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network_fundamentals [2022/02/11 13:51]
richard [Network Topology Architectures]
network_fundamentals [2022/02/11 14:52] (current)
richard [Spine-Leaf LAN Design (aka Clos Architecture)]
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 ====== Network Topology Architectures ====== ====== Network Topology Architectures ======
  
 +As a general rule, there is no typical computer network that fits all situations. Networks will be adapted for the place and purpose it is for. There are some general fundamentals that all networks have:
 +
 +  * Star topology - All devices in a network connect to one central node (like a router or switch or wireless AP)
 +  * Partial mesh - some devices connect to each other, but not all
 +  * Full mesh - all devices connect to each other
 +
 +Three-tier and Two-tier LAN designs and Spine-Leaf will be tested on the CCNA. These designs combine elements of Star, Partial mesh and full mesh.
 +===== Campus LAN Design =====
 +
 +Traditional campus network design involves splitting up a network into different "​tiers"​ or layers.\\
 +  * Access Layer - provides access to end user devices (typically made of L2 switches)
 +  * Distribution Layer - aggregates the access layer 
 +  * Core layer - fast forwarding of traffic for the Distribution layer. Ideally don't have ACLs or QoS, just fast traffic.
 +{{:​cisco:​three-tier-01fig06_alt.jpg?​400|}}\\
 +//​https://​www.ciscopress.com/​articles/​article.asp?​p=2202410&​seqNum=4//​ \\
 +The three-tier design has all 3 of the hierarchical layers.\\
 +\\
 +{{:​cisco:​two-tier-01fig08_alt.jpg?​400|}}\\
 +//​https://​www.ciscopress.com/​articles/​article.asp?​p=2202410&​seqNum=4//​ \\
 +The two-tier "​collapses"​ the core and distribution layers into one for smaller networks.
 +===== Spine-Leaf LAN Design (aka Clos Architecture) =====
 +The traditional campus LAN design is intended for networks where there is "​North-South"​ traffic, that meaning traffic going from the access layers to the core layers.\\
 +For a data center where traffic may be going from server to server, having to send data North-South begins to be inefficient as you may have to go through a core layer. Data centers may have more East-West traffic.\\
 +Spine-Leaf design is better for Data Centers.\\
 +Each spine connects to every leaf and each leaf connects to every spine.\\
 +Spines do not connect to each other. Leaves do not connect to each other.\\
 +Traffic can easily flow east-west as at most it will only require 3 hops to reach a device on another leaf. It is also more readily scalable as to make this bigger you only need to add on more spine and leaf switches. ​  
 +\\
 + 
 +{{:​cisco:​spine-leaf-16fig10_alt.jpg?​400|}}\\
 +https://​www.ciscopress.com/​articles/​article.asp?​p=2995354&​seqNum=3
 +
 +===== Further resources =====
 {{youtube>​PvyEcLhmNBk?​medium}} {{youtube>​PvyEcLhmNBk?​medium}}
  
network_fundamentals.1644587504.txt.gz ยท Last modified: 2022/02/11 13:51 by richard