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Nexus 5020 and 1Gbps connections

darryll.plumb
Level 1
Level 1

Hi

I'm having problems connecting 1Gbps interfaces (just a simple autonegotiating 1 Gbps Laptop) direct to a Nexus 5020 port. I'm using a GLC-T in one of the ports that supports 1 Gbps (ports 1-16), and I've configured the speed to 1000.

The link tries to come up for a fraction of a second (by looking at the laptop port)then drops.

I've tried several ports and a couple of different GLC-T SFPs, and I'm using the latest software (n5000-uk9.4.1.3.N1.1.bin). I've even tried fixing negotiation, using a crossover cable, but no luck. Does anyone have any suggestions or know if this is a known problem?

Thanks

Darryll

5 Replies 5

Yudong Wu
Level 7
Level 7

can you post the following when the link is in down state?

show interface x/y

show interface x/y trans

show system internal ethpm event-history errors | grep x/y

Thanks, I'm off-site at the moment, but I'll get the information to you tomorrow

Output from the switches below

CPLUKLONNXS0001# sh int eth 1/1

Ethernet1/1 is down (Link not connected)

Hardware: 1000/10000 Ethernet, address: 000d.ecb4.dac8 (bia 000d.ecb4.dac8)

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

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

Encapsulation ARPA

Port mode is trunk

auto-duplex, 1000 Mb/s, media type is 1/10g

Beacon is turned off

Input flow-control is off, output flow-control is off

Rate mode is dedicated

Switchport monitor is off

Last link flapped never

Last clearing of "show interface" counters never

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

1 minute output rate 0 bits/sec, 0 packets/sec

Rx

0 input packets 0 unicast packets 0 multicast packets

0 broadcast packets 0 jumbo packets 0 storm suppression packets

0 bytes

Tx

0 output packets 0 multicast packets

0 broadcast packets 0 jumbo packets

0 bytes

0 input error 0 short frame 0 watchdog

0 no buffer 0 runt 0 CRC 0 ecc

0 overrun 0 underrun 0 ignored 0 bad etype drop

0 bad proto drop 0 if down drop 0 input with dribble

0 input discard

0 output error 0 collision 0 deferred

0 late collision 0 lost carrier 0 no carrier

0 babble

0 Rx pause 0 Tx pause

0 interface resets

CPLUKLONNXS0001#

CPLUKLONNXS0001# sh int eth 1/1 trans

Ethernet1/1

sfp is present

name is Methode Elec.

part number is SP7041

revision is A

serial number is MTC009044

nominal bitrate is 1300 MBits/sec

cisco id is --

cisco extended id number is 4

CPLUKLONNXS0001#

The grep 1/1 output of the show system internal command didn't return with any output. I have added an attachment with the command without the grep command

Yours SFP looks OK. In general, we will see "SFP validation failed" under "show interface". I validated its SN as well.

Can you try the following?

1. "speed 1000" must be configured.

2. try a different cable.

3. hard code your laptop seed to 1gig

4. upgrade laptop NIC driver

5. try a different laptop.

If the above still does not help, please open TAC case.

Thanks for Validating the SN for us. We have tried all of the tests above, and also tried cross-over cables, a couple of SPF, and connection to a 3750 switch on site. None of these have worked for us, in all cases the link comes up for a fraction of a second then fails, so we are going to raise a TAC case .Thanks for the response. If I get any resolution I will post it here.

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