GB2300789A - Transmission time measurement in data networks - Google Patents
Transmission time measurement in data networks Download PDFInfo
- Publication number
- GB2300789A GB2300789A GB9509656A GB9509656A GB2300789A GB 2300789 A GB2300789 A GB 2300789A GB 9509656 A GB9509656 A GB 9509656A GB 9509656 A GB9509656 A GB 9509656A GB 2300789 A GB2300789 A GB 2300789A
- Authority
- GB
- United Kingdom
- Prior art keywords
- time
- location
- cell
- data
- transmitting
- 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.)
- Granted
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0478—Provisions for broadband connections
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0644—External master-clock
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0658—Clock or time synchronisation among packet nodes
- H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
- H04J3/0664—Clock or time synchronisation among packet nodes using timestamps unidirectional timestamps
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5603—Access techniques
- H04L2012/5604—Medium of transmission, e.g. fibre, cable, radio
- H04L2012/5608—Satellite
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5638—Services, e.g. multimedia, GOS, QOS
- H04L2012/5646—Cell characteristics, e.g. loss, delay, jitter, sequence integrity
- H04L2012/5649—Cell delay or jitter
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
Abstract
A data network comprises a first and a second location, transmitting means at the first location for transmitting a data item including a time-stamp corresponding to the time of transmission of the item and receiving means at the second location for receiving the data item, for reading the time-stamp and for calculating therefrom and from the current time the time elapsed between transmission and receipt of the data item, characterised in that each location comprises a Global Positioning System receiver 12 for providing a synchronised time signal to the transmitting or receiving means. The invention also provides a method of measuring data transit time between two locations in a data network particularly an ATM network.
Description
DATA NETWORK
Field of the Invention
This invention relates to a data network, and in particular to a data network including means for determining the time taken by a data item to travel between two points in the network. The invention is especially, but not exclusively, applicable to Asynchronous Transfer Mode (ATM) networks.
Background to the Invention
A critical quality of service parameter for ATM networks is the Cell Transit
Delay (CTD) and its associated Cell transit Delay Variation (CDV). Unfortunately, it is extremely difficult to measure these parameters in real ATM networks, as measurement requires synchronised clocks at the points between which the cell
CTD is to be measured, and these points will typically be geographically widely separated.
One solution which has been proposed for this problem is to send a cell from the measurement point and to loop it back from the end point to the measurement point again. The original cell contains a time-stamp indicating the time at which the cell was transmitted so that, when the cell is received again, the timestamp can be subtracted from the current time. This gives the Round Trip Time (RTT) for the path at that particular moment. The problem is that the RTT is not the same as the CTD. If the traffic were symmetrical in each direction of transfer between the two measurement points, and with equal congestion levels, the CTD could be obtained from the RTT simply by dividing by 2. In reality, the traffic is not normally symmetrical and congestion levels are not the same in both directions at any given time.
Summary of the Invention
According to the invention, there is provided a data network comprising a first and a second location, transmitting means at the first location for transmitting a data item including a time-stamp corresponding to the time of transmission of the item and receiving means at the second location for receiving the data item, for reading the time-stamp and for calculating therefrom and from the current time the time elapsed between transmission and receipt of the data item, characterised in that each location comprises a Global Positioning System receiver for providing a synchronised time signal to the transmitting or receiving means.
The data network is preferably an ATM network, the first and second locations each comprising a data switch, for example of the type disclosed and claimed in our earlier UK Patent Applications Nos 9225480.4, 9321165.4 and 9505358.3.
Preferably both locations include the transmitting and receiving means to permit the time interval to be measured in either direction.
The invention also provides a method of measuring data transit time between two locations in a data network, comprising:
determining at a first of the locations an absolute time by means of a
Global Positioning System receiver;
generating at the first location a performance measuring data item including a time stamp corresponding to said absolute time;
transmitting the data item to the second location;
receiving the data item at the second location and reading therefrom the time stamp;
determining at the second location by means of another Global Positioning
System receiver an absolute time value for the arrival of the data item; and
subtracting the time stamp from the arrival time to give a transit time for the data item between the two locations.
