IS-IS OL Bit. Avoiding Traffic Black-hole.

This post introduces the IS-IS LSP Database Overload Bit and how it can be used to avoid traffic black-whole during certain transient network conditions. It includes a sample scenario where such issue might occur along with the relevant tests and verification used throughout. Taking full advantage of the opportunity, it briefly demonstrates how IS-IS handles older LSPs on point-to-point links.
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CLNS and CLNP. What Is The Difference?

The best way I’ve found in order to understand the differences between CLNS and CLNP was to step back a bit and briefly go over some of the networking fundamentals including basic data network communication whilst at the same time trying to correlate any of these ISO terms to the little I know about TCP/IP.

In that way, with some luck, I could create a mental link between the two and hopefully facilitate the learning process. Haven’t we looked at the OSI and TCP/IP models for ages now in an attempt to break down the more complex parts of data communication in bits so we can digest and understand? Well, let’s give it a go.

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IS-IS or Integrated IS-IS?

If you’re new to IS-IS you might have come across different people, posts and or different documentation referring to it as IS-IS or Integrated IS-IS among others. This post very briefly attempts to introduce and clarify why that might be the case if you ever wondered.
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