Title of Invention	A METHOD AND APPARATUS TO PROVIDE PROTECTION TO EQUIVALENT PAYLOAD BANDWIDTH
Abstract	The present invention relates to a method of providing protection through dissimilar communication links provided those links carry equivalent payload and bandwidth. This is useful in being able to use old legacy equipments along with newer technology network deployment. The protection here means protecting one link with another to provide high service availability to the client signal by transmitting the signal through two separate links and choosing receive of the signal through better link. Figure 4

Title of Invention

A METHOD AND APPARATUS TO PROVIDE PROTECTION TO EQUIVALENT PAYLOAD BANDWIDTH

Abstract

The present invention relates to a method of providing protection through dissimilar communication links provided those links carry equivalent payload and bandwidth. This is useful in being able to use old legacy equipments along with newer technology network deployment. The protection here means protecting one link with another to provide high service availability to the client signal by transmitting the signal through two separate links and choosing receive of the signal through better link. Figure 4

Full Text	FIELD OF THE INVENTION The present invention relates to a method and apparatus for offering protection to equivalent payload bandwidth irrespective of the physical media or multiplexing structure in which such payload is carried. BACKGROUND OF THE INVENTION In SONET/SDH networks, typically path protection is defined/considered for paths (AU/TU) on optical (STM-N/OC-N) ports only, the reason primarily being that that is what is likely to fail/get cut most of the time. The figure 1 depicts the classical model of deployment of SONET/SDH ADM products for the wireless backhaul where fiber connectivity is available. The traffic is normally carried through the working STM-N optical link. If there is any failure along the working link, traffic is carried along the protect link. PDH (e.g. E1/DS1/E3/DS3/E4) and Ethernet ports are typically within the room or a building and therefore not considered useful to include in protection framework. However, there are applications where PDH ports can be used as protecting channel in some applications. OBJECTS OF THE INVENTION The primary object of the present invention is to offer protection to equivalent bandwidth irrespective of the physical media or multiplexing structure. Yet another object of the instant invention is to provide a method which enables the protection in which working and protecting port types are decoupled. STATEMENT OF THE INVENTION Accordingly, the present invention provides for a method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link, and provides for an apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises transmitter for transmitting client signal; plurality of dissimilar communication links to carry the transmitted signal; and receiver with receive protection logic for receiving the signal and to monitor failure and/or degradation of the received signal. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS The features described in this disclosure are set forth with particularity in the appended claims. These features and attendant advantages will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings and in which: Figure 1 shows classical model of deployment of SONET/SDH ADM products for the wireless backhaul where fiber connectivity is available. Figure 2 shows mobile backhaul network having BTS to BSC/MSC primary connectivity through fiber-optic cable based STM-N link and backup (protecting) link through legacy microwave links which is 2 Mbps El rate or multiple of them. Figure 3 shows typical BSC/MSC/BTS station connectivity using protected micro-wave link where use of a transport device (typically a STM-N multiplexer without optical ports) helps save ports on the BSC/MSC/BTS. Figure 4 diagrammatically illustrates the mechanism implementing 1+1 protection scheme for equivalent payload bandwidth. DETAILED DESCRIPTION OF THE INVENTION The primary embodiment of the present invention is a method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link. In yet another embodiment of the present invention the protection means protecting one link with another to provide high service availability to the client signal. In still another embodiment of the present invention the transmit signal at one end is bridged to working as well as protection path and said signals are monitored at other end for failure and/or degradation. In still another embodiment of the present invention the signal failure and/or degradation criteria for PDH ports are line and/or path alarms and performance counter thresholds depending on the application. In still another embodiment of the present invention the method enables the protection in which working and protecting port types are decoupled. In still another embodiment of the present invention the ports or paths objects representing equivalent bandwidth acts as working and/or protect entities with no restrictions. In still another embodiment of the present invention the method is applicable to all combinations that the working and the protecting entities are paired without any restrictions is selected from a group comprising a) VC12 and VC12, VC12 and El, El and VC12, El and El; b) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1; c) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3; d) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3; and e) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4. In still another embodiment of the present invention the dissimilar link is that the communication link or medium of working and protecting path is different from each other. Another important embodiment of the present invention is an Apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises transmitter for transmitting client signal; plurality of dissimilar communication links to carry the transmitted signal; and receiver with receive protection logic for receiving the signal and to monitor failure and/or degradation of the received signal. The instant disclosure describes a method of providing protection through dissimilar communication links provided those links carry equivalent payload and bandwidth. This is useful in being able to use old legacy equipments along with newer technology network deployment. The protection here means protecting one link with another to provide high service availability to the client signal by transmitting the signal through two separate links and choosing receive of the signal through better link. As described above in the background of the invention, the known prior arts and classical models make use of similar links in transmitting the signal. Well established 1+1 SNCP/UPSR used for protection in SONET/SDH equipment lacks in addressing the application scenario as explained below. The description provides examples of El as one type of PDH link, but it is applicable to other cases equally i.e. DS1, E3/DS3/E4 etc. 1. Mobile backhaul network may have BTS to BSC