DHCP / VLAN / Wireless connectivity

Unanswered Question
Mar 11th, 2008


I have a CISCO Catalyst 2924 (2900 XL), which has a WS-X2914-XL-V module.

I would like to connect my 4 port Wireless Broadband router to the 4 ports on the X2914, then have 4 VLAN's using the 24 ports of the main switch.

I would like the 4 ports on the X2914 to obtain their IP Addresses from the router.

I would like the VLANs to be able to 'get out' to the internet via the router.

I have tried using the Cluster Management Suite to do this, but I'm getting lost very quickly. Can someone offer a suggestion on how I go about this OR where to look for more information?

Thank you VERY much in advance.


I have this problem too.
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bmcginn Wed, 03/12/2008 - 00:16

Hi Craig,

You can create four VLANs on the 2924 (or 2914 if you like) which can be propogated to the other switch via VTP if required.

Do you need to go to that length for the expansion module? I would have thought that the VLANs will be present in both the 2914 and 2924... if they're created in either one?

I also assume that you will give the Wireless Router's 4 ports individual IP addresses. If you connect those ports to the 4 port expansion module in the 2924, you can make each individual port an access port for each VLAN.

eq Port 1 on wireless router connects to port 1 on 2914. Port 1 on 2914 is made an Access port for VLAN10.

Port 2 on wireless router connects to port 2 on 2914. Port 2 on 2914 is made an Access port for VLAN20

Port 1 on wireless router connects to port 3 on 2914. Port 3 on 2914 is made an Access port for VLAN30.

Port 2 on wireless router connects to port 4 on 2914. Port 4 on 2914 is made an Access port for VLAN40.

I hope that helps mate..

craig.burtenshaw Tue, 03/25/2008 - 20:52

The 2914 is a 4-port expansion module in a Catalyst 2900 switch. The Switch itself is the 2924, with 24 ports.

Does this mean there are two switches in one?

I'm not sure if I can specify IP addresses for the router itself. Currently it deals out DHCP addresses.

The router is a 2wire - Telstra supplied - wireless router.

When I plug items into the ports for each VLAN will they get separate IP addresses?

That is if I plug something into

VLAN / Port IP address

1 1

1 2

2 1

2 2



4 3

4 4



bmcginn Tue, 03/25/2008 - 21:11

Hi Craig,

Mate, does your router allow you to assign specific IP addresses to individual physical addresses (layer 3 interfaces)?


Does it allow you to create Virtual Interfaces and then assign the physical interfaces to virtual addresses (layer 2 interfaces)?


Does is allow you to create Virtual Interfaces and then use trunked sub-interfaces from a physical interface?

any of the above should allow this scenario to work (assuming the wireless router can do virtual interfaces). I think the expansion module for the 2924 will just increase the switchport density only; not create an extra switch.

Assuming the router can indeed do VLANs, you will also need to create the VLANs on the switch (in the VLAN database). Use dot1q as the trunking method as ISL may not be understood by the Telstra router thing..



Hi Craig

Just wondering what 4 port Wireless router you are using and if it supports 4 VLAN's?

I ask because we have a couple of 877's in work with the Adv Security IOS which only support a single VLAN. I have an 877W at home as my personal ADSL router. This router has the Adv IP Services IOS and supports 2 VLAN's. I believe if I upgraded to the Adv Enterprise IOS then it would support 4 VLAN's.

With the 877's I could not assign IP addresses directly to the Fast Ethernet ports as they are L2 ports. I had to create virtual VLAN interfaces to which I could assign ports. I configured the IP addresses on the VLAN interfaces.

If your wireless router does not support multiple VLAN's then you might have a problem.

Best Regards,



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