GPON settings

[#1]

Newby here. Can somebody tell me the ONT VLAN tag for 900Mbps fibre ? And also the maximum MTU. I have tried 9100 but it doesn't like it.

[#2]

Can somebody tell me the ONT VLAN tag for 900Mbps fibre ? And also the maximum MTU. I have tried 9100 but it doesn't like it.

@aa29a Assuming you mean the VLAN tag in the router that's connecting to the ONT , then there isn't one! VALN tagging in the router MUST be disabled, the ONT will automatically handle any VLAN tagging required. MTU is normally fine at the default 1492.

[#3]

Thanks for MisterW for your reply,

Unfortunately the standard MTU is NOT suitable. My home LAN uses iscsi over 10 Gbps and achieves 8900 Mbps using an MTU of 9000. When connecting the HUB2 at 1492 my LAN throughput falls to 2300Mbps. My France Telecom fibre connection in france has a max MTU of 9100 and copes easily. I have a fully managed 10Gbps switch and a fast pfSense 2.4 Router.

Also, GPON implementations have a VLAN tag field, so I need to know the VLAN tag for this. Because the ONT is connected to the main managed switch all my broadcast traffic will be sent to the first openreach router which will be constantly forced to drop it. I do not wish to create a DDOS attack - even by accident. This tag exists as it enables other ISP to separate Internet, TV and Phone services at the WAN port and route them differently. I can't believe PlusNet don't set it, even if they don't enforce its use.

Perhaps this is why PlusNet say the ONT MUST be connected directly to the router, which is clearly not the case.

Do you think that I should ask PlusNet to release me to BT ?

[#4]

@aa29a  Forget what you can do in France. Openreach FTTP has a fixed Vlan ID of 101 which as @MisterW  is dealt with by the ONT.  There are no other Vlan tags on the WAN side. The ONT output which is your WAN connection to the internet has to go to the Router which then uses NAT to connect to devices on your local network. I guess you need to set up your own Vlans on your local network if you require different MTU values

BT will be exactly the same so moving to them will not help.

[#5]

@aa29a and just to add to what @RealAleMadrid said...

The internet connection is PPPoE using your Plusnet username/password 

Also, GPON implementations have a VLAN tag field, so I need to know the VLAN tag for this. Because the ONT is connected to the main managed switch all my broadcast traffic will be sent to the first openreach router which will be constantly forced to drop it. I do not wish to create a DDOS attack - even by accident. This tag exists as it enables other ISP to separate Internet, TV and Phone services at the WAN port and route them differently. I can't believe PlusNet don't set it, even if they don't enforce its use.

You are correct , GPON does  have a VLAN tag field BUT the ONT controls the insertion and removal. There are no other services provided over FTTP by Openreach , therefore ISP's don't need or have control over the VLAN tag.

[#6 · Accepted solution]

Hi,

I may be new here but I'm not an idiot. All my network ports are on separate VLANs on a single switch.

I NEED the ONT to have a VLAN tag. I will put a 5 port Managed 1Gbps switch in the path with the ONT connected to an untagged port and the main switch connected to a VLAN port. What an unnecessary expense and bother. Basically, by setting a VLAN on the main switch I can keep my [-Censored-] off the fibre.

I have worked in Telecoms for the last 45. I think you will find the VLAN setting has exactly nothing to do with demultiplexing the data stream. If I wanted to I could completely bypass the ONT and extract my TDM slot directly at the router, but of course I can't be bothered.

As for the "Direct to Router" issue, the ONT outputs standard Level 2 Ethernet frames and I can connect them to any infrastructure I like . This is on my side of the boundary.

Regarding France, this is just another example of the UK going off half-[-Censored-] and rolling out outdated technology in the interest of "keeping taxes low". Will the MTU still be 1500 when 10Gbps Internet arrives in 10 years time ?

Fortunately, the solution to my MTU problem is to provide a completely separate 1Gbps network connection to each of my 8 PCs and route them so they can access the Internet but not see each other. Fortunately 6 of these already have a vacant port.

My irritation is that it makes mirroring my SAN box off site more difficult.

I have no choice but to regard this as closed now.

[#7]

@aa29a Best of luck with your proposed scheme but the ONT does not have a Vlan tag and has no user interface to change anything. End of ...

[#8]

Thanks. I have added VLAN tag 201 to the ONT. The rest of the network already exists.