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ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
xDSL test, xDSL testing, xDSL installation, xDSL maintenance xDSL tester
Figure 1 Reach achieved by different xDSL technologies and Spectral efficiency.
IDSL
HDSL2
2.5
2
1.5
1
.5
2.5 5.0 7.5Average Reach Achieved (km)
Mbit/s
20 1404
PSD
1100400
SDSLADSL upADSL downSHDSLPOTS
Frequency (kHz)
Technology Pairs Symmetric POTS StandardADSL 1 or 2 No Yes G.992.1, G.992.2, ANSI TI.413.2HDSL 1 or 2 Yes No T1.418IDSL 1 Yes No I.430, I.431SDSL 1 Yes No NoneSHDSL 1 or 2 Yes No G.991.2
Figure 2 Technologies comparison.
AuroraPrestoA multi-layer xDSL tester developed to pro-vide all the features necessary for a techni-cian to install, maintain and troubleshoot Asym-metric and Symmetrical Digital Subscriber Lines and services. Its flexi-ble build architecture allows different modem types, as well as data interfaces and ana-logue test functions including TDR, DMM, ADSL, SHDSL, ATM, IP, PPP, HTTP and inter-net download test.
AuroraTangoMulti-technology Per-sonal Test Assistant Platform for simple, fast and effective testing of ADSL, SHDSL, ISDN and GbE. It can oper-ate in both One-button mode and Expert mode by using pre-defined test scripts and parame-ters. A PDA provides an intuitive graphical menu structure for testing and workflow organization. Bluetooth interface pro-vides Tango wireless access and host inde-pendent test.
AuroraForteA powerful tool for the Physical, ATM and IP layer operation of ATM circuits. Provides E1, E3, DS1, DS3, ATM25,STM1/OC3 and STM4/OC12connectivity for unparalleled multi-cir-cuit testing ATM, xDSL and 3G networks. Phys-ical and ATM BER test-ing is provided. Advanced features, AAL5, OAM, QoS, SVC support and IP Ping over ATM, protocol decoding and remote testing.
LT2000It is a hand-held tester for analogue qualifica-tion of copper pairs.
It will determine their suitability for use by xDSL services prior to and during installation and maintenance.
ALT2000This is the right tool for any physical qualifica-tion, monitoring or main-tenance of copper pair subscriber loops. Exten-sive range of analogue measurements for xDSL make it attractive to engineers needing a high-performance ana-lyzer with precision measurements. It includes ultra low noise floor, spectrum ana-lyzer, zero blindspot TDR, DMM, and a col-lection of predefined masks.
FlexaNetxDSLA cost-effective solu-tion that provides com-plete loop fault management for Control Centres that support a large number of xDSL installations. Its remote testing capacities include: emulation of equipment at both cen-tral offices and cus-tomer premises, TDR, DMM, an extensive range of analogue mea-surements, spectrum analysis, ATM, PPP, IP and higher level proto-col test.
Trend´s xDSL GuideQuick Reference
Tren
dCom
mun
icat
ions
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
Wide-bandnetwork
V-C
xTU-CPhys.level
U-C2
POTS or ISDNNarrow-bandnetwork
C Splitter
R Splitter
xTU-RPhys.level
User installation
network
SM SMPOTS/ISDN
U-R2
U-C U-R
T/S
T-R
Figure 3 xDSL Reference model.
Transmission Network
Access Network
User NetworkTerminal
ATMAAL5
ADSL
RFC2684
PPP
ATM ATMAAL5
RFC2684 L2TP
PPP
L2TP
PPP
Gateway NSP
(Internal modem)
LLC
10-BT
MAC
ATMAAL5
xDSL
BridgeRFC2684
10-BT ATMAAL5
PHY
RFC2684
EtherPPOE
PPP
L2TP
10-BT
Ether
PPPoEPPPIP
ATMAAL5
xDSL
RFC2684
PPPLLC
RouterNATPATDHCP
10-BT
MAC
IP
L2TP
PPP
IP
Figure 4 Structure and protocols involved in the xDSL service.
bridge-type
router-type
ATM FR IP
ATM FR
IP...
ATM, FR, IP,...
IPIP
xDSL SDH/PDH SDH/PDH
ATM, FR, IP
ATMAAL5
RFC2684
PPP
ATM ATMAAL5
RFC2684 L2TP
PPP
L2TP
PPP
User DTE xTU-C (DSLAM)
ATM, FR, IP,...
IPIP
xDSL SDH/PDH SDH/PDH
ATM, FR, IP,...
