token ring NIC plugged into Ethernet Switch

[m-carey]

Just discovered a that someone has a Token Ring 16/4 NIC plugged into my ethernet Cisco 3500XL switch. First, I am suprised the traffic is passing and only passes because that particular port is at 10/half. 2nd, what type of damage could this cause to my network?

[thisisshanky]

I doubt if there will be any kind of damage to your network...but the TR nic shouldnt pass any traffic, because every TR interface goes through Lobe test, physical cable test etc..and the link should be down on that port because TR NICs dont understand Ethernet protocol.

[Richard Burts]

I agree with Sankar that probably no damage has been done. Other than the fact that if the token ring terminates in an RJ45 the plug will physically fit into the port on the switch there is such a degree of incompatibility between token ring and ethernet that I do not think anything has happened.

The original post implied that traffic was passing. I am not clear whether that just meant that the ethernet network was still working or if there is any reason to think that any traffic was passing over the token ring connection. Beyond the factors that Sankar mentioned there is the factors of the voltages being different, the understanding of bit order in the MAC address being different, and the protocol that they use to access the media being different (possessing the token vs contention based) so that I seriously doubt that anything passed over the token ring.

HTH

Rick

[m-carey]

That is what I thought would happen, but it does get a link and it does pass traffic. I don't know how it can be working? Here is the output:

FastEthernet0/14 is up, line protocol is up

Hardware is Fast Ethernet, address is 0007.8567.c38e (bia 0007.8567.c38e)

Description: PP1PRT17 Ultrasound

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Half-duplex, 10Mb/s, 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 1 packets/sec

5 minute output rate 6000 bits/sec, 4 packets/sec

1180429 packets input, 1500388666 bytes

Received 8627 broadcasts, 52168 runts, 0 giants, 0 throttles

52560 input errors, 194 CRC, 198 frame, 1 overrun, 1 ignored

0 watchdog, 0 multicast

0 input packets with dribble condition detected

1510593 packets output, 347771085 bytes, 0 underruns

0 output errors, 33999 collisions, 18 interface resets

0 babbles, 0 late collision, 231924 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

WCH_RAD_CISCO38#

[Richard Burts]

Most of the output could possibly reflect counters generated by some previous connection (note the Last clearing of "show interface" counters never). The parts I am especially surprised at are the interface status of up/up and the 5 minute input and output rates which sure do look like a live connection.

Have you actually traced the connection and the cables back and are certain that it is a token ring connection? I do not see how a token ring NIC is working here.

HTH

Rick

[thisisshanky]

What kind of NIC is it ?? There are FE nics which can still receive TR encapsulated in ethernet packets (like 3Com has TR on FE type nics)..Can you paste a snapshot of that PC -> My computer (right click)-> Device Manager window..

[jesparksibm]

What you are describing is physically impossible. TR and Ethernet use different wire pairs.