CCNA R&S version 3 Topic: Collapsed Core vs. Three-Tier Architectures

hey everybody this is kevin wallace CC CIA and creator of the CCNA routing and switching version 3 complete video course and in this video you're going to learn a new topic on the CCNA exam it's an architectural topic it's a design topic it's all about the collapsed core how does that differ from the traditional three-tier model stay tuned the concepts of network architecture and design are huge in the Cisco world in fact the most prestigious cisco certification that you can get is the cisco certified architect certification that's above and beyond the CCA level certification and there's a lot to it there's a lot that goes into design but we want to take a look at some basic design concepts in this video taking a look at a couple of different types of architectures that we might run into within something like an office building like this let's zoom in on the network that might be inside of this office building we're going to compare specifically a collapsed core network with a three-tier network first of all the three-tier network or the three-tier architecture is going to be a topology divided up into three areas the access the distribution and the core layers and we want to talk about each of those first of all let's focus on the access layer notice down at the access layer we have water probably layer two Ethernet switches layer two meaning that we're not doing any routing these devices are making forwarding decisions based on MAC address information we've got these devices like laptops maybe printers maybe other Ethernet devices maybe IP phones connected into these Ethernet switches at the access layer this is how we're getting from our cubicle or from our office we're plugging into the wall jack and we're getting back to the wiring closet at this layer this is where these Ethernet switches live however we need to send traffic maybe from one switch to another switch maybe there's a server connected to one switch and we're trying to reach that server how do we do that well we probably don't want to have a full mesh of interconnections between all of our switches because that would be a lot of interconnections what do we do instead we use or we can use this three-tier architecture where our access layer switches connect up to distribution layer devices and the icon I have there that's still a switch but it's a multi-layer switch in other words it's capable of doing routing it's a very fast switch it has a high capacity typically it's going to be able to handle a fairly decent network load and it's probably going to have some high-speed ports on it and some literature calls the distribution layer a building distribution layer because maybe we have on a campus where we have multiple office buildings in close proximity maybe we have a building distribution layer in every building but then we want to interconnect to the buildings well we could do that up at the core layer that's the job of the core layer to get traffic as quickly as possible from one distribution layer switch to another distribution layer switch moving packets as quickly as possible but also the core layer is our gateway app to the rest of the world we're going to go out to the Internet possibly or maybe to some remote site through the core layer we're going to connect in this case I'm connecting to a couple of firewall enabled routers and these routers are connecting out maybe two different service providers and those service providers get us out to the internet by the way back to the core layer notice that there's sort of an oval surrounding a couple of Link's interconnecting those switches again these are multi-layer switches when we see links with an oval around them like this that's called an ether channel we're going to be talking about that later on in the course but here's the high-level overview of that an ether channel allows us to have more throughput between a couple of switches by aggregating multiple physical connections maybe these are 10 gig connections at the core layer and we have two of these 10 gig connections we could bundle those in an ether channel so that logically it looks like one interface 120 gig interface that's going to allow us to send traffic very very rapidly between these core layer devices and remember in some of our prior videos we talked about different types of topologies we talked about a star topology and a full mesh and a partial mesh if we zoom in on different areas of this architecture we can really see that we've got multiple types of topologies inside of this architecture we have for example down at the access layer a star topology would you agree with that we've got that centralized device the Ethernet switch and radiating out from that centralized device we've got our end stations we've got up links to other switches but they're the access layer if we just focus in on that that's a star topology but if we look at the core distribution layers you'll notice that we've got some redundant connections that's great but it's not a full mesh there's not a connection between those two distribution layer switches directly would look at those two layers and say that's really a partial mesh topology do you see that in this three-tier architecture we really have components of a star topology and a partial mesh topology this leads us to another term I want you to know and that's a hybrid topology a hybrid topology that's a network topology that contains elements of multiple topology types in this case we've got an element of a star topology and we've got an element of a partial mesh topology however some networks they're simply not large enough to justify all these multi layers which is maybe we don't need a core layer and a distribution layer there is another approach called a collapsed core architecture let's see what that would look like if we take the distribution layer and we combine it with the core we end up with is a collapsed core layer we still have redundant interconnections between our access layer switches but we've eliminated a layer now this might not work well for a large campus where we have lots and lots of buildings that we want to interconnect but for some installations maybe within a single building or maybe just a couple of buildings this might be a great solution and again this is called the collapsed core architecture and this is a two-tier topology and the two tiers are made up of the axis layer and the combined core layer and distribution layer they've been consolidated into this collapsed core layer if you want to learn even more about cisco routing and switching technologies just click the link in the description or on the right side of the screen and I'll send you more training videos and also if you don't to miss any of my youtube videos be sure and subscribe thanks for watching and I'll see you next time

Channel: Kevin Wallace Training, LLC

Views: 34,734

Keywords: collapsed core, ccent, icnd1, icnd2, 100-105, 200-105, 200-125, ccna, ccnp, ccie, ccna training, ccna training video, ccna version 3, ccnav3, #kwtrain

Id: gKTxTOrjXs0

Length: 6min 38sec (398 seconds)

Published: Wed Oct 26 2016