Hi Dan,

Had you considered not using VRRP, and configuring both of your MX IRBs to use 
the same IP address and MAC? You’ll need to think about it for your own 
situation, but this could achieve the redundancy you require?

Each MX will announce the same MAC via EVPN BGP. If either next-hop is used, 
either should forward traffic OK for you. Should one gateway fail, standard BGP 
path selection will then simply select the other gateway. You could probably 
even play with Local Preference to prefer one gateway over the other?

Hope this helps – good luck with it!

Alex.



From: Users [mailto:[email protected]] On Behalf Of Dan Houtz
Sent: 25 June 2015 05:31
To: [email protected]
Subject: [Users] Redundant L3 gateways using MX80s

Hi,

I've been working hard to get BMS / TOR switch VXLAN overlays working and, with 
the gracious help of Praveen, I believe everything is mostly working as 
expected now. With that functionality in a working state I'm now looking at 
adding in L3 gateway support using a pair of MX80s. This seems pretty straight 
forward with one MX but I haven't quite got a redundant setup working properly. 
Are there any documented 'best practices' for this?  In an attempt to add 
redundancy I am trying to configure VRRP (I'm not sure EVPN anycast gateways 
are viable in this setup. Hopefully someone can confirm).

At present VRRP does converge across the overlay, my hosts can ping the 
physical IP addresses configured on each MX IRB, and my hosts succeed in 
getting ARP for the VRRP VIPs. They can not, however, complete a ping (I do 
have accept-data configured for VRRP so MX should reply to pings). After a bit 
of digging I believe this is because the virtual MAC address of the VIP is not 
being announced via BGP so my TOR switches never learn the MAC via OVSDB.

root@gw1z0> show configuration interfaces irb.5
family inet {
    address 10.10.10.146/29<http://10.10.10.146/29> {
        vrrp-group 13 {
            virtual-address 10.10.10.145;
            priority 105;
            accept-data;
        }
    }
}

root@gw1z0> show route advertising-protocol bgp 10.10.10.139

Demo-NetworkA.evpn.0: 13 destinations, 13 routes (13 active, 0 holddown, 0 
hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  2:10.10.20.70:2::4::f8:c0:01:19:b1:88/304
*                         Self                         100        I
  
2:10.10.20.70:2::4::f8:c0:01:19:b1:88::10.10.10.145/304<http://10.10.10.145/304>
*                         Self                         100        I
  
2:10.10.20.70:2::4::f8:c0:01:19:b1:88::10.10.10.146/304<http://10.10.10.146/304>
*                         Self                         100        I
  3:10.10.20.70:2::4::10.10.20.70/304<http://10.10.20.70/304>
*                         Self                         100        I

__default_evpn__.evpn.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 
hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  1:10.10.20.70:0::050000ff840000000400::FFFF:FFFF/304
*                         Self                         100        I

As you can see in the advertised BGP routes above the MX is announcing .145 
with the actual MAC of the IRB:

root@gw1z0> show interfaces irb | grep hardware
  Current address: f8:c0:01:19:b1:88, Hardware address: f8:c0:01:19:b1:88

not the virtual MAC that has been assigned for VRRP:

root@gw1z0> show vrrp extensive | grep mac
  Virtual Mac: 00:00:5e:00:01:0d

I suspect that because the MX never announces an EVPN mac of 00:00:5e:00:01:0d, 
my TOR never learns where that MAC lives:

oot@leaf1z0> show ovsdb mac
Logical Switch Name: Contrail-12905c4b-60db-4d71-8fab-972051db1386
  Mac                    IP                 Encapsulation      Vtep
  Address                Address                               Address
  ff:ff:ff:ff:ff:ff      0.0.0.0            Vxlan over Ipv4    10.10.20.65
  d4:ae:52:c6:c9:e1      0.0.0.0            Vxlan over Ipv4    10.10.20.65
  50:c5:8d:d4:af:f0      0.0.0.0            Vxlan over Ipv4    10.10.20.71
  54:9f:35:05:fa:2e      0.0.0.0            Vxlan over Ipv4    10.10.20.66
  f8:c0:01:19:b1:88      0.0.0.0            Vxlan over Ipv4    10.10.20.70
  ff:ff:ff:ff:ff:ff      0.0.0.0            Vxlan over Ipv4    10.10.10.139


Is there perhaps a knob I'm missing? Is there something other then VRRP that is 
preferred for redundant gateways in Contrail?

I have the same question out to a few other resources but figured someone on 
the mailing list might have some good pointers as well.

Thanks!
Dan
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