I want to ask some questions related to Link Aggregation Group - LAG:

  1. Can LAG be configured in Active Standby Mode? Or can LAG only be used in the standard operation as Load Sharing mode?

  2. What will be the MAC address of the LAG bundle? Will it take the MAC address of one of the member interface by default?

  3. Similarly with VLAN and IP address, do I assign it to each member interface with identical information or do I only need to assign VLAN and IP address on the bundle logical interface? I assume LACP does not seek agreement of this information between members when it brings up the LAG

Many Thanks :)

  • STP sets up in Active/Standby, but LACP is to fool STP into thinking that multiple interfaces, which would normally be Active/Standby, into being Active/Active.
    – Ron Maupin
    Jun 15 '18 at 2:01
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Dec 25 '18 at 8:38
  1. This may depend on the device in question but generally, LAG trunks (LACP or passive) are independent of the port/trunk forwarding status. If active/standby refer to device modes you'll have to check the documentation.
  2. A LAG trunk is an aggregated group of layer-1 links, forming a single, logical link. It doesn't have a MAC address which is a property of a layer-2 endpoint. If you refer to "teamed" NIC interfaces you need to check which options the teaming driver offers.
  3. The VLAN setup of each LAG member must be the exact same. (On some device you configure the trunk instead of the members.) IP addresses are mapped to MAC addresses, so you should sort that out. LACP only sets up the L1 links, it doesn't care for L2 or L3 properties.

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