it seems the device does not - Page 2

ahmetemrah · ‎06-12-2014

Hi,

I have a Cisco 2960 S 24-TSL switch and a simple LAN of a few devices. I fail to connect to one of my devices from my PC both of which are connected to the switch. However, when I connect the PC and the device to another switch(unmanaged), or use a direct connection without using a switch there seems to be no problem.

Leo Laohoo · ‎06-16-2014

So i concluded from your comments that the cabling inside the device or NIC is faulty.

You also forgot to mention that the NIC you've got in question will ONLY talk in 10 Mbps (even half duplex). Like an old printer NIC of some sort.

The question now is, is there a way to connect this device to the network formed by 2960S?

Ok, so now we've ruled out cable issue. I've also noticed in your post below that you've posted the interface configuration. What I'd like to know is what is this device you've been trying to connect? I presume the device is not getting a valid IP address ... partly because STP portfast is not enabled on the port?

ahmetemrah · ‎06-17-2014

The device I'm trying to connect is an antenna switching unit. I contacted its manufacturer and learnt that device has an PIC18F97J60 microcontroller for its ethernet connection. It seems it has an inherent 10 Mbps connection. Can you explain a bit about your STP portfast guess? How can I check if that's the case?

Martin Carr · ‎06-17-2014

Portfast amongst other things should be enabled on access ports, what happens is when the DHCP request is sent, the port will be blocked due to the time STP takes to converge, when this happens the request in itself can time out, thus leaving devices without configuration.

Portfast as the name suggests allows a faster convergence to take place faster, and so preventing this problem.

As a tip, there is a nice macro in IOS, namely 'switchport host', this does three things, two of which is enable Portfast and BPDU guard, which should be used in conjunction with one another.

Martin

ahmetemrah · ‎06-17-2014

I tried enabling portfast and BPDU guard on the port. I still can't connect to the device. By the way why is the green LED on even though I cannot reach that port?

Leo Laohoo · ‎06-17-2014

I still can't connect to the device.

Ok, you've enabled STP portfast. But still doesn't mean that the device has a valid IP address. Your switch configuration is plain "vanilla".

Can I ask you to do this:

config t
ip device tracking
interface range Gi1/0/7 , Gi1/0/9
ip device tracking maximum 10
end

Now once you've entered the above commands, wait for about 15 seconds then run the command "sh ip device track max 10" and find out what the IP address comes out.

ahmetemrah · ‎06-17-2014

Ok here's the result, it seems the device does not have an IP address:

Switch#show ip device tracking all
IP Device Tracking = Enabled
IP Device Tracking Probe Count = 3
IP Device Tracking Probe Interval = 30
IP Device Tracking Probe Delay Interval = 0
-----------------------------------------------------------------------
IP Address MAC Address Vlan Interface STATE
-----------------------------------------------------------------------
10.10.27.12 0025.9053.9818 1 GigabitEthernet1/0/9 ACTIVE

Total number interfaces enabled: 2
Enabled interfaces:
Gi1/0/7, Gi1/0/9

Leo Laohoo · ‎06-18-2014

it seems the device does not have an IP address

That's the point. Your device don't have a valid IP address.

You can statically configure your device with an IP address or you can enable DHCP on the 2960S (or anywhere in your network).

ahmetemrah · ‎06-18-2014

But how is that possible? The device is statically configured to have IP address 10.10.27.11 with subnet mask 255.0.0.0 and when I connect it to some other switch I can reach it through this IP.

As you suggest I tried enabling DHCP on 2960S yet the documentation states it's enabled by default. So is there something I'm missing here?

ahmetemrah · ‎06-18-2014

These are the static network settings of the device, I'm just working on LAN so no gateway or DNS is described:

3: Change static IP address: 10.10.27.11
4: Change static gateway address: 0.0.0.0
5: Change static subnet mask: 255.0.0.0
6: Change static primary DNS server: 0.0.0.0
7: Change static secondary DNS server: 0.0.0.0

Leo Laohoo · ‎06-18-2014

        4: Change static gateway address:       0.0.0.0

Specify the gateway IP address and see if it works.

ahmetemrah · ‎06-19-2014

Specifying gateway did not work.

Here's something I tried though, about the device not getting an IP:

I connected another switch (unmanaged) to 2960S. Connected to this unmanaged switch are PC (10.10.27.12) and the device (10.10.27.11).

2960S can now ping 10.10.27.12 (PC), but not 10.10.27.11.

At the same time PC can ping 10.10.27.11.

So, the device has an IP adress, thus PC that is connected to the same switch can ping it.

However 2960S cannot reach the device although it can reach the PC.

ahmetemrah · ‎06-13-2014

Some other details:

The LED of the port that the device is connected to is on and green.

I cannot ping the device from the switch (I can ping other devices that are in the same subnet)

If duplex/speed is set to auto, interface settings show that the port is 10 Mb/half duplex.

If duplex/speed is manually set to any other value than 10Mb/half duplex the LED of the port turns off.

What other settings can I try?

Or basically is there a way to use the 2960S as an "unmanaged" switch?

Martin Carr · ‎06-13-2014

As Leo said, it's a cable problem.

Gigabit uses all four pairs, so it will work on your fast Ethernet switch, but the 2960 cannot negotiate properly.

Seen as you haven't done it yet, swap the cable with the one of your other working devices, this should work...

Martin

ahmetemrah · ‎06-14-2014

Ok. I tried several cables that work fine in other devices. The tdr result always seems to be:

Interface Speed Local pair Pair length        Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi1/0/7   10M   Pair A     2    +/- 0 meters N/A         Normal
                Pair B     2    +/- 0 meters N/A         Normal
                Pair C     1    +/- 1 meters N/A         Short
                Pair D     1    +/- 1 meters N/A         Short

So I guess regardless of the cable the tdr result will show up like this.

Is there any way to configure 2960S to be able to work this device?

ahmetemrah · ‎06-14-2014

Would using an unmanaged switch connected to 2960S solve the problem?

Cisco 2960S connection problem