VLANs with non-cisco switches not working Grrrr!!

[penguinroundup]

are there any known issues with trying to implement VLAN's using Cisco and non-cisco switches? We tried to configure a new VLAN over the weekend using 7 cisco2950 switches and one 48-port gigabit Linksys switch, and it completely blew up in our faces.

We had ALL the ports on ALL the 2950's configured to use the new VLAN, and each switch was patched in to its own port on the Linksys switch (not daisy-chained), each of which was configured to use the new VLAN as well. (see my attempt at a diagram below):

vlan1 (192.168.14.x)
\
Linksys Gb switch-- 2821 router
|||||||
7-cisco2950 switches
|
vlan2 (192.168.12.x)
(approx. 120 pc's)

What's bizarre is that out of 120 workstations patched into the new VLAN, about 45 of them actually got IP addresses and were working fine - the rest couldn't get an IP address or do anything. There was no rhyme or reason to it. The computers that were working were plugged into different switches. We banged our heads against the wall trying to figure it out, and eventually we just put everything back on the native VLAN and it was fine. What on earth were we missing??

 

[catchphrase]

Did you set up trunk links between the Linksys and Cisco switches? I'm never used Linksys switches but I do know that Cisco utilizes proprietary ISL tagging(encapsulation) to identify the VLan for data going over the trunk. In order for a trunk link to work with a non-Cisco device, you must ensure that you utilize 802.1q tagging on your VLan trunks.

I may be way off the wall here, but it's something you can check.

 

[vipergg]

You would probably have to post the router and switch configs . Is the linksys a manageable switch ?? You might be better off using one of your 2950's as the aggregation switch off the 2821 router . Have never configured a Linksys ,in fact the only ones we have dealt with are dumb 10/100 switches .

 

[robertjo24]

If you are trunking between the Linksys and the Cisco switches:
Ensure all the connected ports on the Linksys are set to trunk
-Ensure all the devices are on the same management VLAN
-Ensure all the switches are set to 802.1Q trunking (this is default for the 2950’s)
-Ensure all the switches have the same VTP domain
-Ensure the connected interfaces on the Cisco switches are set to auto speed and duplex, (the 2950’s are notorious for having issues with non Cisco equipment)


If you are not trunking between the Linksys and the Cisco switches:
-Set the connected ports on the Linksys to the desired VLAN
-Set the connected ports on the Cisco switches to switchport mode access, (this will keep them from auto trunking)
-Set the connected ports on the Cisco’s to auto speed and duplex
-Set the management VLAN on the Cisco’s to match the VLAN on the Linksys

 

[vipergg]

The funny thing is Linksys is made by Cisco so it shouldn't be a problem getting these to work but we all know how that goes .

 

[penguinroundup]

That's one of the reasons (besides saving a lot of $$) why we bought the Linksys instead of going with all Cisco equipment.

We shouldn't have had to configure any trunks on anything, since the ciscos were plugged directly in to the Linksys, which was vlan'ed into 2 sep. vlans - each sep. vlan was patched into a sep. port on our router which was doing all the routing. There were no shared trunk ports on any of the switches. We did exactly what robertjo24 listed in the second scenario, but still got mixed results. I just wanted to make sure we hadn't overlooked some stupid mistake.

We're ordering another Linksys switch and we're just going to plug each switch in to the gigabit ports on the router to eliminate the vlan's altogether.

 

[robertjo24]

FYI,
Cisco bought Linksys no too long ago.

Merging technologies and engineering groups takes a long time, and Cisco is great at alot of things, but, in my humble and often ill-informed opinion, peaceful easy interation is not one of them.


When you say you are getting mixed results, what type of things/errors are you seeing? Are you getting errors on the Cisco ports? Ports on the Cisco not syncing up?
You could try forcing speed and duplex on the Linksys, leaving the Cisco set to auto/auto if you are getting CRC errors or duplex mismatch error notices.

 

[vipergg]

You could try forcing speed and duplex on the Linksys, leaving the Cisco set to auto/auto if you are getting CRC errors or duplex mismatch error notices.

No you can't do this , this will cause speed/duplex mismatches , if you hardcode one end you must hardcode the other end .

 

[gp1200x]

I do not believe it is possible to trunk a LINKSYS SRW224 and later managed switches to Cisco switches. Both Linksys and Cisco say they have not tried it and no one can give me any help or support. I do not really see the options (forget about VTP etc...

 

[vipergg]

They both support 802.1Q which should allow you to trunk and the linksys supports up to 128 separate vlans , think it is just a matter of getting the correct parameters to get it working .

 

[BuckWeet]

what number of vlans can the linksys support?

vlan1 thru 128??