Ethernet Port Settings

Link speed

The Ethernet services are presented in different ways depending on the link speed you have requested.

100Mb/s

For 100Mb/s links (and below) the service is presented using a normal Ethernet (copper) RJ45 connector. You use a normal cat-5 Ethernet patch lead to connect this to your switch, router or firewall as you required.

IMPORTANT the link is configured as fixed full duplex. This means that if it is connected to a un-managed switch or un-configured port on a switch, router or firewall then it will not work correctly. It will seem to work, but as soon as any reasonable level of traffic flows there will be dropped packets seriously hindering upload speeds. You must have a managed switch or port connected to the link and configure the port to be fixed full duplex 100Mb/s for it to work correctly. We can supply a small managed switch for this purpose if you require.

Cabling is a straight through cat5e patch lead to your managed switch.

1Gb/s

For 1Gb/s the link is presented using single mode fibre on SC connectors, and you will need a fibre port and fibre patch lead to connect to the service. We can supply a media converter if you require which will convert to RJ45 copper Ethernet.

This link should be used with an auto-negotiation port which is the default for giga-bit links

10Gb/s

For 10Gb/s you will need special 10Gb/s equipment, contact sales when ordering for details.

VLANs

Normally the link you have can carry one or more services on the link - the common one being 10Mb/s internet access. However the same link can have internet access and site-to-site access, and multiple such services and different speeds. We also offer a dedicated site-to-site fibre as well.

Where there is more than one service on the link then all of the services will have a VLAN tag. This is used to differenciate between the services. In this case site-to-site access can use Q-in-Q double tagging to pass VLAN tags to the other site. The internet access does not have any secondary VLAN tagging that would apply.

Where there is only one service on the link then this can be set to operate with no VLAN tag.

Where a dedicated site-to-site fibre is used then any packets simply go to the other end including any VLAN tags. This link is effectively a very long Ethernet cable, though still subject to packet size limits.

Note that if you have VLAN tagging on any link then all links on that connection will have a VLAN tag (you can't have one un-tagged). The VLAN tag could be any of the valid tag values so check your switch does not have a limited on VLAN tag values.

Packet size

Packet sizes up to 1548 are permitted on site-to-site traffic. Internet access is limited to 1500 bytes (plus VLAN tag where needed).

Technical details

See [https://www.btwholesale.com/pages/downloads/.../SIN_476v1p3.pdf

BT SIN 476] for technical details.