3Com S7906E Configuration Manual page 2592

To do...
Enter the view of the port that
connects to the BFD MAD
detection link
Access port
Assign the
Trunk port
port to the
VLAN used
for BFD MAD
Hybrid port
detection
If there is an intermediate device in a BFD-MAD enabled IRF, to ensure that the BFD packets can be
transmitted among members normally, you also need to add the port that connects to the BFD MAD
detection link on the intermediate device into the VLAN used for the detection.
You are not allowed to configure other services on a Layer 3 interface with BFD MAD enabled.
A VLAN interface enabled with BFD MAC detection and the interfaces of this VLAN do not support
any Layer 2 and Layer 3 protocol applications, including ARP and LACP.
You cannot enable BFD MAD detection on VLAN interface 1.
The MAD function is mutually exclusive with VPN; therefore, Layer 3 interfaces with BFD MAD
enabled cannot be bound with VPN.
A MAD IP address and a common IP address are not mutually interfered; they can coexist: the
MAD IP address automatically becomes the slave address after being configured, and the common
IP address becomes the primary address.
If an IRF configured with the BFD MAD function splits into two or more IRFs, routing collision
information may be generated because the new IRFs still keep the forwarding entries with the
destination being the original master device. This collision information does not affect the device
forwarding and automatically stops to be generated with the aging of the forwarding entries.
Enabling LACP MAD detection
LACP MAD detection is implemented by expanding the content of an LACP packet, namely, add a TVL
data field that is used for exchanging the active IDs of the IRF in the preserved field of the LACP packet.
An IRF system has a unique active ID, which is represented by the member ID of the master.
After the LACP MAD detection is enabled, a member device exchanges the active ID with other
member devices using the LACP packets.
When the IRF operates normally, the active IDs in the LACP packets sent by all member devices
are the same, and no multi-active collision.
When the IRF splits into two or multiple IRFs, the active IDs in the LACP packets sent by member
devices in different IRFs are different, and the multi-active IDs are detected.
Follow these steps to enable LACP MAD detection:
Use the command...
interface interface-type
interface-number
port access vlan vlan-id
port trunk permit vlan vlan-id
port hybrid vlan vlan-id
1-16
Remarks
—
Required
The three approaches have
the same effect; you can
choose one according to the
port type.
By default, the port is an
access port.