Connecting a 3750 switch to existing network

[charlesbrindley]

Hi all - I run a small group of programmer types (not the networking group). We have our own simple network (tied to the main site network) with a few servers, clients, etc. We are using two 2950 switches that worked fine out of the box. Turned them on, gave them an IP, hooked them together (via CAT 5) and good to go. We recently inherited a Cisco 3750 new in the box and we needed a new switch so we broke it out, turned it on...nothing. It POSTs fine, computers that are hooked to it can see it but we can't trunk it to the other switch (i.e. run CAT 5 from one switch to the other). We are only using the default VLAN, flat IP address (no routing). Any thoughts?

[Georg Pauwen]

Hello Charles,

are you actually running a trunk (ISL or 802.1Q) between the switches, or have you just connected the switches together with a crossover cable ? In the first case, you might have a VTP domain name mismatch, issue the command:

show vtp status

on both switches, and make sure the VTP domain name is the same on both switches (the name is case-sensitive)...

HTH,

Georg

[charlesbrindley]

Georg - Thanks for the advice. Do we need to explicitly designate the ports on both the 3750 and 2950 as trunks? Also, I can't remember entering a VTP name (I assume VTP is VLAN trunking Protocol). Is there a deafult one assigned or do I need one? Any help would be appreciated.

[Georg Pauwen]

Hello Charles,

if you are using the default VLAN (1) on all switches, you do not need trunks or VTP. Can you post the configuration of the 3750 and the 2950 to which it is connected ?

Regards,

Georg