connectivity through legacy microwave links (2 Mbps). While operators migrate to use SONET/SDH optical backhaul they may want to use the microwave link as protecting channel to make the best use of the investment they may have made earlier. In the model as depicted in figure 2, the El traffic is normally carried over the working path which is through the El carried inside TU12 over the STM-N optical fiber. For the protect path, traffic is carried over Els which are transported through microwave medium. The operator had micro-wave backhaul to start with and later on, they had fiber access though the fiber access is not fully available for the protect path. 2. Typical BSC/MSC station may have some number (say x) of El ports. They need to burn 2 ports if they wish to have protected Microwave link between BTS and BSC for every 2 Mbps worth of backhaul. This effectively reduces the number of ports on BSC to half the physical ports. This is shown in figure 3. Typically, the cost of each El port in BTS or BSC is typically much higher than the cost of equivalent port in SONET/SDH transport ADM equipment. This is primarily due to the complexity of hardware/software logic in a BTS/BSC as compared to that of SONET/SDH equipment. The proposal here is to save the port usage on BTS/BSC which protection being made possible through the use of SONET/SDH equipment. Traffic from the BSC uses only a single El port. The co-located SONET/SDH equipment bridges the traffic to two E1s which feeds the microwave transmitter. At the other end at BTS, the better quality (in terms on low error rate) El is chosen from the microwave receiver and provided to the BTS. Traffic in the other direction i.e. from BTS to BSC is handled exactly in the same way. Therefore, it is necessitate developing a generalized scheme which provides the solution for aforementioned limitation. The present invention makes an effort in addressing the limitations as described above. The solution is to have a generalized protection scheme which is 1+1 protection on the lines similar to 1+1 SNCP/UPSR. The figure 4 visualizes the description of the mechanism implementing 1+1 protection. In 1+1 protection scheme, the transmit signal at one end is bridged to the working as well as the protection path. The exact mechanism for bridging the signal typically depends on the architecture of the product, but one of the ways is to map the El signal into TU-12 container and bi-cast it through the use of TDM cross connect fabric. When the bridged TU-12 is to be transmitted over the STM-N link, it is multiplexed into STM-N signal according to the SONET/SDH multiplexing structure. When the bridged TU-12 is to be sent over the microwave link, El is demapped from the TU12 on the egress card and transmitted as PDH El signal. Both these signals are carried to the other end-points through a series of equipments (kindly mention the equipments that are used). The other end monitors the two receive signals for failures and/or degradation. The receive 1+1 protection logic chooses the better of the two copies of the signal e.g. 1. If one copy is good and other copy is degraded or failed, good copy is chosen. 2. If one copy is degraded and another copy is failed, the degraded copy is selected. Traditionally, only E1s carried in VC12 inside STM-N optical ports are considered as candidates for working/protection path pair. The change is to have protection scheme where working and protecting port types are decoupled. What really matters is that ports/paths objects representing equivalent BW act as working/protect entities with no restrictions e.g. VC12 and El, VC11 and DS1, VC3 and E3/DS3. The capability provides for all the following options where working are protecting entities are paired without any restrictions. a) VC12 and VC12, VC12 and El, El and VC12, El and El. b) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1. c) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3. d) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3. e) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4. For PDH signals carries inside optical ports, the signal fail criteria are LOS/LOF/MS-AIS at Section and Line layers, LOP/AIS/UNEQ at higher order path layer and LOP/AIS/UNEQ at lower order path layers. The signal degradation criteria are typically threshold-crossing error based on monitoring performed using B2 counts at Line, B3 counts at higher order path and BIP-2 counts at lower order path layer. For the PDH ports, the failure and degradation triggers can be line and/or path alarms and performance counter thresholds depending on the application e.g. in case of El used as either working or protect channel, LOS/AIS/LOF/LOM and high CRC/LCV error (say 10e-3 to 10e-5) rate can be treated as SF (Signal Fail) trigger. Lower CRC/LCV error (say 10e-6 to 10e-8) can be used to deduce SD (Signal Degrade) trigger. Poor weather or something similar might result in path failure/degradation for the El. Power failure or some other failure of the microwave equipment or poor wiring might result in Line failure/degradation for the El. We Claim: 1. A method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link. 2. The method as claimed in claim 1, wherein the protection means protecting one link with another to provide high service availability to the client signal. 3. The method as claimed in claim 1, wherein the transmit signal at one end is bridged to working as well as protection path and said signals are monitored at other end for failure and/or degradation. 4. The method as claimed in claim 3, wherein the signal failure and/or degradation criteria for PDH ports are line and/or path alarms and performance counter thresholds depending on the application. 5. The method as claimed in claim 1, wherein the method enables the protection in which working and protecting port types are decoupled. 6. The method as claimed in claim 6, wherein the ports or paths objects representing equivalent bandwidth acts as working and/or protect entities with no restrictions. 7. The method as claimed in claims 1 and 7, wherein the method is applicable to all combinations that the working and the protecting entities are paired without any restrictions is selected from a group comprising f) VC12 and VC12, VC12 and El, El and VC12, El and El; g) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1; h) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3; i) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3; and j) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4. 8. The method as claimed in claim 1, wherein the dissimilar link is that the communication link or medium of working and protecting path is different from each other. 9. An Apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises i. transmitter for transmitting client signal; ii. plurality of dissimilar communication links to carry the transmitted signal; and iii. receiver with receive protection logic for receiving the signal and to monitor failure and/or degradation of the received signal. 10. A method and an apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure.

