Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring Interfaces (Rev. 03)
Link Aggregation Groups (LAG)
© 2008 Foundry Networks, Inc.
Page 28 of 57
LAG ID Numbers on the Devices
LAG ID numbers, in the range <1-31>, are used to identify specific LAGs in configuration
commands. Up to 8 ports can be added to each LAG.
MAC Addresses Learned on LAG Ports
The MAC addresses are displayed with the assigned aggregated interface. The
show mac-address-
table
command displays the MAC address and the LAG ID number.
For example, the LAG named AG01 comprises ports 1/1/1-1/1/4:
device-name
#
show mac-address-table
===+======+====================+==============+==========+==========+
# | VID | Mac | PORT | STATUS | PRIORITY |
---+------+--------------------+--------------+----------+----------+
1 | 0001 | 00:00:00:00:09:01 | AG01 | dynamic | 0 |
2 | 0001 | 00:00:00:00:09:02 | AG01 | dynamic | 0 |
3 | 0001 | 00:00:00:00:12:01 | 1/1/4 | dynamic | 0 |
4 | 0001 | 00:00:00:00:12:03 | 1/1/4 | dynamic | 0 |
5 | 0001 | 00:12:F2:22:13:00 | | self | 0 |
LAG on the Devices
The switches may include both static and LACP LAGs simultaneously, assuming the following
restrictions:
•
LAG IDs of both static and dynamic LAGs occupy the same available LAG IDs’ space.
•
Static LAG and LACP cannot be defined with the same LAG ID number.
•
Each port may be included in a single LAG that is either static or dynamic.
Creating and Removing Dynamic LAGs by the LACP
Dynamic LAG can be created by LACP on a local system, if the LACP detects any compatible
connected pairs of LACP-enabled ports. The role of the LACP exchange is to detect that a local
LACP port is connected to another LACP port, and to share between these two ports the operative
settings of each port in the connection.
An active LACP port sends frames periodically (every 30 seconds), or transmits them every second
for a few seconds after connecting the link. If a transmitted LACP PDU is answered, further
exchange is performed corresponding to LACP requirements.
A passive LACP port doesn’t initiate transmission of LACP frames. Rather, it answers incoming
frames when they arrive. An active LACP port is also able to answer incoming frames.
An LACP exchange is therefore possible either between an active and a passive LACP port, or
between two active LACP ports.
An LACP frame includes parameters of the LACP sender port, including the operation parameters
of the local port (Actor), and its knowledge of the connected port (Partner) parameters.
When receiving an LACP frame, the LACP Actor accepts configuration parameters of the Partner,
analyzes them, updates its own parameters if necessary, and transmits back an LACP frame with
updated parameters. This exchange continues until both sides agree about each other current
settings. Then the LACP system decides which of its LACP-connected ports to be aggregated.
To sum up, the requirements for aggregation of groups of LACP ports are:
•
Local LACP ports connected to LACP ports on the other side.