Cisco CCNA ICND2 640-816

IPv6: Understanding Basic Concepts and Addressing

by Jeremy Cioara

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Video Title Duration
1. Review: Rebuilding the Small Office Network, Part 1
2. Review: Rebuilding the Small Office Network, Part 2
3. Review: Rebuilding the Small Office Network, Part 3
4. Switch VLANs: Understanding VLANs
5. Switch VLANs: Understanding Trunks and VTP
6. Switch VLANs: Configuring VLANs and VTP, Part 1
7. Switch VLANs: Configuring VLANs and VTP, Part 2
8. Switch STP: Understanding the Spanning-Tree Protocol
9. Switch STP: Configuring Basic STP
10. Switch STP: Enhancements to STP
11. General Switching: Troubleshooting and Security Best Practices
12. Subnetting: Understanding VLSM
13. Routing Protocols: Distance Vector vs. Link State
14. Routing Protocols: OSPF Concepts
15. Routing Protocols: OSPF Configuration and Troubleshooting
16. Routing Protocols: EIGRP Concepts and Configuration
17. Access-Lists: The Rules of the ACL
18. Access-Lists: Configuring ACLs
19. Access-Lists: Configuring ACLs, Part 2
20. NAT: Understanding the Three Styles of NAT
21. NAT: Command-line NAT Configuration
22. WAN Connections: Concepts of VPN Technology
23. WAN Connections: Implementing PPP Authentication
24. WAN Connections: Understanding Frame Relay
25. WAN Connections: Configuring Frame Relay
26. IPv6: Understanding Basic Concepts and Addressing
27. IPv6: Configuring, Routing, and Interoperating
28. Certification: Some Last Words for Test Takers
29. Advanced TCP/IP: Working with Binary
30. Advanced TCP/IP: IP Subnetting, Part 1
31. Advanced TCP/IP: IP Subnetting, Part 2
32. Advanced TCP/IP: IP Subnetting, Part 3

