IGRP Timers and Stability Features
The IGRP update period is 90 seconds. A random jitter variable of up to 20% is subtracted from each update time to prevent update timer synchronization, so the time elapsed between individual updates will vary from 72 to 90 seconds. When a route is first learned, the invalid timer for that route is set for 270 seconds, or three times the update period. The flush timer is set for 630 seconds—seven times the update period. Each time an update is received f..
As with WAN and MPLS VPN QoS models, site-to-site V3PN QoS models can range from a basic number of classes (in this case, the minimum number of recommended classes is 6) to a complex QoS Baseline model (11 classes). Each enterprise must determine present needs and comfort level of QoS complexity, along with future needs, to more easily migrate to progressively more complex QoS models, as required. Six-Class Site-to-Site V3PN Model The six-class V3PN model technically should..
Let us start with the idea that complex problems are usually broken down into modular components to facilitate understanding and to make the solution more tractable. For this purpose, data communications make use of the Open Systems Interconnection (OSI) reference model. Given the extensive coverage of this model available in other books, this book does not intend to provide a complete and exhaustive overview of the OSI reference model. Instead, this section provides a brief ..
Checking IPSec Protocol Status
There are several useful commands for displaying IPSec parameters. The command show crypto isakmp sa shows all of the ISAKMP security associations. Router1#show crypto isakmp sa And you can look at the IPSec security associations with this command: Router1#show crypto ipsec sa Even if you aren't using a key management protocol such as ISAKMP, you can see information on all of the active IPSec connections with the following command: Router1#show crypto engine connections ..
Monitoring PPP over Frame Relay
The PPP over Frame Relay feature is configured between two Cisco routers, as shown in Figure 10-4. This figure is used to explain the show and debug commands for PPP over Frame Relay. Figure 10-4. PPP over Frame Relay Configuration Between Two Routers Example 10-3 shows the configuration files of routers R1 and R2. Example 10-3. Running Configuration of R1 and R2 ! R1 <output omitted> interface Virtual-Template1 ip address 192.168.1.2 255.255.255.0 ..
