Cisco CCDA Video Training - Cisco Hierarchical Network Model

you hi this is David Voss CCIE 1 1 3 7 2 and in this video you're going to learn about the Cisco hierarchical network model specifically you're going to learn about what cisco calls the core distribution and access layers of a campus network the information is rather straightforward but it is information you'll need to know very well to do well on your CCDA exam so let's begin the most important idea concerning the Cisco hierarchical network model is the step by step construction of the network which implements one module at a time starting with the foundation the implementation of each module can be supervised by a network architect but the details are covered by a specialized team such as routing or security or voice teams this modular approach is the key to simplifying the network before we cover each module within the network model let's talk about the main advantages of the cisco hierarchical network model there are eight key advantages ease to understand and implement flexibility cost savings modularity it's easily modified it allows for network growth it facilitates summarization of networks and there is also built-in fault isolation the three-tier model was created in order to make the construction of networks easier to understand cisco has always tried to make efficient and cost effective networks with a modular structure so they can easily be divided into building blocks the modular network design facilitates modifications in certain modules after their implementation and makes it easy to track faults in the network the Cisco hierarchical network model is defined by three layers the core or backbone layer the distribution layer and the access layer now if you're working for a small company these layers might be collapsed core and distribution are often collapsed into a single layer or sometimes all three layers are collapsed that being said let's dive into each of the layers the access layer is the on-ramp to the network so for the most part any end user or device that wants to connect to the network will do so via the access layer as you can see access layer switches should have redundant connectivity to the distribution layer this will ensure network connectivity for the hosts even when there is an equipment failure you could take it another step further and provide redundant connectivity for the hosts to the access layer switches but this is the exception to the rule and certainly not the norm the access layer is comprised of layer 2 switches workstations IP telephones or any other device that requires access to the network here are some specific features you should be aware of at the access layer it should provide high availability and flexible security features you can also implement authentication broadcast control and it's where you would define Q West trust boundaries in the access layer you would also also implement rate limiting techniques and it's where you would often program spanning tree protocol include power over ethernet for your phones and configure voice VLAN settings as you can see the distribution layer has redundant connectivity to both the access and core layers the distribution layer is often where the brains of the network resides since many decisions such as filtering quality of service and policy based routing are performed in the distribution layer as you can see the distribution layer has redundant connectivity to the access and core layers the distribution layer normally has advanced layer 3 switches that can support a wide array of functionality to support the services required from this layer here are the attributes of the distribution layer it gives access control to core devices it has redundancy to access devices it's where the boundaries are for routing protocols you redistribution occurs at this layer as well as filtering route summarization policy routing and here you will see your security implemented it provides separate multicast and broadcast domains using layer 2 and layer 3 technologies and provides routing between VLANs it is a media translation and provides boundaries for media and also provides redistribution there is a lot going on in the core layer the high-speed switching fabric ensures that all modules which connect to the core are serviced immediately you rarely will put any programming on these switches that could cause them to slow down processing for example no QoS no ACLs rather you want to keep it so that these high-end switches spend their time processing forwarding traffic rather than doing anything else although it's not always required to have redundancy to and from the distribution and access layers redundancy is certainly required in the core as you can see the core is the hub for the connects in the network it connects to the server farm to the distribution layer and then off to the enterprise edge as well so having a high-performing core is critical here are some key features of the core layer that you will want to memorize the core layer is high speed it's reliable it's redundant it has fault tolerance and load balancing and has manageability and scalability in the core layer there are no filters packet handling or other overhead that would slow traffic down or the processing of traffic down it has a limited but consistent diameter and it can provide quality of service the Cisco core distribution and access layer hierarchical model is rather straightforward but that's the point cisco wants you to know this by memory and the features of each of the modules in preparation for your CCDA exam not only by watching this video are you prepared for your CCDA exam regarding these areas you're also a much better engineer now that you understand the basic organization of a campus network good luck in your studies

Channel: Paul Browning

Views: 75,694

Rating: 4.9155846 out of 5

Keywords: CCDA, Cisco 640-864 DESGN

Id: lTF28lN0md0

Length: 8min 6sec (486 seconds)

Published: Wed Jul 08 2015