You can add a text description to a switch port’s configuration to help identify it. This description is meant as a comment field only, as a record of port use or other unique information. The port description is included when displaying the switch configuration and interface information. To assign a comment or description to a port, enter the following command in interface configuration mode: Switch(config-if)# description description-string The descri..
An IPv6 anycast address is a global unicast address that is assigned to two or more devices. Other devices route to the closest active device with the anycast address; the routing protocol metric determines which is closest. Figure 20-5 shows an example network topology from which there are two connections to an ISP. Both border routers have been configured with the same IPv6 anycast address; the internal routers simply route the client to the closest one (Route..
Integrated IS-IS NBMA Design Solutions
Designing IS-IS networks across NBMA WANs is not as straightforward as designing other protocols, such as EIGRP, because IS-IS does not explicitly support NBMA. On the other hand, IS-IS over NBMA is not as complicated as OSPF either. In the good old days, most organizations had a broadcast network (such as Ethernet) for the LAN and point-to-point links (such as serial links) for the WAN. Accommodating these different technologies when building a routing protocol made ..
The purpose of the default route in any routing protocol is to forward traffic to destinations that are not in the router's routing table. It is not possible for all the routers in a network to have full Internet routes. For this purpose, routers without full routes to all the destinations forward traffic to the default originating router. Level 1 routers never maintain information about any destination that is outside their area, so all level 1 routers merely s..
Mitigating the Detrimental Effects of the BGP Restart
To sum up the earlier discussion, BGP restart causes route flaps, which can lead to transient black holes and increased consumption of link bandwidth and control processor resources. Thus route flaps can degrade the overall network performance. The source of route flaps can be traced back to the BGP restart behaviorspecifically, deletion of routes derived from the failed session. As mentioned previously, peers withdraw routes from a restarting speaker to find alternative pat..
