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Advice, VOIP and DATA on 3500XL switch 7940 SIP phone

Here is what I have:

Residential internet (dynamic IP)

Linksys wrt54 router with dd-wrt firmware

Cisco c3500XL switch with v12 firmware (WS-C3524-PWR-XL-EN)

2 7940's with SIP firmware

1 asterisk PBX with with Elastix

10 Computers

Here is what I need:

Advice  on how best to set up the switch for voip and data. I've only done one  thing to the switch so far: a factory reset of the config and turned on  'switchport trunk encapsulation dot1q' for f0/24 (hooked up the router  to port f0/24).

As  it stands, everything is working, but I know the setup is not ideal.  The phones get their inline power and IP address, but they take a long  time to boot up (phones display "configuring vlan" for a long time after  reboot).

The PBX system sees the phones and can deliver config data.

My Questions:

1)  What type of VLAN setup do you recommend I put on the switch  considering I do not have an advanced router? I've read having voip and  data on separate vlans is a good idea. But still do not know why...

2) How should I configue the ports for:

A) Computers only

B) Phones only

C) Phones and Computers

Thanks for any advice.

xpost from


Advice, VOIP and DATA on 3500XL switch 7940 SIP phone

Hi Burt,

For a small network with only 2 phones you only need
1 vlan.

The switch will already have the default VLAN 1 configured.

Is your eouter running more than 1 vlan ?
If it is not then you should connect it to an
access port not a trunk.

If you need to run more vlans you will need to
set up routing between the vlans and external access
on your router.

Default the switch again

erase start


Reconfigure every interface to use spanning tree portfast

int fas 0/1
spanning-tree portfast
no shut
int fas 0/2
spanning-tree portfast
no shut
int fas 0/3
spanning-tree portfast
no shut
etc etc

This will speed up connectivity to your devices.

The config manual for these old switches is still available at:-

Please rate useful posts.

Regards, Alex. Please rate useful posts.
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