ATMADSL
PPP
IP
ATMxDSL SDH/PDH
L2TP
ATM FR IP
ATMAAL5
RFC2684 L2TP
PPP
ATM, FR, IP,...SDH/PDH
ATMxDSL SDH/PDH
ATMF 25.6 ATMF 25.6
xTU-R
802.3
802.3
internal modem
ATM-25 interface
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
Figure 5 ANSI masks for copper qualification.
Noise
Return Loss
Insertion Loss
Longitudinal Balance
Cross Talk
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
fast AS0 AS1 AS2 AS3 LS0 LS1 LS2 AEX LEX FEC bytes
sync AS0 AS1 AS2 AS3 LS0 LS1 LS2 AEX LEX FEC bytes
fast LS0 LS1 LS2 LEX FEC bytes sync LS0 LS1 LS2 LEX FEC bytes
Figure 6 ADSL frame models.
Fast Fast data FEC Interleaved data
Fast buffer Interleaved buffer
ADSL Frame
Fast buffer (ATU-C)
Interleaved buffer (ATU-C)
Fast buffer (ATU-R) Interleaved buffer (ATU-R)
(at the constellation coder input) (at the constellation encoder input)
250 µs
Figure 7 Handshake frame format. Messages: MS, MR, CL, CLR, ACK(1), ACK(2), NAK-EF, NAK-NR, NAK-NS, NAK-CD, REQ-MS, REQ-MR, REQ-CLR.
Flag FCS1Message (optional)(optional)Flag=7Ex
Identification Standard info Non-standard info(optional)
Flag Flag Flag Flag FCS1 Flag Flag Flag
Type of message Version number Manufacturer Parameters
Handshake frame
Figure 8 Handshake sessions.
CLR CL
CLR: the ATU-R sends a list with all the operation modes it acceptsCL: the ATU-C responds with a list of modes it acceptsACK: the ATU-R has received the list of modes correctly MS: the ATU-R demands a operation mode ACK: the ATU-C accepts itMS: the ATU-R requires a certain operation modeREQ-MR: the ATU-C wants to select the mode and makes a request for an MR messageMR: the ATU-R requires an MS operation modeMS: the ATU-R demands a certain operation mode ACK: the ATU-R accepts the request
ACK
MS
ACK
MS
REQ
-MR
MR
MS
ACK
ATU-R
ATU-C
t ATU-R
ATU-C
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
Figure 9 ATM Cell format according to the ATM Forum.
GFC: General Flow ControlVPI: Virtual Path IdentifierVCI: Virtual Channel IdentifierPT: Payload TypeCL: Cell Loss PriorityHEC: Header Error Control
123456···
53
GFC VPIVPI
VCI
PT CLHEC
Payload
VPIVPI
VCI
PT CLHEC
Payload
UNI Format NNI Format
byte 123456···
53
CS-PDU
SAR-PDU
ATM-PDU
ATM-PDU
ATM-PDU
ATM-PDU
AAL-SAP
PL-SAP
AAL
ATM
Physical
ATM-SAP
AAL-SAP
SAR-PDU
SAR-PDU
SAR-PDU
ATM-SAP
PacketsContinuous
48 bytes
53 bytes
Convergence
Segmentation& reassembly
ATM cells
n bytes
ATM-PDU
ATM-PDU
ATM-PDU
sublayer
Data
Figure 10 Protocol Data Unit (PDU) exchange between ATM layers.
User DataStream
Higher layers
Layer
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
Figure 11 AAL2 format.
CPS: Packet Header (3 bytes)
STF: Start Field (1 byte)
CID: Channel Identifier (0 not allowed)LI: Indicates the length of the CPS-SDUUUI: Indications between end users
OSF Indicates the offset where the next CPS packet startsSN: Sequence number (varies between 0 and 1)P: Parity Bit
Padding the payload of an ATM cell with zeros if no channel has information available to send
CPS-SDU
Channel 1 Channel 2 Channel 3 Channel 4
CID
CPS-SDU CPS-SDU
ATM Cell PayloadHeader
ATM Cell PayloadHeader
CID=x CID=y CID=x CID=xm, n, o, p, ...
m+3, n+3,....
48
53
Size (bytes)
LI UUI HEC0 7 13 18 23 HEC: Header Control Error
CPS-SDU
OSF SN0
Pbits 6 7
CPS-PDU CPS-PDU CPS-PDUCPS-PDU
ATM Cell PayloadHeader
bits
Figure 12 AAL5 format.
