для Cisco Cisco IOS Software Release 12.2(14)S
BGP Link Bandwidth
Prerequisites for BGP Link Bandwidth
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Cisco IOS Release 12.2(2)T, 12.2(14)S, 12.2(11)T, and 12.0(24)S
Prerequisites for BGP Link Bandwidth
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BGP load balancing or multipath load balancing must be configured before this feature is enabled.
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BGP extended community exchange must be enabled between iBGP neighbors to which the link
bandwidth attribute is to be advertised.
bandwidth attribute is to be advertised.
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Cisco Express Forwarding (CEF) or distributed CEF (dCEF) must be enabled on all participating
routers.
routers.
Restrictions for BGP Link Bandwidth
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This feature can be configured only under IPv4 and VPNv4 address family sessions.
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BGP can originate the link bandwidth community only for directly connected links to eBGP
neighbors.
neighbors.
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Both iBGP and eBGP load balancing are supported in IPv4 and VPNv4 address families. However,
eiBGP load balancing is supported only in VPNv4 address-family.
eiBGP load balancing is supported only in VPNv4 address-family.
Information About BGP Link Bandwidth
To configure the BGP Link Bandwidth feature, you must understand the following concept:
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BGP Link Bandwidth Overview
The BGP Link Bandwidth feature used to enable multipath load balancing for external links with
unequal bandwidth capacity. This feature is enabled under an IPv4 or VPNv4 address family sessions by
entering the bgp dmzlink-bw command. This feature supports both iBGP, eBGP multipath load
balancing, and eiBGP multipath load balancing in Multiprotocol Label Switching (MPLS) Virtual
Private Networks (VPNs). When this feature is enabled, routes learned from directly connected external
neighbor are propagated through the internal BGP (iBGP) network with the bandwidth of the source
external link.
unequal bandwidth capacity. This feature is enabled under an IPv4 or VPNv4 address family sessions by
entering the bgp dmzlink-bw command. This feature supports both iBGP, eBGP multipath load
balancing, and eiBGP multipath load balancing in Multiprotocol Label Switching (MPLS) Virtual
Private Networks (VPNs). When this feature is enabled, routes learned from directly connected external
neighbor are propagated through the internal BGP (iBGP) network with the bandwidth of the source
external link.
The link bandwidth extended community indicates the preference of an autonomous system exit link in
terms of bandwidth. This extended community is applied to external links between directly connected
eBGP peers by entering the neighbor dmzlink-bw command. The link bandwidth extended community
attribute is propagated to iBGP peers when extended community exchange is enabled with the neighbor
send-community command.
terms of bandwidth. This extended community is applied to external links between directly connected
eBGP peers by entering the neighbor dmzlink-bw command. The link bandwidth extended community
attribute is propagated to iBGP peers when extended community exchange is enabled with the neighbor
send-community command.