source-specific multicast.

What problem does IGMP snooping solve in multicast networks?

IGMP snooping helps switches manage multicast streams more efficiently. Without IGMP snooping, switches flood multicast traffic to all devices in a segment, even if they don’t want the stream. IGMP snooping ensures the multicast stream is only sent to the appropriate receiver.

What tools is the speaker using to prepare for multicast in the CCIE exam?

The speaker is watching content on multicast in CBT Nuggets and using virtual labs to practice and configure multicast. They also plan to use Boson practice exams closer to their exam date.

What challenges is the speaker experiencing with their CCIE preparation?

The speaker feels overwhelmed by the volume of content and is reconsidering their initial timeline to take the exam by the end of June or early July. They want to ensure they master the content and pass the exam on the first try.

What are the next steps in the speaker's preparation for the CCIE exam?

The speaker will continue following their method of studying and practicing labs. They also plan to take practice exams from Boson and will demo these exams on their channel when the time comes.

Outlines

00:00

📚 CCIE Journey Progress and Multicast Challenge

The speaker reflects on their CCIE journey, highlighting a missed week due to family priorities. Despite not recording a video last week, they made significant progress, reaching halfway through the Encore textbook and supplementing learning with CBT Nuggets videos. The study strategy involves watching videos for a high-level understanding, followed by reading textbooks and practicing exams. This week focused on multicast, QoS, and IP services like NTP and NAT. The speaker also revisited IP routing concepts (EIGRP, OSPF, BGP). A viewer challenged them to explain multicast in five minutes, which pushes the speaker beyond their comfort zone.

05:02

🎯 Explaining Multicast in Networking

Multicast addresses the problem of one device (e.g., a server) sending data to multiple endpoints efficiently, without clogging bandwidth like unicast or broadcasting. Unicast would overload the system, while broadcasting sends unnecessary data to all devices. Multicast sends one stream that devices can subscribe to. Two main protocols manage this process: IGMP (for endpoint and router communication) and PIM (for efficient route determination across routers). The speaker explains how PIM, with modes like rendezvous points, helps find the best path for multicast streams and how multicast routing differs from unicast.

🔧 How Multicast Data is Distributed

Once the multicast stream reaches the router, it needs to be sent to the appropriate clients. The router sends the stream out, but initially, it reaches all devices in the segment, including those not subscribed. The switch handles this via MAC addresses. Without IGMP snooping, the multicast frame is sent to all ports, but with snooping enabled, the switch learns which clients want the stream, optimizing delivery to only the subscribed clients. The speaker touches on PIM modes, multicast complexity, and the value of CBT Nuggets Encore content for deeper multicast learning.

🚀 Personal Reflection on the CCIE Journey

Reflecting on their progress, the speaker shares feelings of being overwhelmed by the vast amount of content. While following along with CBT Nuggets and being halfway through the Encore textbook, they reconsider the aggressive goal of completing by the end of June or early July. The speaker emphasizes the importance of mastering the content and passing the exam on the first attempt. To prepare, they plan to use Boson practice exams and demo them on their channel. The speaker ends by summarizing the week’s focus on multicast, QoS, and IP services.

Keywords

💡Multicast

Multicast is a network routing method where data is sent from one server to multiple receivers, allowing efficient bandwidth usage. In the video, multicast is explained as a solution to the issue of unicast and broadcast, where instead of sending multiple individual streams or flooding all devices, one stream is sent, and only subscribed receivers access it.

💡IGMP (Internet Group Management Protocol)

IGMP is a protocol used in multicast to enable devices to join or leave multicast groups. In the video, IGMP is described as facilitating communication between the endpoint and the router, with the endpoint requesting to join a multicast stream. This process is crucial for receivers to get the desired data stream.

💡PIM (Protocol Independent Multicast)

PIM is a routing protocol used to efficiently route multicast packets through a network. The video introduces PIM as the mechanism responsible for finding the most efficient path for delivering multicast data from the server to the receivers. The video also mentions different deployment modes of PIM, such as rendezvous points, that help optimize this process.

💡QoS (Quality of Service)

QoS refers to the ability to manage network traffic to ensure the performance of critical applications. In the video, QoS is one of the topics the speaker focuses on during their CCIE preparation, highlighting its importance in controlling data flow and prioritizing network traffic to maintain a high quality of service.

💡NAT (Network Address Translation)

NAT is a method used to map private local addresses to a public one before sending data to another network. The speaker mentions NAT as part of the IP services they are studying, indicating its role in managing IP addresses and maintaining security and scalability in the network environment.

💡Encore Textbook

The 'Encore' textbook refers to the core study material for the Cisco CCNP/CCIE Enterprise exam, focusing on advanced networking concepts. The speaker is halfway through this textbook and uses it in combination with other study resources, such as CBT Nuggets, to prepare for their exam.

💡CBT Nuggets

CBT Nuggets is an online learning platform that offers video training for IT certifications, including CCIE. The speaker references using CBT Nuggets as a supplementary resource to gain high-level explanations before diving into the textbook, making it an essential part of their study routine.

