Learn Juniper and Cisco networking – with jokes!
Let’s learn how to stretch an MPLS VPN between ISPs using a thing called “Option B”. It involves a little bit of trust between the ISPs – but as we’ll see, it greatly reduces the complexity in configuration!
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Hey there: you smell good! That’s probably because you just read Part 1 of this two-part blog post, where we learned all about BGP communities, and how route-targets are used in MPLS VPNs. Well, now you know the theory, let’s look at a problem ticket. Click here to read Part 2!
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I fixed a ticket recently that I wanted to share with you, because it hits on three big topics at once: BGP communities, MPLS VPNs, and Junos routing policy. In this first of two posts, we’re going to learn about the theory. Click here to read all about BGP communities!
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(DISCLAIMER: This blog post was written at the end of 2018, and was accurate to the JNCIA-Cloud syllabus at the
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This is a post about the different ways, and reasons why, we might move prefixes between the inet.3 and inet.0 tables on a Juniper router. You know: like George Clooney does in his spare time. Probably. Don’t look that up.
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In this first of a two-part post, I’m going to take you on a magical journey. And by “take you on a magical journey” I mean “teach you what the inet.3 table does on a Juniper router.” Which is basically the same thing as a magical journey, right?
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Imagine a user who says they’re only able to access even-numbered IPs in a destination subnet. “Help!”, they say. “I can’t leave the office until this is fixed, and I need to leave now because my seven large sons require their tri-daily feed of protein shakes. They will whither and die unless I nourish them immediately. The fate of my powerful sons is in your hands, and yours alone.” This exact problem came in to us recently. Well, apart from the bit about the large sons.
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This is the third and final part of my whistle-stop tour of IS-IS, for people studying for their Juniper JNCIS-SP and JNCIS-ENT exams. In this post, we learn how to troubleshoot IS-IS. Are you wearing your safety hat? Then, let’s go!
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In Part 2 we take a deeper-dive into IS-IS. We do packet captures of LSAs, we look at the metrics, the Designated Intermediate-System, and we even explore our feelings together, so that we can finally find inner-peace with ourselves. Great!!!
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Here’s the first of our three-part beginners guide to IS-IS. We’ll compare it to OSPF; we’ll talk about Level 1 and Level 2; we’ll explain the bizarre addressing system; we’ll look at a basic config, and we’ll talk about why Googling for IS-IS is very different from Googling for ISIS.
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