The Global Positioning System (GPS) is a system using a plurality of satellites circling the earth, the receivers being arranged to receive transmissions from several of the satellites at the same time to determine their locations in three di- mensions and also to determine very accurately the GPS time which has a fixed relationship to UTC (Universal Time Coordinated). Each receiver requires an aerial or antenna with a clear view of the sky. In order to provide an accurate time, the
GPS requires that four satellites must be visible to a receiver. The numbers are such that, normally, at least four satellites will be visible to any receiver.Although the network of the invention uses the GPS to give an accurately synchronised time for the determination of data transit times across the network, the ability of the
GPS receiver to give an accurately-determined location for the receiver means that any of the locations could use this data to create a network diagram, for example.
GPS receivers, for example the receiver sold under the trade mark Oncore by Motorola Inc., are arranged to output a one pulse per second time signal with a pulse leading-edge accuracy of 130ns, in addition to a time-of-day output and the location data. The former two outputs are used in the network of the invention to provide clocks at network nodes remote from each other sufficiently accurately synchronised to permit accurate measurement of the CTD and CDV in an ATM network, for example.
The system of the invention allows accurate measurements of CTD in
ATM networks using standard Performance Management cells. User cells are not affected by these measurements, so they can be carried out on a routine basis in normal operation.
Brief Description of the Drawings
In the drawings, which illustrate diagrammatically part of an ATM network in accordance with an exemplary embodiment of the invention:
Figure 1 illustrates two ATM network switches between which CTD and
CDV are to be measured;
Figure 2 represents the system controller (SYSCON) in one of the switches;
Figure 3 represents the time register forming part of the SYSCON shown in
Figure 2;
Figure 4 illustrates in more detail one of the network switches of Figure 1; and
Figure 5 illustrates one of the slot controllers from the network switch of
Figure 4.
Detailed Description of the Illustrated Embodiment
Referring to Figure 1, the two switches 10 form parts of a more extensive
ATM network, with the network data links between the switches being represented by the arrowed line 11. Each switch is provided with a GPS receiver 12, for example of the type sold by Motorola Inc under the trade mark Oncore. Each receiver 12 is linked to its respective switch 10 by means of an RS-232 serial link 13, the switch being provided with a UART-based interface as hereinafter described with reference to Figure 2. Each GPS receiver 12 has its own antenna 14 located in such a position as to have a clear "view" of the sky.
Figure 2 shows the system controller or SYSCON 20 in one of the switches 10. The SYSCON 20 includes the RS-232 interface 21 to which the serial link 13 is connected. The interface 21 passes to a time register 22 the time data from the
GPS receiver, together with a 1 PPS (1 Pulse Per Second) signal also output by the receiver. The time register 22 has a 625 kHz input derived from an accurate 10
MHz oscillator 23 in the SYSCON 20 via a divide by sixteen counter 24. The operation of the time register is described further with reference to Figure 3, but its output is an accurate time distributed by output means 25 to all the slot controllers in the switch every four cell internal times t2.56ys).
Figure 3 shows the format of the time register. This is a 58-bit register that contains the time and date obtained from the GPS receiver, and a running count.
The least significant 20 bits are the outputs of a free-running counter being clocked at a very accurate 625kHz, derived as hereinbefore described. The 10MHz oscillator used gives an accuracy or +/- 4.6 ppm, which determines the accuracy of the
CTD measurements that are obtained. The free-running counter is reset by the rising edge of the 1 PPS signal. The counter is arranged so that it can be forced to all is if the GPS receiver is not operating.
The next 6 bits consist of a modulo 60 time measurement seconds register.
This is set by software every second to reflect the seconds value obtained from the
GPS receiver. It is also incremented by the 1 PPS rising edge. This guarantees that the counter is incremented as the running counter is reset and that the value of the counter is correct. This counter can also be forced to all ls if the GPS receiver is not operating. The remaining 32 bits contain the remainder of the time and date. 6 bits are used for the minutes, 5 bits are used for the hours (H), 5 bits are used for the days (D), 4 bits are used for the months (M), and 12 bits are used for the year (C & Y). These 32 bits are loaded by the software every second to ensure that they are correct.
