Upgrade ASR903 step by step

[maverick0]

Hi Guys

I am looking for a step by step to upgrade ASR 903 to version 17.3.5 and rommon.

The ASR has two RPs and I need to upgrade both. Which are the best option available? 

[balaji.bandi]

you need consider below :

1. what is the current version

2. is the device in high availability

3. what modules installed.

check the release notes and upgrade opton :

https://www.cisco.com/c/en/us/td/docs/routers/asr903/release/notes/17-3-1/b-rn-xe-17-3-1-asr900/m-new-features-17-3-x-asr900.html

Note : Upgrade steps will be changed from environment to environment, depends on downtime and impact of upgrade path.

[maverick0]

I want to upgrade the current version 16.6.1 to 17.3.5.

The ASR has two A900U-RSP2A-64 modules.

How I can use ISSU in this situation to avoid the downtime?

[balaji.bandi]

Following the above guide, you should able to achieve, what is the difficulties you see here?