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Cisco iOS Scripting with Tcl (cisco.com)
21 points by teleforce 11 days ago | hide | past | favorite | 10 comments

This brings back memories. I used to work at Cisco in the early 2000s.

Unlike many of the places I worked at since, Cisco (atleast the BU where I worked at) had a dedicated team to implement the libraries and tools needed to script/automate the routers via the consoles. It was a library based on TCL/Expect that connected directly to the command line to get things done. It had a core library maintained by the team and an extensions directory that had modules developed by separate teams for their own features. Finally, there was a regression suite that tested complex setups to make sure that everything was performing well. It also had routines to connect to traffic generators. The one we used was from a company called Ixia. The whole thing had regular release cycles and was treated as a first class internal product rather than just a script someone had written. As part of the work I needed to do, I even wrote a little Emacs mode to handle IOS config files https://github.com/nibrahim/IOS-config-mode

I thought this was the standard way of doing things but several of the companies I worked in since didn't have this polished an infrastructure team and it showed.

I don't know if was because of lack of adoption of TCL but several years later (2017 or so), they moved a lot of the tooling from TCL to Python and I actually went back to deliver some trainings to reskill the engineers on the new technologies.

I thought Cisco was invested in Scheme - but perhaps that's at a different level in the stack?


MBAs don't allow these sort of cost centers any more.

In this case, I don't think this is true. Tcl saw enough use that they couldn't just axe it. For example, you might be surprised how many times Tcl snippets running on IOS are in the critical path of phone calls.

This is too cynical. I don’t doubt the GPS comment and am interested in where they worked after Cisco. But, every larger vendor has some sort of automation these days. Certainly all of Cisco’s products. Whether it’s hot I don’t know but the effort is there.

Things were likely different in the past.


Every vendor worth their salt allows their gear to be configured via an API.

The title is kinda misleading. It’s worth changing iOS to IOS

Perhaps data-entered on a phone that auto-corrected? Could have been an Apple device?

Probably! I had to explicitly override this correction on my phone.

Yeah, I was like "what does Cisco care about scripting on Apple devices?" ... "ooooh, they meant IOS; not iOS"

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