Bridge Layer 2 Protocol Tunneling

A VXLAN connects layer 2 domains across a layer 3 fabric; however, layer 2 protocol packets, such as LLDP, LACP, STP, and CDP stop at the ingress VTEP. If you want the VXLAN to behave more like a wire or hub, where the switch tunnels protocol packets instead of terminating them locally, you can enable bridge layer 2 protocol tunneling.

Configure Bridge Layer 2 Protocol Tunneling

To configure bridge layer 2 protocol tunneling for all protocols:

cumulus@switch:~$ sudo nano /etc/network/interfaces
...
auto swp1
iface swp1
    bridge-access 10
    bridge-l2protocol-tunnel all

auto swp2
iface swp2

auto swp3
iface swp3

auto swp4
iface swp4
...
interface vni10
    bridge-access 10
    bridge-l2protocol-tunnel all
    bridge-learning off
    mstpctl-bpduguard yes
    mstpctl-portbpdufilter yes
    vxlan-id 10
    vxlan-local-tunnelip 10.10.10.1

To configure bridge layer 2 protocol tunneling for a specific protocol, such as LACP:

cumulus@switch:~$ sudo nano /etc/network/interfaces
...
auto swp1
iface swp1
    bridge-access 10
    bridge-l2protocol-tunnel lacp

auto swp2
iface swp2

auto swp3
iface swp3

auto swp4
iface swp4
...
interface vni10
    bridge-access 10
    bridge-l2protocol-tunnel lacp
    bridge-learning off
    mstpctl-bpduguard yes
    mstpctl-portbpdufilter yes
    vxlan-id 10
    vxlan-local-tunnelip 10.10.10.1

LLDP Example

Here is another example configuration for Link Layer Discovery Protocol. You can verify the configuration with lldpcli.

cumulus@switch:~$ sudo lldpcli show neighbors
-------------------------------------------------------------------------------
LLDP neighbors:
-------------------------------------------------------------------------------
Interface: swp23, via LLDP, RID: 13, TIme: 0 day, 00:58:20
  Chassis:
    ChassisID: mac e4:1d:2d:f7:d5:52
    SysName: H1
    MgmtIP: 10.0.2.207
    MgmtIP: fe80::e61d:2dff:fef7:d552
    Capability: Bridge, off
    Capability: Router, on
  Port:
    PortID: ifname swp14
    PortDesc: swp14
    TTL: 120
    PMD autoneg: support: yes, enabled: yes
      Adv: 1000Base-T, HD: no, FD: yes
      MAU oper type: 40GbaseCR4 - 40GBASE-R PCS/PMA over 4 lane shielded copper balanced cable
...

LACP Example

H2 bond0:
Bonding Mode: IEEE 802.3ad Dynamic link aggregation
Transmit Hash Policy: layer 3+4(1)

802.3ad: info
LACP rate: fast
Min links: 1
Aggregator selection policy (ad_select): stable
System priority: 65535
System MAC address: cc:37:ab:e7:b5:7e
Active Aggregator Info:
    Aggregator ID: 1
    Number of ports: 2

Slave Interface: eth0
...
details partner lacp pdu:
    system priority: 65535
    system MAC address: 44:38:39:00:a4:95
...
Slave Interface: eth1
...
details partner lacp pdu:
    system priority: 65535
    system MAC address: 44:38:39:00:a4:95

Pseudowire Example

In this example:

• Only two VTEPs are in the VXLAN. VTEP1 and VTEP2 point to each other as the only remote VTEP.
• The bridge on each VTEP is in 802.1ad mode.
• The host interface is an 802.1Q VLAN trunk.
• The setting for bridge-l2protocol-tunnel is all.
• The VTEP host-facing port is in access mode and the PVID maps to the VNI.

Considerations

Use caution when enabling bridge layer 2 protocol tunneling:

• Layer 2 protocol tunneling is not a full-featured pseudo-wire solution; End-to-end link status tracking or feedback does not exist.
• Layer 2 protocols typically run on a link-local scope. Running the protocols through a tunnel across a layer 3 fabric incurs higher latency, which require you to tune protocol timers.
• The lack of end to end link or tunnel status feedback and the higher protocol timeout values make for a higher protocol convergence time when there are changes.
• If the remote endpoint is a Cisco endpoint using LACP, you must configure etherchannel misconfig guard on the Cisco device.