Filtering BGP Updates Based on NLRI
Most of the logic behind BGP distribution lists, prefix lists, and route maps has already been covered in previous chapters. For example, Chapter 11 explains the logic behind the ip prefix-list command, and Chapters 8 through 10 cover filtering in IGP routing protocols using the distributelist command. This section shows some brief examples to cover the syntax when these methods are used with BGP, plus a few quirks unique to BGP. One difference between BGP distribute lists an..
Small Office and Home Wireless LANs
It is much easier to install a wireless LAN at home than a wired network. A typical homeowner will not consider running cables throughout the house. It is time-consuming and requires stringing wires through the walls, which can be tricky and frustrating. With a wireless LAN, employees can bring laptops home from work and continue working just as they do from their offices. For many professions, this makes it possible for people to work from home more effectively, whether it i..
Topology Changes with Feasible Successor
In Figure 8-3, router 4 wants to reach network N. Router 4 has two choices: either through router 2 or through router 1. Each interface has a pretend metric (45 and 55, respectively) as an example. Figure 8-3. Convergence Due to Feasible Successor The metric from router 3 to its destination is 40, and this metric is less than router 4's current metric (45) via router 2 to reach network N. Therefore, the feasibility condition is satisfied. In this c..
Appreciating what QoS tools and methods do to packets in a network is fundamental to appreciating the effect of individual QoS tools discussed in later chapters, and ultimately understanding the network designs and methods that constitute the material in this book. End-to-End QoS Regardless of how it is measured, QoS is a vital element in any converged network. To ensure the highest level of quality, however, QoS must be implemented across all areas of the network. QoS is d..
The more difficult task with OSPF route summarization occurs when planning the design of IP address blocks and OSPF areas. When the IP addressing plan and OSPF design have been completed, if the subnet numbers inside an area happen to be from the same general range, and none of the subnet in that range exist in other OSPF areas, then a reasonable summary route can be created at the ABRs connected to that area. Without first having such a reasonable block of addresses, route s..