Review: Rebuilding the Small Office Network, Part 1

Review: Rebuilding the Small Office Network, Part 2

Review: Rebuilding the Small Office Network, Part 3

Switch VLANs: Understanding VLANs

Switch VLANs: Understanding Trunks and VTP

Switch VLANs: Configuring VLANs and VTP, Part 1

Switch VLANs: Configuring VLANs and VTP, Part 2

Switch STP: Understanding the Spanning-Tree Protocol

Switch STP: Configuring Basic STP

Switch STP: Enhancements to STP

General Switching: Troubleshooting and Security Best Practices

Subnetting: Understanding VLSM

Routing Protocols: Distance Vector vs. Link State

Routing Protocols: OSPF Concepts

Routing Protocols: OSPF Configuration and Troubleshooting

Routing Protocols: EIGRP Concepts and Configuration

Access-Lists: The Rules of the ACL

Access-Lists: Configuring ACLs

Access-Lists: Configuring ACLs, Part 2

NAT: Understanding the Three Styles of NAT

NAT: Command-line NAT Configuration

WAN Connections: Concepts of VPN Technology

WAN Connections: Implementing PPP Authentication

WAN Connections: Understanding Frame Relay

WAN Connections: Configuring Frame Relay

IPv6: Understanding Basic Concepts and Addressing

00:00:00 - It's the final topic of the CCNA series, and I'd like to say
00:00:04 - we saved the best for last because it's a cool one,
00:00:08 - TCP/IPv6.
00:00:10 - This marks a pretty monumental day because TCP/IPv6
00:00:14 - has actually been out for a long time, more than
00:00:18 - a decade. I remember teaching back in 1997-98
00:00:22 - timeframe. One of, one of the first areas
00:00:26 - I taught in was Microsoft and I was teaching Microsoft Internet
00:00:29 - Information Server 3, and I remember saying, I believe that
00:00:34 - the whole Internet will be TCP/IPv6 by the year 2003
00:00:37 - because I just, I pulled the data out of the
00:00:41 - year because I figured it's gotta be by then, right?
00:00:45 - And well 2003 came and went and my prediction went unheard until
00:00:49 - now, until 2008 timeframe and we're now looking at TCP/IPv6
00:00:54 - as a very viable alternative and it's starting to move into all
00:00:59 - CISCO curriculums. So what we're going to talk about as we get into
00:01:02 - here is understanding the basic concepts and addressing.
00:01:05 - We're not going to be able to go in depth into every, everything
00:01:08 - TCP/IPv6, but this will give you a very good idea
00:01:13 - of where this technology is going and what it's going to look
00:01:16 - like. First question I want to ask is will we ever need to upgrade
00:01:20 - to IPv6? Meaning we've survived this long in IPv4,
00:01:23 - is there really a need? We'll then look at the IPv6
00:01:27 - addressing format and what the new kinds of addressing
00:01:30 - look like. They're big. We'll then look at the headers and address
00:01:34 - types because there's many different kinds of IP addresses
00:01:37 - in IPv6, and we'll do some in-depth exploration
00:01:40 - into what these new addresses look like and even basics of
00:01:45 - how we can start subnetting.
00:01:47 - Do we really need IPv6? The answer is yes, but it's
00:01:53 - more of a hidden thing, kind of like spam,
00:01:57 - email spam. Email spam in recent years has reached all new
00:02:02 - levels in that there are literally hundreds of thousands of
00:02:05 - spam emails being sent out every single minute all around the
00:02:09 - globe. We know there's a problem but we've got spam filters
00:02:13 - that are good enough to detect most of the spam and filter it
00:02:16 - out of our corporate email accounts. So we just kind of are
00:02:19 - turning a blind eye, but we need to fix the spam problem. We
00:02:23 - need a solution. It's just as of right now we kind of have this
00:02:26 - band-aid in place of filtering that people are just like, okay, we'll just,
00:02:29 - we'll pretend the spam is not really there. In the same sense
00:02:33 - we've got IP addresses on the Internet, and we've had
00:02:37 - TCP/IPv4 for years that has been running NAT.
00:02:40 - We have NAT happening to where we can have hundreds of
00:02:45 - clients share the same public IP address on the Internet
00:02:48 - as they go out. So there's a problem, there's an IP address
00:02:52 - shortage but it's so hidden. It's kind of like the spam filter.
00:02:55 - It's like, well we'll just pretend that there's not really a shortage
00:02:59 - because NAT fixes most of that.
00:03:01 - The U.S. Have, yes, Virginia, there is an IP address shortage.
00:03:05 - It's kind of like the, the famous Santa Claus editorial, but the U.S.A.,
00:03:10 - the United States who invented the Internet is still sitting
00:03:12 - pretty in the sense that they have tons of public addresses
00:03:16 - left, a lot of them just sitting there idle and unused. It's
00:03:20 - the rest of the world where the problem is. Until very recently,
00:03:23 - how generous, right, the United States gave Asia and Africa
00:03:28 - a single class C IP address range for their entire country.
00:03:33 - Wow. And they were, it was expected that Asia and Africa
00:03:37 - would use NAT to, to have that one class C IP address kind of
00:03:40 - last the country. Now recently they have gotten more and that
00:03:44 - the IP addresses are spreading out, but at the same time there
00:03:48 - are extreme shortages in countries outside of the United States.
00:03:52 - So what I will say, I'll add this little bonus piece right here, the
