In the previous three parts, we learned about all the interesting things that go on in the PHY with scrambling, descrambling, synchronization, auto negotiation, FEC encoding, and so on. This is all essential knowledge that we need to have to
Troubleshooting vPC in My Virtual Lab
I’m preparing a blog post on setting up vPC in a VXLAN/EVPN environment. While doing so, I ran into some issues. Rather than simply fixing them, I wanted to share the troubleshooting experience as it can be useful to see
1000BASE-T Part 3 – Autonegotiation
In this post, we’ll take a closer look at auto negotiation. Auto negotiation has the following characteristics: The Auto Negotiation transmitter and receiver is actually a separate system in its own right. In multi-speed PHY devices, auto negotiation is used
1000BASE-T Part 2 – Deepdive
In 1000BASE-T Part 1, we reviewed the layers and what their purpose is. Now we’re going to go much deeper into the layers that relate to the PHY, which is PCS, PMA, and Autonegotiation. First though, let’s review the objectives
1000BASE-T Part 1 – Introduction
How does Ethernet detect that a link goes down? This, what I thought was a simple question, I asked myself a couple of weeks ago. I realized I didn’t have a very good answer. I realized I had more to
How Anycast VTEP Broke My Lab And What I Learned
I’m preparing a massive blog post on vPC in the context of VXLAN/EVPN and while doing so I accidentally broke my lab. What a great learning experience! I thought I would share it with you and how to perform troubleshooting
Routed Packet Walk in VXLAN/EVPN Network
In a previous post, I walked through how a packet gets bridged in a VXLAN/EVPN network. In this post, I’ll go through how a packet gets routed, that is, packet from one VNI to another VNI. The following topology will
EVPN – Asymmetric vs Symmetric IRB
It is well known that VXLAN supports bridging frames, that is, forwarding frames that belong to the same L2 segment. In the beginning, this is all that was supported. There was no VXLAN routing. In essence, the HW didn’t support
EVPN Terminology
Reading RFCs is a great source of information for understanding all the details of a protocol. Often they do require the reader to be quite technical and the terminology can be confusing if you aren’t used to the type of
Bridging Packet Walk In VXLAN/EVPN Network
In this post I walk you through all the steps and packets involved in two hosts communicating over a L2 VNI in a VXLAN/EVPN network. The topology below is the one we will be using: The lab has the following