Non-cisco to Cisco switch connection problem

[nunoscosta]

The setup is 4x 24 port switches are connected to 15 PC's each, and the upload port from the switch is then connected to one Cisco switch.

All PC's are set up to run 10Mbit/s, the line from 24 port to Cisco switch is 100Mbit/s. When using the Cisco Catalyst 2950 series to connect the PC's (WS-C2950-24) the PC's are running fine.

When using the D-Link DES-1026G however we are having massive problems. We can only boot 5 PC's at a time to load some software to the RAM with 1,4MB size from the server and have to wait 3-5 min before we can start the boot of the next.

All the cisco switch ports are access links and vlan is vlan 7.

The D-link does not support 802.1q standard.

[scottmac]

Verify your duplex settings.

More than likely, one side is working full-duplex, the other side is half duplex and seeing massive collisions.

Good Luck

Scott

[glen.grant]

On the connecting ports make sure both sides are set as auto/auto for speed and duplex . Like other poster said sounds like speed duplex mismatches . Also make sure the pc nics are set as auto/auto also ..

[nunoscosta]

I do not think is about speed and duplex cause with cisco catalyst everything works great, only with D-Link goes wrong.

Maybe something about native vlan or using vlan 8 instead of vlan 1 cause d-link does not support vlan tagging.

What you guys think?

[scottmac]

It is alsmost certainly a speed/duplex issue.

10 meg clients or ports are virtually all set for half duplex (that's 10BASE-T standard - full duplex is not part of the 10BASE standards).

10/100 connections nearly all default to full duplex.

"Older" switches from Cisco and other vendors have "problems" doing auto-duplex and frequently end up with a duplex mismatch ... which, by the way, has exactly the symptoms you describe.

PCs with standard NICs have no sense of VLAN.

When you connect two switches from access-port to access-port, there is no VLAN info passed ... VLAN info is stripped at the access-port egress, and added (if necesary) to ingress traffic if it is leaving the VLAN (either through trunk port or to a L3 process in the host switch)

If you're not going to consider the answers, please don't post the questions.

Good Luck

Scott

[nunoscosta]

Thank you all for the answers. They are good welcome!

There's nothing to do about consider the answers or not. You must agree that's hard to believe that duplex / speed mismatch is the problem here, cause when i use the Cisco 2950, everything goes fine.

I will take your advice and check all the parameters on D-Link switch.

I agree with you when you said "When you connect two switches from access-port to access-port, there is no VLAN info passed.."

Cisco is the winner here :) cause it works fine!

Regards,

Nuno

[Edison Ortiz]

Nuno,

I agree with Scott, you have a duplex mismatch issue. Most likely the access port where the D-link is connecting is reporting a huge amount of errors at the Cisco switchport. You can verify by typing

show int fa0/x and post the results here.

You should let the interface auto-negociate with the D-link since the D-link is a non-managed device and by default it's set to auto/auto. You should do the same with workstations connecting to the Cisco switches and to the D-Link.

For more info on duplex mismatches, please check out this URL

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00800a7af0.shtml