[stock_toaster]

huh. I thought they were using a QNX based one on the new stuff.

[jauer]

Plain old IOS is a monolithic program and tends to be used in older routers and current small-to-medium routers & modern spins of older product lines.

IOS XR runs on QNX and tends to be used on routers in a carrier role.

IOS XE runs on Linux and tends to be used on service/aggregation routers.

[stock_toaster]

Good to know. Thanks for the info.