Category: Junos

Hub and Spoke with BGP

In my previous post, we saw the theory behind hub-and-spoke VPN. We saw how H/S involves multiple VRFs with cross-importation between them, and we traced the basic flow of a route advertised from one spoke to another. Next, we...

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Hub and Spoke VPN Part 1

One of the JNCIE-SP exam objectives I found difficult was hub and spoke VPN. Conceptually it’s not easy, and as is often the case, the documentation is only somewhat helpful. This series of posts is designed to walk you through...

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RIB Group Confusion

This article continues to be the most popular one on this blog.  However, I published it back in 2014 while I was working on my JNCIE-SP, and that was a long time ago.  I now work at Cisco and do not have access to Junos, and my...

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IS-IS Levels and Adjacencies

In this post, we’ll be looking at IS-IS inter-area concepts, and hopefully clearing up some of the confusion ISIS areas create in the minds of engineers who are used to OSPF.  ISIS handles areas quite differently from OSPF, and...

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