Xdsl modem Interface Description




Дата канвертавання28.04.2016
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xDSL Modem Interface Description

Table of Contents



1.Introduction 2

2.Technical Requirements and Interoperability with xDSL Technology Standards 2

3.Interoperability with Installed Equipment 2

4.Customer Side Installation 3

5. Cyta’s Technical Specifications of Services 3

5.1.High Speed Internet (HSI) 3

5.2.IP TV Service 3

5.3.Broadband Telephony 3

5.4.SIP Trunk Telephony 4

5.5.Office Internet Access 4


  1. Introduction


This document describes the xDSL Interface at the Customer Side in order to ensure interoperability between CYTA΄s xDSL Network and xDSL Customer Premises Equipment (CPE) other than those supplied by CYTA.

This document is not a specification of xDSL CPEs. It simply describes the parameters available at the customer side of CYTA΄s xDSL network, taking into consideration all applicable CYTA΄s xDSL transmission systems and related connection topologies. It also describes some specific requirements regarding the xDSL CPEs in order to ensure interoperability.



  1. Technical Requirements and Interoperability with xDSL Technology Standards


The device shall support xDSL INP values of 0, ½, 1, 2 and 4.

The device shall support all requirements in ITU-T Rec. G.997.1 (Physical layer management for Digital Subscriber Line transceivers)

The device shall support PSD (power spectrum density) shaping according to G997.1.

The device shall support carrier set A43 and A43C according to G994.1

The device shall support standard ATM (AAL5) payload format

The device shall support encapsulation of bridged Ethernet over AAL5 (without FCS) in accordance with IETF RFC 2684.

The device shall comply with ITU G.992.3 (ADSL2), ITU G.992.5 (ADSL2+), ADSL2+ Annex M and all amendments defined in the standard.

The device shall support rate-adaptive profiles

The device shall support trellis coding.
Additionally in the case of VDSL2 support:

The device shall be compliant with ITU-T G.993.2 - Annex B [Europe]. Frequency allocation plans derived from bandplan "998" for region B shall be supported.

The device shall support profiles 8b, 12a, 17a

The device shall include support for the following application reference models from ITU-T G.993.2:


- G.993.2 clause 5.4.2, Data with POTS service
- G.993.2 clause 5.4.1, Data service (no POTS or ISDN)

The device shall support simultaneous transmission of US0 and US1 in profiles for which the capability of US0 has been indicated.



The device shall support UPBO/DPBO (Upstream/Downstream Power Backoff) according to ITU-T G.993.2

  1. Interoperability with Installed Equipment


The device shall pass the functionality test plan of TR-115 and the VDSL2 performance and interoperability test plans of TR-114 for the DSLAM/MSAN already in Cyta’s network as described below:


    Access Nodes Types:

    1. ECI HiFoCus 4 SAM 480. The physical interfaces used are ADSL2+ Annex A and M (ATU-C ADSL2+ POTS 32 lines)

    2. ALU, ISAM 7302 XD. The physical interfaces used are ADSL2+ Annex A and M (line cards: EBLT-C | EBLT-D | EBLT-E)

    3. ALU, ISAM 7302 FD. The physical interfaces used are VDSL2 (12a/17a, plan 998) which are also backwards compatible with ADSL2+ CPEs. (Line card NVLT-C | NVLT-G | NVLT-P)

    4. ECI HiFoCus 5. The physical interfaces used are VDSL2 (12a/17a, plan 998) which are also backwards compatible with ADSL2+ CPEs. (line cards: VTU-C64P | ATU-C64P)



  1. Customer Side Installation


Installation and connection guides can be found at https://www.cyta.com.cy/faq-internet-guides.
Especially in the case of VDSL2 service, customer shall follow the instructions in the “Wiring Guide for Broadband Services” available at https://www.cyta.com.cy/mp/informational/support/files/wiring-guide-for-broadband_GR.pdf. This guide contains detailed instructions regarding the home wiring and the installation of a centralized splitter for the best quality of service.
In case of Naked DSL, the installation of a splitter is not required.

  1. Cyta’s Technical Specifications of Services

    1. High Speed Internet (HSI)


A dedicated WAN PVC / VLAN is used for this service. In case the modem operates in ADSL2+ mode, PVC 8/42 is used, terminating the traffic using PPPoE IPv4 protocol (as defined in IETF RFC 2516). In the case the modem operates in VDSL2 mode, using EFM, VLAN 42 is used.
Customer authentication is performed using PPP circuit ID Tag from the DSLAMs /MSANs Relay agent so no specific username and password is needed.

    1. IP TV Service


In case the modem operates in ADSL2+ mode, PVC 8/36 is used for this service. A bridged interface is used and all STB’s generated traffic (DHCP requests, IGMP, multicast and VoD) shall be forwarded to the above bridged PVC.
The above configuration principle shall also be utilized when the modem operates in VDSL2 mode using EFM. In this case VLAN 36 shall be used for the connection between the STB and the DSLAM/MSAN.

    1. Broadband Telephony


In case the IAD operates in ADSL2+ mode, 8/41 WAN PVC is used for connecting to the IMS network using IPoE. All voice, video, SIP signaling traffic etc directed to the Session Border Controller of IMS platform will be routed through this PVC. All Voice over Broadband (VoB) traffic originating from devices connected behind the NAT of the modem shall also be routed through this WAN interface.
In the case the modem operates in VDSL2 mode, using EFM, VLAN 41 is used.

    1. SIP Trunk Telephony


In case the modem operates in ADSL2+ mode, a bridged PVC 8/51 connected to a specific LAN port shall be used for this service.

In the case the modem operates in VDSL2 mode, using EFM, VLAN 51 shall be used.



    1. Office Internet Access


When operating in ADSL2+ mode, a bridged PVC 8/35 connected to a specific LAN port shall be used for Office Internet Access and in case of VDLS2 mode VLAN 35. Tag or untagged traffic shall be accepted from this LAN port and shall be forwarded unmodified to the bridged interface.


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