Gig switch port not working set 100/full

[jeckert]

I do many internet turn ups and one of the providers I work with always hands off the internet hardcoded to 100 full duplex.

If I have to patch it through a gig switch it comes up 100 half duplex on the switch side. If I hard code the speed or duplex at all the interface does not come up. If I call and have the provider and have them set their side Auto then both come up fine 1000/full. For the most part this has come up on 2960x/s or 3750 switches. The product the provider is using is ADVA FSP150CCF.

Does anyone have a setting for the switch that would allow me to hard code the interface and have it work?

[Leo Laohoo · Accepted solution]

No. It's better to leave it auto/auto.

[jeckert]

I know, but that means I need to spend an hour on the phone with the provider on almost every install.  I was hoping someone had a way where I could skip that step.

[Vishesh Verma]

leave to auto/auto and police/shape traffic at 100 Mbps.

[jeckert]

The real issue is it come up Half duplex and I get a fraction of the performance I am supposed to because the provider side is set to full.

[jay.digwa]

Apologies for resurrecting a very old thread but I was wondering if you managed to get an answer to this question?

I have a service provider handing over their connection at 100Mbps Full Duplex via their ADVA Fibre Optic Carrier Ethernet Switch, which we have no control of.

When we hook up an RJ45 between it and our Cisco router, the Cisco interface auto negotiates at 100Mbit Half Duplex. I understand this is because we have one side (service provider side) hard coded.

But the weird part is IF we set the Cisco Interface to 100 Full, the link goes down. If I set to Full Auto, it goes back to 100 Half.

I know the simple answer is to have the service provider set their side to AUTO/AUTO but what could I do to get the link up without having to contact the provider each time? The provider requires a new order to be raised to change these settings and it takes a day if not longer to generate these orders.

Thanks

[Leo Laohoo]

But the weird part is IF we set the Cisco Interface to 100 Full, the link goes down. If I set to Full Auto, it goes back to 100 Half.

If your router is set at Auto/Auto then MDI/MDI-X is enabled.  If hardcoded, then MDI/MDI-X is disabled.  So the next question is:  Is the cable used to connect the router a cross-over cable or straight-through?

[jay.digwa]

So I have exploring this option and the cable is a straight through and I am beginning to wonder if it should be a cross over? The cable we have been using is a straight through.

Curiously is the rule of thumb to use a cross over when hard coding?

I understand you normally would use a cross over when its router to router but if a straight-through was used, MDI/MDI-X would take care of that by detecting the cable and adjusting the settings on the interface however, your comment states that this would only occur if both sides were set to auto-negotiate?

Is MDI/MDI-X disabled when hardcoding one side or both? And if it is disabled, is a cross over needed?

For my own knowledge purposes - can using the wrong cable make the link default to 100 HALF irrespective of speed/duplex settings?

We  have also connected our laptop directly to the carrier ethernet switch aka ADVA unit. The NIC has been hardcoded 100MB FULL. Its difficult to see in Windows what the hell is going but I suspect there is a duplex issue because a speed test produces 100MB down and 3.2 - 7mbpsmb UP! If we set the laptop to auto/auto same results. There's sadly no tool in Windows to see what the system negotiates at when set to Auto.

For the record - 2 days and still cannot get the provider to get me an answer

[Leo Laohoo]

Curiously is the rule of thumb to use a cross over when hard coding?

The rule-of-thumb is to enable auto/auto so MDI/MDI-X is enabled.  

For my own knowledge purposes - can using the wrong cable make the link default to 100 HALF irrespective of speed/duplex settings?

Wrong cable, no.  

If your router is talking to provider's router then it should be a cross-over cable.  

2 days and still cannot get the provider to get me an answer

The provider is not entitled to give an answer since they've been collecting your money.  

[jay.digwa]

So when is MDI/MDIX disabled? When one side is set hardcoded or both?

[Leo Laohoo]

So when is MDI/MDIX disabled? When one side is set hardcoded or both?

If the provider wants to disable MDI/MDI-X then they hard code speed and duplex.  

If YOU want to disable MDI/MDI-X then YOU need to hard code speed and duplex.

[jay.digwa]

Apologies for the repeat.

So in our scenario we are using a straight through cable.

The provider has hard coded their speed and duplex to 100 Full. When we have our side set to auto/auto, the link is auto negotiated at 100 HALF.

When we set to 100 Full on our side, the link goes down.

Are we likely to establish the link if a cross over was used instead?

[Leo Laohoo]

So in our scenario we are using a straight through cable.

Fact 1.

When we set to 100 Full on our side, the link goes down.

Fact 2.

Are we likely to establish the link if a cross over was used instead?

Correct.  Use a cross-over cable and the link should recover.

[jeckert · Accepted solution]

I never found a solution, and now that I know what to expect, I ask ahead of time to have it set that way. So almost 50% time now the provider has it auto/auto. For me it was a ADVA as well and the provider is Time Warner.

[Palani Mohan]

Hi there

Auto negotiation has come a long way in the 15 years or so and it is very stable/dependable. I 100% understand that providers (50% of them, based on your experience) still live in the past and hard code the settings.

Anytime, the operator chooses to manually configure, they need to take responsibility for their configuration. In today's (complex) world, it is not easy. This is the main reason why manual config fails to work (very often because the provider contact/helpdesk is not the same person who is physically on-site). This is also the reason why auto-negotiation is a better elegant/cleaner way to go.

Props to you, to change your work schedule and engage the provider to configure auto-negotiation, in advance.

Kind regards .... Palani