WO2010063571A1 - Localisation method for bidirectional interruptions of communication links - Google Patents

Localisation method for bidirectional interruptions of communication links Download PDF

Info

Publication number
WO2010063571A1
WO2010063571A1 PCT/EP2009/065324 EP2009065324W WO2010063571A1 WO 2010063571 A1 WO2010063571 A1 WO 2010063571A1 EP 2009065324 W EP2009065324 W EP 2009065324W WO 2010063571 A1 WO2010063571 A1 WO 2010063571A1
Authority
WO
WIPO (PCT)
Prior art keywords
time
stamps
tsl
node
nodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2009/065324
Other languages
French (fr)
Inventor
Thomas Michaelis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Solutions and Networks Oy
Original Assignee
Nokia Siemens Networks Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nokia Siemens Networks Oy filed Critical Nokia Siemens Networks Oy
Publication of WO2010063571A1 publication Critical patent/WO2010063571A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/24—Testing correct operation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092—Error control systems characterised by the topology of the transmission link
    • H04L2001/0097—Relays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L43/00—Arrangements for monitoring or testing data switching networks
    • H04L43/10—Active monitoring, e.g. heartbeat, ping or trace-route
    • H04L43/106—Active monitoring, e.g. heartbeat, ping or trace-route using time related information in packets, e.g. by adding timestamps

Definitions

  • the invention refers to a localisation method for bidirectional interruptions of communication links between nodes in a communication network.
  • Communication networks comprise a plurality of nodes connected by links, e.g. optical fibers.
  • the links are often bidirectional operated, whereas signals are transmitted in both directions between adjacent nodes over one single or over two fibers in the same cable.
  • Opti- cal Time Domain Reflectometers for fiber networks, have to be employed at least at one node adjacent to the incident .
  • a lo- causation method for bidirectional interruptions of communi- cation links between nodes in a communication network comprising the steps of inserting time-stamps into the transmitted data, storing the last received time-stamp, supervising the connection and transmitting the last received time-stamps to a management system, and calculating the distance from a node to an interruption point according to the last received time-stamps transmitted from the nodes (Nl, N2) arranged on different sides of the inter- ruption point (P F ) .
  • This method allows a simple calculation of an interruption point and reduces the service expenses.
  • FIG 1 shows a simplified bloc diagram of a network link and FIG 2 shows a route-time diagram.
  • FIG 1 shows in a bloc diagram a section of a network with two adjacent nodes Nl, N2 connected by a bidirectional link FI.
  • Both nodes use the same exact timescale and the transmitters of both nodes inserts time-stamps TSl and TS2 respectively in the transmitted data signals, e.g. as digital information or any other defined metric.
  • time-stamps TSl and TS2 respectively in the transmitted data signals, e.g. as digital information or any other defined metric.
  • byte boundaries can be used for fragmentation of the received time marks.
  • the time synchronisation between the nodes could be realized by any synchronisation method exchanging information between the nodes or by special receivers for time signals, e.g. of the Global Positioning System.
  • the propagation time tg of transmitted signals between two nodes is measured or calculated. It can also be helpful to know the distance between the nodes.
  • Both nodes Nl, N2 - adjacent nodes or any two nodes of a network, e.g. end nodes, exchanging data signals - are transmit- ting information comprising said time-stamps. If the data between the nodes is transmitted in data frames the time-stamps may be inserted at a certain data frame position. If the information is e.g. transmitted byte-by-byte the time-stamps are inserted periodically. The time-stamps can even be in- serted in an alarm indication signal here also regarded as data signal.
  • the transmission of time-stamps is illustrated by continuous lines.
  • the transmission of a new time-stamp is represented by a new line.
  • the last received time stamps (or the time stamps of the last received complete data frames) are always stored.
  • the time-stamps TSl and TS2 shown in FIG 2 are the last received time-stamps before an interruption.
  • the link is bidirectional interrupted at a "failure time" tf (interruption time) .
  • the receivers of both nodes Nl, N2 notice the interruption and signal it along with the last received time-stamps TSl, TS2 to a management system for interruption localisation (each entity designed for failure lo- cation is here referred to as management system) .
  • the last received time-stamps (or an even exacter calculated last successful transmission time) represent the emission times tl and t2.
  • the distance X F to the failure point P F can be calculated according
  • Vg signal (group) velocity (calculated or measured) , tf - failure time.
  • the unknown failure time can be derived from
  • X F L(t2 - tl + tg) /2tg (5) with L - distance between the nodes Nl, N2 ;
  • discrete components causing an additional time delay can be considered by correction the time transmitted in the time-stamp and a more exact calculation of the interruption time is possible e.g. considering a time span between the last received time-stamp and the detected loss of signal, e.g. by counting the received bytes and transmitting a time span value together with the time-stamp to the management system.
  • time-stamps TSl, TS2 may be forward the time-stamps continuously to the management system or to transmit (additionally) the time-stamp of the last complete received data frame.
  • TSl, TS2 may be the time-stamps TSl, TS2 shown in FIG 2 when the interruption occurred after the complete frames have passed the interruption point otherwise foregoing time stamps.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Small-Scale Networks (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

