How to make GRE + Bonding + Bridge in Ubutnu?

Question

Computer networks

Good day. Colleagues, tell me, I'm clearly missing something :)
Available:
All OS - Ubutnu 14.04
SRV - server at home (let's omit why and why. Let it be academic interest)
GW - home router (PC-based)
VPS - KVM-virtualka outside ETH and PPPoE houses
- 2 ISPs with appropriate connection types
Task:
Establish a reliable channel in one network space between VPS and SRV. So far, for myself, I have thrown this scheme:
Problem:
GRE (tun20 and 21) has risen and works without problems. Bond managed to start only in Broadcast mode, in the rest, if it started working, then only on one GRE, when it was turned off, the second one was not "picked up". An attempt to make a Bridge was stopped by the system with the wording
can't add bond0 to bridge br0: Invalid argument
For the sake of interest, I tried to raise vlan over bond, it was applied on GW without problems, on VPS - RTNETLINK answers: Cannot assign requested address
Configs:
GW:

auto tun20
iface tun20 inet manual
    pre-up iptunnel add tun20 mode gre remote IP.FROM.THE.VPS local IP.FROM.THE.ISP_PPPOE ttl 64
    up ifconfig tun20 multicast
    post-down ip tunnel del tun20
    up ifconfig tun20 mtu 1468
    bond-master bond0

auto tun21
iface tun21 inet manual
     pre-up iptunnel add tun21 mode gre remote IP.FROM.THE.VPS local IP.FROM.THE.ISP_ETH ttl 64
     up ifconfig tun21 multicast
     up ifconfig tun21 mtu 1468
     post-down ip tunnel del tun21
     bond-master bond0

auto bond0
iface bond0 inet static
    address 172.31.200.1
    netmask 255.255.255.0
    up ifconfig bond0 mtu 1468
    bond-slaves none
    bond_mode broadcast
    bond-miimon 100
    bond-downdelay 200
    bond-updelay 200

iface bond0.4000 inet static
    address 172.31.220.1
    netmask 255.255.255.0
    vlan_raw_device bond0

# auto mcbr0
iface br0 inet static
    bridge_ports bond0
    address 172.18.3.10
    netmask 255.255.255.0
    bridge_fd 9
    bridge_hello 2
    bridge_maxage 12
    bridge_maxwait 0
    bridge_stp off

VPS:

auto bond0
iface bond0 inet static
    address 172.31.200.2
    netmask 255.255.255.0
    up ifconfig bond0 mtu 1468
    bond-slaves none
    bond_mode broadcast
    bond-miimon 100
    bond-downdelay 200
    bond-updelay 200

auto tun20
iface tun20 inet manual
     pre-up iptunnel add tun20 mode gre local IP.FROM.THE.VPS remote IP.FROM.THE.ISP_PPPOE ttl 64
     up ifconfig tun20 multicast
     post-down ip tunnel del tun20
     up ifconfig tun20 mtu 1468
     bond-master bond0
     bond-mode broadcast

auto tun21
iface tun21 inet manual
     pre-up iptunnel add tun21 mode gre local IP.FROM.THE.VPS remote IP.FROM.THE.ISP_ETH ttl 64
     up ifconfig tun21 multicast
     up ifconfig tun21 mtu 1468
     post-down ip tunnel del tun21
     bond-master bond0
     bond-mode broadcast

iface bond0.4000 inet static
    address 172.31.220.1
    netmask 255.255.255.0
    vlan_raw_device bond0

Answer 1

You cannot make a bond from different L3 devices.