Cisco Cisco IOS XR Software Release 4.0

graphical representation of the objects in a Cisco router, simplifying the process of configuring and 
managing the router. The CWI allows you to log in to multiple routers and perform management 
tasks.

Availability—Supports rich availability features such as fault containment, fault tolerance, fast 
switchover, link aggregation, nonstop routing for ISIS, LDP, BGP, and OSPF, and nonstop 
forwarding (NSF).

Multicast service delivery in SP NGN—MVPNv4 support carries multicast traffic over an ISP 
MPLS core network.

IPv6 Provider Edge Router support for IPv6 applications—Delivers IPv6 traffic over an 
IPv4/MPLS core with IPv6 provider edge router (6PE) support. 

IPv6 VPN over MPLS (6VPE) support—Delivers IPv6 VPN over MPLS (IPv6) VPN traffic over 
an IPv4 or MPLS core with 6VPE support.

6VPE over L2TPv3 support—Delivers IPv6 VPN traffic over L2TPv3 core with 6VPE support. 
This feature is also available on Cisco IOS software.

IP fast convergence with Fast Reroute (FRR) support for Intermediate System-to-Intermediate 
System (IS-IS) and OSPF

Path Computation Element (PCE) capability for traffic engineering

L2TPv3 Tunneling Mechanism—Service Providers who do not use MPLS in the core, but want to 
offer VPN services can use the L2TPv3 tunneling mechanism. This feature support includes IPv4 
(VPNv4) and IPv6 (6VPE) VPN services using L2TPv3 encapsulation. The L2TPv3 packet is 
encapsulated in an IPv4 delivery header and is carried across an IPv4 backbone. VPN prefixes are 
advertised with BGP labels and resolved over L2TPv3 tunnels. This feature is supported only on the 
Cisco XR 12000 Series Router.

For more information about new features provided on the Cisco XR 12000 Series Router for 
Cisco IOS XR Software Release 4.0.3, see the 

 in this document. 

This section describes the system requirements for Cisco IOS XR Software Release 4.0.3 supported on 
the Cisco XR 12000 Series Router. The system requirements include the following information:

To determine the software versions or levels of your current system, see the 

Cisco IOS XR software is packaged in feature sets (also called software images). Each feature set 
contains a specific set of Cisco IOS XR Software Release 4.0.3 features.