PAD: Complements the PDU up to forming a multiple integer of 48 bytes.UU: Allows for transparent data transmission between AAL5 extremes.CPI: Aligns the PDU in 64 bitsLI: Data sizeCRC: G(x) = x32+ x26+ x23+ x22+ x16+ x12+ x11+ x10+ x8 +x7+ x5+ x4 + x2+ x + 1 (Calculated for the entire PDU)
User data CPI LI CRC
1 to 65,535 4
ATM header
CS-PDU:
SAR-PDU:
PAD
BOM EOM
UU
1 2 0-47
. . .COM
PTI=xx0 PTI=xx0 PTI= xx1
PT payloadpayload
1
48
bytes
. . .
PT payloadPT
ATM
PHY
xDSL
xDSL
DSLAM (xTU-C)
d Cc
a Ab B
dC c
aAbB
ATM link
Figure 13 Multiplexing ATM in the DSLAM.
xTU-R
xTU-R
Local LoopNetworkTermination
SLA
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
Figure 14 PPP encapsulation.
Address
PaddingFCS (cont. if 32 bit)
0 318 16
Flag
Control
FCS
Flag
PPP packet
Padding
Protocol0 318 16bit
Encapsulated Protocol
Protocol: 0001h - Padding
C023h - PAPFlag: 7Eh
C223h - CHAP
0021h - IPC021h - LCP
Address: FFhControl: 03h
PPP encapsulation PPP frame structure
Figure 15 IP Format.
Version Type of service Total lengthIHLIdentification Flags Fragment offset
Time to live Protocol Header ChecksumSource Address
Destination AddressOptions (+padding)Data (variable size)
bit 0 314 8 1916
20 bytes20 bytes
Figure 16 Higher protocols.
IP
TCP
BGP FTP HTTP SMTP SNMPTelnet
UDP
ICMP OSPF
TrendCommunications
Americas: +1 256 461 0790
España:
UK:
Deutschland:
France:India:
93 300 33 13
01628 524977
089 32 3009-0
01 69 35 54 7022 8597 463/4
web:mail:
Trend Communications Ltd.Knaves Beech EstateLoudwater, High WycombeBuckinghamshire HP10 9QZ UK
More information in:Installation and Maintenance of SDH/SONET,
2003 (c) Artech House, ISBN:1580535259 ATM, XDSL, and Synchronization Networks.
ADSL test ADSL testing ADSL tester ADSL installation ADSL maintenance ADSL pocket guide ADSL reference ADSL solutionSHDSL test SHDSL testing SHDSL installation SHDSL maintenance SHDSL pocket guide SHDSL reference SHDSL solutions
AcronymsAAL ATM Adaption Layer LI Length IndicatorACK Acknowledge LLC Logical Link ControlADSL Asymmetric Digital Subscriber Line MAC Media Access ControlAEX A(S) extension byte; byte inserted in the
transmitted ADSL frame structureNAT Network Address Translation
ASx Any one of the simplex bearer channels (0 -3) NSP Network Service ProviderATM Asynchronous Transfer Mode OSPF Open Shortest Path FirstATU-C ADSL Termination Unit Central PAD Padding ATU-R ADSL Termination Unit - Remote PAP Password Authentication ProtocolBGP Border Gateway Protocol PAT Port Address Translation.BOM Begin of message PDH Plesiochronous Digital HierarchyCHAP Challenge Handshake Authentication Protocol PDU Protocol Data UnitCOM Continuation of Message POTS Plain Old Telephone ServiceCPI Common Part Indicator PPP Point to Point ProtocolCRC Cyclic Redundancy Check PT Payload TypeDMM Digital Multi-Meter PVC Permanent Virtual CircuitDSLAM Digital Subscriber Line Access Multiplexer RADSL Rate Adaptive Digital Subscriber LineEOM End of Message SAP Service Access PointFCS Frame Check Sequence SAR Segmentation and ReassemblyFEC Forward Error Correction SDH Synchronous Digital HierarchyFR Frame relay SDSL Symmetric Digital Subscriber LineFTP File Transfer Protocol SHDSL Symmetrical High Bit Digital subscriber LineHDSL High bit-rate Digital Subscriber Line SMTP Simple Mail Transfer ProtocolHEC Header Error Control SNMP Simple Network Management ProtocolHTTP Hypertext Transfer Protocol STF Start FieldICMP Internet Control Message Protocol TCP Transmission Control ProtocolIP Internet Protocol TDR Time Domain ReflectometerISDN Integrated Services Digital Network UDP Universal Datagram ProtocolISP Internet Service Provider UU User-to-User indicationL2TP Layer 2 Tunnelling Protocol VCI Virtual Channel IdentifierLCP Link Control Protocol VPI Virtual Path IdentifierLEX L9S) Extension byte; byte inserted in the
transmitted frame structure