Figure 4 shows in simple form a typical ATM switch 10 having a switch fabric, for example in the form of a crosspoint structure 40, with sixteen slot controllers 41 linked thereto, each with an input and an output connection to the switch fabric 40 and with an input and output connection to an external data link, for example to another such switch at a location remote therefrom. The SYSCON 20 is linked to all the slot controllers 41, for example by an Ethernet control network 42 within the switch, and transmits the 58-bit time information every 4 cell internal cell times, as hereinbefore described. As may be seen from Figure 5, each slot controller 41 comprises an OAM (Operations And Management) controller 50 to generate special Performance Management (PM) cells for use in the monitoring of network performance.Under ATM Forum specifications, such cells have an optional 32-bit Time Stamp (TS) field, and the OAM controller 50 transfers the least significant 32 bits of the 58-bit absolute time value transmitted by the SYSCON 20 to this TS field. These 32 bits contain the free-running counter value, the seconds and the minutes. The slot controller comprises cell transmitting control means 51 and cell receiving control means 52, connected respectively to the output 53 and input 54 lines of the external data link to the slot controller.
In use, under control of a network management system, the OAM controller 50 adds the current time value to the TS filed of a PM cell, and this is then sent by the transmitting control means 51 over the network to the destination switch, in which a similarly-configured slot controller receives the PM cell on its input line 54, and the receiving control means 52 passes the cell to the OAM controller 50, where the TS value in the cell is read out and subtracted from the current time value to give an absolute time difference. This difference value is then passed via line 55 to the network management system, the figure either being used locally or being transmitted back to the source switch for use there.
The basic time accuracy of the 1 PPS output of the GPS receiver is 130ns.
However, the error in the measurement system is up to 11.76us. This comes from the 4.6ppm error in the oscillators at each end causing a total of 9.2us error in the one second free running counter period plus the worst-case error caused by the fact that the absolute time is only sent to the slot controllers once every four internal cell times (2.56us). However, since the minimum delay through an ATM switch is generally more than this, the system of the invention is accurate enough to detect the number of switches in a path (in the worst case where they are lightly loaded).
This is the maximum accuracy needed for CTD measurements.
Claims (5)
1. A data network comprising a first and a second location, transmitting means at the first location for transmitting a data item including a time-stamp corresponding to the time of transmission of the item and receiving means at the second location for receiving the data item, for reading the time-stamp and for calculating therefrom and from the current time the time elapsed between transmission and receipt of the data item, characterised in that each location comprises a
Global Positioning System receiver for providing a synchronised time signal to the transmitting or receiving means.
2. A data network according to Claim 1, which is an Asynchronous
Transfer Mode (ATM) network and the data item is an ATM cell.
3. A data network according to Claim 1 or 2, wherein both locations include the transmitting and receiving means to permit the time interval to be measured in either direction.
4. A data network, substantially as described with reference to, or as shown in, the drawings.
5. A method of measuring data transit time between two locations in an
ATM data network, substantially as described with reference to the drawings.
5. A method of measuring data transit time between two locations in a data network, comprising:
determining at a first of the locations an absolute time by means of a Global
Positioning System receiver;
generating at the first location a performance measuring data item including a time stamp corresponding to said absolute time;
transmitting the data item to the second location;
receiving the data item at the second location and reading therefrom the time stamp;
determining at the second location by means of another Global Positioning
System receiver an absolute time value for the arrival of the data item; and
subtracting the time stamp from the arrival time to give a transit time for the data item between the two locations.
6. A method according to Claim 6, wherein the data network is an
ATM network and the data item is an ATM cell.
7. A method of measuring data transit time between two locations in a data network, substantially as described with reference to the drawings.
Amended claims have been filed as follows
1. An ATM data network comprising a first and a second location, transmitting means at the first location for transmitting an ATM cell including a timestamp corresponding'to the time of transmission of the cell and receiving means at the second location for receiving the cell, for reading the time-stamp and for calculating therefrom and from the current time the time elapsed between transmission and receipt of the cell, characterised in that each location comprises a Global Positioning
System receiver for providing a synchronised time signal to the transmitting or receiving means.
2. An ATM data network according to Claim 1, wherein both locations include the transmitting and receiving means to permit the time interval to be measured in either direction.
