Building network automation solutions

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Category: automation

Network Automation: a Service Provider Perspective

Antti Ristimäki left an interesting comment on Network Automation Considered Harmful blog post detailing why it’s suboptimal to run manually-configured modern service provider network.


I really don’t see how a network any larger and more complex than a small and simple enterprise or campus network can be developed and engineered in a consistent manner without full automation. At least routing intensive networks might have very complex configurations related to e.g. routing policies and it would be next to impossible to configure them manually, at least without errors and in a consistent way.

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netlab Release 1.4.0: EVPN Asymmetric IRB, Anycast Gateways, VRRP

The big three features of the netlab release 1.4.0 are:

  • EVPN asymmetric IRB on Arista EOS, Cumulus Linux, Dell OS10, Nokia SR Linux, Nokia SR OS and VyOS
  • Anycast gateway on Arista EOS, Cumulus Linux, Nokia SR OS and Nokia SR Linux
  • VRRP on Arista EOS, Cisco IOSv/CSR, Cisco Nexus OS, Cumulus Linux and Nokia SR OS

We also added tons of new functionality, including:

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Rant: Cloudy Snowflakes

I could spend days writing riffs on some of the more creative (in whatever dimension) comments left on my blog post or LinkedIn1. Here’s one about uselessness of network automation in cloud infrastructure (take that, AWS!):

If the problem is well known you can apply rules to it (automation). The problem with networking is that it results in a huge number of cases that are not known in advance. And I don’t mean only the stuff you add/remove to fix operational problems. A friend in one of the biggest private clouds was saying that more than 50% of transport services are customized (a static route here, a PBR there etc) or require customization during their lifecycle (e.g. add/remove a knob). Telcos are “worse” and for good reasons.

Yeah, I’ve seen such environments. I had discussions with a wide plethora of people building private and public (telco) clouds, and summarized the few things I learned (not many of them good) in Address the Business Challenges First part of the Business Aspects of Networking Technologies webinar.

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Could I Use netlab instead of GNS3?

I’m often getting questions along the lines of “I’m using GNS3. Could I replace it with netlab?"

TL&DR: No.

You need a set of functions to build a network lab:

  • Virtualization environment (netlab supports VirtualBox, libvirt, Docker, Podman)
  • An orchestration tool/system that will deploy network device images in such an environment (netlab supports Vagrant and containerlab)
  • A tool that will build orchestration system configuration (netlab core functionality)
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Network Automation Considered Harmful

Some of the blog comments never cease to amaze me. Here’s one questioning the value of network automation:

I think there is a more fundamental reason than the (in my opinion simplistic) lack of skills argument. As someone mentioned on twitter

“Rules make it harder to enact change. Automation is essentially a set of rules.”

We underestimated the fact that infrastructure is a value differentiator for many and that customization and rapid change don’t go hand in hand with automation.

Whenever someone starts using MBA-speak like value differentiator in a technical arguments, I get an acute allergic reaction, but maybe he’s right.

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netlab Router-on-a-Stick Example

In early June 2022 I described a netlab topology using VLAN trunks in netlab. That topology provided pure bridging service for two IP subnets. Now let’s go a step further and add a router-on-a-stick:

  • S1 and S2 are layer-2 switches (no IP addresses on red or blue VLANs).
  • ROS is a router-on-a-stick routing between red and blue VLANs.
  • Hosts on red and blue VLANs should be able to ping each other.
Lab topology

Lab topology

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netlab Release 1.3.1: BGP local-as, FRR and Cumulus Data Plane Enhancements

netlab release 1.3.1 contains major additions to FRR and Cumulus Linux, and new BGP features:

Here are some of the other goodies included in this release:

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