BGP router-id

[thegoggel]

Hi

Is there any way of changing the router-id for the EVPN BGP. It uses multicast addresses by default and I can't connect it to the rest of my VXLAN domain since the network equipment wont talk to a device with a router-id that is a multicast address.

I can't find anywhere in the config to change it permanently. I can change it in frr.conf and vtysh. But when I hit apply it returns to a multicast address. I have tried to add it to my frr.conf.local but it won't stick, the rest of the config in the same file does work.

 

[ggoller]

Could you give us a small overview on your setup? Do you use ipv6 in the underlay? do you have an evpn controller + fabric (or manual peers?)? Do you have a bgp or isis controller?

I can see two ways that this could happen: either you have an ipv6 underlay with an ipv4 overlay and it cannot find a local ipv4 address, or it cannot find an ipv4 address on either the loopback or the physical interfaces, so it falls back to generating an ip address from the bridge’s mac address.

 

[thegoggel]

I use IPv6 for both underlay and overlay. I have configured the evpn in the Proxmox SDN and I run a route reflector on an Aruba switch. I have tried to attach a IPv4 address to the loopback address in addition to the IPv6 but it does not help. I use an IPv4 address for management. I have attached the frr config and some of the config files

Building configuration...

Current configuration:
!
frr version 10.6.1
frr defaults datacenter
hostname c5711
log syslog informational
service integrated-vtysh-config
!
route-map MAP_VTEP_IN permit 1
exit
!
route-map MAP_VTEP_OUT permit 1
exit
!
vrf vrf_evpn
 vni 1
exit-vrf
!
interface bond0
 ipv6 ospf6 area 0.0.0.0
 ipv6 ospf6 network point-to-point
exit
!
interface lo
 ip address 10.255.255.11/32
 ipv6 address 2a81:6060:0:300::14a:538/128
 ipv6 ospf6 area 0.0.0.0
exit
!
router bgp 65001
 bgp router-id 225.164.70.214
 no bgp hard-administrative-reset
 no bgp default ipv4-unicast
 coalesce-time 1000
 no bgp graceful-restart notification
 neighbor VTEP peer-group
 neighbor VTEP remote-as 65001
 neighbor VTEP bfd
 neighbor 2a81:6060::2a:929 peer-group VTEP
 use-underlays-nexthop-weight
 !
 address-family l2vpn evpn
  neighbor VTEP activate
  neighbor VTEP route-map MAP_VTEP_IN in
  neighbor VTEP route-map MAP_VTEP_OUT out
  advertise-all-vni
 exit-address-family
exit
!
router bgp 65001 vrf vrf_evpn
 bgp router-id 225.164.70.214
 no bgp hard-administrative-reset
 no bgp deterministic-med
 no bgp graceful-restart notification
exit
!
router ospf6
exit
!
end

root@c5711:~# cat /etc/pve/sdn/zones.cfg
evpn: evpn
        controller evpn-con
        vrf-vxlan 1
        ipam pve
        mac BC:24:11:6C:01:BC
        mtu 9198

root@c5711:~# cat /etc/pve/sdn/controllers.cfg
evpn: evpn-con
        asn 65001
        peers 2a81:6060::2a:929

root@c5711:~# pvesh get /cluster/sdn/controllers
┌────────────┬──────┬───────┬──────────┬────────────────────────┬──────────────────────────────────────────┬──────┬───────────────┬─────────────┬─────────────┬──────────┬──────────┬──────┬───────┬─────────────────┬───────────────────┬─────────┬───────┐
│ controller │ type │   asn │ bgp-mode │ bgp-multipath-as-relax │ digest                                   │ ebgp │ ebgp-multihop │ isis-domain │ isis-ifaces │ isis-net │ loopback │ node │ nodes │ peer-group-name │ peers             │ pending │ state │
╞════════════╪══════╪═══════╪══════════╪════════════════════════╪══════════════════════════════════════════╪══════╪═══════════════╪═════════════╪═════════════╪══════════╪══════════╪══════╪═══════╪═════════════════╪═══════════════════╪═════════╪═══════╡
│ evpn-con   │ evpn │ 65001 │          │                        │ 82a7168d1b38aaa7a82a4ca287616a9ee4aa163f │      │               │             │             │          │          │      │       │                 │ 2a81:6060::2a:929 │         │       │
└────────────┴──────┴───────┴──────────┴────────────────────────┴──────────────────────────────────────────┴──────┴───────────────┴─────────────┴─────────────┴──────────┴──────────┴──────┴───────┴─────────────────┴───────────────────┴─────────┴───────┘

 

[ggoller]

I see. First of all this is wrong by the aruba switch, according to rfc 6286 (https://www.rfc-editor.org/info/rfc6286/) (which is deprecating https://www.rfc-editor.org/info/rfc4271/) the router-id is not a ipv4 address and shouldn't be handled as one.

As a fallback we generate a router-id from the mac address, so you can change the mac address of the interface where the local peer address is. Change the third octet of the mac address (use /etc/network/interfaces and hwaddress x:x:x:x:x:x) to be between 0x01 and 0xdf and you won't hit a multicast address.