00:03:56 - the other countries are actually far ahead of the United States
00:04:00 - in implementing IPv6 because they have a desperate
00:04:03 - need for it. The United States is kind of like, ah, yeah, we know there's
00:04:07 - a problem, but it hasn't really affected us so much yet so we're
00:04:10 - very slow and migrating. But
00:04:13 - the Department of Defense, the people who created the Internet
00:04:17 - have said the year 2008 will be a big year for them because that's
00:04:20 - when they'll move all their networks to TCP/IPv6.
00:04:24 - So it's happening. The United states is just a little slow.
00:04:28 - So current IP addresses are poorly allocated. Agencies
00:04:31 - needing class C back in the day got a whole class B, and they
00:04:35 - now have all these addresses that they're just sitting on and
00:04:38 - not really using especially college universities. College
00:04:42 - universities were the first adopters of the Internet. They
00:04:45 - have tons of IP addresses that, well I won't say all of them
00:04:48 - but many of them have just, I'll, I'll throw one of them out
00:04:52 - there, University of Utah. I was actually talking with somebody
00:04:55 - who worked on the ITs out there. They said they have four unused
00:04:58 - class B public IP addresses just, just because that's what
00:05:03 - they had. Nothing, nothing against University of Utah. They
00:05:06 - just applied for that back in the day, and now they have them
00:05:08 - and they're just not using them. So estimates on IPv4
00:05:12 - exhaustion is largely debated, meaning some people say by
00:05:15 - the year 2009 we'll be out. Frankly, I really doubt that just because
00:05:20 - we've lasted this long, and I think we should be able to last
00:05:23 - a little longer. Some estimates go as far as the year 2041
00:05:27 - one where we'll be out, but hopefully by then we've migrated over
00:05:30 - anyhow. New network devices are on the rise. NAT is currently
00:05:35 - seen as a prohibitor of progress rather than a good solution
00:05:41 - anymore. That NAT is what allows our current Internet
00:05:44 - version to survive even though we've, we'd have no where near
00:05:47 - the amount of IP addresses that we need. So I guess let me
00:05:53 - give you a picture of the future,
00:05:56 - in my humble opinion. I believe that in the future when
00:06:03 - IPv6 is everywhere every single thing on the face
00:06:09 - on this planet will have an IP address. The technology to
00:06:13 - do that has been there for quite a while. We have cars that
00:06:16 - have IP addresses. We have refrigerators and microwave oven,
00:06:20 - Maytag makes them, that have IP addresses. So the technician
00:06:23 - can run diagnostics on the refrigerator remotely without having
00:06:27 - to send somebody out to figure out what's wrong with it. We
00:06:31 - have watches that have IP addresses, cell phones that have IP addresses.
00:06:34 - We have the technology to give pets, animals, dogs, cats IP
00:06:40 - addresses. All of the pets that you buy at the pet store nowadays
00:06:43 - come chipped is what they'll, they'll call it which is a chip
00:06:47 - that allows you to scan the pet and see who that pet belongs to.
00:06:51 - Well it's not too hard to modify that chip to have IP address
00:06:55 - where you could go to
00:06:57 - and find out where your dog is, you know, using
00:07:01 - some GPS signaling and stuff. There was a test done in New York City
00:07:05 - where people were volunteering to have chips the size of a
00:07:09 - grain of rice implanted in them that is biometrically powered, meaning
00:07:13 - their body energy powers these chips, and it allows them to be
00:07:17 - tracked wherever they go. It's part of an experimental program
00:07:20 - that is supposed to help with kidnappings, meaning children
00:07:24 - that are kidnapped will be able to be found much quicker
00:07:27 - because well
00:07:30 - you see where I'm going. If your children are chipped, they will
00:07:33 - be able to be tracked. Now that's somewhere in the middle
00:07:37 - of my digression there. We went from facts of cars and, and microwave
00:07:42 - oven to my theories of pets and people. But my point in all of
00:07:47 - this is the technology is there, and when IPv6 comes
00:07:51 - out you'll have the infrastructure now able to support it. Likewise,
00:07:57 - in the future, future features we're gonna see IPsec
00:08:01 - everywhere, meaning IPv6, this next version, has
00:08:06 - IPsec built in. So all network communication on every network
00:08:10 - work can be encrypted. So you'll see a big security rise. You'll
00:08:16 - see mobility where we can actually move from network to network
00:08:19 - as we're moving that will help with cars and things like that, has
00:08:23 - better mobility functions, and IPv6 has a simpler header
00:08:27 - than IPv4 which will improve on the processing
00:08:30 - power of all the different routers that use it.
00:08:34 - So now let's talk about some of the addressing, IPv6
00:08:38 - addresses. When, when people first started hearing about
00:08:41 - it a lot of people including myself thought it was going to
00:08:43 - be something like this. You had IPv4 so it would be something like
00:08:47 - that for version 6.
00:08:49 - They didn't do that. IPv6 addresses look like that.
00:08:55 - They are eight octets. I'll go right to left, one, two, three, four,