3. An ATM data network, substantially as described with reference to, or as shown in, the drawings.
4. A method of measuring Cell Transmit Delay between two locations in an ATM data network, comprising:
determining at a first of the locations an absolute time by means of a Global
Positioning System receiver;
generating at the first location a performance measuring ATM cell including a time stamp corresponding to said absolute time;
transmitting the cell to the second localion;
receiving the cell at the second location and reading therefrom the time stamp;
determining at the second location by means of another Global Positioning
System receiver an absolute time value for the arrival of the cell; and
subtracting the time stamp from the arrival time to give a Cell Transmit Delay for the cell between the two locations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9509656A GB2300789B (en) | 1995-05-12 | 1995-05-12 | Data network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9509656A GB2300789B (en) | 1995-05-12 | 1995-05-12 | Data network |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9509656D0 GB9509656D0 (en) | 1995-07-05 |
| GB2300789A true GB2300789A (en) | 1996-11-13 |
| GB2300789B GB2300789B (en) | 2000-04-05 |
Family
ID=10774382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9509656A Expired - Fee Related GB2300789B (en) | 1995-05-12 | 1995-05-12 | Data network |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2300789B (en) |
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998013969A1 (en) * | 1996-09-16 | 1998-04-02 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for synchronization of time stamping |
| WO1999033207A1 (en) * | 1997-12-19 | 1999-07-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Synchronization for cellular telecommunications network |
| WO2002025821A2 (en) * | 2000-09-19 | 2002-03-28 | Deutsche Telekom Ag | Method for measuring unidirectional transmission characteristics in a data network |
| WO2002073850A2 (en) * | 2001-03-09 | 2002-09-19 | Thomson Licensing S.A. | Jitter prevention in a digital communication network |
| US6512761B1 (en) * | 1999-02-02 | 2003-01-28 | 3Com Corporation | System for adjusting billing for real-time media transmissions based on delay |
| US6577872B1 (en) | 2000-08-08 | 2003-06-10 | Telefonaktiebolaget Lm Ericsson (Publ) | Base station oscillator regulation independent of transport network clocks in cellular telecommunications network |
| GB2388264A (en) * | 2002-01-10 | 2003-11-05 | Roke Manor Research | GPS based networked time synchronised unit |
| EP1485780A2 (en) * | 2002-03-12 | 2004-12-15 | Deutsche Telekom AG | Method for temporal synchronisation of at least two measuring computers cooperating over a telecommunication network such as internet, intranet or similar |
| GB2426164A (en) * | 2005-05-12 | 2006-11-15 | Agilent Technologies Inc | Network time synchronisation using a determination of network element transit times |
| US7492720B2 (en) | 1998-11-24 | 2009-02-17 | Niksun, Inc. | Apparatus and method for collecting and analyzing communications data |
| US7512158B2 (en) | 2001-03-21 | 2009-03-31 | Thomson Licensing | Jitter prevention in a digital communication network |
| US7570630B1 (en) | 2004-08-02 | 2009-08-04 | Sprint Spectrum L.P. | Dialed-digit based determination of whether to originate a call as a circuit-switched call or a packet-switched call |
| US8275875B2 (en) | 2000-05-12 | 2012-09-25 | Niksun, Inc. | Security camera for a network |
| DE10128927B4 (en) * | 2001-06-15 | 2013-10-17 | Deutsche Telekom Ag | Method for determining the time in at least two interacting measuring computers |
| US8938062B2 (en) | 1995-12-11 | 2015-01-20 | Comcast Ip Holdings I, Llc | Method for accessing service resource items that are for use in a telecommunications system |
| US9191505B2 (en) | 2009-05-28 | 2015-11-17 | Comcast Cable Communications, Llc | Stateful home phone service |
| US9341716B2 (en) | 2001-02-05 | 2016-05-17 | Nokia Technologies Oy | Method, apparatus and system for GPS time synchronization using cellular signal bursts |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995005039A1 (en) * | 1993-08-11 | 1995-02-16 | Glenayre Electronics, Inc. | Method and apparatus for coordinating clocks in a simulcast network |
-
1995
- 1995-05-12 GB GB9509656A patent/GB2300789B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995005039A1 (en) * | 1993-08-11 | 1995-02-16 | Glenayre Electronics, Inc. | Method and apparatus for coordinating clocks in a simulcast network |
