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What triggers flexlink?

Hi all,

i'm trying to verify a planned installation and i'm not sure whether my way of using Flexlink will work.

The idea is to have two switches configured with a SPAN session with two destination ports on each. One of these ports is cross-connected to another two switches in different rooms. When configuring Flexlink on C and D, where they only get RX traffic from the SPAN sessions of A and B, will they notice a link failure?

Sw A | Sw B

| \ / |

| \/ |

| X |

| / \ |

| / \ |

Sw C | Sw D

Thx in advance



Re: What triggers flexlink?

I think the issue is UDLD(uni directional link failure).

To resolve this issue, perform these steps:

Verify that all of the fiber strand pairs or copper wire pairs are connected correctly and that the transmit (Tx) and receive (Rx) fiber connectors are bundled together.

Check that the port functions normally and that the hardware counters operate properly.

If no apparent misconnection or malfunction is found, try to re-enable the port and disable the aggressive mode.

Make sure that the port is not connected to a hub, media converter, or similar device.

The ports and links on both the switches can be troubleshooted by issuing the show counters command on the ports and examine which error counters have high counts. This points out what caused the traffic to stop flowing in one direction, resulting in the link going down. Also check the Gigabit Interface Converters (GBICs) and physical links.

Re: What triggers flexlink?

Hello Dirk,

I believe Flex links are triggered by interface status only.

so, it will only go from standby to active if the other link goes down.

I dont think SPAN will affect its use.


if it does please rate this post.


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