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Routing off of VXLAN to expternal router.

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  • 1.  Routing off of VXLAN to expternal router.

    Posted Feb 27, 2023 09:58 AM

    I am trying to configure  two VSX pairs of Aruba-CX switches for two small DC-s which are supposed to work as a primary and backup site and host VMWare clusters. I am using this guide: https://www.arubanetworks.com/techdocs/AOS-CX/10.09/PDF/vxlan.pdf

    The EVPN part works for me for VLANs defined locally on VSX pair as well as stretched across both clusters and devices connected over MLAG. I have problem with addresses/routes present only on one (primary) switch in eatchpair. 

     

    .Simplified diagram below.

    When I try to connect external router in production VRF (DC3-R1) to one switch in each pair using BGP. I can't communicate with the remote router and ntworks behind it from secondary device in VXS pair. Routes for network behind DC3-R1 are present in ip routing table as well as type 5 routes in l2vpn table.

    I do not have more links to DC3 (and interfaces) to connect all 4 switches.

    Is there any solution for this problem simpler than running BGP in production VRF. Do I miss something important?

    I tried to use vlan interfaces on both switches in a pair and bgp sessions to DC3-R1 and it seemed to be working but I'd like to avoid this because of complexity, there will be way more external routers connected.


    EDIT: fixed addresing and added internet link to the drawing



  • 2.  RE: Routing off of VXLAN to expternal router.

    EMPLOYEE
    Posted Feb 27, 2023 02:52 PM

    Are you using the same AS number at all the devices? If yes, then you need to make a full mesh network or use route reflectors. This because of the iBGP rules.



    ------------------------------
    Willem Bargeman
    ------------------------------



  • 3.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 05:17 AM

    Yes, all aruba switches are in the same AS and they have full mesh iBGP peering. External router works in different AS. 




  • 4.  RE: Routing off of VXLAN to expternal router.

    Posted Feb 28, 2023 02:01 AM

    Hi 

    would it be possible to share your configuration of the DC1/2-S1/2 devices? Or at least the "evpn", "router bgp" and "int vxlan" sections. 

    It's important to activate "address-family ipv4 unicast" in the VRF as well as have a L3VNI in the respective VRF. 

    Regards, 
    Thomas




  • 5.  RE: Routing off of VXLAN to expternal router.

    EMPLOYEE
    Posted Feb 28, 2023 06:39 AM

    Getting some show ip route and show bgp l2evpn evpn output would help on DC1-S1 and DC1-S2 to better understand.

    As it is likely that the EVPN type-5 route on DC1-S2 includes the VSX logical VTEP anycast IP as the next-hop (172.31.101.1), this NH IP being hosted on DC1-S2, the packet is dropped. So, to your point, you would need an iBGP peering inside the tenant VRF (ala VRF-lite) to get routes properly learnt inside the said VRF between the VSX primary and secondary of the same VSX cluster.

    Hope this helps.




  • 6.  RE: Routing off of VXLAN to expternal router.

    EMPLOYEE
    Posted Feb 28, 2023 06:50 AM

    Getting some show ip route and show bgp l2evpn evpn output would help on DC1-S1 and DC1-S2 to better understand.

    As it is likely that the EVPN type-5 route on DC1-S2 includes the VSX logical VTEP anycast IP as the next-hop (172.31.101.1), this NH IP being hosted on DC1-S2, the packet is dropped. So, to your point, you would need an iBGP peering inside the tenant VRF (ala VRF-lite) to get routes properly learnt inside the said VRF between the VSX primary and secondary of the same VSX cluster.

    Hope this helps.




  • 7.  RE: Routing off of VXLAN to expternal router.

    Posted Feb 28, 2023 09:47 AM

    Thank you for the reply. 


    I've attached output from  show bgp l2vpn evpn as files for clarity. How do I configure this  iBGP peering inside the VRF? Only between switches in VSX pair in each DC or between all of them. I would need a bunch of interconnects and IP addresses in the overlay network.  Or can I use  those propagated by evpn?

