LAG Member Interfaces of the S5700 Are in Unselected State When the S5700 Connects to a H3C Switch Through an LAG

Publication Date:  2015-11-20 Views:  940 Downloads:  0
Issue Description
When the S5700 connects to an H3C switch through an LAG, the two devices fail to ping each other.
Handling Process
1. Check member interfaces. The member interfaces are Up, and physical lines work properly.

2. Run the display eth-trunk command to check the link aggregation interface configuration. All member interfaces of the S5700 are in Unselected state, and member interfaces of the H3C switch work properly. That is, link aggregation negotiation fails.

3. Check the configuration at both ends.

S5700 configuration:

interface Eth-Trunk1
mode lacp
interface GigabitEthernet0/0/1
eth-trunk 1

H3C switch configuration:

link-aggregation group 1 mode static
interface Ethernet 1/0/1 
port link-aggregation group 1

According to the preceding configuration, both the S5700 and H3C switch use the static LACP mode; however, the two devices cannot interwork in static LACP mode.

4. Modification methods

− Method 1:
Run the undo mode command to change the link aggregation mode of the S5700 to manual. The member interfaces of the S5700 can work properly after the change.

− Method 2:
Change the link aggregation mode of the H3C switch to link-aggregation mode dynamic. The member interfaces of the S5700 can work properly after the change.
Suggestions
The manual link aggregation mode of the S5700 corresponds to the static LACP mode of the H3C switch.

The static LACP mode of the S5700 corresponds to the dynamic LACP mode of the H3C switch.

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