Cited By (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8938062B2 (en) | 1995-12-11 | 2015-01-20 | Comcast Ip Holdings I, Llc | Method for accessing service resource items that are for use in a telecommunications system |
| US6104729A (en) * | 1996-09-16 | 2000-08-15 | Telefonaktiebolaget Lm Ericsson | Method and apparatus for synchronization of time stamping |
| WO1998013969A1 (en) * | 1996-09-16 | 1998-04-02 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for synchronization of time stamping |
| WO1999033207A1 (en) * | 1997-12-19 | 1999-07-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Synchronization for cellular telecommunications network |
| US6373834B1 (en) | 1997-12-19 | 2002-04-16 | Telefonaktiebolaget Lm Ericsson | Synchronization for cellular telecommunications network |
| US7492720B2 (en) | 1998-11-24 | 2009-02-17 | Niksun, Inc. | Apparatus and method for collecting and analyzing communications data |
| US8873410B2 (en) | 1998-11-24 | 2014-10-28 | Niksun, Inc. | Apparatus and method for collecting and analyzing communications data |
| US8102782B2 (en) | 1998-11-24 | 2012-01-24 | Niksun, Inc. | Apparatus and method for collecting and analyzing communications data |
| US6512761B1 (en) * | 1999-02-02 | 2003-01-28 | 3Com Corporation | System for adjusting billing for real-time media transmissions based on delay |
| US8275875B2 (en) | 2000-05-12 | 2012-09-25 | Niksun, Inc. | Security camera for a network |
| US6577872B1 (en) | 2000-08-08 | 2003-06-10 | Telefonaktiebolaget Lm Ericsson (Publ) | Base station oscillator regulation independent of transport network clocks in cellular telecommunications network |
| WO2002025821A3 (en) * | 2000-09-19 | 2003-10-30 | Deutsche Telekom Ag | Method for measuring unidirectional transmission characteristics in a data network |
| DE10046240A1 (en) * | 2000-09-19 | 2002-03-28 | Deutsche Telekom Ag | Method for measuring the unidirectional transmission properties such as packet transmission time and transmission time fluctuations in a telecommunication network |
| WO2002025821A2 (en) * | 2000-09-19 | 2002-03-28 | Deutsche Telekom Ag | Method for measuring unidirectional transmission characteristics in a data network |
| US8160835B2 (en) | 2000-09-19 | 2012-04-17 | Deutsche Telekom Ag | Method for measuring unidirectional transmission characteristics such as packet propagation time, fluctuations in propagation time and results derivable therefrom, in a telecommunications network |
| US9341716B2 (en) | 2001-02-05 | 2016-05-17 | Nokia Technologies Oy | Method, apparatus and system for GPS time synchronization using cellular signal bursts |
| CN1319297C (en) * | 2001-03-09 | 2007-05-30 | 汤姆森许可公司 | Jitter prevention in digital communication network |
| WO2002073850A3 (en) * | 2001-03-09 | 2003-04-24 | Thomson Licensing Sa | Jitter prevention in a digital communication network |
| WO2002073850A2 (en) * | 2001-03-09 | 2002-09-19 | Thomson Licensing S.A. | Jitter prevention in a digital communication network |
| US7512158B2 (en) | 2001-03-21 | 2009-03-31 | Thomson Licensing | Jitter prevention in a digital communication network |
| DE10128927B4 (en) * | 2001-06-15 | 2013-10-17 | Deutsche Telekom Ag | Method for determining the time in at least two interacting measuring computers |
| GB2388264A (en) * | 2002-01-10 | 2003-11-05 | Roke Manor Research | GPS based networked time synchronised unit |
| EP1485780A2 (en) * | 2002-03-12 | 2004-12-15 | Deutsche Telekom AG | Method for temporal synchronisation of at least two measuring computers cooperating over a telecommunication network such as internet, intranet or similar |
| US7570630B1 (en) | 2004-08-02 | 2009-08-04 | Sprint Spectrum L.P. | Dialed-digit based determination of whether to originate a call as a circuit-switched call or a packet-switched call |
| JP2006319972A (en) * | 2005-05-12 | 2006-11-24 | Agilent Technol Inc | System and method for synchronizing time across networks |
| GB2426164B (en) * | 2005-05-12 | 2010-05-26 | Agilent Technologies Inc | Systems and methods for synchronizing time across networks |
| US7573914B2 (en) | 2005-05-12 | 2009-08-11 | Agilent Technologies, Inc. | Systems and methods for synchronizing time across networks |
| GB2426164A (en) * | 2005-05-12 | 2006-11-15 | Agilent Technologies Inc | Network time synchronisation using a determination of network element transit times |
| US9191505B2 (en) | 2009-05-28 | 2015-11-17 | Comcast Cable Communications, Llc | Stateful home phone service |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2300789B (en) | 2000-04-05 |
| GB9509656D0 (en) | 1995-07-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20110512 |