    I've updated the diagram in original post because I posted wrong loopback addresses and I also added an internet uplink to the setup. The internet uplink behavior  is even stranger. The internet firewall have static routes for private address ranges pointing to an active gateway on shared vlan configured on DC1-S1 and DC1 S2.  All switches can ping to the internet except DC2-S1. It probably is connected to the topic because of how physical and vrrp addresses look from DC1-S1 and DC1-S2. 

    For the interested I have attached also, somewhat cleaned configs.




  • 8.  RE: Routing off of VXLAN to expternal router.

    Posted Feb 28, 2023 10:17 AM

    Hi 

    Thanks for the additional information. 

    Any reason why you have different route-target import/export statements in DC1 and DC2?

    For better understanding, could you please mention the peering VLAN / peering addresses to the external routers (e.g. firewall and DC3-R1) in your diagram? Could you also name the routes (or some of them) you are missing from the external routers?

    Could you please send us the extract of "show ip route vrf prod" of each of the core devices?

    If using EVPN you don't need a separate iBGP peering per VRF. This will be done though the peering used in the global bgp config. Just make sure you activate the ipv4 address-family per VRF and redistribute "connected" which you have. So in my eyes your bgp peerings look fine, given that you use a different BGP AS for the external peering with DC3-R1 and/or the firewall.

    Regards, 

    Thomas




  • 9.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 05:12 AM

    Hi

    Those route targets are leftovers from some, not so educated experiments. I do no fully understand how they work and why rd needs to be uniqe for vsx pair but the route-targets do not.

    For the addresses and vlans I added a more detailed diagram.

    The routing tables for vrf prod

    DC1-CORE1# show ip route vrf prod

    Prefix              Nexthop          Interface     VRF(egress)       Origin/   Distance/    Age
                                                                         Type      Metric
    --------------------------------------------------------------------------------------------------------
    0.0.0.0/0           172.31.90.1      vlan901       -                 S         [1/0]        04d:18h:07m
    10.30.1.0/24        -                vlan300       -                 C         [0/0]        -
    10.30.1.253/32      -                vlan300       -                 L         [0/0]        -
    10.40.1.0/24        172.31.100.2     -             -                 B/EV      [200/0]      21h:53m:22s
    10.100.1.0/24       -                vlan100       -                 C         [0/0]        -
    10.100.1.11/32      172.31.100.2     -             -                 B/EV      [200/0]      21h:53m:22s
    10.100.1.253/32     -                vlan100       -                 L         [0/0]        -
    10.180.10.0/24      172.30.100.70    vlan817       -                 B/E       [20/0]       21h:34m:36s
    10.200.1.0/24       -                vlan200       -                 C         [0/0]        -
    10.200.1.253/32     -                vlan200       -                 L         [0/0]        -
    172.30.1.0/24       -                vlan1         -                 C         [0/0]        -
    172.30.1.253/32     -                vlan1         -                 L         [0/0]        -
    172.30.100.64/29    -                vlan817       -                 C         [0/0]        -
    172.30.100.66/32    -                vlan817       -                 L         [0/0]        -
    172.30.101.64/29    172.30.100.70    vlan817       -                 B/E       [20/0]       21h:34m:36s

