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IOS XR 12000

Level 1
Level 1

I have a few Q's regarding on IOS XR on the 12000

I understand the boot time of XR on 12000 can take a while compared to IOS. How long on average does it take ?

How long does it take to apply SMU ?

Do people prefer XR over IOS and what are the Pro's V Con's of moving to XR. I am assessing whether internally we should start the process of labing XR to convert our existing GSR's to IOS XR as all new features\enhancements are being developed within XR.

3 Replies 3

Alexei Kiritchenko
Cisco Employee
Cisco Employee

Migration from IOX for XR may take between 1 to 3h

a reboot can take between 20 – 40 min. For a SW upgrade have at least 1h of a maintenance window, just in case

normally you don’t restart XR often (and you don’t need it).  Even under critical conditions a process restart or RP switchover to a standby (which is hot ready with processes UP and synchronized) can recover the system pretty fast.

Applying a SMU depends on a SMU. They are different in size and scale. Some SMUs just replace and restart processes, another may require a router reload.

Here you can find a high level XR overview. Feel free to ask more specific questions



It's not really a matter of preference. All new development on GSR are now done for XR only so basically you have to migrate to XR for long term support. Please involve your Cisco SE in this discussion as he can provide a lot of great info about the different way of doing it and which one will best fit your environment.

It's not just a simple upgrade, it's a full migration to a completely new OS with all the implication you can imagine:

- HW assessment: does your current RP/LC support XR ?

- Developping a new configuration template based on XR implementation. It's not a 1:1 feature mapping as some you may be using in IOS don't exist anymore in XR or are not required anymore. Also default values may be different for the same feature between IOS and XR. The idea is to get back to your requirement and re-develop a new config with XR features in mind only. Just forget IOS.

- Huge testing phase

- Update management tools, scripts, provisioning system if necessary to support XR.

- Operational/support team training

- Develop new process (SMU management process for example)

See it like a journey but it worth it ;-)



Booting up of XR takes more time compared to IOS because of the installing and booting of individual processes. I have seen that my routers with all the package files that go into the XR image rar will take approximately about 40 min or so to boot up the first time. If you are migrating from IOS to XR, the boot might take upto one hour or little more and you only have to do the TURBOBOOT procedure. Subsequest boot times should be lesser.

SMU application is rather simple, you have to install the file and watch out if it says reboot required or not. If not then you are lucky else you may have to go for a relaod.This takes the normal boot up time.

You should start evaluating XR if not for deployment atleast for the good features it can offer. Make sure your tests are elaborate for 12k especially, i found a hardway rolling it out in my network.

All the best!