Most people configure an IOS DHCP server once, with three lines - network, default-router, dns-server - and never touch it again. That is fine until you need a switch to PXE-boot from a TFTP server, a phone to find
Two customers connect to your router. Both, entirely by coincidence, use 10.5.5.0/24 internally. Both have a host at 10.5.5.50. Both need to reach the same shared service out one exit interface. In a
A dual-router branch has an obvious problem: you have two WAN Edge routers for redundancy, but you may only have one MPLS circuit. It terminates on one router. If that router fails, the other router - the redundant one - has
For years, branch internet traffic took a ridiculous journey: from the branch, across the WAN, to a central data centre, out through the corporate firewall, to the internet - and all the way back. Every Office 365 request, every YouTube video,
Centralised policy shapes the whole overlay from the Controller. But some things belong on the device itself - the ACL on a specific interface, the QoS treatment as packets leave a port, the route-map filtering what a branch redistributes into
This is the feature people actually buy SD-WAN for. Application-aware routing (AAR) measures the real-time quality of every transport - loss, latency, jitter - and steers each application over the path that currently meets its needs. Voice over the
Here is the thing that makes SD-WAN fundamentally different from a traditional WAN: you do not configure routing policy on the routers. You configure it once, centrally, on the Controller, and it shapes what every WAN Edge sees. A
OMP is to Catalyst SD-WAN what BGP is to the internet: the one protocol that carries everything. Routes, next-hop locations, service advertisements, encryption keys, policy - all of it rides OMP, over a secure connection to the controllers. If
The first thing that trips people up in Catalyst SD-WAN is not OMP or TLOCs or policy - it is provisioning. How does configuration actually get onto a WAN Edge? There are three answers, they arrived in three different eras
Not every network should be a fabric. SD-Access is a genuinely powerful architecture, but it is also a big commitment - a controller, an identity service, compatible hardware, and a operational model your team has to learn. The most valuable
Segmentation is the entire reason most organisations buy SD-Access. Not the automation, not the roaming - the ability to say "guests cannot reach the finance systems, IoT devices cannot reach each other, and contractors only touch the two applications
A fabric that cannot talk to anything outside itself is a very expensive island. The border node is how an SD-Access fabric connects to the rest of the world - the data centre, the WAN, the internet, another fabric - and