Updating the Routing Table in Active Mode with DUAL
Figure 3-6 shows feasible and advertised distance. Figure 3-6. Feasible and Advertised Distance—Active Mode When no alternative route is found in the routing table, the following actions are taken (using the network in Figure 3-6 as an example). The topology table of Router A starts with a path (successor) of A to D to G to X. The feasible distance is 20, and the advertised distance from Router D is 15. When Router D dies, Router A must find an alternative path to ..
Introduction to the Distance-Vector Protocol
In a distance-vector protocol, each router or host that participates in the routing protocol maintains information about all other destinations within the autonomous system. This does not indicate that each router knows which router originated the information, as in link state, but each router is aware of the neighbor that will be used to reach that destination. Each entry in the routing table includes the next hop, to which the datagram should be sent on its route to the des..
Traffic Patterns in a Cisco Unified Wireless Network
Because the LAPs connect to the wired network through logical LWAPP or CAPWAP tunnels, the traffic patterns into and out of the WLAN are different than traditional WLANs. Consider the network shown in Figure 15-10. Two wireless clients are associated with the WLAN that is formed by the LAP and WLC combination. Traffic from Client A to a host somewhere on the network travels through the LAP, through the tunnel to the WLC, and then out onto the switched campus network. Traff..
The Difficulties of Secure Networking
Considering that we as a community have been working at this problem for many, many years, understanding some of the reasons why we still don't have completely secure networks is useful. Security is not as simple as flipping the "secure" switch on a device, and it might never be. There are many reasons for this, and perhaps the most significant reasons have nothing to do with the technology directly. The following paragraphs outline the reasons that pertain directly to the to..
In older IOS releases, when you enable HSRP on an interface, the router will automatically disable ICMP redirection. However, starting with IOS Version 12.1(3)T, Cisco has changed how ICMP redirection works with HSRP, and it is now enabled by default. You can explicitly enable ICMP redirects on HSRP-enabled interfaces with the following commands: Router2#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router2(config)#interface FastEth..
