DIA Connection

[MatthewL]

We have a new DIA connection by our ISP that we have an issue with and wondered if anyone had come accross it before, I've seen similar issues on FTTC before when using the Openreach modem but not exactly the same in this.

 

We have a 1GB connection that works if a device i.e. firewall or laptop is configured on the end but if we put a switch in the middle with say 2 VLAN'd ports (untagged) it doesn't work, tried changing speed on ports but no joy. Clearly something switch related but scratching my head, do have ISP ticket logged but not heard back yet.

 

We have a firewall cluster that we will need to use a switch for, yes its a single point of failure but we have something in place for that. Any suggestions?

[SchoolsBroadband]

is the switch plugged into the carriers NTU or are you plugging the switch into the ISPs router which in turn is then connected to the carriers NTU?

[MatthewL]

The carrier presents at a patch panel and the equipment is located in another cabinet which is on their core network, we have a cabinet in their data centre.

 

The switch goes direct to their kit. If the cable is plugged into the firewall or a laptop it works but not when on 2 untagged ports on a swtich.

 

Set to auto speed, also tried forcing but no joy. Spoke to network engineer today and they cannot see any issue with anything, other than taking another switch down to test I am out of ideas.

[SchoolsBroadband]

I recall something similar to this a long time ago when I used to be an engineer.

 

For some reason spanning tree comes to mind.... maybe something to do with bpdu in particular.

 

Is the device on the other end of the patch panel a switch or a router?

 

Dave

[MatthewL]

Good question I don't know, I know it goes direct into the core so suspect its a router.

 

I will look into that next week when I am back in.

[MatthewL]

Just looked at config, spanning tree is disabled on this switch in question.

[SchoolsBroadband]

At both ends?

 

Also one of the switches isn't super old is it and therefore you could need a cross over cable rather than a normal network cable!?

[MatthewL]

It's disabled on our end, would need to speak to ISP to confirm their end.

 

That had crossed my mine but they are modern. The exact cable works straight into a laptop or firewall so had ruled that out.

[SchoolsBroadband]

It's disabled on our end, would need to speak to ISP to confirm their end.

 

That had crossed my mine but they are modern. The exact cable works straight into a laptop or firewall so had ruled that out.

 

ah yes but switch to switch is a cross over cable. Just like a laptop to laptop is cross over. So if you have a switch and your ISP has a switch also then you may need a cross over cable rather than a normal patch cable.

 

Check if you get a link light briefly. If you do then that rules out cable type. If you get no light at all then it could be the cable.

 

Dave

[MatthewL]

Said cable works in laptop so that is a known working cable, I've used straight through on laptop to laptop, didn't think a crossover would be needed but can try it.

[MatthewL]

Got this working via the switch buts its really wierd.

 

Plugged it into another switch (a Dell one) and it came up, flow control disabled on the DIA port, plugged back into the switch we had no joy. On the VLAN we had setup for 2 other random ports and plugged in and it came up even though those ports were the same as the one initially setup.

 

Not sure if switch needs a kick but came up, even tried with a crossover which made no difference.

[SchoolsBroadband]

Got their in the end well done

[MatthewL]

Wierd though, never seen anything like it before. Don't get why the switch has done what it has though, its one of them things that doen't get touched and it was setup years ago so no one can remember if there was issues in the past.

[MatthewL]

Got to the bottom of this, there was some fault which was resolved but Sophos network threat protection via their Intercept X product has throttled network connection so going from a gig to just shy of 200 meg, turn that off you get gig!!

 

There is a bug which is waiting a patch to resolve this, one to watch out for.