Switch Port Mirroring

[EliasNerius]

Hi,

I currently have a cisco 3750x series switch with me and I would like to do port mirroring on it.

Before I do port mirroring on it, I just want to confirm if the port mirroring works for my case:

My Case:

I want to do port mirroring so when if a port (source port)on the switch is offline or gone faulty for some reason, all data networks goes to the mirrored port (destination port) and everything works fine.

Question:

Does the port mirroring works for this?

Appreciate your kind response

 elias

Note from teh Moderator: This was originaly posted as a blog. Deleted the blog and posted as a discussion to get faster responses. Blogs are not used for asking questions. 

[Reza Sharifi]

Hi,

Here is a good explanation from the config guide for the 3750 series:

You can analyze network traffic passing through ports or VLANs by using SPAN or RSPAN to send a copy of the traffic to another port on the switch or on another switch that has been connected to a network analyzer or other monitoring or security device. SPAN copies (or mirrors) traffic received or sent (or both) on source ports or source VLANs to a destination port for analysis. SPAN does not affect the switching of network traffic on the source ports or VLANs. You must dedicate the destination port for SPAN use. Except for traffic that is required for the SPAN or RSPAN session, destination ports do not receive or forward traffic.

link:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_53_se/configuration/guide/3750xscg/swspan.html

HTH