Localisation method for bidirectional interruptions of communication links (FI) between nodes (N1, N2) in a communication network, comprising the steps of inserting time-stamps (TS1, TS2) into transmitted data signals, storing the last received time-stamp, supervising the connection and transmitting the last received time-stamps to a management system (MSY) and calculating the distance (XF) from a node (N1) to a failure point (PF) according to the last received time-stamps (TS1, TS2).

Description

LOCALISATION METHOD FOR BIDIRECTIONAL INTERRUPTIONS OF COMMUNICATION LINKS
FIELD OF THE INVENTION
The invention refers to a localisation method for bidirectional interruptions of communication links between nodes in a communication network.
BACKGROUND OF THE INVENTION
Communication networks comprise a plurality of nodes connected by links, e.g. optical fibers. The links are often bidirectional operated, whereas signals are transmitted in both directions between adjacent nodes over one single or over two fibers in the same cable.
Several protection methods like e.g. 1:1, 1+1 protection and rerouting methods are known to maintain connectivity if a link is interrupted.
Nevertheless the disrupted link has to be repaired, the exact position of the failure has to be located.
Nowadays, repair teams need to visit the adjacent nodes of the interrupted link. Special measurement devices, e.g. Opti- cal Time Domain Reflectometers (OTDR) for fiber networks, have to be employed at least at one node adjacent to the incident .
OBJECTS AND SUMMARY OF THE INVENTION
Therefore it is an object of the present invention to provide a method for quick failure localization.
According to the present invention, there is provided a lo- causation method for bidirectional interruptions of communi- cation links between nodes in a communication network comprising the steps of inserting time-stamps into the transmitted data, storing the last received time-stamp, supervising the connection and transmitting the last received time-stamps to a management system, and calculating the distance from a node to an interruption point according to the last received time-stamps transmitted from the nodes (Nl, N2) arranged on different sides of the inter- ruption point (PF) .
This method allows a simple calculation of an interruption point and reduces the service expenses.
Signalling and calculation can be executed by methods according to the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS Examples of the invention including a presently preferred embodiment are described below with reference to accompanying drawings, where
FIG 1 shows a simplified bloc diagram of a network link and FIG 2 shows a route-time diagram.
DETAILED DESCRIPTION OF THE INVENTION
FIG 1 shows in a bloc diagram a section of a network with two adjacent nodes Nl, N2 connected by a bidirectional link FI. Both nodes use the same exact timescale and the transmitters of both nodes inserts time-stamps TSl and TS2 respectively in the transmitted data signals, e.g. as digital information or any other defined metric. In addition e.g. byte boundaries can be used for fragmentation of the received time marks. The time synchronisation between the nodes could be realized by any synchronisation method exchanging information between the nodes or by special receivers for time signals, e.g. of the Global Positioning System.
The propagation time tg of transmitted signals between two nodes is measured or calculated. It can also be helpful to know the distance between the nodes.
The location method is now explained with reference to FIG 2. Both nodes Nl, N2 - adjacent nodes or any two nodes of a network, e.g. end nodes, exchanging data signals - are transmit- ting information comprising said time-stamps. If the data between the nodes is transmitted in data frames the time-stamps may be inserted at a certain data frame position. If the information is e.g. transmitted byte-by-byte the time-stamps are inserted periodically. The time-stamps can even be in- serted in an alarm indication signal here also regarded as data signal.
The transmission of time-stamps is illustrated by continuous lines. The transmission of a new time-stamp is represented by a new line. The last received time stamps (or the time stamps of the last received complete data frames) are always stored. The time-stamps TSl and TS2 shown in FIG 2 are the last received time-stamps before an interruption.
Now, the link is bidirectional interrupted at a "failure time" tf (interruption time) . The receivers of both nodes Nl, N2 notice the interruption and signal it along with the last received time-stamps TSl, TS2 to a management system for interruption localisation (each entity designed for failure lo- cation is here referred to as management system) . The last received time-stamps (or an even exacter calculated last successful transmission time) represent the emission times tl and t2. The distance XF to the failure point PF can be calculated according
XF = Vg (tf " tl) (1)
with Vg = signal (group) velocity (calculated or measured) , tf - failure time.
The unknown failure time can be derived from
(tf - tl) + (tf - t2) = tg (2)
with tf = (tg + tl + t2) /2 (3)
inserted in (1)
XF = Vg (t2 - tl + tg) /2 (4)
or avoiding vg
XF = L(t2 - tl + tg) /2tg (5) with L - distance between the nodes Nl, N2 ;
Of course, discrete components causing an additional time delay can be considered by correction the time transmitted in the time-stamp and a more exact calculation of the interruption time is possible e.g. considering a time span between the last received time-stamp and the detected loss of signal, e.g. by counting the received bytes and transmitting a time span value together with the time-stamp to the management system.
For supervising reasons it may be advantageously to forward the time-stamps continuously to the management system or to transmit (additionally) the time-stamp of the last complete received data frame. These may be the time-stamps TSl, TS2 shown in FIG 2 when the interruption occurred after the complete frames have passed the interruption point otherwise foregoing time stamps.
The present invention is not limited to the details of the above described principle. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalents of the scope of the claims are therefore to be embraced by the invention.
REFERENCE SIGNS
Nl, N2 nodes
FI link, fiber MSY management system
TSl, TS2 time stamps
PF interruption point
XF distance to the interruption point tF failure time tl emission time of TSl t2 emission time of TS2
L distance between adjacent nodes

