11-21-2012 07:33 AM - edited 03-07-2019 10:11 AM
I'm running into a very confusing duplex issue that I just can't figure out.
At one of my sites, I have a 100mbit TLS. For this connection to work properly, the port on my end needs to be setup for 100mbit, full duplex. When I connect the TLS to an interface on my Cisco 2821, configured at 100/full, it works perfectly. Now the confusing part, I'm trying to connect the TLS to a Catalyst 2960. I configure the necessary port for 100/full, and get 'notconnect' on that interface. I set the interface to auto/auto, and it negotiates at 100/half and causes collisions and packet loss.
I have no access to the ISP's switch at this time.
Anybody know what might cause an issue like this?
11-21-2012 08:27 AM
Is that 100 Meg TLS coming into one of those Cieana devices? And hand off to you is fiber?
11-22-2012 06:11 AM
TLS hand off is Ethernet. Port is connected to a switch, model unknown, somewhere in the building (which I have no access to).
11-21-2012 08:39 AM
the 100/half is the recommended result for autoconfigured 100Mbit/s ports which can't complete the negotiation
notconnected might have several reasons. udld, some port security settings, err-disable settings
what's the show interface, sh errdisable, sh interface transc properties etc...
11-22-2012 06:41 AM
Well I'm going to rule out port security right away because it works at 100/half. Same goes for udld.
Why would I be able to force a router interface to 100/full, but not a switchport?
Here's the switch autoconfiguring 100/half:
Switch#sh int Gi0/4
GigabitEthernet0/4 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 64ae.0cb9.f084 (bia 64ae.0cb9.f084)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:04, output 00:00:05, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 192000 bits/sec, 31 packets/sec
5 minute output rate 49000 bits/sec, 20 packets/sec
12073490 packets input, 7649871485 bytes, 0 no buffer
Received 397983 broadcasts (27912 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 27912 multicast, 0 pause input
0 input packets with dribble condition detected
12190225 packets output, 9134113547 bytes, 0 underruns
0 output errors, 54848 collisions, 1 interface resets
0 babbles, 88355 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out
Now forced to 100/full:
Switch#sh int Gi0/4
GigabitEthernet0/4 is down, line protocol is down (notconnect)
Hardware is Gigabit Ethernet, address is 64ae.0cb9.f084 (bia 64ae.0cb9.f084)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:13, output 00:00:17, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 250000 bits/sec, 41 packets/sec
5 minute output rate 26000 bits/sec, 23 packets/sec
12086279 packets input, 7659696828 bytes, 0 no buffer
Received 398465 broadcasts (27945 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 27945 multicast, 0 pause input
0 input packets with dribble condition detected
12198220 packets output, 9134974749 bytes, 0 underruns
0 output errors, 54882 collisions, 1 interface resets
0 babbles, 88359 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out
11-22-2012 08:51 AM
Does Your TLS device support autonegotiation. Can you try 'speed nonegotiate' on 2960?
11-22-2012 01:30 PM
Same goes for udld.
You have UDLD enabled on a copper port???? Turn it OFF! You won't get any benefits unless you have fibre optic.
In regards to the 100 Mbps half duplex, try the interface command "speed auto 100".
11-22-2012 06:43 PM
Hi Zach,
Force the speed to full/100, change cable on your side and issue the speed nonegotiate command below interface config. This should work. By the way, if the collisions increase(issue a clear counters command to reset the value) once you force the duplex parameters , there is a massive possibility that the layer 1 is the problem. Do not keep 100/half because it is a very unstable configuration. Hard coding speed and duplex is a best practise.
Hope this helps
Alessio
Sent from Cisco Technical Support iPad App
11-26-2012 01:44 PM
What is the TLS device that Verizon gave you? It can also be an issue with the firmware. I encountered something similar but with Fiber. Found out that the Firmware on the Ciena 311v was way to old to handle the latest IOS on the Cisco switch.
11-23-2012 06:40 AM
better if you contact with your TLS ISP as they migh have set 100/half thats why you are negotiating with 100/half too, and once you force set it to 100/Full it will break the connection
call them and ask for their device edge setting and request them to set it to 100/Full
Just guessing, problem may be at TLS ISP edge
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