08-30-2012 08:15 AM - edited 03-07-2019 08:37 AM
Hello,
I currently have a C3750G connected to a C3560G with default auto-negotiation settings. Ports are up and connected a-100 and a-full.
I am trying to change the ports speed to 1G, and have tried all possible combinations of "speed 1000" and "duplex full" setting on both ends to no avail.
What should port settings be for 1G speed between the two switches?
Here are the current port settings:
C3750G:
interface GigabitEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport mode trunk
end
C3560G:
interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport mode trunk
srr-queue bandwidth share 1 30 35 5
priority-queue out
mls qos trust cos
auto qos trust
end
Thanks for your assistance
Solved! Go to Solution.
08-30-2012 08:18 AM
Hello Highmiles2,
autonegotation should work, however 1Gbps speed requires a cable with 4 working pairs.
Try to change the cable ( I suppose the ports are RJ-45 )
Hope to help
Giuseppe
08-30-2012 08:18 AM
Hello Highmiles2,
autonegotation should work, however 1Gbps speed requires a cable with 4 working pairs.
Try to change the cable ( I suppose the ports are RJ-45 )
Hope to help
Giuseppe
08-30-2012 08:19 AM
hi High,
try to issue the switchport nonegotiate on both the ports and then to set again speed 1000 and duplex full
Alessio
08-30-2012 10:33 AM
Hi Alessio,
Any need to use the switchport nonegotiate here? To my best knowledge, this command is related only to DTP and has no effect on Ethernet autonegotiation. I don't see a reason to use switchport nonegotiate in this case.
Best regards,
Peter
08-30-2012 12:57 PM
Hi Peter,
This time is more matter of experience. I was in the same situation with a very similar configuration and only after disabling the trunk negotiation the link was available to be configured at the speed I wanted. according theory, Giuseppe is right and possibly even some sources of frequencies or calor can block the Ethernet cable to use the frequencies necessary to 1g. But I do believe that sometimes, to share our own experience can be very helpful even if no Cisco book would agree
Alessio
08-30-2012 03:47 PM
autonegotation should work, however 1Gbps speed requires a cable with 4 working pairs.
I'll agree with Giuseppe's post. For GigabitEthernet to work, make sure you run a TDR (just to make sure) that Pair D is "Normal". If not then the link won't negotiate to 1 Gbps but either 10 Mbps (if cable length >100 metres) or 100 Mbps.
I recommend you run the TDR command from the 3750G. Here's how you run TDR:
1. Command: test cable tdr interface Gi
2. Wait for approximately 5 to 7 seconds;
3. Command: show cable tdr interface Gi
4. Post the output to #4.
WARNING: Running the TDR may cause your link to drop for approximately 5 seconds.
speed 1000
I wouldn't use this. Instead I'd use the command "speed AUTO 1000".
08-31-2012 11:15 AM
Hi everyone,
Switches are on seperate floors. There is a 60' CAT6 cable run extended from one floor to the other and terminates on a stand alone single RJ45 wall mount ports just couple of feets away from switches at both ends:
I've contacted the vendor to check internal wiring....something in the wiring allowed ports at defualt settings to connect at a-100M/a-Full but denied/blocked 1G negotiation!...
Thanks everyone for your help, I never thought it is wiring simply because ports connected at 100M/Full.
Thanks
08-31-2012 05:02 PM
I twice replaced the patch cables on both ends this past Tuesday, but no luck.
Did you run the TDR commands on the 3750G switch?
08-31-2012 02:19 PM
Any wiring I have done gets fully tested and a report comes to me to review.
It's the only way to get cabling teams to check their work.
For patch cables I might try a few cables but typically buy tested patch cables to avoid hassles in the field.
Cheers
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