RSPAN

[johnleeee]

Hi all,

I have basic question about configuring

RSPAN on Catalyst 2950.

I want to monitor one specific port Fa0/20 on remote switch. This switch is conected to other switch through trunk .1Q. On those second switch I have probe.

My configuration is shown below, vlan 3

is RSPAN Vlan:

monitor session 1 source interface Fa0/20

monitor session 1 destination remote vlan 3 reflector-port Fa0/2

monitor session 1 destination interface Fa0/12

monitor session 1 source remote vlan 3

I think that configuration is right but

I dont see anything on my probe.

Any suggestions or help for troubleshooting.

BR

jl

[szahid]

Verify couple of things .

1. Make sure vlan 3 is in spanning-tree forwarding state on a trunk that connects the 2 switches.

2. Did you define vlan 3 as an rspan vlan ?

vlan 3

remote-span

HTH.

thanks

Salman Z.

[johnleeee]

Hi ,,

I have looked at Vlan 3 and is in FW state on trunk

which connects two switches.

Vlan 3 is configured as remote-span.

I dont know if it is possible configure RSPAN only

on 2950 switches.

Any suggestions, pls

BR

jl

[szahid]

One other thing you want to check is the span destination port . Does the status of the span destination port show as "connected" before configuring the port as a span destination port. Because after you configure it as a span dest. port , it goes to down ( monitoring ) state. Also , make sure nothing is connected on a reflector port.

thanks

Salman Z.

[johnleeee]

Hi,

I have new news.

Yes my reflector port is not connected

and destination span port was before conf.

connected and now is in monitoring state.

But what Iv observed is:

Way which I do RSPAN is only two C2950 connected

through trunk. But PCs are in VLAN 1. I have

RSPAN VLAN configured too.Trunk between two switches

passes RSPAN VLAN.

But after configuration both directions on source port (tx and rx) it doesnt work.

But when I configure only one direction (tx or rx)

it starts to function only after time and only after time I see on my probe packets related to direction

what I configured on source span port.

And from now Im little bit confused.

Why this function only after time and why I can use only one direction to monitor in the same time?

Any suggestions?

BR

jl

[amit-singh]

Hi,

What u r seeing the is expected behaviour of RSPAN on 2950. This is the hardware limitaion on 2950.

# If traffic for a port is monitored in one direction, you can use Catalyst 2950 or 2955 switches as source, intermediate, or destination switches.

# If traffic for a port is monitored in both directions, make sure that the intermediate switches and the destination switch are switches other than Catalyst 2950 or 2955 switches, such as Catalyst 3550, 3750, or 6000 switches.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/12119ea1/2950scg/swspan.htm#40504

HTH,

-amit singh