As a follow-up to the post yesterday on native VLANs, there was a question on what would happen to 802.1Q-tagged frames traversing an unmanaged switch. Unmanaged in this case being a switch that does not support VLANs. While this might
Why Do We Have Native VLANs?
Recently, my friend Andy Lapteff asked an excellent question. Why do we have native VLANs? As in, why allow untagged frames on a trunk link? There was a time where we didn’t have VLANs. At first there was hubs, then
Why Didn’t We Have Anycast Gateways Before VXLAN?
A while back I started thinking about why it took so long before we started using anycast gateways. I started thinking about what would be the reason(s) for not doing it earlier. I came up with some good reasons and
Cisco vPC in VXLAN/EVPN Network – Part 6 – vPC Enhancements
There are a lot of options when it comes to vPC. What enhancements should you consider? I’ll go through some of the options worth considering. Peer Switch – The Peer Switch feature changes how vPC behaves in regards to STP.
Cisco vPC in VXLAN/EVPN Network – Part 5 – Potential Pitfalls
Like I hinted at in an earlier post, there are a some failure scenarios you need to consider for vPC. The first scenario we can’t really do much with, but I’ll describe it anyway. The topology is the one below:
Cisco vPC in VXLAN/EVPN Network – Part 4 – Fabric Peering
Like I mentioned in a previous post, normally leafs don’t connect to leafs, but for vPC this is required. What if we don’t want to use physical interfaces for this interconnection? This is where fabric peering comes into play. Now,
Cisco vPC in VXLAN/EVPN Network – Part 3 – Verifying Connectivity
The following topology is used: We want to verify connectivity and traffic flow towards: Let’s start with the gateway. The gateway is at 10.0.0.1 and has a MAC address of 0001.0001.0001: This is an anycast gateway MAC. When initiating a
Cisco vPC in VXLAN/EVPN Network – Part 2 – Configuring vPC
When building leaf and spine networks, leafs connect to spines, but leafs don’t connect to leafs, and spines don’t connect to spines. There are exceptions to this and vPC is one of those exceptions. The leafs that are going to
Cisco vPC in VXLAN/EVPN Network – Part 1 – Anycast VTEP
Many vendors offer MLAG features, that is, the ability to form a PortChannel (some vendors call it trunk or bond) towards two separate devices. In this post, I will cover the following: Traditional vPC On Cisco Nexus switches, virtual Port
CCNA 200-301 Updated To Version 1.1
Cisco is updating the Cisco Certified Network Associate (CCNA) exam to version 1.1. In the past, Cisco only did major updates to their exams. Since then, they have moved to doing more frequent and minor updates, in a more agile