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Webcast-Catalyst9k
New Member

Multi-VLAN Ports

I have came across this topic, and I am wondering if this images can be uploaded to any 2900 series switches or not, and if this will work as access port for more than vlans.

http://www.cisco.com/en/US/docs/switches/lan/catalyst2900xl_3500xl/release12.0_5_wc5/swg/swvlan.html#wp1028684

Thanks,

Ali

2 REPLIES
Cisco Employee

Multi-VLAN Ports

Hello Ali,

I must admit I did not know about the multi-VLAN port type before you posted your question. According to the document you have referenced, the multi-VLAN port simply belongs to all associated VLANs and makes the attached device to be a member of all VLANs. However, these VLANs are not tagged on the multi-VLAN port, and hence the attached device can not tell the difference between these different VLANs - for that device, none of those VLANs exist, just a single broadcast domain that is the union of all associated VLANs on a multi-VLAN port.

This feature was, in my humble opinion, used for inter-VLAN routing in times the routers did not support the ISL or 802.1Q trunking. Using the multi-VLAN port, the router could be attached via a single interface to the switch, configured with several IP addresses on a single interface (using secondary addresses, obviously), and perform the inter-VLAN routing just like a common router-on-stick today.

This feature is not available on any recent Catalyst switches. Also, the images from 2900XL are not usable in any other switch platform. To put it plainly, this feature is discontinued with 2900XL series.

May I ask you if you needed this functionality? If so, can you describe in what scenario? Supposing that your devices support 802.1Q (and they should), you would not need the multi-VLAN port anyway.

Best regards,

Peter

New Member

Multi-VLAN Ports

Thanks Peter for your replay,

I am guessing that this feature differ from 802.1q, where multi-vlans support access port i.e. work as access port (correct me if I am wrong).

In our case we have a mobile wireless site that moves on the field (every three days) from location to location, and we have four towers each having thier specific vlans, for example if the site moves from location x to location y, the vlan configuration must be changed to the nearest tower configuration. I need this feature to configure the ports to capture each towers vlans i.e. to configure more than tow vlans on each access port.

Ali

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