00:09:00 - five, six, seven, eight. With four characters each, it is now converted
00:09:05 - to hexadecimal, so A through F are valid characters
00:09:09 - along with numbers zero through nine. The point is that they
00:09:13 - don't want to do this upgrade ever again. We want to make sure
00:09:17 - that we can pick in a protocol and stay with it forever. Now
00:09:20 - I'm sure when people were creating TCP/IPv4
00:09:24 - they thought this will last forever and we ran out of addresses.
00:09:28 - And here I am IPv6 saying this will last forever, and
00:09:32 - maybe some guy like me in 50 years will be saying, oh, no,
00:09:35 - we, we thought we'd have enough addresses. But look at this, when
00:09:38 - we moved from 32-bit to 128-bit
00:09:41 - addressing we moved up to that many addresses. I say that
00:09:47 - many because I don't know how to pronounce that number. Somewhere
00:09:51 - around here we have the millions, billions, trillions, and then
00:09:55 - you lose me. I think somebody told me once it was like a
00:09:59 - quintillion or quintrillion, I don't know.
00:10:03 - It's a lot of addresses. Somebody far geekier than me figured out
00:10:07 - that with that many addresses we can give every square inch
00:10:12 - of the planet earth approximately 3.6 million addresses
00:10:17 - per square inch. Every three square feet of the Milky Way
00:10:20 - galaxy can be given an IP address with this scheme. So
00:10:25 - to tell you that's a lot of addresses. We're not going to be running
00:10:29 - out any time, any time soon. So because the addresses are so
00:10:34 - long, they decided to make them more manageable. They divided
00:10:37 - them into eight groups. So instead of dots like we have
00:10:40 - 192.168, we have colons. Each group is four
00:10:45 - hexadecimal
00:10:47 - characters each. Now you can see these are quite long to write so
00:10:51 - they came up with rules to eliminate some zeros and make them
00:10:54 - easier to manage. First off, rule number one is in an IPv6
00:10:59 - address you can eliminate groups of consecutive zeros by
00:11:03 - using a double colon,
00:11:05 - but you can only use it once per address. So you can see
00:11:10 - I had three groups of zero and I was really able to shorten that
00:11:14 - by just representing those three groups by putting double colons.
00:11:17 - But you could only use that once in an address. You should never
00:11:21 - see an address that has two sets of double colons because otherwise
00:11:24 - you wouldn't know how many zeros went in each location.
00:11:28 - Rule number two to shorten addresses is that you can drop
00:11:32 - leading zeros. So things like 0050 become 50,
00:11:36 - 0AB4 becomes AB4. So that allows you to really
00:11:42 - shorten this down to make it more manageable. Now it's still pretty
00:11:45 - long when you compared it to an IPv4 address, but at
00:11:48 - least if you're writing it, you're not going to be writing addresses
00:11:50 - like that every single time.
00:11:53 - Along with the bigger address IPv6 also provides
00:11:58 - a simpler header. I mentioned this when I was talking about
00:12:01 - the rationale for moving. In ICND1 we talked about
00:12:05 - an IPv4 four header and all these different fields that are
00:12:08 - in there like time to live, protocol, the checksum, flags,
00:12:12 - all kinds of stuff in the header that makes the, the packet harder
00:12:16 - to process for every single router.
00:12:18 - Down here is an IPv6 header. It still has some flags
00:12:22 - in there like how many hops it can go. Oops, I missed it.
00:12:25 - This one right here takes the place of time to live and, and, you know,
00:12:29 - the next header field provides a field for expanding headers
00:12:33 - and so on. And I don't mean to get into all those. The point is that it is much
00:12:37 - simpler. It's a bigger header meaning lengthwise it actually
00:12:42 - adds more data to the packet because our addresses are so big,
00:12:46 - but at the same time it's simpler for a router to process because
00:12:49 - it doesn't have to look at as many fields.
00:12:53 - Now we'll get into the real meat of the differences between
00:12:56 - IPv4 and v6 as we look at how they communicate.
00:13:01 - First off, in IPv6 there are only three types
00:13:05 - of messages, a unicast, a multicast and an anycast.
00:13:12 - Notice that one is missing from the IPv4.
00:13:16 - Which one?
00:13:18 - Broadcast. It's gone. Good riddance. Broadcasts are now a
00:13:24 - thing of yesteryear. In IPv6 there is no such
00:13:28 - thing as broadcast. It has been replaced by multicast meaning
00:13:32 - one-to-many. By using multicast I can dictate exactly where messages
00:13:38 - are sent to just a certain group of computer, all the computers.
00:13:41 - Now I will tell you that using multicast you can actually
00:13:45 - accomplish the same goals as broadcast, and there are some
00:13:48 - multicast messages that you'll see in IPv6 that
00:13:51 - are very similar to a broadcast. But the good old broadcast
00:13:55 - is gone. We now have unicast which is one-to-one,
00:13:59 - multicast, one-to-many or, or a group of people,
00:14:03 - and then an anycast which is one-to-closest. Anycast is going
00:14:06 - to be pretty awesome because you can, with anycast, give multiple
00:14:10 - devices the same IP address. So let's say that we have two routers
