huawei ma5616 vdsl2 dslam support 32 port vdsl2+ . support adsl2 + .
The 16-port very-high-speed digital subscriber line 2 (VDSL2) over plain old telephone service (POTS)
board that supports 8a, 8c, 8d, 12a, 12b, 17a, spectrum profiles .
VDSL2 supports various features, such as high-speed transmission, long-distance transmission and flexible profile configuration solutions.
The VDSL2 standard was included in the agenda of ITU-T in 1998 but was progressing slowly. One reason is that back then the situation of broadband access was not definite, and the asymmetric digital subscriber line (ADSL) technology soon met the bandwidth requirements owing to its practicality. Another reason is that the bandwidth stipulated by the VDSL standard was far higher than the bandwidth required by the market. At the same time, VDSL put much more requirements on loops than ADSL does. Owing to these reasons, VDSL was in only small- scale application in the market. In 2003, ITU-T stipulated two new recommendations for ADSL, G.992.3 and G.992.5. It was then that the industry eyed VDSL more important as it provides a higher bandwidth.
In October 2003, ITU-T completed the VDSL1 recommendation and meanwhile kicked off the
VDSL2 project. In actual application, few products supported the VDSL1 recommendation G.
993.1. However, operators were in imperative needs for a more definite VDSL standard. Driven by such a market, ITU-T made a more specific definition of VDSL2 in G.993.2, which was rolled off in February 2006.
VDSL2 supports the following features.
VDSL2 specifies a band plan that covers the frequency as high as 30 MHz, and provides for a bidirectional high-speed data transmission at 200 Mbit/s within short distances. The 30a spectrum profile supports a total minimum upstream and downstream rates of 200 Mbit/s, and
17a supports a total of 100 Mbit/s.
The VDSL2 standard specifies enhanced downstream transmit power (20.5 dBm). Together with the application of frequency band US0 and techniques such as echo cancellation and time domain equalization, VDSL2 achieves a maximum transmission reach of over 2.5 km. Figure 3-6 shows the comparison between VDSL2 and ADSL/ADSL2/ADSL2+/VDSL in terms of downstream rate and distance.
Flexible Profile Configuration Solutions
The highest frequency of VDSL2 is 30 MHz. Between 1 MHz and 12 MHz, VDSL2 still applies Band Plan 997 and Band Plan 998 of ITU-T Recommendation G.993.1. 12-30 MHz can be divided into just one or more upstream and downstream frequency bands to meet different application requirements.
Compatibility with ADSL/ADSL2+
VDSL2 adopts discrete multi-tone (DMT) as the only modulation mode. VDSL2 supports the packet transfer mode (PTM) mode that is based on IEEE 802.3ah 64/65-byte encapsulation, and also supports the asynchronous transfer mode (ATM) encapsulation mode that is employed by ADSL/ADSL2+.
Stronger Support for Video Service
According to the characteristics of the video service, VDSL2 implements pulse noise protection by using the interleaving technique. In addition, VDSL2 can dynamically adjust the interleaving depth according to the condition of error bits. VDSL2 also specifies dual-latency channels to meet the requirements of different services (especially the video service) that have different degrees of sensitivity to packet loss and latency. Moreover, VDSL2 provides functions such as power spectrum density (PSD) control, loop diagnosis, and online reconfiguration.
3.3.5 Support for Multiple Spectrum Profiles
Very-high-speed digital subscriber line 2 (VDSL2) supports multiple spectrum profiles to fulfill the needs of different application scenarios.
Owing to different network environments, the influence of different factors on communication loops may vary. Thus, it is difficult to address the application requirements of different environments by using the same mechanism. VDSL2 defines eight spectrum profiles (8a, 8b,
8c, 8d, 12a, 12b, 17a, and 30a) to fulfill the needs of different application scenarios and builds a holistic mechanism to strengthen its adaptability to the environments.