    DC1-CORE2#  show ip route vrf prod

    Prefix              Nexthop          Interface     VRF(egress)       Origin/   Distance/    Age
                                                                         Type      Metric
    --------------------------------------------------------------------------------------------------------
    0.0.0.0/0           172.31.90.1      vlan901       -                 S         [1/0]        04d:18h:07m
    10.30.1.0/24        -                vlan300       -                 C         [0/0]        -
    10.30.1.254/32      -                vlan300       -                 L         [0/0]        -
    10.40.1.0/24        172.31.100.2     -             -                 B/EV      [200/0]      21h:53m:21s
    10.100.1.0/24       -                vlan100       -                 C         [0/0]        -
    10.100.1.11/32      172.31.100.2     -             -                 B/EV      [200/0]      21h:53m:21s
    10.100.1.254/32     -                vlan100       -                 L         [0/0]        -
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      21h:28m:51s
    10.200.1.0/24       -                vlan200       -                 C         [0/0]        -
    10.200.1.254/32     -                vlan200       -                 L         [0/0]        -
    172.30.1.0/24       -                vlan1         -                 C         [0/0]        -
    172.30.1.254/32     -                vlan1         -                 L         [0/0]        -
    172.30.100.64/29    172.31.100.2     -             -                 B/EV      [200/0]      21h:28m:51s
    172.30.101.64/29    172.31.100.2     -             -                 B/EV      [200/0]      21h:31m:38s
    172.31.8.1/32       172.31.100.2     -             -                 B/EV      [200/0]      21h:28m:51s
    172.31.90.0/28      -                vlan901       -                 C         [0/0]        -
    172.31.90.13/32     -                vlan901       -                 L         [0/0]        -

    DC2-CORE1#  show ip route vrf prod

    Prefix              Nexthop          Interface     VRF(egress)       Origin/   Distance/    Age
                                                                         Type      Metric
    --------------------------------------------------------------------------------------------------------
    0.0.0.0/0           172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:35s
    10.30.1.0/24        172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:35s
    10.40.1.0/24        -                vlan400       -                 C         [0/0]        -
    10.40.1.253/32      -                vlan400       -                 L         [0/0]        -
    10.100.1.0/24       -                vlan100       -                 C         [0/0]        -
    10.100.1.10/32      172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:35s
    10.100.1.251/32     -                vlan100       -                 L         [0/0]        -
    10.180.10.0/24      172.30.101.70    vlan817       -                 B/E       [20/0]       21h:28m:51s
    10.200.1.0/24       -                vlan200       -                 C         [0/0]        -
    10.200.1.251/32     -                vlan200       -                 L         [0/0]        -
    172.30.1.0/24       -                vlan1         -                 C         [0/0]        -
    172.30.1.251/32     -                vlan1         -                 L         [0/0]        -
    172.30.100.64/29    172.30.101.70    vlan817       -                 B/E       [20/0]       21h:28m:51s
    172.30.101.64/29    -                vlan817       -                 C         [0/0]        -
    172.30.101.66/32    -                vlan817       -                 L         [0/0]        -
    172.31.8.1/32       172.30.101.70    vlan817       -                 B/E       [20/0]       21h:28m:51s
    172.31.90.0/28      172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:35s

    DC2-CORE2#  show ip route vrf prod

    Prefix              Nexthop          Interface     VRF(egress)       Origin/   Distance/    Age
                                                                         Type      Metric
    --------------------------------------------------------------------------------------------------------
    0.0.0.0/0           172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    10.30.1.0/24        172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    10.40.1.0/24        -                vlan400       -                 C         [0/0]        -
    10.40.1.254/32      -                vlan400       -                 L         [0/0]        -
    10.100.1.0/24       -                vlan100       -                 C         [0/0]        -
    10.100.1.10/32      172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    10.100.1.252/32     -                vlan100       -                 L         [0/0]        -
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    10.200.1.0/24       -                vlan200       -                 C         [0/0]        -
    10.200.1.252/32     -                vlan200       -                 L         [0/0]        -
    172.30.1.0/24       -                vlan1         -                 C         [0/0]        -
    172.30.1.252/32     -                vlan1         -                 L         [0/0]        -
    172.30.100.64/29    172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    172.30.101.64/29    172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s
    172.31.8.1/32       172.31.100.1     -             -                 B/EV      [200/0]      19h:16m:34s




  • 10.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 05:27 AM

    I forgot to reply about iBGO peering. On all switches I have very simple config for now an each switch has something like this: 


    router bgp 65001
    ! underlay neighbors
        address-family l2vpn evpn
            ! underlay neighbors activate and options
        exit-address-family
    !
        vrf prod
        ! overlay external neighbors
            address-family ipv4 unicast
                          ! overlay external  neighbors activate and options
                redistribute connected
                redistribute static
            exit-address-family

    I've attached full configs in the reply 7




  • 11.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 07:31 AM

    Okay, that's looking quite good in my eyes. 