Full Text

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for offering protection to equivalent payload bandwidth irrespective of the physical media or multiplexing structure in which such payload is carried.

BACKGROUND OF THE INVENTION

In SONET/SDH networks, typically path protection is defined/considered for paths (AU/TU) on optical (STM-N/OC-N) ports only, the reason primarily being that that is what is likely to fail/get cut most of the time. The figure 1 depicts the classical model of deployment of SONET/SDH ADM products for the wireless backhaul where fiber connectivity is available. The traffic is normally carried through the working STM-N optical link. If there is any failure along the working link, traffic is carried along the protect link. PDH (e.g. E1/DS1/E3/DS3/E4) and Ethernet ports are typically within the room or a building and therefore not considered useful to include in protection framework. However, there are applications where PDH ports can be used as protecting channel in some applications.

OBJECTS OF THE INVENTION

The primary object of the present invention is to offer protection to equivalent bandwidth irrespective of the physical media or multiplexing structure.

Yet another object of the instant invention is to provide a method which enables the protection in which working and protecting port types are decoupled.

STATEMENT OF THE INVENTION

Accordingly, the present invention provides for a method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link, and provides for an apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises transmitter for transmitting client signal; plurality of dissimilar communication links to carry the transmitted signal; and receiver with receive protection logic for receiving the signal and to monitor failure and/or degradation of the received signal.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The features described in this disclosure are set forth with particularity in the appended claims. These features and attendant advantages will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings and in which:

Figure 1 shows classical model of deployment of SONET/SDH ADM products for the wireless backhaul where fiber connectivity is available.

Figure 2 shows mobile backhaul network having BTS to BSC/MSC primary connectivity through fiber-optic cable based STM-N link and backup (protecting) link through legacy microwave links which is 2 Mbps El rate or multiple of them.

Figure 3 shows typical BSC/MSC/BTS station connectivity using protected micro-wave link where use of a transport device (typically a STM-N multiplexer without optical ports) helps save ports on the BSC/MSC/BTS.

