Highest Local Preference (LOCAL_PREF)
The BGP LOCAL_PREF PA allows routers in an AS with multiple exit points to choose which exit point is used to reach a particular NLRI. To do so, the router that is the desired exit point sets the LOCAL_PREF for its eBGP route for that NLRI to a relatively high value, then advertises that route via iBGP. The other routers in the same AS can learn of multiple routes to reach the NLRI, but they will choose the route with the higher LOCAL_PREF as the best route. Table 13-11 summ..
OSPF develops neighbor relationships with routers on the same link by exchanging hello messages (sometimes shortened to hellos). Upon initial exchange of hello messages, the routers add each other to their respective neighbor tables. A neighbor table is a list of connected OSPF speakers (devices running OSPF). OSPF speakers send multicast hellos with destination address 224.0.0.5 on all OSPF-enabled interfaces. OSPF sends out hello packets every 10 seconds on a broadcast link..
Packet-switched networks fundamentally differ from circuit-switched networks. As shown in Figure 3-2, a connection must first be established between two end hosts in order for them to communicate in a circuit-switched network. This can be achieved by i n-band signaling (call_setup) within a circuit—in other words, the end host transmits a set of signals that allows the circuit to be extended, hop-by-hop, through the network. Alternatively, as in the case of the Integrated S..
Network-Based Intrusion Detection Systems
You will be forgiven for looking at this new blueprint objective and wondering what exactly is to be expected of a candidate taking the new CCIE Security written exam. This section unravels this objective and provides you with the best preparation possible to ensure that you pass this portion of the exam on your first attempt. Network-based intrusion detection has been defined by many security vendors, such as Cisco, which has defined IDS as a method of detecting an illegal ..
This section addresses the characteristics of real-time interactive traffic and standard data traffic on the network and discusses the QoS requirements of each major type of traffic. This section also introduces the RSVP feature and describes how it allows end systems to request QoS guarantees from the network. Standard Data Traffic Versus Real-Time Traffic The emergence of voice traffic into traditional data networks has made it very common to see both voice an..
