Ethernet traffic replication

[mgupta]

I wnat to mirror a Gigabit ethernet traffic to 8 ports to get the copy of the same traffic at 8 ports.This is just like a HUB functionality for gigabit ports. How this can be achieved? Is their any such device available in the market. Pl help.

Thanks

[ankurbhasin]

Hi Mgupta,

I think the easient way can be a broadcast which is possible by just making the mac address aging time as 0.

If you just change the mac address aging time in your switch time to 0 which is default of 5 minutes it will not keep the mac address and any traffic will be a broadcast to all the ports.

OR what else can be done is to configure SPAN session where you can monitor and get the replica traffic of all the ports on one single port but there can be only one destination port in one SPAN session.

Both can be done on any normal layer 2 cisco switch.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/12113ea1/2950scg/swspan.htm#1036749

This is what you are looking for or something else.

hope this help, if yes please rate the post.

Ankur

[mgupta]

Hi Ankur,

I want to replicate the traffic of one port to 8 destinations and port spanning or mirroring does not allow this. Making MAC address aging time 0 will affect the traffic of other ports. How ever the mirrored output can be connected to another switch and on that switch we can apply MAC aging 0 to make the traffic on all ports but I doubt that aging time can be made 0 ?.

Thanks

[ankurbhasin]

Hi Mgupta,

MAC aging can be set to 0 with command

mac address-table aging-time 0

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12120ea2/3550cr/cli1.htm#wp1862251

To collect mirroed output on another switch you can configure RSPAN (remote span) but the destination can be only 1 port not 8 ports.

HTH, if yes please rate the post.

Ankur

[mgupta]

Hi Ankur,

I think you have misinterprated the aging-time 0. The minimum aging-time is 10 and if you make it 0 then aging is disabled at all, i.e static entries will never age out, removed or deleted from the table.

M.K.Gupta