Cisco IOS-XR introduces a new prompt format that is "breaking" Net::Telnet::Cisco. Basically, the Route Processor and CPU instance is added with a colon ":" before the router hostname. I was wondering why my Telnet sessions were "failing" but the logs showed they connected and got the prompt.
I looked for an update to Net::Telnet::Cisco, but the latest version I could find was 1.10, which is what I have installed. To get around this, I used the -prompt option when calling Net::Telnet::Cisco->new() from my script.
Under the "sub new" procedure in Cisco.pm, I found the existing prompt regex (you can't miss it). I copied that code and added the new piece and passed that in when I make the Net::Telnet::Cisco->new() call via the "-prompt" option. (See Net::Telnet for more info.)
All we're doing is adding a check for the Route Processor and CPU instance and colon before the hostname - optionally, so we don't break what's currently working. This is done with the addition of:
near the beginning of the existing regex.