[j-nsp] BGP load-balancing

[Aamir Saleem]

Dear all,

thanks for your inputs.

Regards.
Aamir

On Wed, Mar 25, 2009 at 1:58 AM, Patrik Olsson <df at webkom.se> wrote:

> Hello!
>
> bgp multipath only enables per prefix loadbalancing.
> To achieve per flow loadbalance aswell you need to apply a per packet
> loadbalance policy under routing-options forwarding-table.
>
> Cheers
> Patrik
>
>
> Aamir Saleem wrote:
> > Hi All,
> >
> > I need your input regarding BGP loadbalancing with multipath option.
> >
> > In JNCIP-M study guide, one of the requirement given in iBGP case study
> is
> > to "Redistribute a summary of the RIP routes into IBGP from both r6 and
> r7"
> > and in second requiement "r5 must IBGP load-balance to the summary route
> > representing the RIP prefixes".
> >
> > After advetiseing RIP summary route (192.168.0.0/22) from R6 and R7. R5
> > router is able to see two viable next-hops after enabling multipath in R5
> > ibgp group but in forwarding table of R5 shows only one path via R6 is
> > available.
> >
> > My question is:
> >
> > Is only enabling multipath option will achive above mention requirement
> > regarding BGP loadbalancing ?
> >
> > As junos perform per-prefix loadbalncing by default so the iBGP case
> study
> > requiremnt that "r5 must IBGP load-balance to the summary route
> representing
> > the RIP prefixes" cannot be achiedved by with multipath only. All other
> > router behind R5 router also following the same path as chosen by R5.
> >
> > some output from test senario are below:
> >
> > aamir at LAB1 <aamir at LAB1># run show route protocol bgp logical-router R5
> > 192.168.0.0/22
> > inet.0: 80 destinations, 136 routes (80 active, 0 holddown, 0 hidden)
> > + = Active Route, - = Last Active, * = Both
> > 192.168.0.0/22     *[BGP/170] 01:50:49, localpref 100, from 10.0.9.6
> >                       AS path: I
> >                     > to 10.0.8.6 via lt-1/2/0.116
> >                       to 10.0.8.10 via lt-1/2/0.117
> >                     [BGP/170] 01:50:49, localpref 100, from 10.0.9.7
> >                       AS path: I
> >                     > to 10.0.8.10 via lt-1/2/0.117
> > [edit]
> > aamir at LAB1#
> >
> > Forwarding table:
> > Logical router: R5
> > Routing table: inet
> > Internet:
> > Destination        Type RtRef Next hop           Type Index NhRef Netif
> > 192.168.0.0/22     user     0                          indr  262148
> 3
> >                                          10.0.8.6             ucst  974
> > 7 lt-1/2/0.116
> >
> >
> > Any input is more then welcome.
> >
> > Regards.
> > Aamir
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