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  • 1.  Question on EVPN Labels

     
    Posted 09-24-2021 08:56

    Hi.

     

    Please consider the following EVPN+MPLS topology.

     

    CE1 ----- PE1 ----- P ----- PE2 ----- CE2

     

    PE1 advertises a Type 3 EVPN route to PE2 for received flooded traffic. The advertised label is 25.

    * 3:172.11.20.1:101::610::172.11.20.1/248 IM (1 entry, 1 announced)

    BGP group my-int-group type Internal

         Route Distinguisher: 172.11.20.1:101

         Route Label: 25

         PMSI: Flags 0x0: Label 25: Type INGRESS-REPLICATION 172.11.20.1

         Nexthop: Self

         Localpref: 100

         AS path: [65512] I

         Communities: target:65512:101

         PMSI: Flags 0x0: Label 25: Type INGRESS-REPLICATION 172.11.20.1

     

     

    PE1 also advertises Type 2 EVPN routes to PE2 for received traffic destined to advertised MAC addresses. The advertised label is 16.

    * 2:172.11.20.1:101::610::52:54:00:fb:c3:59/304 MAC/IP (1 entry, 1 announced)

    BGP group my-int-group type Internal

         Route Distinguisher: 172.11.20.1:101

         Route Label: 16

         ESI: 00:00:00:00:00:00:00:00:00:00

         Nexthop: Self

         Localpref: 100

         AS path: [65512] I

         Communities: target:65512:101

     

     

    My question is the following:

    Why are we advertising two different labels for the above two routes when they are both meant to lead received traffic to the same EVPN instance?

     

    user@VMX> show route label 25   

     

    mpls.0: 16 destinations, 16 routes (16 active, 0 holddown, 0 hidden)

    + = Active Route, - = Last Active, * = Both

     

    25                 *[EVPN/7] 00:04:28, routing-instance EVPN1, route-type Ingress-IM, vlan-id 610

                          to table EVPN1.evpn-mac.0

     

     

    user@VMX> show route label 16  

     

    mpls.0: 16 destinations, 16 routes (16 active, 0 holddown, 0 hidden)

    + = Active Route, - = Last Active, * = Both

     

    16                 *[EVPN/7] 00:04:32, routing-instance EVPN1, route-type Ingress-MAC, vlan-id 610

                          to table EVPN1.evpn-mac.0

     

     

    Thanks,

    Deepak


    Juniper Business Use Only



  • 2.  RE: Question on EVPN Labels

    Posted 05-29-2022 12:29
    Hi, 


    That's because type3 and type2 routes in EVPN have a different purpose. 

    Type 3 deals with efficient replication of BUM traffic and type 2 deals with MAC/IP advertisement. 

    When PE1 is sending a type3 route is communicating that he expects to receive BUM traffic marked with label 25. based on that label PE1 will know that the traffic is BUM and forward accordingly. 


    By sending a type 2 route, PE1 is communicating that he expects to receive traffic marked with label 16 if the traffic is destined to mac :52:54:00:fb:c3:59



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    Alin Bandiu
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