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3550, 12.0(5)WC9, "switchport multi vlan 24,25"==>3750, 12.2(25)SEC2, ?

Dear all;

Many IOS trains for the 2950, the 3550 and the 6500 has mode "multi" for its ports to make one port belonging to different vlans. It is issued as follows:

interface FastEthernet0/16

description xxxxxxxxxx

duplex full

speed 100

switchport multi vlan 24,25

spanning-tree portfast

What is the corresponding mode for the 3750 platforms running under 12.2(25)SEC2 IOS?



Hi Friend,

AFAIK "switchport multi" command was only supported on old Catalyst 2900/3500 XL series switches and not on 2950,3550 and cat6500 series switch.

When you say Many IOS trains for the 2950, the 3550 and the 6500 has mode "multi" can you please list the IOS version where you see this option on 2950.3550 and cat6500 series switches as I am pretty sure this command is not at all supported in any switches other then old XL switches.



Hi Ankur;

The IOS version was listed in the discussion title.I apologize if you haven't seen it. this mode "multi" present in the 12.0(5)WC9, for example, is available for many platforms among them the 2900, 3500 but also 3550 and 6500 Catalyst...

Anyway, I found a solution to my problem. In fact, I need the "multi" mode to use it for monitoring some VLAN. For this use, SPAN is the response and I replaced the multi by the following commands in global configuration mode:


no monitor session all

monitor session 1 source vlan 24 - 25 both

monitor session 1 destination interface Fa1/0/16 encapsulation replicate


Thank you anyway.


Hi Friend,

At no cost multi command is supported on 3550 and cat6k switches and it is only supported on 2900 and 3500 XL switches.

I saw your IOS posted but that was for 3750 switch so I asked you to post the IOS on which this command is supported in cat6k switches and cat6k switches does not come with IOS 12.0 release, it comes with minimum 12.1E.

Anyways good to know you got what you want.




I back one of your "no cost ..." confirmations and reject the second. In fact, you're alright about the "multi" mode is present only in the 2900XL and 3500XL (please visit the following link: ).

However, the "multi" mode was present in the 12.0 (Earlier than the 12.1E. Heredown what the output of "show ver" gives:

SWITCH#sh ver

Cisco Internetwork Operating System Software

IOS (tm) C3500XL Software (C3500XL-C3H2S-M), Version 12.0(5)WC9, RELEASE SOFTWAR

E (fc1)

Copyright (c) 1986-2003 by cisco Systems, Inc.

Compiled Fri 19-Sep-03 10:01 by antonino

Image text-base: 0x00003000, data-base: 0x0034E434

ROM: Bootstrap program is C3500XL boot loader

SWITCH uptime is 38 weeks, 2 days, 20 hours, 10 minutes

System returned to ROM by power-on

System restarted at 17:57:10 FR+2 Sun Aug 14 2005

System image file is "flash:c3500xl-c3h2s-mz.120-5.WC9.bin"

cisco WS-C3524-XL (PowerPC403) processor (revision 0x01) with 8192K/1024K bytes

of memory.

Processor is running Enterprise Edition Software

Cluster command switch capable

Cluster member switch capable

24 FastEthernet/IEEE 802.3 interface(s)

2 Gigabit Ethernet/IEEE 802.3 interface(s)

32K bytes of flash-simulated non-volatile configuration memory.


Model number: WS-C3524-XL-EN


Thank you anyway


Rising star

There is no corresponding mode for the 3750 platforms running under 12.2(25)SEC2 IOS...

Just use trunk ports.



I do agree with Ankur.The switchport multi command was supported on older 1900's and 2900/3500Xl's IOS switches. That was the traditional way for setting a port as a member of multiple vlans like a trunk port.

If you have another switch connected on Fa 0/16 and wants to set up a trunk port to carry multiple Vlans then define the port a trunk.

interface FastEthernet0/16

switchport encapsulation dot1q

switchport mode trunk

Also, when you are connected 2 switches never use " spanning-tree portfast" command which might result in STP loops in your network.

HTH, please rate if it does.

-amit singh

The fa1/0/16 is connected to a sensor monitoring traffic on the two VLANs (24 and 25)

Hi Mohammad,

You can setup a VLAN SPAN on 3750 and have you Vlans monitored to the sensor connected on fa0/16. You need that port to be a multivlan port to achieve this.

HTH, Please rate if it does.

-amit singh


Nope! There is no prerequisite -other than sited in this document. And there is no "multi vlan" condition.

Please review the same document you've posted."

Step 4

monitor session session_number destination {interface interface-id [, | -] [encapsulation replicate]}

Specify the SPAN session and the destination port (monitoring port).

For session_number, specify the session number entered in step 3.

Note For local SPAN, you must use the same session number for the source and destination interfaces.

For interface-id, specify the destination port. The destination interface must be a physical port; it cannot be an EtherChannel, and it cannot be a VLAN.

(Optional) [, | -] Specify a series or range of interfaces. Enter a space before and after the comma; enter a space before and after the hyphen.

(Optional) Enter encapsulation replicate to specify that the destination interface replicates the source interface encapsulation method. If not selected, the default is to send packets in native form (untagged).

Note You can use monitor session session_number destination command multiple times to configure multiple destination ports. "

And hereafter an example:

"This example shows how to remove any existing configuration on SPAN session 2, configure SPAN session 2 to monitor received traffic on all ports belonging to VLANs 1 through 3, and send it to destination Gigabit Ethernet port 2. The configuration is then modified to also monitor all traffic on all ports belonging to VLAN 10.

Switch(config)# no monitor session 2

Switch(config)# monitor session 2 source vlan 1 - 3 rx

Switch(config)# monitor session 2 destination interface gigabitethernet1/0/2

Switch(config)# monitor session 2 source vlan 10

Switch(config)# end