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  • 1.  Controlling BGP EVP routes via export policy

    Posted 03-08-2024 20:28

    Hi everyone,

    I have a simple set up:

    DC3 ( 199.199.199.1)--EVPN BGP-----199.199.199.4 ( DC4)

    DC3 has following config:

    We can see DC3 is announcing  EVPN  Type2/3 routes with community :target:1000:1000  to DC4 ( 199.199.199.4):

    Let's say we want to stop DC3 to stop advertising these Type2/3 routes tagged with community target:1000:1000.

    I configured a following a policy that matches on community target:1000:1000 and deny as an action, This policy is then applied as export policy under BGP towards 199.199.199.4:

    Policy is applied as export:

    But it has no effect, DC3 continues to advertises type2/3 routes tagged with community target:1000:1000:

    What am I missing ?

    Thanks !!



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    Be kind!!
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  • 2.  RE: Controlling BGP EVP routes via export policy

    Posted 03-09-2024 03:17

    Hi,

    Configuration looks OK, according to the documentation, vrf-target under VNI overrides any other global route-targets and applies only to Type 2/3 routes.

    Interesting case.

    Could you share output of show route advertising-protocol bgp 199.199.199.4 detail for one Type 2 or Type 3 entry?



    ------------------------------
    FARID AKHUNDOV
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  • 3.  RE: Controlling BGP EVP routes via export policy

    Posted 03-09-2024 14:34
    Edited by LEEBAHI 03-09-2024 14:36

    Thanks Farid.

    I  do see what you mentioned:  explicit defined VNI target using  vni vrf-target takes precedence over globally defined  RT.

    Below is the output:

    root@DC3> ...ising-protocol bgp 199.199.199.4 extensive                     

    SW1.evpn.0: 15 destinations, 15 routes (15 active, 0 holddown, 0 hidden)
    * 2:3.3.3.3:1::1000::00:00:5e:00:01:01/304 MAC/IP (1 entry, 1 announced)
     BGP group EVPN type Internal
         Route Distinguisher: 3.3.3.3:1
         Route Label: 1000
         ESI: 05:00:00:00:01:00:00:03:e8:00
         Nexthop: 3.3.3.3
         Localpref: 100
         AS path: [1] I 
         Communities: target:1000:1000 encapsulation:vxlan(0x8)

    * 2:3.3.3.3:1::1000::00:05:86:71:c4:f0/304 MAC/IP (1 entry, 1 announced)
     BGP group EVPN type Internal
         Route Distinguisher: 3.3.3.3:1
         Route Label: 1000
         ESI: 00:00:00:00:00:00:00:00:00:00
         Nexthop: 3.3.3.3
         Localpref: 100
         AS path: [1] I 
         Communities: target:1000:1000 encapsulation:vxlan(0x8)

    * 2:3.3.3.3:1::1000::2c:6b:f5:6d:b3:f0/304 MAC/IP (1 entry, 1 announced)
     BGP group EVPN type Internal           
         Route Distinguisher: 3.3.3.3:1
         Route Label: 1000
         ESI: 00:00:00:00:00:00:00:00:00:00
         Nexthop: 3.3.3.3
         Localpref: 100
         AS path: [1] I 
         Communities: target:1000:1000 encapsulation:vxlan(0x8) evpn-default-gateway

    • 2:3.3.3.3:1::1000::00:00:5e:00:01:01::100.100.100.10/304 MAC/IP (1 entry, 1 announced)
       BGP group EVPN type Internal
           Route Distinguisher: 3.3.3.3:1
           Route Label: 1000
           ESI: 05:00:00:00:01:00:00:03:e8:00
           Nexthop: 3.3.3.3
           Localpref: 100
           AS path: [1] I 
           Communities: target:1000:1000 encapsulation:vxlan(0x8)

    * 2:3.3.3.3:1::1000::2c:6b:f5:6d:b3:f0::100.100.100.1/304 MAC/IP (1 entry, 1 announced)
     BGP group EVPN type Internal
         Route Distinguisher: 3.3.3.3:1
         Route Label: 1000
         ESI: 00:00:00:00:00:00:00:00:00:00
         Nexthop: 3.3.3.3
         Localpref: 100
         AS path: [1] I 
         Communities: target:1000:1000 encapsulation:vxlan(0x8) evpn-default-gateway

    * 3:3.3.3.3:1::1000::3.3.3.3/248 IM (1 entry, 1 announced)
     BGP group EVPN type Internal
         Route Distinguisher: 3.3.3.3:1
         Route Label: 1000
         PMSI: Flags 0x0: Label 1000: Type INGRESS-REPLICATION 3.3.3.3
         Nexthop: 3.3.3.3
         Localpref: 100
         AS path: [1] I 
         Communities: target:1000:1000 encapsulation:vxlan(0x8)
         PMSI: Flags 0x0: Label 62: Type INGRESS-REPLICATION 3.3.3.3



    ------------------------------
    Be kind!!
    ------------------------------



  • 4.  RE: Controlling BGP EVP routes via export policy

    Posted 03-10-2024 01:54

    Hello,

    Precisely, explicit VNI route-target will override global route-target, BUT only for Type 2/3 routes.

    This is odd, route-policy should match that VNI RT community and reject it.



    ------------------------------
    FARID AKHUNDOV
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  • 5.  RE: Controlling BGP EVP routes via export policy

    Posted 03-10-2024 11:05

    Can you post the full BGP group configuration for the DCI? If you don't already have the 'vpn-apply-export' configuration option configured (set protocols bgp group <> vpn-apply-export), please configure that and test again. 



    ------------------------------
    Aninda Chatterjee
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  • 6.  RE: Controlling BGP EVP routes via export policy

    Posted 03-10-2024 22:50

    Works like a charm:)

    After I apply vpn apply export as you suggested, I see the expected behavior: Type2/3 routes are filtered, only type 1 routes are advertised:

    root@DC3> ...route advertising-protocol bgp 199.199.199.4                

    __default_evpn__.evpn.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
      Prefix                  Nexthop              MED     Lclpref    AS path
      1:3.3.3.3:0::0500000001000003e800::FFFF:FFFF/192 AD/ESI            
    *                         3.3.3.3                      100        I

    That already made my day!!



    ------------------------------
    Be kind!!
    ------------------------------



  • 7.  RE: Controlling BGP EVP routes via export policy

    Posted 03-11-2024 02:37

    Thank you for the information, will note it down.



    ------------------------------
    FARID AKHUNDOV
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