    Regarding the prefix behind the Mikrotik router (10.180.10.0/24), this is present on all the 4 VSX devices either as eBGP route or as BGP-EVPN route (type 5) depending on the switch. And the default gateway towards the firewall is present as well on all 4 Aruba cores. 

    This leaves me with the question, what issue you still have. How do you test whether communication from a network attached to the core with hosts in net 10.180.10.0/24 works or not? Do you have a machine connected to for instance DC2-S2? Or do you use a ping (send us the exact command) from the CLI of DC2-S2? What is the source and the destination?

    You also need to make sure that the other end knows about the networks behind your Aruba cores. Did you check? Are prefixes like 10.100.1.0/24, 10.200.1.0/24 and 10.40.1.0/24 present? Otherwise the forwarding towards the network works but the reverse path is unknown/wrong.

    Another thing which may be connected to post 11 by vincent.giles. It's usually good practice to have an "IGP continuity" peering between the two VSX nodes per VRF to exchange routes in case BGP/EVPN peerings brake for a reason on one node. This is more important in a leave-spine topology than with your full-mesh network but still something you perhaps want to have. Either activate OSPF also within the VRFs just between the two VSX nodes (as systems connected with MCLAG/LACP don't possibly know about the fact that L3 routing on one of the VSX nodes is not ready) in order to still have an exit on layer3 if EVPN goes down for whatever reason. The other option is to use BGP.

    Regards, 

    Thomas




  • 12.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 02, 2023 09:44 AM

    > How do you test whether communication from a network attached to the core with hosts in net 10.180.10.0/24 works or not? Do you have a machine connected to for instance DC2-S2?

    For testing I use a hosts witch vm in each DC. The hosts in dc1 and dc2 have  two port uplink to each device in vsx pair with applicable vlans tagged. The host in DC3 has single uplink to the router.

    Today I started to test failure scenarios and results are  puzzling for me. When I shutdown an interface to the Microtik in DC3 on either DC1-S1 or DC2-S1  I  (after some time, no t instantly) loose connection to the network 10.40.1.0/24 in DC2 from  host 10.180.10.10 but not to host 10.30.1.10 in DC1. What is interesting there is a delay between shutting down the interface and stopping the traffic.

    The delay between interface shutdown and ping stopping  seems to be equal to the BGP hello time (which I set to 30s between Aurba and Mikrotik)

    I could expect  breaking connection to respective DC not always the same. It might have something to do with the way how vmware vswitch routes frames from VM to physical NIC. Probably  one VM hits primary switch in its DC and the other hits the secondary

    Tables when all links are working: 

    Aruba:

    DC1-CORE1# show bgp l2vpn evpn | inc 10.180.10
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    DC1-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.30.100.70    vlan817       -                 B/E       [20/0]       00h:32m:13s

    DC1-CORE2# show bgp l2vpn evpn | inc 10.180.10
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    DC1-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      00h:00m:10s
    DC2-CORE1# show bgp l2vpn evpn | inc 10.180.10
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    DC2-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.30.101.70    vlan817       -                 B/E       [20/0]       00h:00m:10s

     

    DC2-CORE2# show bgp l2vpn evpn | inc 10.180.10
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    DC2-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      00h:32m:12s
    DC2-CORE2# show bgp l2vpn evpn | inc 10.180.10
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    DC2-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      00h:32m:12s

    and Mikrotik in DC3

    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.30"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    D b 10.30.1.0/24  172.30.101.66        20
    DAb 10.30.1.0/24  172.30.100.66        20
    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.40"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    D b 10.40.1.0/24  172.30.101.66        20
    DAb 10.40.1.0/24  172.30.100.66        20

