Configuring Routing Protocols In The Core; Configuring Mpls In The Core; Determining If Fib Is Enabled In The Core - Cisco CRS Configuration Manual

Implementing MPLS Layer 3 VPNs
SUMMARY STEPS
1. Identify the size of the network.
2. Identify the routing protocols in the core.
3. Determine if MPLS High Availability support is required.
4. Determine if BGP load sharing and redundant paths are required.
DETAILED STEPS
Step 1 Identify the size of the network.
Identify the following to determine the number of routers and ports required:
• How many customers will be supported?
• How many VPNs are required for each customer?
• How many virtual routing and forwarding (VRF) instances are there for each VPN?
Step 2 Identify the routing protocols in the core.
Determine which routing protocols are required in the core network.
Step 3
Determine if MPLS High Availability support is required.
MPLS VPN nonstop forwarding and graceful restart are supported on select routers and Cisco IOS XR software releases.
Step 4 Determine if BGP load sharing and redundant paths are required.
Determine if BGP load sharing and redundant paths in the MPLS VPN core are required.

Configuring Routing Protocols in the Core

To configure a routing protocol, see the .

Configuring MPLS in the Core

To enable MPLS on all routers in the core, you must configure a Label Distribution Protocol (LDP). You can
use either of the following as an LDP:
• MPLS LDP—See the Implementing MPLS Label Distribution Protocol chapter in the Cisco IOS XR
• MPLS Traffic Engineering Resource Reservation Protocol (RSVP)—See Implementing RSVP for

Determining if FIB Is Enabled in the Core

Forwarding Information Base (FIB) must be enabled on all routers in the core, including the provider edge
(PE) routers. For information on how to determine if FIB is enabled, see the Implementing Cisco Express
MPLS Configuration Guide for the Cisco CRS Router for configuration information.
MPLS-TE and MPLS O-UNI module in the Cisco IOS XR MPLS Configuration Guide for the Cisco CRS
Router for configuration information.
Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router, Release 6.1.x
Configuring the Core Network
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