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Aggregate Routes vs Generated Routes.

  • 1.  Aggregate Routes vs Generated Routes.

    Posted 07-01-2016 18:55

    Hi, I'm not sure about the difference between these types of routes. Could anyone clarify this for me? It would be great if someone gives an example using networks. 

     

    Thank you



  • 2.  RE: Aggregate Routes vs Generated Routes.

     
    Posted 07-01-2016 19:03
    An aggregate route is a route you define but which is not used for forwarding traffic (next-hop is discard or reject).
    Only if there are more specific routes (contributing routes) will the aggregate be active in the routing table and therefore available for use in the export policy.
    root@SRX# set routing-options aggregate route 2.2.0.0/16
    root@SRX> show route protocol aggregate detail
    inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
    2.2.0.0/16 (1 entry, 1 announced)
    *Aggregate Preference: 130
    Next hop type: Reject
    Address: 0x11717f0
    Next-hop reference count: 3
    State: <ACTIVE int="" ext="">
    Age: 13
    Task: Aggregate
    Announcement bits (1): 0-KRT
    AS path: I (LocalAgg)
    Flags: Depth: 0 Active
    AS path list:
    AS path: I Refcount: 1
    Contributing Routes (1):
    2.2.2.0/30 proto Direct


    Generate routes are almost similar to aggregate routes as they have the same preference of 130 and even show up with the show route protocol aggregate command (there is no protocol generate option).
    The difference between an aggregate route and generate route is that generate route can use the next-hop of its primary contributing route, so it can have a real next-hop (discard is also option). This also means that only routes with a real-next hop can contribute to an generate route!!
    Since we have a valid next-hop with generate route it can forward traffic.
    Traffic which matches the generated route (and not more specific routes) will be forwarded using the same next-hop as the first contributing route. A generated-route is typically combined with a policy to match which routes we want to be contributing and thus used as NHs.
    The generated-route is typically the default 0/0 with a policy matching to upstream routes - ie: provide connectivity if certain upstream routes exist.</ACTIVE>


  • 3.  RE: Aggregate Routes vs Generated Routes.

    Posted 08-14-2017 18:31

    From 'show route x.x.x.x' how can we tell if it is aggregate or generate routes?

     



  • 4.  RE: Aggregate Routes vs Generated Routes.

    Posted 08-14-2017 23:41

    Yes with the detail knob.

    show route x.y.y.z  exact detail

    Aggregate

    Aggregate Preference: 130 <==== Both aggregate and generated routes will show the same here

     Next hop type: Reject <=== default always be reject for aggregate routes; can be configured discard

     

    Generated 

    Next hop type: Router, Next hop index: 546  <==== Will be type router

    Next hop: x.y.y.t via ge-0/0/1.200, selected  <======Will have a valid next-hop- The presence of an IP tells you it is a generated route


    #Acceptedsolution


  • 5.  RE: Aggregate Routes vs Generated Routes.

    Posted 08-15-2017 02:54

    aggregate route.png

    Are we able to tell is this aggregate or generate route?



  • 6.  RE: Aggregate Routes vs Generated Routes.

    Posted 08-15-2017 10:52

     

    @kennethgoh wrote:

    aggregate route.png

    Are we able to tell is this aggregate or generate route? No.



    Please see the response I gave with the qualifier. I should have just said No.

     

    "Yes with the "detail"  knob.

    show route x.y.y.z  exact detail <=======With the "detail" knob!



  • 7.  RE: Aggregate Routes vs Generated Routes.

    Posted 12-28-2018 01:38

    The presence of IP address in next-hop confirms that is a generated route.