00:14:15 - right here that connect to the Internet. One of them is
00:14:19 - in a, a branch office and, you know, connects over here and maybe
00:14:23 - one is a corporate office or, I just went bad somewhere
00:14:29 - in that. We've got two routers, and we'll say they're
00:14:32 - both connected. They're, they're redundant for each other in a corporate
00:14:35 - office. We have a router here that connects to, you know, one group
00:14:38 - of users and another connection over here that's another group
00:14:42 - of users. With an anycast IP address I could actually give both
00:14:46 - of these routers the same IP address. And when the users go
00:14:50 - out to surf the Internet they'll just use whatever IP address is
00:14:53 - closest to them. Now this example that I gave is, is kind of
00:14:57 - silly. Here's a better one. Let's say that you have
00:15:03 - the world.
00:15:06 - I know, an artist at his best. This is the world and this over
00:15:11 - in North America or, you know, here's Russia, this is Australia,
00:15:14 - you're catching the drift. So we've got the world, and let's
00:15:17 - take a, a worldwide Internet site like eBay.
00:15:22 - eBay has servers all over the world, and today they actually
00:15:26 - is some pretty complex systems to make sure that they load
00:15:29 - balance correctly and are redundant. So they might have a bunch
00:15:32 - of servers in the United States. And when I go to
00:15:36 - it directs me to those servers and I access the ones closest
00:15:39 - to me. When I am in Russia, if I go to
00:15:43 - there will be a DNS infrastructure set up that will somehow get
00:15:47 - me to the server closest to me. Now to set something like
00:15:50 - that up it's very complex, and you have to use load balancers
00:15:53 - caching servers, there's a lot to it. But within an anycast address you'll
00:15:57 - be able to, with IPv6, just give all those servers
00:16:01 - the same IP address no matter where they are in the world,
00:16:04 - and the routing protocols will automatically find the closest
00:16:08 - server to you any time you're trying to communicate with any
00:16:12 - eBay website. Pretty powerful.
00:16:15 - So those are the types of messages. Now in red you can see the
00:16:19 - types of addresses. This is going to be something we have to
00:16:22 - get used to as well. In IPv6 your device can have
00:16:27 - many IP addresses and often times will have many IP addresses
00:16:31 - that it uses to communicate. There are three different addresses
00:16:35 - that are defined right now. First off is a link local address.
00:16:40 - This is something that you use to communicate in your Layer 2
00:16:43 - domain. For example, if you have people that are plugged into
00:16:46 - the same switch they will use the link local address to communicate
00:16:51 - with each other. It's just one type of address that's used for local
00:16:54 - communication. The next step up is an interesting story, it's
00:17:01 - the unique or site-local address.
00:17:05 - Now the name has changed as the IPv6 protocol
00:17:09 - has evolved, and that address was originally eliminated because
00:17:13 - people were like, we don't need this. Let me explain what it
00:17:16 - is. We today in our organizations use private addressing.
00:17:22 - We use private addressing because we have a shortage of
00:17:25 - Internet addresses, and we don't want to pay to assign public
00:17:28 - addresses to all of our clients. So we're used to this idea
00:17:31 - of private address, private address, private address. Well in IPv6
00:17:34 - we have enough IP addresses to give every device
00:17:40 - an IP address in the world for years and years and years to
00:17:43 - come. We don't have any shortage anymore. So this whole concept
00:17:47 - of private address should go away meaning we don't need
00:17:51 - private addresses anymore. But we're so used to them. We
00:17:59 - have them in the unique and site scope. It's going to be your
00:18:04 - option whether or not you would like to use a unique local
00:18:08 - or site local scope in your organization, but those fill the
00:18:11 - role of "private addresses." You don't have to use
00:18:15 - them. It's just that people are so used to using them that,
00:18:21 - you know, you just can't change. For example, if, if somebody
00:18:26 - came up with a new way of brushing teeth where I could just walk
00:18:30 - and push a button and my teeth would automatically get brushed, I
00:18:33 - would still probably instinctively go to my cabinet and grab
00:18:37 - the toothbrush and start brushing my teeth every night at least for a couple
00:18:40 - years because I've just brushed my teeth my whole life, and the fact
00:18:44 - that I push this button doesn't make me feel like my teeth got
00:18:47 - brushed. That's, that's a really weird example, but that's kind
00:18:50 - of the example of this. For years and years to come we'll probably
00:18:53 - use unique and site-local scope addresses in IPv6
00:18:57 - because it's just what people are used to. They can't fathom.
00:19:01 - It's even difficult for me to fathom a network without private
00:19:04 - addresses, but I have a feeling in maybe five to 10 years
00:19:08 - after IPv6 is adopted we'll be talking about this
00:19:12 - as like, oh, yeah, we used to have these things called unique and
00:19:15 - site-local addresses.
