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SPAN port switchport mode?

chinpohpang851
Level 1
Level 1

I can't find the doc to explain the switchport mode for SPAN. 

1. if source port is switchport access vlan x, should the destination port follow exactly?

2. if source is mode trunk, destination port settings should follow?

7 Replies 7

balaji.bandi
Hall of Fame
Hall of Fame

Take example :

 

If you like to span port Gi0/0 as source and destination Gi 0/1 (where your connected sniff device)

There is no config required on the switch port.

 

you need to configure monitor session (make sure you follow some guide lines, you can not mix source and destination.)

 

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/10570-41.html

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i see. So what switchport mode on destination port doesn;t matter right?

yes correct for Local span, as long as both are not same.

 

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Hello

What re you trying to accomplish - local span or remote span sessions?


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Paul

local span.

Hello


@chinpohpang851 wrote:

1. if source port is switchport access vlan x, should the destination port follow exactly? 


No-  the destination port cannot be a source port, its either one or the other and it also becomes a monitor port as such it isn't an access port or trunk, stp is disabled to 

 

 


@chinpohpang851 wrote:

2. if source is mode trunk, destination port settings should follow?


No -  again it becomes a monitor port , as long as its capable of carrying traffic from multple vlans sourced from the trunk, hence when you want to span a trunk, Best to create a new connection and just allow only those vlans you wish to capture over that trunk and also within the span session.

 

example:

interface x/x
description span session 1 to destination port x/y
switchport trunk allowed vlan a, b, c, d-f
switchport trunk encapsulation dot1q
switchport mode trunk


monitor session 1 source vlan a, b, c, d-f
monitor session 1 destination interface x/y


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

actually i mean the switchport mode on the dest int. So, the port mode on dest interface regardless access/trunk mode it doenst matter?

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