6.4. Link Aggregation

Multiple data interfaces can be combined into a single logical bond interface to increase fault tolerance and simplify routing configuration. Currently, aggregation of interfaces via the LACP protocol is supported in accordance with the IEEE 802.3 standard.

Use the following command to create a bond interface:

interface IFNAME

The IFNAME parameter is specified in the bondX format, where X is the index of the created interface (can be any number).

To configure the bond interfaces, the same commands as for normal data interfaces, as well as additional commands described below are available.

lacp min-links (1-64)

Set the minimum number of interfaces with active connections in the bond, required to consider the bond active. By default, this number is 1.

lacp timeout <fast|slow>

Set the interval between sending the LACP protocol control messages. fast - 1 second, slow - 30 seconds. By default, the slow interval is used.

Show Commands

show bond IFNAME

Display all bonds and the interfaces that are bonded into them. You can specify the bond by IFNAME.

The LACP port state (also known as the actor state) field is a single byte, each bit of which is a flag indicating a particular status. In this table, mux (i.e., a multiplexer) refers to the logical unit aggregating the links into a single logical transmitter/receiver.

Bit ID	Bit value	Name	Description
0	0 = Passive 1 = Active	LACP_Activity	The Device intends to transmit periodically to find potential members for the aggregate. This is toggled by the mode active in the channel-group configuration on the member interfaces. The default is active
1	0 = Long Timeout 1 = Short Timeout	LACP_Timeout	The LACP Timeout flag indicates that the participant wishes to receive frequent periodic transmissions and will aggressively times out received information.
2	0 = No 1 = Yes	Aggregation	The flag indicates that the participant will allow the link to be used as part of an aggregate. Otherwise, the link will be used as an individual link, i.e., not aggregated with any other. This flag is set or reset as a consequence of local key management: the participant may know that the link has a unique key and, hence, will not be aggregated. Signaling this information allows the receiving actor to skip protocol delays that are otherwise invoked. This allows all links with the same system ID and key combinations to be collected into one aggregate port without successive rapid changes to aggregate ports and accompanying higher-layer protocol disruption. If set the flag communicates Aggregatable, if reset Individual
3	0 = Not in sync 1 = In sync	Synchronization	The flag indicates that the transmitting participant’s mux component is in sync with the system id and key information transmitted. This accommodates multiplexing hardware that takes time to set up or reconfigure
4	0 = No 1 = Yes	Collecting	TRUE (encoded as a 1) means collection of incoming frames on this link is definitely enabled; i.e., collection is currently enabled and is not expected to be disabled in the absence of administrative changes or changes in received protocol information
5	0 = No 1 = Yes	Distributing	FALSE (encoded as a 0) means the distribution of outgoing frames on this link is definitely disabled; i.e., distribution is currently disabled and is not expected to be enabled in the absence of administrative changes or changes in received protocol information
6	0 = via LACP PDU 1 = default settings	Defaulted	If TRUE (encoded as a 1), this flag indicates that the Actor’s Receive machine uses Defaulted operational Partner information, administratively configured for the Partner. If FALSE (encoded as a 0), the operational Partner information in use has been received in a LACPDU
7	0 = No 1 = Yes	Expired	If TRUE (encoded as a 1), this flag indicates that the Actor’s Receive machine is in the EXPIRED state; if FALSE (encoded as a 0), this flag indicates that the Actor’s Receive machine is not in the EXPIRED state

In most cases, lacp fast mode is chosen. To understand that the link aggregation is established in this mode, look at the port state line for actor LACPDU and partner LACPDU. The state should be 63. Convert this value from decimal to binary. The binary will be 00111111, where the leftmost bit is the high bit and its bit ID is 7, and the rightmost bit is the low bit and its bit ID is 0. So, the state 63 will mean LACP Activity is active, and the Actor’s Receive machine is not in the EXPIRED state.