I have a QFX5100 with 4x IP Transits (4x 10G) and I do not have bgp full table from them, is there anyway that I load balance my outgoing traffic? because with default route I can only force them to one of them, or add default route with different distance in route table just cause the backup and does not have load balance.

  • 1
    What type of load balance? Round-robin will break TCP, and it will create out-of-order packet delivery that will break real-time protocols, e.g. VoIP. You need to set up some type of flow-based balancing, where every packet of a flow uses the same WAN interface.
    – Ron Maupin
    Oct 27 '21 at 12:27
  • Junos only does per-flow load balancing, despite the "per-packet" nomenclature in the forwarding policy. Oct 28 '21 at 17:59
  • Are you saying you have 4 internet providers? Some kind of network drawing would be useful here. Nov 3 '21 at 17:15
  • Benjamin's answer using "show route forwarding-table" is the right answer, but in case you came to the conclusion that you weren't load balancing based on the ">" character only being present on one hop in "show route" (not "show route forwarding-table"), please know that it is purely cosmetic. Nov 11 '21 at 14:19
  • Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
    – Ron Maupin
    Dec 23 '21 at 23:11

The QFX5100 does support ECMP (Equal Cost MultiPath) forwarding/routing, however assuming that your 4 transits are from different providers, it is highly unlikely that your paths to all destinations are Equal Cost, and so load-balancing could possibly cause you a lot of problems.

If you're still keen to try it however, then the following configuration will activate ECMP:

set policy-options policy-statement ECMP then load-balance per-packet
set routing-options forwarding-table export ECMP

To confirm that the QFX is now treating all your default routes equally, use:

show route forwarding-table destination

And you should see output that looks like:

Destination        Type RtRef Next hop           Type Index NhRef Netif          user     0                    ulst 262668    2
                              x.x.x.1            ucst   540     3 xe-0/0/1.0
                              x.x.x.2            ucst   541     3 xe-0/0/2.0
                              x.x.x.3            ucst   542     3 xe-0/0/3.0
                              x.x.x.4            ucst   543     3 xe-0/0/4.0

showing four different next-hops installed for

As Jordan mentioned - despite the per-packet terminology Junos will actually load-balance per-flow - this is just a legacy command, which will hopefully get aliased in a future version of Junos.

  • It might be important to add that despite the configuration statement saying "per-packet" it is in fact loadbalanced per flow. Nov 11 '21 at 14:20
  • true - updated, thanks. Nov 11 '21 at 20:52

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