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December 2022

  • in sda, lisp
  • 5 min read

Cisco SDA Part IX - need for duplicate IPs on fabric borders

In this post, we look at why SD-Access borders have the anycast IP addresses configured as loopback addresses.

Introduction and topology

Looking at the some of the configuration that is automatically pushed from DNAC, you should spot some very interesting things in there. This post aims to demystify these and help the reader understand why these were needed in the first place, hopefully giving you a better understanding of how the SDA fabric is built.

Let's consider the following topology for this:

static1

  • in sda, lisp
  • 6 min read

Cisco SDA Part VIII - DHCP challenges in SDA

In this post, we look at various DHCP challenges in Cisco's SD-Access fabric and how it is solved.

Introduction and topology

Remember that in SD-Access, we do not use vanilla LISP. To achieve macro segmentation, multi-instance LISP (VRF-aware LISP) is used. However, this poses a problem for DHCP. Consider the following topology for this (this topology is also a simple example of SD-Access design):

static1

  • in sda, lisp
  • 4 min read

Cisco SDA Part VII - multi-instance LISP

In this post, we look at multi-instance LISP, which is another core construct for Cisco's SD-Access.

Introduction and topology

We're slowly getting closer to the true implementation of LISP in Cisco's SD-Access. LISP has the capability of being VRF-aware - this is achieved via multi-instance LISP.

The idea is fairly simple - you have multiple instances of LISP (mapped to corresponding VRFs) - all your LISP tables are now maintained per instance.

We will be using the following topology for this:

static1