Which Cisco router platform supports running either the Cisco IOS or IOS XR operating system?

Which Cisco router platform supports running either the Cisco IOS or IOS XR operating system?

A.
Cisco CRS

B.
Cisco ASR9k

C.
Cisco ASR1K

D.
Cisco ISR-G2

E.
Cisco 12000 GSR

Explanation:
The CRS-1 platform natively runs the IOS XR operating system. The c12000 platform, originally
being an IOS router, can be upgraded to run IOS XR. However, c12000 hardware, including line
cards (LC) as well as route processors (RP), must be checked for XR compliance.

TURBOBOOT refers to a fresh boot of the router from ROMMON. TURBOBOOT is required if an
IOS router is being converted to IOS XR or as a last resort disaster recovery in the case of CRS-1.
If the router is already running an IOS XR image, there is no need to TURBOBOOT the router for
an upgrade or downgrade. Later sections in this chapter address the upgrade scenario. This
section deals with a fresh boot of the router from ROMMON.
A new c12000 platform can be ordered prebaked as an IOS XR router; however, there will always
be cases where an IOS running c12000 needs to install IOS XR.