    Tables when link from DC1-CORE1 to DC3 is shut down: 

    Aruba

    DC1-CORE1# show bgp l2vpn evpn | inc 10.180.10
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    DC1-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.30.100.70    vlan817       -                 B/E       [20/0]       00h:39m:42s

    DC1-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      00h:00m:10s
    DC1-CORE2# show bgp l2vpn evpn | inc 10.180.10
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    DC1-CORE2# show  ip route  vrf prod | inc 10.180

    DC2-CORE1# show bgp l2vpn evpn | inc 10.180.10
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    DC2-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      00h:39m:42s

    DC2-CORE2# show bgp l2vpn evpn | inc 10.180.10
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    DC2-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      00h:39m:42s

    Mikrotik

    [admin@DC3] > /ip ro print where dst-address ~ "10.30"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    DAb 10.30.1.0/24  172.30.100.66        20
    [admin@DC3] > /ip ro print where dst-address ~ "10.40"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    DAb 10.40.1.0/24  172.30.100.66        20




  • 13.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 02, 2023 09:55 AM

    > Either activate OSPF also within the VRFs just between the two VSX nodes (as systems connected with MCLAG/LACP don't possibly know about the fact that L3 routing on one of the VSX nodes is not ready) in order to still have an exit on layer3 if EVPN goes down for whatever reason. The other option is to use BGP.

    Do I understand  it correctly that to achieve this I need to add a secondary transit vlan on the VSX ISL link  and SVIs  in the production VRF?

    If I use ospf it does not need to know anything about  the other dc, right?

    I am not sure how to use BGP for that. Just and iBGP peering in the same AS as the Underlay using the additional addresses?

    PS. The lack of proper quoting and threading in this forum is at least inconvenient. 




  • 14.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 03, 2023 07:09 AM

    > Do I understand  it correctly that to achieve this I need to add a secondary transit vlan on the VSX ISL link  and SVIs  in the production VRF?

    Yes, you need a transit VLAN per VRF in use for L3 routing between the two VSX nodes in a clean design. However, you may also use one of the VLAN interfaces with an IP on both nodes (you typically have 1 or more vlan interfaces in the VRF). Technically this does the same job but is a bit of a misuse.So the recommendation clearly is a separate transit VLAN. 

    > If I use ospf it does not need to know anything about  the other dc, right?

    Nope, only between the two VSX node in the same cluster. The inter-DC connectivity is handled by BGP-EVPN (with ipv4 address-family activated)

    > I am not sure how to use BGP for that. Just and iBGP peering in the same AS as the Underlay using the additional addresses?

    A single Aruba switch/router only can have one AS number assigned to it. In your case it is 65001. This automatically results in an iBGP type peering between the two VSX node if you configure a neighborship in the VRF "prod". But there is nothing against it. So just configure a transit VLAN, activate a neighborship within the VRF on it and add it as network. If everything is "normal", there shouldn't be any route in your routing table coming from that peering. However, if you for instance shutdown OSPF on one of the VSX nodes and therefore lose the connectivity to the other VTEPs you still have "a way out" by routing the traffic to the other VSX node. 

     




  • 15.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 03, 2023 09:33 AM

    Thank you a lot for explanation. 


    What do I need to redistribute in the ospf ?

    In case of BGP, I already have  redistribute connected and redistribute static in address-family ipv4 unicast.

    So I only need to add the transit network, right?

    I added the following configuration everything seems to be working.  I can ping every where form VM in DC3, I can ping DC3 VM from other VMs.

    Failover to DC3, when I shutdown a interface on Mikrotik,  takes about 30 seconds. It is expected because Microtik does not support bfd for now. 

