BGP Messages and Neighbor States
The desired state for BGP neighbors is the established state. In that state, the routers have formed a TCP connection, and they have exchanged Open messages, with the parameter checks having passed. At this point, topology information can be exchanged using Update messages. Table 12-3 lists the BGP neighbor states, along with some of their characteristics. Note that if the IP addresses mismatch, the neighbors settle into an active state. Table 12-3 BGP Neighbor States
802.11 shared key authentication goes a step further than open system authentication by using the common WEP key to authenticate radio cards. This is a four-way handshaking process: 1. The radio card sends an authentication request. 2. The access point responds with an authentication frame containing challenge text, which is a string of unencrypted text. 3. The radio card encrypts the challenge text with the WEP key and sends the result to the access point. 4. The access ..
Before delving into the typical topologies, it is wise to understand the overall network design process. As with any systems design effort, network design is an exercise in meeting new and old requirements while working within certain constraints. These constraints include money, labor, technology, space, and time. In addition, there may be social or political constraints, such as the mandated use of certain standards or vendors. Economic constraints play a major role in an..
Viewing DLSw Status Information
This command shows the status of a DLSw peer relationship: Router>show dlsw peers Peers: state pkts_rx pkts_tx type drops ckts TCP uptime TCP 10.1.1.5 CONNECT 350 350 conf ..
Using an Async Modem on the AUX Port
Many Cisco routers include an AUX port that is a low-speed asynchronous serial interface that can connect to a standard modem and support PPP: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router2(config)#interface Async65 Router2(config-if)#encapsulation ppp Router2(config-if)#dialer in-band Router2(config-if)#dialer pool-member 1 Router2(config-if)#ppp authentication chap Router2(config-if)#async default routing Router2(conf..