00:19:18 - Those were for the people that were just so stuck in their ways, they
00:19:20 - could handle a global scope, you know. That's, that's probably the way people
00:19:24 - will talk about it, and they'll be describing people like
00:19:26 - you and I because we're so used to private addresses. But the
00:19:29 - global scope this is the Internet or what people are now
00:19:34 - calling the Internet 2. Global scope are public addresses
00:19:39 - or addresses that are alive on the Internet. Now the good news
00:19:43 - is that your organization will be able to have Internet addresses
00:19:47 - or global addresses for every device that is available within
00:19:51 - them. Let's look at those addresses in detail starting off with
00:19:55 - the link local address. That's the one that's auto-generated just
00:20:00 - like the PCs nowadays that can't find a DHCP server and they
00:20:04 - auto-generate that 169.254 address. But
00:20:07 - the difference is this is auto-generated regardless of DHCP
00:20:11 - server or not. Every device will have a link local address. Now
00:20:15 - this is where we get into a little of the technicalities of
00:20:18 - our IP addressing. The RFC has specified that these addresses
00:20:23 - will always begin with FE80. Now that is because
00:20:28 - the first 10 bits must be 1111111010.
00:20:33 - Now when I get into IPv6 addressing I needed
00:20:37 - a little hexadecimal review just because I'm so used to decimal and binary
00:20:41 - from IPv4. Moving into the hex world was a little
00:20:44 - tough. But the first thing you have to remember is that every
00:20:47 - single one of these digits are represented by four binary bits,
00:20:52 - one, two, three, four. Now the way it works is very similar
00:20:55 - to decimal. You have every character in the, in the address has
00:20:58 - four bits. All zeros is really zero. 0001 is really
00:21:03 - one. 0010 is two. We all know this. This is, this
00:21:08 - is basic binary, and you can keep going with that all the way up
00:21:11 - to just nine, you know, that would be 1001 equals
00:21:16 - nine. Now this is where the hexadecimal gets a little
00:21:19 - bit different because we also have up to 16 values. It's
00:21:23 - actually zero through 15. That's possible with four bits.
00:21:26 - So when we go to 1010 zero which would typically
00:21:31 - be 10, we then go to an A. 1011 ends up being B.
00:21:40 - We keep going, 10 or actually, hang on, 1100
00:21:46 - would end up being C and so on. You have 1101 is
00:21:51 - D. 1110 is E. And then finally, all 1's is how
00:21:56 - we end up with the F. So when you see that the first 10
00:21:59 - bits must be 1111
00:22:03 - for the first bits, it means that we're going to have F
00:22:05 - as the first one. You can see the E because that's the second
00:22:09 - set of four bits. Now you may be wondering well how did you get eight with
00:22:12 - only two bits? Well remember that the RFC specifies that the first
00:22:16 - 10 bits must be this. However, every single character in hex
00:22:22 - requires four bits to take place. So we have eight coming because
00:22:27 - it's 10 and not specified here, but the others are going
00:22:30 - to be zero to make up that character because these link local
00:22:34 - addresses always begin with these first 10 bits and are followed
00:22:38 - with 54 bits of zero. So you can assume that every single
00:22:42 - one of these characters is going to take four bits and if you
00:22:45 - ever see two bits, you only need two more to make a character. So that's
00:22:48 - where we get the eight from. And of course the zero bops in because
00:22:52 - every IPv6 address has four characters, four hexadecimal
00:23:00 - characters per octets separated by colon. So that's why we
00:23:03 - end up having that FE80. Technically speaking most of the
00:23:06 - time you'll see it written FE8 in the RFC standards,
00:23:10 - but zero is what you'll always have on your address because
00:23:13 - of the following 54 bits of zeros. So that's our first
00:23:16 - octet. All of these right here, first 64 bits is what we
00:23:20 - just talked about. Now the last 64 bit is where it gets
00:23:25 - a little bit weird. Let me clear this off here. The last 64
00:23:28 - bits is the 48-bit MAC address from the host, whatever
00:23:33 - host this is being generated on followed by or I should say squished
00:23:38 - between FFFE or that is squeezed in the middle.
00:23:42 - It's hard to say that because here's the idea. Let's say we've
00:23:46 - got host with this MAC address. Well that's 48 bits,
00:23:49 - but we need 64 to complete the 128-bit IP
00:23:52 - address. So what the last 64 bits will be is first four
00:23:57 - of the MAC address 0019, 0019,
00:24:02 - second D1, D1, and then for some reason the designers
00:24:07 - and the powers that be decided to squeeze FFFE
00:24:09 - right in the middle. So in every single link local address
00:24:13 - you'll always see the MAC address with this kind of sandwiched
00:24:16 - between the two ends and then you can see the rest of the
00:24:18 - MAC address, 22, 22, DCF3, DCF3. So
00:24:24 - that will end up comprising the last 64 bits of that
00:24:27 - IP address that is only used for link local communication.
00:24:31 - Now it doesn't have to be used, for instance, if you had other IP
00:24:35 - addresses that were being used to communicate outside. Those