    Transit vlans

    DC1-CORE1# show running-config interface vl 4001
    interface vlan 4001
        description vsx-vrf-transit
        vrf attach prod
        ip address 172.31.255.128/31
        exit
    DC1-CORE2# show running-config interface vl 4001
    interface vlan 4001
        description vsx-vrf-transit
        vrf attach prod
        ip address 172.31.255.129/31
        exit
    DC2-CORE1# show running-config interface vl 4001
    interface vlan 4001
        description vsx-vrf-transit
        vrf attach prod
        ip address 172.31.255.130/31
        exit
    DC2-CORE2# show running-config interface vl 4001
    interface vlan 4001
        description vsx-vrf-transit
        vrf attach prod
        ip address 172.31.255.131/31
        exit

    and bgp neigbors 

    DC1-CORE1# show running-config bgp
    router bgp 65001
       [...]
    !
        vrf prod
            [...]
            neighbor 172.31.255.129 remote-as 65001
            neighbor 172.31.255.129 fall-over
            address-family ipv4 unicast
                [...]
                neighbor 172.31.255.129 activate
                redistribute connected
                redistribute static
                network 172.31.255.128/31
            
    DC1-CORE2# show running-config bgp
    router bgp 65001
       [...]
    !
        vrf prod
            [...]
            neighbor 172.31.255.128 remote-as 65001
            neighbor 172.31.255.128 fall-over
            address-family ipv4 unicast
                [...]
                neighbor 172.31.255.128 activate
                redistribute connected
                redistribute static
                network 172.31.255.128/31

    DC2-CORE1# show running-config bgp
    router bgp 65001
       [...]
    !
        vrf prod
            [...]
            neighbor 172.31.255.131 remote-as 65001
            neighbor 172.31.255.131 fall-over
            address-family ipv4 unicast
                [...]
                neighbor 172.31.255.131 activate
                redistribute connected
                redistribute static
                network 172.31.255.130/31

    DC2-CORE2# show running-config bgp
    router bgp 65001
       [...]
    !
        vrf prod
            [...]
            neighbor 172.31.255.130 remote-as 65001
            neighbor 172.31.255.130 fall-over
            address-family ipv4 unicast
                neighbor 172.31.255.130 activate
                redistribute connected
                redistribute static
                network 172.31.255.130/31




  • 16.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 03, 2023 07:34 AM

    > The delay between interface shutdown and ping stopping  seems to be equal to the BGP hello time (which I set to 30s between Aurba and Mikrotik)

    Make sure you have bgp fast-external-fallover and neighbor fall-over active in order to optimize switchover times to redundant links

    What I don't like to see when looking at your outputs:

    • In normal situation with both links up to DC3-R1:
      • DC1-CORE2 points the route to 10.180.10.0/24 towards DC2 (logical VTEP 10.31.100.2). I would expect this to be DC1-CORE1. A corrective measure would be an iBGP peering between DC1-CORE1 and DC1-CORE2
      • DC2-CORE2 points the route to 10.180.10.0/24 towards DC2 (logical VTEP 10.31.100.1). I would expect this to be DC2-CORE1. A corrective measure would be an iBGP peering between DC2-CORE1 and DC2-CORE2
    • When 1 link shutdown
      • Are you sure you shut down the link between DC1-CORE1 to DC3? The output of Mikrotik still shows the address of DC1-CORE1 (172.30.100.66) as the next-hop for your 10.30.x/10.40.x routes. 
      • Does DC1-Core2 really show no route to 10.180.10.0/24 or is this a typo / copy&paste mistake?

    Does the situation change (to the positive) after all BGP timers expired?

    >  Probably  one VM hits primary switch in its DC and the other hits the secondary

    Yes, if using standard vSwitch on VMware with 2 redundant links (both in "active" state) to the physical network each VM (not the portgroup!) has a "preferred" uplink NIC and the other is standby. This results in a behavior that same VMs use the first uplink and other use the secondary. You can influence it by setting one to "standby" in the portgroup settings. This may be useful for testing in order to have a more deterministic behavior. 