💡First Hop Redundancy Protocols

First Hop Redundancy Protocols (FHRP) provide a backup for the default gateway, ensuring continuous network access in case of a router failure. The speaker mentions studying this as part of their focus on IP services, emphasizing its role in network availability and failover processes.

💡IGMP Snooping

IGMP Snooping is a method used by network switches to limit multicast traffic to only the ports that have requested it, improving efficiency. In the video, the speaker describes how this technique reduces unnecessary traffic by sending multicast packets only to subscribed devices instead of flooding the network.

💡CCIE Journey

The CCIE (Cisco Certified Internetwork Expert) journey refers to the speaker's personal process of preparing for one of the most challenging certifications in networking. Throughout the video, the speaker shares their progress, study methods, and challenges, like balancing family responsibilities with their CCIE preparation.

Highlights

The speaker balances family responsibilities with their CCIE study journey, prioritizing family when necessary, especially when their child was sick.

Despite not recording a video the previous week due to family commitments, the speaker made significant progress in their studies, focusing on multicast, QoS, and IP services.

The speaker’s study method involves watching CBT Nuggets first to gain high-level understanding, then diving into the textbook for details, and finally practicing with exams.

This week, the speaker focused heavily on multicast, QoS, IP services like NTP, first-hop redundancy protocols, and NAT.

In previous weeks, they finished studying IP routing protocols, such as EIGRP, OSPF, and BGP, which they were already comfortable with but continued to lab and review.

Multicast solves the problem of one device initiating sessions to multiple endpoints by allowing devices to subscribe to a data stream instead of creating individual sessions for each endpoint.

IGMP (Internet Group Management Protocol) allows receivers to subscribe to a multicast stream by communicating with the router at Layer 2, requesting specific multicast IPs.

PIM (Protocol Independent Multicast) operates at Layer 3 and helps routers find the most efficient path to a server, utilizing methods like rendezvous points to connect receivers and servers.

Switches in multicast scenarios initially flood packets to all ports, but with IGMP snooping, switches can send multicast packets only to subscribed devices, reducing unnecessary bandwidth usage.

The speaker explains the complexity of multicast and emphasizes that it requires a deep understanding of different PIM modes, such as dense mode, sparse mode, and source-specific multicast.

The speaker relies heavily on CBT Nuggets' Encore course for in-depth explanations and multicast lab configurations, praising its detailed approach.

They express a growing sense of being overwhelmed by the sheer volume of content, though they remain committed to mastering it for their CCIE exam.

The speaker considers adjusting their exam timeline, feeling that aiming for the end of June or early July might be too aggressive, as they want to ensure thorough mastery of the material.

They plan to use Boson practice exams to gauge their progress and will demo the exams on their channel when the time comes.

Overall, the speaker remains focused on passing the CCIE exam on their first try, emphasizing the importance of feeling confident in practice exams before scheduling the real test.

