Unsure of proper configuration for SF300-24 & router

[virodeath]

Hello,

Our company lost a switch and replaced it with a SF300-24.  The other components are a Westell modem and an Amped Wireless R10000G router.

The current configuration has the Westell DLS modem going into the R10000G router, the router is the DHCP server and from there it is plugged into port 1 of the switch (DHCP is off on the switch).

I am not sure who set this up but apparently we have no one around that is able to fix the situation.

So the problem is the computers on the network randomly drop off the network during the day and sometimes upon booting them up in the morning won't even see the local network.  If I unplug the R10000G and then plug back in that fix's the problem for a few hours but then sooner or later the computers randomly drop off.

There is one network printer set to a static IP address.  It never seems to have an issue.  I have tried setting some of the computers to static but they still have connection issues at some point.

Would anyone have some suggestions on how this configuration "should be" properly setup?

Thank you for your time and help,

Matt

[Tom Watts]

Hi Matt, I am thinking it may be a spanning tree issue. Can you log in to the switch and verify port fast did not negotiate for the link connecting from the switch to the router?

Spanning tree -> Interface settings

Also, you may want to ensure you're using at least the 1.1.2.0 firmware. The 1.2.7.76 is the latest but in my opinion 1.1.2.0 is the most stable.

-Tom
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[virodeath]

Thanks for the post Thomas, I had not thought of port fast being an issue.  I will try to get into the office this weekend and check that setting and turn it off if it is enabled.  I will also verify the firmware.

I wish I knew how to setup the switch so I could remotely login but that was never covered in my classes.

Thanks again!

Matt

[virodeath]

I checked the spanning tree area and there are many interface settings none of which came right out and had a port fast option.

However under STP Status & Global Settings there were the following options.

Global Settings:

Spanning tree state: Enabled

STP Operation Mode:

Classic STP

Rapid STP (currently checked)

Multiple STP

BPDU Handling:

Filtering

Flooding (currently checked)

Path Cost Default Values:

Short

Long (currently checked)

Bridge Settings:

Priority: 32768

Hello Time: 2sec

Max Age: 20sec

Forward Delay: 15sec

Thanks again for your time!

Matt

[Tom Watts]

Matt, it should be classified as edge port in the STP interface settings page

-Tom
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[virodeath]

Oddly Edge Port is enabled on some and disabled on other ports.  But I do not see any see any location to actually enable or disable the "Edge Port" feature.   There is only the radio button at the beginning of each line.

Matt

[Tom Watts]

Matt, within the edit section of each port, there should be "auto, disable, enable". By default all ports are set to auto. If you have a router that is running spanning tree and for some reason the switch negotiates portfast, it will receive a bpdu on the port and make it flap (up/down).

What happens, as you may know spanning tree has three states, listening, learning, forwarding. Portfast puts the state to forwarding immediately and does not send a topology change notification (tcn). This can create network loops in a spanning tree topology.

A lot of times, if the switch is the problem, and there is no port fast (or edge port) it can take up to 52 seconds to obtain a DHCP address as it will cycle through the entire spanning-tree process.

If the switch is the only spanning-tree device on the LAN, you can disable spanning tree globally and see if it makes a difference for you.

-Tom
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[virodeath]

I will be doing that on Sunday.  I was looking through the router setting and I didn't see any spanning tree setting but I did see where it says:802.1d Spanning Type (disabled).

Is that similar in what the spanning tree does?

Matt

[virodeath]

Well I have let the system run all week with those changes however since I turned off the Spanning tree I am having issues with some of the software not being able to see our server as "server01" instead I have to use the IP address.  So I am not sure if by turning off the spanning tree it affected the Naming portion of the DHCP.

This is so very frustrating.  I wouldn't think this would be so hard, just 15 computers that need to see a few databases on a network...

Viro