H3C Technologies H3C SecPath F1000-E - Manual (Page 93)

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Table 2 Basic and extended LACP functions
Category Description
Basic LACP functions
Implemented through the basic LACPDU fields, including the system LACP priority,
system MAC address, port aggregation priority, port number, and operational key.
Each member port in a LACP-enabled aggregation group exchanges the above
information with its peer. When a member port receives an LACPDU, it compares
the received information with the information received on the other member ports. In
this way the two systems reach an agreement on which ports should be placed in the
Selected state.
Extended LACP
functions
Implemented by extending the LACPDU with new Type/Length/Value (TLV) fields.
This is how the LACP multi-active detection (MAD) mechanism of the Intelligent
Resilient Framework (IRF) feature is implemented.
• If a device supports both LACP extensions and IRF, it can participate in LACP
MAD either as an IRF member device or an intermediate device.
• If a device supports LACP extensions but not IRF, it can participate in LACP MAD
only as an intermediate device.
2. LACP priorities
There are two types of LACP priorities: system LACP priority and port aggregation priority, as described
in Table 3 .
Table 3 LACP priorities
Type Description Remarks
System LACP
priority
Used by two peer devices (or systems) to determine which one is
superior in link aggregation.
In dynamic link aggregation, the system that has higher system LACP
priority sets the Selected state of member ports on its side first and then
the system that has lower priority sets port state accordingly.
Port aggregation
priority Determines the likelihood of a member port to be selected on a system.
The higher port aggregation priority, the higher likelihood.
The smaller the
priority value,
the higher the
priority.
3. LACP timeout interval
The LACP timeout interval specifies how long a member port waits to receive LACPDUs from the peer port.
If a local member port fails to receive LACPDUs from the peer within three times the LACP timeout interval,
the member port assumes that the peer port has failed. You can configure the LACP timeout interval as
the short timeout interval (1 second) or the long timeout interval (30 seconds).
Link aggregation modes
There are two link aggregation modes: dynamic and static. Dynamic link aggregation uses LACP and
static link aggregation does not. Table 4 compares the two aggregation modes.