Ok, hopefully this will all make sense etc...
I have 4 buildings, each with a Draytek G1240 switch (we refer to this as the backbone).
In 1 of the buildings we have a VoIP phone system
In another building we have a 100mb leased line internet circuit
Currently the switches are all connected using fibre SFP modules, into port 24. Port 24 on every switch is configured as a trunk port to allow it to pass all VLAN IDs
I have configured vlan1 - this is for the phones. Port 1 of each switch is in this, and subsequently uplinks to a number of Netgear PoE switches (depending on the size of the building - from 4 switches to 8 switches). From the phone system i can ping any of these PoE switches, and get a response time of around 4-5ms.
I have configured vlan2 - this is for the 100mb circuit, and again i have no problems with this vlan.
I have now configured vlan3 - this is for our company to be able to put an office into each of these buildings, and utilise the fibre links back. We have a draytek 2820 router, wan1 is the ADSL connection for the broadband service, and wan2 is plugged into the phone system to allow us to administer the phones.
When i ping from building 1 to building 2 on vlan3, i see a few pings around 13-15ms - and then it will spike to 375ms.. it might hold this for a few, and then come back down again. This is when the office is closed, so i know there is no network usage happening.... but i cannot fathom why this is happening at all....
Really looking for pointers to work out whats going on..... as the connections are obviously ok, as vlan1 and vlan2 dont have any problems at all.... only this new vlan..... :-/
Thanks in advance...