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Category Archive for: ‘Study Time’

Juniper Default Routing Tables

Juniper 01

The first time I saw these I remember thinking what is going on here. It can be pretty foreign the first time someone sees it especially coming from Cisco IOS. The two CLIs wrap and abstract the underlying standardized frameworks pretty differently. I think it helps to decouple what the function of the table is before ever operating the gear. …

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Juniper and Cisco Comparisons of RIB, LIB, FIB and LFIB Tables

A quick overview before we start: It starts off with the ingress packet. As a packet comes into the Label Edge Router (LER) the Layer2 frame header will be examined and forwarded to the appropriate table, based on the Ethertype field to determine what protocol in payload of the Ethernet frame. The table interactions in principle are the same between …

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How Headers Encapsulate in the OSI stack

How Headers Encapsulate in the OSI stack:¬†Part 2 of some refreshers. We send application data or payload by encapsulating or framing each layer within the previous layer. We looked at each one individually and now here is how they look when each layer is wrapped inside the previous layer. ¬†Figure 1. Here is how application data gets passed to each …

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What are Ethernet, IP and TCP Headers in Wireshark Captures

1 Slide11

If I could go back in time when I was a n00b kid wanting to go from zero to a million in networking, the one thing I would change would be spending about 6 months on the fundamentals of networking headers and framing before ever touching a single peice of vendor gear. Ethernet, IP and Transport headers (L2-L4) are the …

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