00:24:38 - would be used but if you're speaking to somebody on the same
00:24:41 - link and you realize that you have a source address coming from
00:24:44 - that link then you can use your link local address to communicate
00:24:47 - with them.
00:24:49 - Now let's move into the second debated IP address type,
00:24:53 - the unique-local or site-local addresses. I think I mentioned this
00:24:57 - backwards before and corrected myself. Unique-local is the new name, RFC
00:25:02 - 4193. Site local is the old name that was an
00:25:05 - RFC 3513. So we're supposed to be calling
00:25:09 - these unique-local addresses which I actually like the old
00:25:13 - name better, site-local, because it really describes what
00:25:16 - they do. They are used within enterprise networks to identify the
00:25:20 - boundary of their networks. So
00:25:23 - you can expect that these addresses will be relatable to the
00:25:28 - private addresses of IPv4, for the 10 range 192.168,
00:25:33 - all that. This is kind of the same thing. Now as
00:25:36 - it is specified in the RFC, they will use the following format.
00:25:40 - You can see that the first seven bits must be all 1's for
00:25:44 - the first one, that's our F. You can see, you can see C
00:25:48 - as the second one and then 00. But the RFC specifies
00:25:52 - that only those seven bits must be that way. So that's why
00:25:57 - we have 11, so there's four bits there, five, six, seven.
00:26:02 - The RFC mentions that this last bit right here, the one with the L,
00:26:07 - is going to be up to you.
00:26:10 - But it's kind of funny because they say all locally assigned
00:26:13 - addresses, meaning assigned by you, you should set the L to 1. So
00:26:19 - our real first eight bits are typically going to be
00:26:23 - 11111101. Zero is currently reside, reserved
00:26:28 - for future use by setting the L to zero. So
00:26:33 - currently the site addresses will all begin with FD00::8
00:26:37 - because even though the RFC says only
00:26:41 - this first seven bits have to be set, they say, oh, yeah, by the
00:26:44 - way, that last little L bit on the end should be set to 1 which
00:26:48 - means it's locally assigned by an administrator thus making
00:26:51 - all enterprise addresses or all private, I guess you could
00:26:56 - say, IPv6 address starting with FD00/8.
00:27:00 - Now it seems funny when you look at something like
00:27:03 - that to be like, oh, no, you're locking it down. There is not enough
00:27:06 - private IP addresses. But remember, we've got seven full octets
00:27:11 - of four hexadecimals each that, I mean you're, that's a gazillion
00:27:17 - different Ip addresses that you could use within your organization
00:27:20 - and likewise that's why they split up these separate sections.
00:27:23 - You have 40 bits which represent the global ID. That's intended
00:27:27 - to be your company like everybody in your company will have
00:27:32 - the same 40 bits starting their IP address or I should
00:27:35 - say following the FD00. The next 16 bits
00:27:39 - here are going to be the subnet ID because you're going to have
00:27:42 - VLANs, you're going to have subnets within your company's
00:27:45 - WAN links and so on. So this will identify the specific subnets.
00:27:48 - And then finally the last 64 bits just as we saw
00:27:52 - with the link local address will be the interface ID, it
00:27:57 - will be spliced into a MAC address style format like the other
00:28:01 - one was or you could come up with your own interface ID depending
00:28:04 - on the host that you're working with. It could be a DCHP pool.
00:28:07 - There is the DHCPv6, whatever, whatever way
00:28:10 - you're assigning interface IDs that is what this one will
00:28:14 - be and that will result in a global unique at least within your
00:28:17 - your enterprise IPv6 address.
00:28:21 - So we've seen the unique-local addresses or site-local. We've
00:28:25 - seen the link local. Next up is the global, not so local addresses.
00:28:30 - These are going to be the new pool of IP addresses that
00:28:34 - will build the IPv6 Internet. As of right now the
00:28:38 - only thing the standard will say is that they have to have
00:28:41 - their first three bits, high level three bits set to 001.
00:28:44 - And what that comes out to be is 2000 or
00:28:49 - 2 something ::3. You can just see the, the first
00:28:53 - three bits are what make that number two show up, but everything
00:28:56 - else is fair game. Now you can see the global running prefix.
00:29:00 - This address is divided into three major sections. The global
00:29:03 - routing prefix is 48 bits or less. They could be, could
00:29:07 - be smaller, could be larger. The subnet ID is going to be comprised
00:29:11 - of whatever bits are left over after you have this global routing
00:29:14 - prefix. Here's the idea that the powers that be have decided
00:29:20 - on for the Internet addresses. We've got this pool starting
00:29:23 - with 2xxx. You know, anything after that is fair game.
00:29:27 - So we can go ahead and assign, you know, maybe 2000:0,
00:29:33 - you know, da da da da da, some 40, you know, up to 48 bits
00:29:36 - right here for this global routing. And that'll go to Asia and 2,
00:29:40 - you know, da da da da da down the line, that will go to Egypt. Where did that
00:29:44 - come from? Egypt. How about like Australia or Egypt. Why not?