  • 17.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 03, 2023 10:58 AM

    After I configured BGP peering in VRF thing seem to be working as I wrote in post 15. I am not sure if I messed something when pasting the routing tables. Now situation looks like this:


    When everything is UP

    ========================================================================================================
    DC1-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.30.100.70    vlan817       -                 B/E       [20/0]       01h:20m:52s
    10.180.10.0/24      172.30.100.70    vlan817       -                 B/E       [20/0]       01h:20m:52s
    DC1-CORE1# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.2    0            65008 i
    * e 10.180.1.0/24      172.30.100.70   0            65008 i
    * i 10.180.1.0/24      172.31.100.2    0            65008 i
    *>  10.180.10.0/24     172.31.100.2    0            65008 i
    * e 10.180.10.0/24     172.30.100.70   0            65008 i
    * i 10.180.10.0/24     172.31.100.2    0            65008 i
    DC1-CORE1# show bgp l2vpn evpn | inc 10.180
    *>  [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.1    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i

    ========================================================================================================
    DC1-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.31.100.2     -             -                 B/EV      [200/0]      01h:47m:33s
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      01h:47m:33s
    DC1-CORE2# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.2    0            65008 i
    * i 10.180.1.0/24      172.31.100.2    0            65008 i
    *>  10.180.10.0/24     172.31.100.2    0            65008 i
    * i 10.180.10.0/24     172.31.100.2    0            65008 i
    DC1-CORE2# show bgp l2vpn evpn | inc 10.180
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.1    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i

    ========================================================================================================
    DC2-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.30.101.70    vlan817       -                 B/E       [20/0]       01h:47m:33s
    10.180.10.0/24      172.30.101.70    vlan817       -                 B/E       [20/0]       01h:47m:33s
    DC2-CORE1# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.1    0            65008 i
    * e 10.180.1.0/24      172.30.101.70   0            65008 i
    * i 10.180.1.0/24      172.31.100.1    0            65008 i
    *>  10.180.10.0/24     172.31.100.1    0            65008 i
    * e 10.180.10.0/24     172.30.101.70   0            65008 i
    * i 10.180.10.0/24     172.31.100.1    0            65008 i
    DC2-CORE1# show bgp l2vpn evpn | inc 10.180
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i

    ========================================================================================================
    DC2-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.31.100.1     -             -                 B/EV      [200/0]      01h:20m:52s
    10.180.10.0/24      172.31.100.1     -             -                 B/EV      [200/0]      01h:20m:52s
    DC2-CORE2# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.1    0            65008 i
    * i 10.180.1.0/24      172.31.100.1    0            65008 i
    *>  10.180.10.0/24     172.31.100.1    0            65008 i
    * i 10.180.10.0/24     172.31.100.1    0            65008 i
    DC2-CORE2# show bgp l2vpn evpn | inc 10.180
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.1    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.1    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i

    ========================================================================================================
    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.30"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    D b 10.30.1.0/24  172.30.100.66        20
    DAb 10.30.1.0/24  172.30.101.66        20
    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.40"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    D b 10.40.1.0/24  172.30.100.66        20
    DAb 10.40.1.0/24  172.30.101.66        20

    When interface to the  DC1-CORE1 is shutdown on the Mikrotik in DC3

    ========================================================================================================
    DC1-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.31.100.2     -             -                 B/EV      [200/0]      01h:52m:27s
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      01h:52m:27s
    DC1-CORE1# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.2    0            65008 i
    * i 10.180.1.0/24      172.31.100.2    0            65008 i
    *>  10.180.10.0/24     172.31.100.2    0            65008 i
    * i 10.180.10.0/24     172.31.100.2    0            65008 i
    DC1-CORE1# show bgp l2vpn evpn | inc 10.180
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i


