Chapter 15. Troubleshooting Juniper Networks Routers

So far, you have been provided with a lot of information on everything from the architecture of the router to the command structure of JUNOS, from the configuration of interfaces to the configuration of routing protocols. All of this information has helped you to gain insight into the structure and reasoning behind not only the router, but the Internet itself. However, consider that even the most reliable router in the most stable network will encounter problems sooner or later. What happens when you encounter a problem on a Juniper Networks router?

This chapter is designed to explain the process of troubleshooting the routers and to provide you with some sample output, in addition to what has already been provided in earlier chapters. Besides pointing out ways to identify problems from hardware clues, you will be introduced to further traceoptions commands and the Juniper Networks recommended troubleshooting model to use when problems occur.

This chapter will focus mainly on the commands to use for troubleshooting RIP, OSPF, IS-IS, BGP, and multicast and will also provide some guidance on debugging MPLS and VPNs when troubleshooting a router or network problem. Because this is an introduction to troubleshooting on the Juniper Networks router, this chapter will spend more time on the tools than on complex scenarios.