1.1 Hierarchical Network Design Model
1.1.3 Examples of Cisco routers at each layer
You should know where the router is located in the hierarchy and what the key needs are for a given layer so that the router can be configured to meet the specific needs of the layer. Although some needs are common to all layers, other needs are unique, or more critical to certain layers, as in the following example: Core routers must be reliable because they carry information about all the routers in an internetwork. If one of these routers goes down, it affects routing on a larger scale than when an access router goes down.
  • Distribution routers need to be able to select the best path to different locations in order to make efficient use of bandwidth.
  • Access routers are typically where you provide security and filtering. Access routers reduce the amount of overhead by keeping unnecessary traffic out of the core of the network.
  • Examples of Cisco routers that can be used at each layer of the hierarchy follow:
  • Core --- Cisco 7000 and 12000 series routers
  • Distribution --- Cisco 3000 and 4000 series routers
  • Access --- Cisco 1700 and 2600 series routers