OSPF creates adjacencies between neighboring routers for the purpose of exchanging routing information. Not every neighbor becomes adjacent in a broadcast environment. The Hello protocol is responsible for establishing and maintaining an adjacency. Hello packets are sent periodically out all router functional interfaces. Two-way communi-cation is established when the router is listed in the neighbor's Hello packet. On broadcast and NBMA networks, Hello packets are used to el..
Case Study: MPLS VPN QoS Design (CE/PE/P Routers)
Continuing the example from the previous design chapters, the fictitious company ABC, Inc., has been growing and expanding, both geographically and technologically. It has multiple data centers in geographically diverse regions to which its field needs to connect efficiently. Additionally, to increase collaboration and simultaneously reduce travel expenses, ABC, Inc., plans to roll out any-to-any videoconferencing. For these business reasons, ABC, Inc., has decided to migrate..
The value proposition of a network is that it ties together different entities and enables exchange of information. The network's value is also directly related to its size. The more entities that are connected and partake in the network, the higher the impact of the network is. For exchange and scaling to occur in a relevant and orderly manner, the connected entities must use the same language. As such, standards form an integral component of networks because they enforce or..
Implementing Custom Queuing on a router is a two-step procedure. First, you must define the traffic types that will populate your queues. And then you apply the queuing method to an interface: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#access-list 103 permit ip any any precedence 5 Router(config)#access-list 104 permit ip any any precedence 4 Router(config)#access-list 105 permit ip any any precedence 3 Router(..
Note that the examples in this chapter generally use simpler examples of summary routes, using prefix lengths like /24 and /16 most often. However, for the exam, you need to be comfortable interpreting prefix/prefix length pairs, and subnet/mask pairs, whether they represent an actual subnet or a summary route. The math to analyze a subnet/mask pair, or prefix/length pair, is identical to the math included as part of the CCNA certification. As such, this book does not attempt..
