Why Are OSPF Type 5 LSAs Flooded?
I recently saw a great question on Reddit, on why Type-5 (AS-external) LSAs are flooded, in comparison to Type-3 (Summary) […]
OSPF
Ethernet
Some History on VLAN 1 in Cisco Switches
Over the years, there has been a lot of discussion on if VLAN 1 in Cisco switches is special or
Ethernet, Spanning tree
Encapsulation of PDUs On Trunk Ports
When I studied for my CCIE almost 15 years ago, I recall that I was fascinated by how different PDUs
CML
Adding Arista Switch to CML
I wanted to add Arista switches to CML to do some STP interopability testing. However, the process of adding them
Spanning tree
Detecting Mismatched Native VLANs
Many people have seen the message logged to their switch about a mismatched native VLAN on a trunk, but how
Ethernet
802.1Q-Tagged Frames Through Unmanaged Switch – Forwarded or Dropped?
As a follow-up to the post yesterday on native VLANs, there was a question on what would happen to 802.1Q-tagged
Ethernet
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
Network Design
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
EVPN, VXLAN
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
EVPN, VXLAN
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.