Cisco has added another virtual router to its portfolio, this one based on the IOS XR operating system.

It's called the IOS XRv 9000, and it was announced Tuesday with some other router enhancements targeting service-provider networks. It's due to be available in the second quarter of 2015.

There's already a Cisco virtual router on the market, the Cloud Services Router 1000v. (Note that we're talking about virtual routers, not virtual switches.) But the CSR 1000v runs IOS, the Internetwork Operating System that powers Cisco's routers and switches for the enterprise.

The IOS XRv gives Cisco a foil to the virtual routers introduced recently by Ericsson and Juniper, both of which emphasize the service provider market with their normal routers. Ericsson announced a virtual version of its SSR8000 during Mobile World Congress, and Juniper introduced its vMX 3D Universal Edge Router, based on its MX line, in November.

Also in November, Alcatel-Lucent brought out its Virtualized Service Router (VSR), which is really about virtualizing router-based services rather than the router itself. And while it's not primarily a service-provider product, we should also mention Brocade's Vyatta family of virtual routers, which come from the acquisition of startup Vyatta.

IOS XR was introduced in 2004 on Cisco's then-new line of core routers. Features such as its modular structure targeted service provider networks were intended to help Cisco compete against Juniper and its Junos operating system. (At the time, it also helped fuel snarky comments about operating-system sprawl, as Cisco had already created many branches of IOS.)

In 2008, the release of the ASR 9000 router spread IOS XR to service-provider edge networks. But it also continues to live in the core; IOS XR was at the heart of the NCS 6000 router announced in 2013.

Cisco announced one customer for the IOS XRv 9000: Telefónica, which is initially using the product as a virtual route reflector.