Catalyst 2940 limitations

[sorvarit]

Have tried to connect a little cute 2940 into our existing infrastructure without any success. My problem is that it cannot take any vtp domain information. Try to set it as a client and the config with password etc is the same as the other 2950 and 3500 switches we have. Know it supports only 16 vlans and 4 on the switchports, but we do not have over 16 vlans in our vtp domain. Im i missing out something?

Orjan

[Georg Pauwen]

Hello,

make sure that you are running the same VTP version on your 2940 as on your other switches. Is the trunk link that connects the switch with the rest of your network ok ? Can you post the configuration of the switch, as well as the output of the command 'show vtp status' ?

Regards,

GP

[Prashanth Krishnappa]

2940 can support only 4 VLANs and not 16.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2940/12120ea2/2940scg//swvlan.htm#wp1353846

Once it gets a VTP update with more than 4 vlans, it changes to transparent mode and syslogs a message like

SW_VLAN-6-VTP_MODE_CHANGE: VLAN manager changing device mode from CLIENT to TRANSPARENT.

[sorvarit]

Ok, was afraid of that:( We currently use 12 vlans. BUT what does it mean that it supports 16 vlans locally then? Look bellow:

cat2940#sh vtp stat

VTP Version : 2

Configuration Revision : 0

Maximum VLANs supported locally : 16

Number of existing VLANs : 12

VTP Operating Mode : Transparent

VTP Domain Name : ourcomp.com

VTP Pruning Mode : Enabled

VTP V2 Mode : Enabled

VTP Traps Generation : Disabled

We bought this because we read in the specs that it supported 16 Vlans, but only four of them on the switchports.

Do Cisco have any solutions for us who wants small fully manageable noiseless switches that can fit in environments under 19" ? Need a small switch to fit in a outdoor box for BR1310 bridges.

Orjan

[Prashanth Krishnappa]

It can support upto 16 with VTP transparent mode. You just cannot use it as a client with more than 4 VLANs

[sorvarit]

I see. So for us it could do the job for interconnecting three Aironet BR1310?

We currently use 12 vlans in the wireless trunk. Native vlan included.

Suppose we must create the same vlans we use in the existing VTP domain on the 2940 and set the three switchports for the wireless bridges to trunk the native vlan and trunk mode.

Orjan

[npritchett]

So there is no way to filter what is advertised by the upstream VTP switch so only 4 VLANs are advertised?

The 2940 switch is the perfect solution for my outside-the-wiring-closet locations where I need something silent and manageable.

[Prashanth Krishnappa]

No you cannot use VTP mode client. Any reason why you cannot use VTP transparent? Do you keep adding/removing VLANs regularly to the network?

[npritchett]

I'd say semi-frequently. Can I live without VTP on the 2940's? Probably, but life would be more pleasant with it.

[sorvarit]

Agree with npritchett that the 2940 switch is the perfect solution for my outside-the-wiring-closet locations !

I strongly advice Cisco to come up with a switch solution for places where silence or a small footprint is needed. Why not release a EI upgrade for the 2940 so that we can make fully use of it in large enterprise networks with many vlans etc.? Know the 2955 series could be used, but this industrial switch is overkill to use in a classrom! For us this is a big problem. In many old buildings we need more switchports and have to put the switches where people work. Even a good cabinet cant reduce the noise from a bulky 2950. If the cabinet gets too tight the switch dies of heat or try to speed up the fans even more!

Please let us have a EI upgrade for the 2940. The price we payed for this thing justifies that!

Orjan