Claims

1. Localisation method for bidirectional interruptions of communication links (FI) between two nodes Nl and N2 in a communication network, the two nodes Nl and N2 being located on different sides of an interruption point (PF) , the interruption point (PF) being located at a distance (XF) from the node Nl, the communication network comprising a management system (MSY) ; the method comprising the steps of
- inserting time-stamps (TSl, TS2) into transmitted data signals, the data signal including the time-stamps (TSl, TS2) being exchanged between the two nodes Nl and N2 in data frames and the time-stamps (TSl, TS2) being inserted at a certain data frame position,
- receiving the transmitted data signals and storing a last received time-stamp, the last received time stamp (TSl, TS2) being the time stamp of the last complete data frame received by each node (Nl, N2) before an interruption occurs, - transmitting the last received time-stamps (TSl, TS2) to the management system (MSY) when an interruption occurs, each node (Nl, N2) transmitting its last received time stamp (TSl, TS2) to the management system (MSY),
- calculating the distance (XF) from a node (Nl) to an inter- ruption point (PF) according to the last received time-stamps
(TSl, TS2) transmitted from the nodes (Nl, N2) .
2. Localisation method according to claim 1, further comprising the step of - calculating the distance (XF) from a node (Nl) to the interruption point according to XF = Vg (t2 - tl + tg) /2; with Vg - signal velocity; tg - propagation time from node to node; tl - time in which TSl has been transmitted; t2 - time in which TS2 has been transmitted.
3. Localisation method according to claim 1, further comprising the step of
- calculating the distance (XF) from a node (Nl) to the interruption point (PF) according to
XF = L(t2 - tl + tg) /2tg; with L distance between the adjacent nodes Nl, N2 ; tg - propagation time from node to node; tl - time in which TSl has been transmitted; t2 - time in which TS2 has been transmitted.
4. Localisation method according to claim 1, 2 or 3, further comprising the step of wherein
- the time-stamps (TSl, TS2) are inserted into the transmitted data signals of adjacent nodes.
5. Localisation method according to claim 1, 2 or 3, wherein
- the time-stamps (TSl, TS2) are inserted into the transmitted data signals of end nodes.
6. Localisation method according to one of the claims 1 - 4, wherein
- the time-stamps (TSl, TS2) are continuously transmitted to the management system.
PCT/EP2009/065324 2008-12-05 2009-11-17 Localisation method for bidirectional interruptions of communication links Ceased WO2010063571A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP08105941A EP2194670A1 (en) 2008-12-05 2008-12-05 Localisation method for bidirectional interruptions of communication links
EP08105941.2 2008-12-05

