I started this blog as somewhere to make notes on the various projects I experiment with, along with some study notes for myself. It’s mostly networking (a fair bit of Cisco and UniFi) plus Python, Linux and cloud. Maybe someone will find something useful.
I’m not a programmer. I’ve dabbled over the years and can normally find a way to do what I want, but it probably won’t be the best way of doing things, so excuse my code.
Latest from the blog
- Multi-Pod, Multi-Site and remote leaf: picking a failure domain
The choice between Multi-Pod and Multi-Site is not about latency or distance. It is about how big you want your change domain to be. Everything else follows. - VRF leaking, shared services and handoff options
VRF leaking in ACI used to be configured by accident, through contracts and subnet flags. ESGs separate leaking from filtering, and that changes the design. - Route control, external EPGs and transit routing
Three defaults in ACI will drop your traffic without telling you: subnet scope flags, external EPG scoping across the VRF, and the OSPF route tag in a transit design. - L3Out: getting traffic out of an ACI fabric
The L3Out is where ACI stops being novel and starts being VRF-lite on a leaf switch. Border leaf design, interface types, floating L3Out and convergence. - The ACI policy model, and the chain that catches everyone
Tenants, VRFs, bridge domains, EPGs and contracts are the easy part. The access policy chain is configured in a separate tree, and that is what catches people. - What an ACI fabric actually is
Most ACI explanations start with the policy model, which is backwards. Start with the three planes and the fact that the APIC is not in the data path.