Routing

The forwarding next hops for both the active route and alternative paths will be used for load balancing with below command

under routing options of vrf 

Alternate path include route with different cluster-list ? , IGP metric ?  ,Could you provide some document for me ?

Thank you

Your understanding is correct indifferent igp metric and cluster list length will be considered.

vpn-unequal-cost knob load balancing to VPN routes that are equal until their interior gateway protocol (IGP) metrics in route selection process

It means it  considers indifferent igp metrics and cluster list length(any attribute starting from IGP metric and after in path selection can be indifferent and be considered for load balancing )and load balances them ....as per above definition whichever attibutes falling before igp metric will not  be load balanced unequally (Attributes like Local preference ,Origin, As path length ,Med should be same before being considered for unequal cost load balancing for VPNV4).

Below link states the same:

https://www.juniper.net/documentation/en_US/junos15.1/topics/reference/configuration-statement/vpn-unequal-cost-edit-routing-options.html

I will check if thery any good doc on the same and get back.

Please mark my answer as accepted solution , if you agree it solves the question

http://www.juniper.net/documentation/en_US/junos15.1/topics/reference/configuration-statement/multipath-edit-routing-options.html

Protocol-independent load balancing is applied to VPN routes that are equal up to their router identifiers (router-id) with regard to route selection.

Basically there are two types of load balancing for VPNV4 routes 1) Equal cost  2) Unequal cost 

 Equal cost load balancing for VPNV4 is the same as IPV4 load balancing 

Equal cost load balancing cannot load balance VPNV4 routes received from different igp metrics and different cluster list length , which I beleive is your requirement .

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Protocol-independent load balancing is applied to VPN routes that are equal up to their router identifiers (router-id) with regard to route selection/

This is the default load balancer for vpnv4 routes (i.e equal cost load balancer), which is the same as ipv4 load balancing in which load balancing occurs if untill router-id ,other attributes before that having same cost. .

This is the default behavior , if  unequal-cost knob is not configured.

With Unequal cost knob enabled my last mentioned Post explanation holds good.

Hi Guy

When compare VPNv4 routes IGP metric for BGP next-hop that use to compare use inet.3 or inet.0 ? 

Inet.0 entry  is sufficient for igp metric comparison . 

I test and result bgp use metric on inet.3 to mpbgp (all = 1) when compare igp metric .the way to copy metric from inet.0 to inet.3 (LDP route) is using cli "track-igp-metric"