[j-nsp] evpn trouble

[Baldur Norddahl]

Hello

I am deploying EVPN and while it works, we are having some issues. Here is
the first one:

An EVPN instance configured for testing on a MX204 and an ACX5448 both
running 21.1R1. The have the same exact configuration except for the IP
address of the IRB interface:

baldur at formervangen-core3# show interfaces irb.20
family inet {
    address 185.24.168.92/29;
}

[edit]
baldur at formervangen-core3# show routing-instances evpntest
instance-type evpn;
protocols {
    evpn;
}
vlan-id 20;
routing-interface irb.20;
interface xe-0/0/42.20;
vrf-target target:60876:20;

[edit]
baldur at formervangen-core3# show interfaces xe-0/0/42
flexible-vlan-tagging;
encapsulation flexible-ethernet-services;
unit 20 {
    encapsulation vlan-bridge;
    vlan-id 20;
}

Also irb.20 is in a layer 3 VRF called "internet".

On the MX204 the interface irb.20 comes online but on the ACX5448 the
irb.20 interface stays in the state hardware-down:

baldur at formervangen-core3# run show interfaces irb.20
  Logical interface irb.20 (Index 76) (SNMP ifIndex 563)
    Flags: Hardware-Down Up SNMP-Traps 0x4004000 Encapsulation: ENET2
    Bandwidth: 1Gbps
    Routing Instance: None Bridging Domain: None
    Input packets : 0
    Output packets: 0
    Protocol inet, MTU: 1514
    Max nh cache: 100000, New hold nh limit: 100000, Curr nh cnt: 0, Curr
new hold cnt: 0, NH drop cnt: 0
      Flags: Sendbcast-pkt-to-re, Is-Primary
      Addresses, Flags: Dest-route-down Is-Preferred Is-Primary
        Destination: 185.24.168.88/29, Local: 185.24.168.92, Broadcast:
185.24.168.95
    Protocol multiservice, MTU: Unlimited

In fact I can not get the irb interface to go up at all on the ACX5448
platform. Is IRB unsupported? Without it a lot of EVPN features are not
available.

In our production environment the mx204 routers do not have any servers
directly connected. The irb interface will therefore not come online. But
since the acx5448 switches refuse to have their own irb interfaces, I need
the mx204 to do the task. My solution right now is to add a dummy interface
to the evpn instance on the mx204. Is there a better way? Why did Juniper
not include a knop to bring irb up even without any physical interfaces
active in the vpn?

Thanks,

Baldur