You can establish the primary HSRP interface using the standby priority command and configure the ISDN to be brought up if the secondary interface goes down which will achieve the closest to what you want, however, if the secondary interface fails, it would not be possible to prevent the ISDN from being activated even though the primary interface is still active.
Pretty easy really. Place the ISDN on the 'Primary' router (HSRP Active). If you use HSRP and track the Serial interfaces so you can fail initially from the Primary router to the secondary and then also track the Serial interface on the secondary router so that if it goes down it will fail back to the Primary router. Add some floating static routes to use the ISDN
Primary router HSRP priority of 100, tracking serial-X and decrement by 10.
Secondary router HSRP priority of 95, tracking serial-X and decrement by 10.
This way it will fail from Primary to Secondary if the Primary Serial-X goes down, then back to Primary if the Secondaries Serial-X goes down. Make sure standby preempt is enabled.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...