Transcripts

another week on my CCIE journey is in

the books what have I been up to and can

I explain multicast in five minutes

let's find out

I didn't record a video last week and

that's okay I had a sick child it's very

important to put family first and when

he's sick that's what really matters to

me I don't want to spend my time

studying and recording when I need to be

taking care of my family but that

doesn't mean I didn't make progress I've

made a lot of progress at this point I'm

actually about halfway through with the

encore textbook and of course I'm

watching CBT Nuggets to supplement that

my method has always been watched the

Nuggets first just so I get the high

level great explanation and

understanding dig into the details with

the textbook and then finish with

practice exams before taking the exam so

I've already watched these Nuggets

before I get access to watching them

before they're even released so I'm

watching them again while I'm reading

the relevant topic and this week I

focused heavily on multicast QoS and the

IP services so that's things like NTP

the first hop redundancy protocols and

then NAT so that's been what I've been

focusing on this week last week in since

I didn't bring this up I did finish up

pretty much all of the IP routing items

that I was worried about there that

would be eigrp OSPF and of course bgp

which are things that i've already been

pretty comfortable with in the past but

it doesn't hurt to dig into them lab

them up even some more so this week

somebody tweeted me and said they would

love for me to try to explain multicast

and what I'm gonna try and do is I'm

just gonna give a high-level summary I'm

gonna try and get it done in under five

minutes

this always helps me to talk about these

topics that I'm learning about too and

while I've done multicast in the past

this is really pushing me beyond my

comfort zone so without further ado

let's jump on the whiteboard see if I

can explain multicast in five minutes so

multicast solves the problem of one

device like this server here trying to

initiate sessions to multiple endpoints

what we call receivers which are going

to be these green squares that are

supposed to represent computers but I'm

terrible at drawing so in a unicast

setting all of these devices could form

sessions directly to this server and get

the streaming information that way but

that would obviously clog a bandwidth

all of these routers along the way and

the server itself would have to maintain

sessions for each one of these devices

and here we've only got five devices on

the screen but what if we had thousands

or even tens of

well that would obviously be

unmanageable a broadcast is also a way

that we could handle these situations

but now every single device on the

network has to manage that packet

whether it wants the data or not

multicast solved this problem by the

server sending in one stream of data

into the network and then the devices

choosing to subscribe to that stream if

they want to multicast packets have to

be routed just like a router has to

route unicast packets but it does all of

this subscription and routing through a

couple different protocols the first

protocol that comes into play here is

called IGMP and this occurs at layer two

IGMP is basically started by the

endpoint here the receiver who tells the

router hey I want to subscribe to a

stream that's on a multicast IP

something like 224 one two three so the

endpoint the computer here the receiver

says I want to subscribe to 224 dot one

to two to three please mister router go

find that for me there's a lot more that

goes into IGMP but that's the gist of it

IGMP just occurs between the router and

the endpoint these receiver here from

there

pim steps into play and that occurs at

layer 3 there are a bunch of different

flavors and deployment methods or modes

for pim but the idea here is that this

router at this point is now trying to

find the most efficient path to get to

the server so when all the interfaces on

this router that pim is running it will

start sending messages out to the next

router saying hey if you see a stream

for 220 4.1.2 dot three I want it now

how it arrives to this conclusion that

depends on the flavor of pim that you're

deploying there could be things called

like a rendezvous point where all the

routers check in first before receiving

the stream or these streams check in

with that first before sending it on to

a client the rendezvous point is

basically like the friend who's hooking

you up with a blind date hay receiver

meet the server server mate the receiver

and then from there they go on the date

and they figure out their own path

forward and once they figured out the

own path forward at least in Cisco

deployments the router were then build

the

fastest path or the shortest path to the

end point to make the most efficient way

to collect the stream from the server

and get it into the hands of the end

points but how the router gets it into

the hands of the end points is where it

gets pretty interesting let's clear the

screen and talk about what happens in

this link right here think about the

goal of multicast again for a moment

multicast stream has made its way into

the router and now it's time to get it

into the hands of our green receiver

here the orange receiver doesn't want

that stream it's not subscribed to it

how does it work the point of multicast

was to simply send a stream out towards

a group of clients and if the group of

clients want that stream they can access

it so by default what this router is

going to do is it's going to send that

stream into the segment which hits this

switch and the switch by default is

going to send it to all of the receivers

on that segment so even the orange

client that doesn't want that multicast

stream is going to get it and it's gonna

have to end up discarding what's really

happening under the hood here is we have

the multicast IP address the multicast

group here to 24.1 2.3 that's all great

and all because that's layer 3 but now

at this point we're on layer 2 so layer

2 technologies are what's gonna have to

carry the stream from the router into

the endpoint so what happens under the

hood is a multicast MAC address 0 1 0 0

5e and then the remaining 3 portions are

gonna be built using the multicast IP

address so just for simplicity sakes

this isn't correct I'm going to put this

1 2 3 so the destination frame will be

this MAC address the router sends that

destined to that MAC address into the

switch and here's the kicker because no

device has that MAC address as their

source that MAC address does not exist

in the MAC address table on this switch

and what does a switches default

behavior when it receives a frame that

it doesn't know the destination to it

sends it out every port in the same V

link so when the green client says I

want that stream it does begin listening

on that MAC address but again it will

never source a frame with that MAC

address so the switch will never learn

about that mac-address from that poor

again because the default behavior is

going to be descended out all ports on

that segment it's gonna get sent out

towards the orange client here too and

because the orange client isn't

listening on that MAC address it will be

dropped at the Nick that still creates a

lot of unnecessary choke in this segment

right here so what the switch kit enable

is something called igmp snooping that

way when the green client sends in its

IGMP join request basically saying hey

mr. router I want to listen to this

group the switch can then associate the

destination MAC address with that port

and it will only ever be sent out the

correct port again so that's been the

crash course of multicast obviously

multicast is a lot more complicated than

that when you start talking about the

different PIM modes like dense mode

sparse mode source-specific multicast

and one of the cool things about

multicast and specifically on core

training is that Keith Parker didn't

explain it in five minutes he goes into

detail and even demos how to configure

in-lab multicast within the virtual labs

in the CBT Nuggets encore course it's

been crucial for my multicast training

watching his content on CBT Nuggets so

if you haven't checked out the encore

content on CBT Nuggets or if you're

interested in multicast I can't stress

it enough check out the description for

my link to the Encore content and you'll

get fired up ready to go learning for

encore training so how am I feeling

overall about my journey towards CCIE

and getting towards encore at this point

and halfway through the book I'm doing

good following along with CBT Nuggets

but it is a tremendous amount of content

I'm starting to get that overwhelmed

feeling like maybe end of June or early

July is a bit aggressive I need to take

my time a little bit slower and master

this content even more I really want to

nail this exam I don't need to crush it

but I want to pass it for sure I want to

pass it on my first try so it really

comes down to how I'm performing on the

practice exams I am going to be using

the boson practice exams and I will demo

those practice exams here on my channel

when that time comes so look at that for

the end of June

but until then that's been the progress

towards my CCIE journey tackling

multicast QoS and was I

services this week thanks for stopping

by I'll see you in the next one