Black hole filtering is an alternative technique you can deploy in place of access control lists to filter out undesired traffic. You create black hole filters by creating specific routes for the traffic that needs to be filtered and then pointing these routes to a null interface. A null interface cannot pass traffic, so it drops the traffic. This has some performance gains over traditional access list filtering. In the case of access lists, the traffic first has to be routed..
The MPLS architecture, as discussed so far, enables the smooth integration of traditional routers and ATM switches in a unified IP backbone (IP+ATM architecture). The real power of MPLS, however, lies in other applications that were made possible, ranging from traffic engineering to peer-to-peer Virtual Private Networks. All MPLS applications use control-plane functionality similar to the IP routing control plane shown in Figure C-6 to set up the label switching database. Fig..
It is debatable whether OSI or IPX represented the most serious contender to TCP/IP as the ubiquitous networking technology of the future. At one time, IPX enjoyed an installed base that far exceeded IP, and numerous plans arose to build the IPX equivalent of the Internet. Novell NetWare (see Figure 1-12) is based upon a client-server paradigm, with the initial intent of sharing large disk volumes among a set of relatively meagerly equipped clients. As with Appl..
Layer 2 Virtual Private Networks
An L2VPN interconnects customer devices (such as a host, a router, or a Layer 2 switch) at multiple sites and allows them to communicate using Layer 2 frames.[13] An L2VPN service provider can offer several types of L2VPN services to its customers, such as point-to-point and point-to-multipoint. In any type of L2VPN service, a PE performs the following tasks: • Receives a Layer 2 frame from a CE over an attachment circuit (which could be an FR DLCI, an AT..
Use the NTP and clock show commands to verify the status of NTP on your router. The best place to start is the show clock detail command, which provides information on the current time, time source, and time zone configuration: Router>show clock detail 15:54:33.079 EST Sun Jan 29 2006 Time source is NTP Summer time starts 02:00:00 EST Sun Apr 2 2006 Summer time ends 02:00:00 EDT Sun Oct 29 2006 Router> To display the current NTP status of the local router, the comman..
