Vodafone achieves a data transmission rate of 2 GBit / s in download and 100 MBit / s in upload in its cable network open to customers in Stuttgart. The network operator demonstrated this in a speed test on July 28, 2020. Vodafone has so far offered the best cable network tariff Red Internet & Phone with 1 GBit / s for download and 50 MBit / s for upload.
Company spokesman Helge Buchheister said: “2 GBit / s in download and 100 MBit / s in upload are already possible under practical conditions, even if they are not yet marketed. Not only fiber is very powerful, the cable network is absolutely equal.” Vodafone will probably offer a higher upload speed next year.
For comparison: With Super Vectoring, Deutsche Telekom can achieve VDSL data rates of up to 250 Mbit / s in download and an upload of up to 40 Mbit / s.
The speed test in the network in Stuttgart was demonstrated by Reik Elftmann, Manager Network Quality & Architecture at Vodafone, and Tobias Uberär, Director Quality Analysis at Vodafone. 2040 MBit / s and 103 MBit / s were achieved with a Fritzbox 6660. “If we didn’t offer television on the cable network, we would even get up to 3 Gbit / s and more downstream”, emphasized Elftmann. The Docsis 3.1 cable network standard works “better than we expected at launch”, he said.
The cable is still a shared medium, all households in a network section share the available bandwidth. In the network, a fiber node is a component in which the optical signal from the glass fiber is converted into an electrical signal on a coax cable. According to previous statements, there could be a few hundred households in a node, but also several thousand. In the case of a node split, an additional Fibernode is basically set up and some of the customers of the original Fibernode are moved over to a newly established node. The number of households per node is reduced and more capacity is available on both.
According to Elftmann, there were upstream in some network segments during the Corona crisis “Impairments”, which is why segmentations were preferred. “There were no problems downstream for the Corona wedding, and solutions were quickly found in the upstream.” Buchheister emphasized that Vodafone performs several hundred node splits every year. According to Elftmann, there will even be significant increases in the future, “to keep minimizing the number of customers in the node”. This also against the background that the requirements for capacity planning in the upstream have changed by Corona, said Reikmann.
Chips for the successor standard 4.0 are not yet available. The manufacturers worked on it. Elftmann emphasized: “We are already exchanging many passive components in the network as part of our regular network upgrade projects for components that are suitable for Docsis 4.0.”
Senior Executive Advisor Volker Leisse spoke for the Cablelabs, the research and innovation lab of the cable industry:“The new Docsis 4.0 standard is a collection of various specifications and technologies that enable 10G and reduce latency in the cable network.”
New specification for Docsis 4.0 only came in April
According to Leisse, two technology options are possible here: Full Duplex (FDX), simultaneous transmission in the downstream and upstream at the same time on the same frequency, and FDD (Frequency Division Duplex), the expansion of the spectrum for upstream and downstream transmission. The choice of options depends on the strategy for network expansion. If it is about the electrical part of the network (coaxial cable) without an amplifier, FDX is suitable. When it comes to shifting the upper limit frequency for upstream transmissions, FDD is the right choice.
The full specification, including FDX and FDD for Docsis 4.0, was only released in April 2020, Leisse explained.
When asked by Golem.de, Elftmann said that with FDX Full Duplex Vodafone with the glass fiber must be close to the house, “up to the roadside, so Fiber To The Curb”. At FDD, you don’t have to get that close to shorten the amplifier cascades. The company has not yet decided which way Vodafone will choose.