Cisco 10000 - Manual (Page 136)

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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
The IGP Convergence Acceleration feature leverages the load balance infrastructure of equal paths for
unequal paths. An indirection object is inserted for table output chain building. When the interface goes
down, the routing protocols purge their routes and the inplace modifier prevents marking of labels with
incomplete adjacency. Therefore, the indirection object can use the new adjacency labels. This update in
the IGP Convergence Acceleration feature makes the convergence independent of the number of BGP
prefixes, thereby allowing a faster failover.
Configuring IGP Convergence Acceleration
To configure the IGP Convergence Acceleration feature for unequal cost paths, enter the following
commands beginning in global configuration mode:
Configuring BGP Multipath Load Sharing for eBGP and iBGP in an MPLS
VPN
To configure the BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS VPN feature,
perform the following configuration tasks:
• Configuring Multipath Load Sharing for eBGP and iBGP, page 4-5
• Verifying Multipath Load Sharing for eBGP and iBGP, page 4-5
Command Purpose
Step 1 Router(config)# cef table output-chain
build favor convergence-speed
Enables the output chain building to favor convergence.
Step 2 Router(config)# cef table output-chain
build inplace-modify load-sharing
Enables the output chain building for inplace-modify.
Step 3 Router(config)# ip routing protocol purge
interface
Allows the routing protocol to purge routes without letting RIB
delete BGP prefixes.