I´m trying to test this etherchannel configuration but did´t work properly.

The goal is:

I want to entablish a L2 communication channel between A and B, but i neet to put on the middle 2 equipments and try to load balance the traffic accross then. To do that i figure out the use of an etherchannel configuration like i described on the image, but did not work properly, i generate a lot of traffic and neither get to its destination

Any help will be appreciatedenter image description here

  • @RonMaupin I´m trying this configuration with huawei equipment(switches) and servers like bridges. All the equipment is etherchannel capable in load balance and LACP mode Jan 10 '17 at 16:53
  • Is the trunk with 4 links in one single group or two seperate groups of 2 links?
    – SleepyMan
    Jan 10 '17 at 16:56
  • On A and B, the trunk contains 4 links, but on bridges, one trunk have 2 links Jan 10 '17 at 17:08

If I understand you correctly, you have four bridges in a loop, but you want to load balance. The problem is that STP will block one direction in order to prevent layer-2 looping.

An etherchannel must start on one device, and terminate on another device. You cannot channel from one device through two other devices to a fourth device.

You can channel from A to each of the two middle bridges, but it will be two separate links, one to each of the middle bridges. The same goes for B to the middle bridges.

LACP is a link protocol that cannot be sent through a bridge. It is only between the two devices on each end of the physical link. LACP frames are sent with the special 01:80:c2:00:00:02 multicast MAC address. The IEEE has reserved the 01:80:c2 OUI for link protocols, and frames with this special multicast OUI are not allowed to be forwarded from the interface on which they are received to another interface on 802.1D compliant bridges.

  • From the bridge view, the 2 links on the 2 sides form a eth-trunk, then, one bridge will have 2 eth-trunk of 2 links each one, one to A and another to B. Jan 10 '17 at 17:05
  • With LACP I'm sure that did't work, 'cause LACP negotiation do never occurs, and trunk do never get UP Jan 10 '17 at 17:07
  • You need two LACP links on A and on B. Each channel goes to one intermediate bridge. For example, A should have one LACP link to the top bridge, and one LACP link to the bottom bridge. STP will block one of those links, and you cannot load balance across the intermediate bridges.
    – Ron Maupin
    Jan 10 '17 at 17:11
  • @OrlandoGaetano, The LACP links from A to the intermediate bridges must terminate on the intermediate bridges. You cannot channel from A to B.
    – Ron Maupin
    Jan 10 '17 at 17:12
  • I don't want to use LACP, only in normal mode, that's it, in load balance working mode, also i disabled STP and result is the same Jan 10 '17 at 18:57

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