Cisco 10000 - Manual (Page 134)

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Cisco 10000 Series Router Software Configuration Guide
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Chapter 4 Configuring Multiprotocol Label Switching
BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN
Cisco Express Forwarding (CEF) uses the multipaths to perform load sharing, which can be performed
on a per-packet or per-source/destination pair basis. By default, the BGP Multipath Load Sharing for
Both eBGP and iBGP in an MPLS VPN feature performs unequal cost load sharing by selecting BGP
paths that do not have an equal cost of the Interior Gateway Protocol (IGP). To enable the feature,
configure the router with MPLS VPNs that contain virtual routing and forwarding instances (VRFs) that
import both eBGP and iBGP paths. You can configure the number of multipaths separately for each VRF.
Note The BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS VPN feature operates within
the configuration parameters of the existing outbound routing policy.
The BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN feature is described in the
following topics:
• Feature History for BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN, page 4-2
• Restrictions for BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN, page 4-3
• Prerequisites for BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN, page 4-3
• IGP Convergence Acceleration, page 4-3
• Configuring BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN, page 4-4
• Configuration Examples for BGP Multipath Load Sharing for eBGP and iBGP in an MPLS VPN,
page 4-5
• Monitoring and Maintaining BGP Multipath Load Sharing for eBGP and iBGP, page 4-7
Feature History for BGP Multipath Load Sharing for eBGP and iBGP in an
MPLS VPN
Cisco IOS Release Description Required PRE
12.3(7)XI1 This feature was introduced on the Cisco 10000 series
router. PRE2
12.2(28)SB This feature was integrated into Cisco IOS Release
12.2(28)SB. PRE2
12.2(33)SB The IGP convergence acceleration feature was added on
Cisco 10000 series router. PRE3 and PRE4
12.2(33)SB3 The IGP convergence acceleration feature was updated to
include support for unequal cost paths on Cisco 10000
series router. PRE3 and PRE4