00:29:48 - Or these will go to Iran. These will go to Canada, you know. You get
00:29:52 - the idea. They're going to be chopping these up into giganto
00:29:55 - blocks and assigning them to the nations which they already
00:29:58 - have done. Many assignments have already been made. You can look
00:30:01 - at the RFC and they'll show you, you know, who's got what
00:30:05 - blocks. All these different unions have been assigned different
00:30:07 - blocks. But the primary addresses expected to comprise the
00:30:12 - IPv6 Internet
00:30:14 - are these. The ones that are coming from 2001::/16
00:30:19 - subnet, that is the IA and A's block.
00:30:23 - That is their range that they've chosen to use and,
00:30:27 - and start assigning. So you're going to see ISPs everywhere start getting
00:30:31 - blocks of those. As a matter of fact you probably are able
00:30:33 - to go and apply for your own block right now. Who knows? Maybe
00:30:37 - you'll be one of the early comers to the IPv6 address
00:30:40 - space and like 20 years from now you'll be looking
00:30:43 - back saying, I'm glad I got that block. Who would have known we'd run out, you know.
00:30:47 - Who knows? But that's, that's how they splice up all of those
00:30:51 - different global addresses and those will be public on the Internet.
00:30:56 - There is the idea behind the new IPv6 addressing.
00:31:00 - Pretty different, huh? There's going to be a huge learning
00:31:03 - curve when we really started seeing this move all way down
00:31:06 - to the desktops because remember this not only affects us as
00:31:10 - CISCO people but also affects everybody dealing with operating
00:31:14 - systems. Microsoft is going to use this. Linux is going to use this.
00:31:17 - Apple computers are all going to use this. So everybody is going to have
00:31:21 - to learn at least that are in the IT field. They're going to have to learn how
00:31:25 - IPv6 addresses work. So hopefully, I answered
00:31:29 - the question, will we need to upgrade? Yes, we will and the upgrade
00:31:33 - has already begun. As a matter of fact, oh, I just thought of this.
00:31:37 - Great, great thing I want to show you. If you go to Google and search for
00:31:42 - a BGP Looking Glass, that will let you see the routing table
00:31:46 - of the Internet. And this first link right here is just kind of, if you
00:31:50 - go there, it gives you a massive list of all kinds of websites
00:31:54 - that lets you look at Internet routing tables. And
00:31:59 - see the one I'm looking for is actually in Hawaii. Where
00:32:04 - did they go?
00:32:06 - LavaNet. That's it. LavaNet Looking Glass. If
00:32:10 - you go to the LavaNet Looking Glass and say, I would like,
00:32:13 - they actually have, if you look right here, the LavaNet IPv6
00:32:16 - Looking Glass. This shows the current routing table of
00:32:21 - the Internet 2, the new Internet that is existing. It says, what
00:32:25 - would you like to see? You can actually filter it. I'll just hit
00:32:27 - submit. It will display the whole IP routing table.
00:32:32 - Oh, wait a sec. That's not what I want to see. That's a show version. Give me the prefix-list.
00:32:37 - That's what I want to see. Submit. This will be the, my goodness.
00:32:42 - Oh, show IP BGP. That's what I want. There we go.
00:32:46 - I'm going to hit submit. This is going to show me the, there we go, the whole
00:32:50 - Internet routing table right now that is currently running
00:32:53 - the Internet 2. If you look, all the prefixes start with
00:32:56 - 2001 just like I was saying. And look at this. I'm going to scroll. These
00:33:03 - are all Internet locations on the Internet 2. And you know,
00:33:07 - I'm scrolling but the scroll bar is getting smaller and smaller
00:33:11 - over here on the right. This is just how many
00:33:15 - networks are already existing on the Internet 2.
00:33:19 - Five we go. This, this is to show you that the Internet 2
00:33:23 - exists. It is currently being built primarily in areas outside
00:33:27 - the United States. Will we need to upgrade to IPv6? Yes.
00:33:31 - It's already happening. We then saw the IPv6 address
00:33:34 - format, the eight octets of hexadecimal, 128-bit address.
00:33:38 - The headers are simpler and we saw
00:33:41 - the three different address types that exists, link local, unique-local,
00:33:44 - and the global addresses.
00:33:48 - Finally, we did an in-depth exploration of each one of those
00:33:52 - new addresses and how they're going to be used in the future.
00:33:55 - I hope this has been informative for you, and I'd like to thank
00:33:58 - you for viewing.

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Advanced TCP/IP: IP Subnetting, Part 1

Advanced TCP/IP: IP Subnetting, Part 2

Advanced TCP/IP: IP Subnetting, Part 3

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Jeremy Cioara

Jeremy Cioara

CBT Nuggets Trainer

Cisco CCNA, CCDA, CCNA Security, CCNA Voice, CCNP, CCSP, CCVP, CCDP, CCIE R&S; Amazon Web Services CSA; Microsoft MCP, MCSE, Novell CNA, CNE; CompTIA A+, Network+, iNet+

Area Of Expertise:
Cisco network administration and development. Author or coauthor of numerous books, including: CCNA Voice 640-461 Official Cert Guide; CCNA Voice Official Exam Certification Guide (640-460 IIUC); CCENT Exam Prep (Exam 640-822); CCNA Exam Cram (Exam 640-802) 3rd Edition; and CCNA Voice 640-461 Official Cert Guide.

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