TTT
0
On my travels through the net, I found this interesting document, which includes a section on actual transmission speed, which explains just why speed test results can never be as fast as the sync speed.
It also stipulates that the customer modem must support g.vector, g.inp and aelem, which I found very interesting (my cabinet runs ITFN (ECI) equipment, and does not support vectoring, but g.inp seems to be on downstream).
Sadly, it does not mention support for 30a, which is a shame (having said that, the attainable rate on my 80/20 line is indeed over 100Mbit/s).
"...For example, if the reported downstream VDSL2 data rate is 40,000 kbit/s and the IP packet size is 1500 bytes (i.e. Ethernet frame size at End User LAN is 1514 bytes) the maximum throughput achievable is actually 39,178 kbit/s (when measured at the EU LAN i.e. no VLAN header, but including Ethernet header). Alternatively, if the IP packet size is 64 bytes the maximum throughput achievable is further reduced to 35,721 kbit/s. This overhead is particularly important to consider in respect to the downstream shaper setting on the CP’s BRAS. CPs are advised to understand and account for the method that their BRAS uses to implement traffic shaping."
It also stipulates that the customer modem must support g.vector, g.inp and aelem, which I found very interesting (my cabinet runs ITFN (ECI) equipment, and does not support vectoring, but g.inp seems to be on downstream).
Sadly, it does not mention support for 30a, which is a shame (having said that, the attainable rate on my 80/20 line is indeed over 100Mbit/s).
"...For example, if the reported downstream VDSL2 data rate is 40,000 kbit/s and the IP packet size is 1500 bytes (i.e. Ethernet frame size at End User LAN is 1514 bytes) the maximum throughput achievable is actually 39,178 kbit/s (when measured at the EU LAN i.e. no VLAN header, but including Ethernet header). Alternatively, if the IP packet size is 64 bytes the maximum throughput achievable is further reduced to 35,721 kbit/s. This overhead is particularly important to consider in respect to the downstream shaper setting on the CP’s BRAS. CPs are advised to understand and account for the method that their BRAS uses to implement traffic shaping."