    ========================================================================================================
    DC1-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.31.100.2     -             -                 B/EV      [200/0]      01h:52m:27s
    10.180.10.0/24      172.31.100.2     -             -                 B/EV      [200/0]      01h:52m:27s
    DC1-CORE2# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>  10.180.1.0/24      172.31.100.2    0            65008 i
    * i 10.180.1.0/24      172.31.100.2    0            65008 i
    *>  10.180.10.0/24     172.31.100.2    0            65008 i
    * i 10.180.10.0/24     172.31.100.2    0            65008 i
    DC1-CORE2# show bgp l2vpn evpn | inc 10.180
    *>i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i


    ========================================================================================================
    DC2-CORE1# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.30.101.70    vlan817       -                 B/E       [20/0]       01h:52m:27s
    10.180.10.0/24      172.30.101.70    vlan817       -                 B/E       [20/0]       01h:52m:27s
    DC2-CORE1# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>e 10.180.1.0/24      172.30.101.70   0            65008 i
    *>e 10.180.10.0/24     172.30.101.70   0            65008 i
    DC2-CORE1# show bgp l2vpn evpn | inc 10.180
    *>  [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i


    ========================================================================================================
    DC2-CORE2# show  ip route  vrf prod | inc 10.180
    10.180.1.0/24       172.31.255.130   vlan4001      -                 B/I       [200/0]      00h:02m:34s
    10.180.10.0/24      172.31.255.130   vlan4001      -                 B/I       [200/0]      00h:02m:34s
    DC2-CORE2# show bgp vrf prod ipv4 unicast paths | inc 10.180
    *>i 10.180.1.0/24      172.30.101.70   0            65008 i
    *>i 10.180.10.0/24     172.30.101.70   0            65008 i
    DC2-CORE2# show bgp l2vpn evpn | inc 10.180
    *>  [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.1.0]                          172.31.100.2    0          100        0       65008 i
    *>  [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i
    * i [5]:[0]:[0]:[24]:[10.180.10.0]                         172.31.100.2    0          100        0       65008 i

    ========================================================================================================
    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.30"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    DAb 10.30.1.0/24  172.30.101.66        20
    [admin@DC3-R1] > /ip ro print where dst-address ~ "10.40"
    Flags: D - DYNAMIC; A - ACTIVE; b, y - COPY
    Columns: DST-ADDRESS, GATEWAY, DISTANCE
        DST-ADDRESS   GATEWAY        DISTANCE
    DAb 10.40.1.0/24  172.30.101.66        20




  • 18.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 07:34 AM

    I think I've foudd the problem. OSPF cost on interfaces connecting DCs where different. After fixing that and clearing bgp session everything started to work as expected

    interface 1/1/49
        description dci-1
        no shutdown
        mtu 9198
        ip address 172.30.255.128/31
        l3-counters
        ip ospf 1 area 0.0.0.0
        no ip ospf passive
        ip ospf cost 50 ! <-----here
        ip ospf network point-to-point
    interface 1/1/50
        description dci-2
        no shutdown
        mtu 9198
        ip address 172.30.255.130/31
        l3-counters
        ip ospf 1 area 0.0.0.0
        no ip ospf passive
        ip ospf cost 100  ! <-----here
        ip ospf network point-to-point




  • 19.  RE: Routing off of VXLAN to expternal router.

    Posted Mar 01, 2023 07:42 AM

    Hmm, to be honest that doesn't sound very logical to me. Maybe the restart of BGP made the difference rather than the OSPF cost. Anyway, I think having ECMP activated (check with "show ip route" and look for the VTEP addresses which now should have 2 routes) is desirable in your scenario unless you have reasons to run somehow in active/passive mode. 




  • 20.  RE: Routing off of VXLAN to expternal router.

    EMPLOYEE
    Posted Feb 28, 2023 11:08 AM

    Only between primary and secondary in each DC, not across DC.