Publications (1)

Publication Number Publication Date
WO2010063571A1 true WO2010063571A1 (en) 2010-06-10

Family

ID=40671135

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/065324 Ceased WO2010063571A1 (en) 2008-12-05 2009-11-17 Localisation method for bidirectional interruptions of communication links

Country Status (2)

Country Link
EP (1) EP2194670A1 (en)
WO (1) WO2010063571A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104284351B (en) * 2013-07-04 2018-02-09 中国人民解放军信息工程大学 A kind of distance-finding method and device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS645147A (en) * 1987-06-29 1989-01-10 Nec Corp Location device for faulty point
US5991338A (en) * 1996-10-21 1999-11-23 Koninklijke Ptt Nederland N.V. Pinpointing interruptions
US20040225916A1 (en) * 2003-04-14 2004-11-11 Clark Alan D. System for identifying and locating network problems
US20060029016A1 (en) * 2004-06-29 2006-02-09 Radware Limited Debugging application performance over a network
US20070076622A1 (en) * 2005-09-30 2007-04-05 Mukherjee Shubhendu S Handling hot spots in interconnection networks
US20070274712A1 (en) * 2005-12-08 2007-11-29 Ralph Leppla Method for detecting and localizing faults in an optical transmission path, and optical transmission system
US20080232795A1 (en) * 2007-03-21 2008-09-25 Adva Ag Optical Networking Method And System For Localizing An Attenuation Change Location In An Optical Waveguide

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS645147A (en) * 1987-06-29 1989-01-10 Nec Corp Location device for faulty point
US5991338A (en) * 1996-10-21 1999-11-23 Koninklijke Ptt Nederland N.V. Pinpointing interruptions
US20040225916A1 (en) * 2003-04-14 2004-11-11 Clark Alan D. System for identifying and locating network problems
US20060029016A1 (en) * 2004-06-29 2006-02-09 Radware Limited Debugging application performance over a network
US20070076622A1 (en) * 2005-09-30 2007-04-05 Mukherjee Shubhendu S Handling hot spots in interconnection networks
US20070274712A1 (en) * 2005-12-08 2007-11-29 Ralph Leppla Method for detecting and localizing faults in an optical transmission path, and optical transmission system
US20080232795A1 (en) * 2007-03-21 2008-09-25 Adva Ag Optical Networking Method And System For Localizing An Attenuation Change Location In An Optical Waveguide

Also Published As

Publication number Publication date
EP2194670A1 (en) 2010-06-09

Similar Documents

Publication Publication Date Title
JP5671619B2 (en) Method for correcting delay asymmetry
US9264213B2 (en) Time synchronization method for communication system, slave station apparatus, master station apparatus, control device, and program
US9178755B2 (en) Time-based link fault localization
US9680567B2 (en) Fault localization and fiber security in optical transponders
CN103155450B (en) Method and device for determining asymmetry in a communication network
CN104797947A (en) Sequence-based link fault localization
US9813175B2 (en) Method for detecting timing references affected by a change in path delay asymmetry between nodes in a communication network
EP3577799A1 (en) Optical fibre event location
CN103168440B (en) Time path compensation method and device
CN113381804A (en) Method and device for detecting co-cable probability
KR102132491B1 (en) Fast protection switching method for Passive Optical Network
US20090028553A1 (en) Method and apparatus of detecting abnormal behavior in a passive optical network (PON)
US20120219283A1 (en) System And Method For Identifying A Length Of An Installed Fiber Cable
CN101635610A (en) Optical communications system without using a special-purpose evaluation signal
CN103684580B (en) The method of Remote Radio Unit and reporting links fault thereof, wireless communication system
CN105187275A (en) Method and device for measuring optical fiber transmission link asymmetric time delay
US20110280567A1 (en) Identifying fault locations in a network
CN106411401A (en) Industrial Ethernet switch with optical power detection
CN101540936A (en) Station terminal device, communication system, subscriber device management method
CN102546009B (en) Optical fiber symmetry detecting method and device
EP2194670A1 (en) Localisation method for bidirectional interruptions of communication links
WO2016045516A1 (en) Method and apparatus for measuring length of optical fiber
CN112534746B (en) Monitoring device and monitoring method
CN109981166B (en) Method and device for positioning optical fiber in error connection
EP3177030A1 (en) Connection qualified link pass through applicable to media converters

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09751943

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09751943

Country of ref document: EP

Kind code of ref document: A1