Figure 4 diagrammatically illustrates the mechanism implementing 1+1 protection scheme for equivalent payload bandwidth.

DETAILED DESCRIPTION OF THE INVENTION

The primary embodiment of the present invention is a method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link.

In yet another embodiment of the present invention the protection means protecting one link with another to provide high service availability to the client signal.

In still another embodiment of the present invention the transmit signal at one end is bridged to working as well as protection path and said signals are monitored at other end for failure and/or degradation.

In still another embodiment of the present invention the signal failure and/or degradation criteria for PDH ports are line and/or path alarms and performance counter thresholds depending on the application.

In still another embodiment of the present invention the method enables the protection in which working and protecting port types are decoupled.

In still another embodiment of the present invention the ports or paths objects representing equivalent bandwidth acts as working and/or protect entities with no restrictions.

In still another embodiment of the present invention the method is applicable to all combinations that the working and the protecting entities are paired without any restrictions is selected from a group comprising

a) VC12 and VC12, VC12 and El, El and VC12, El and El;

b) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1;

c) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3;

d) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3; and

e) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4.

In still another embodiment of the present invention the dissimilar link is that the communication link or medium of working and protecting path is different from each other.

Another important embodiment of the present invention is an Apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises transmitter for transmitting client signal; plurality of dissimilar communication links to carry the transmitted signal; and receiver with receive protection logic for receiving the signal and to monitor failure and/or degradation of the received signal.

The instant disclosure describes a method of providing protection through dissimilar communication links provided those links carry equivalent payload and bandwidth. This is useful in being able to use old legacy equipments along with newer technology network deployment. The protection here means protecting one link with another to provide high service availability to the client signal by transmitting the signal through two separate links and choosing receive of the signal through better link.

As described above in the background of the invention, the known prior arts and classical models make use of similar links in transmitting the signal. Well established 1+1 SNCP/UPSR used for protection in SONET/SDH equipment lacks in addressing the application scenario as explained below. The description provides examples of El as one type of PDH link, but it is applicable to other cases equally i.e. DS1, E3/DS3/E4 etc.

1. Mobile backhaul network may have BTS to BSC connectivity through legacy microwave links (2 Mbps). While operators migrate to use SONET/SDH optical backhaul they may want to use the microwave link as protecting channel to make the best use of the investment they may have made earlier. In the model as depicted in figure 2, the El traffic is normally carried over the working path which is through the El carried inside TU12 over the STM-N optical fiber. For the protect path, traffic is carried over Els which are transported through microwave medium. The operator had micro-wave backhaul to start with and later on, they had fiber access though the fiber access is not fully available for the protect path.

2. Typical BSC/MSC station may have some number (say x) of El ports. They need to burn 2 ports if they wish to have protected Microwave link between BTS and BSC for every 2 Mbps worth of backhaul. This effectively reduces the number of ports on BSC to half the physical ports. This is shown in figure 3. Typically, the cost of each El port in BTS or BSC is typically much higher than the cost of equivalent port in SONET/SDH transport ADM equipment. This is primarily due to the complexity of hardware/software logic in a BTS/BSC as compared to that of SONET/SDH equipment. The proposal here is to save the port usage on BTS/BSC which protection being made possible through the use of SONET/SDH equipment. Traffic from the BSC uses only a single El port. The co-located SONET/SDH equipment bridges the traffic to two E1s which feeds the microwave transmitter. At the other end at BTS, the better quality (in terms on low error rate) El is chosen from the microwave receiver and provided to the BTS. Traffic in the other direction i.e. from BTS to BSC is handled exactly in the same way.

Therefore, it is necessitate developing a generalized scheme which provides the solution for aforementioned limitation. The present invention makes an effort in addressing the limitations as described above.

The solution is to have a generalized protection scheme which is 1+1 protection on the lines similar to 1+1 SNCP/UPSR. The figure 4 visualizes the description of the mechanism implementing 1+1 protection. In 1+1 protection scheme, the transmit signal at one end is bridged to the working as well as the protection path. The exact mechanism for bridging the signal typically depends on the architecture of the product, but one of the ways is to map the El signal into TU-12 container and bi-cast it through the use of TDM cross connect fabric. When the bridged TU-12 is to be transmitted over the STM-N link, it is multiplexed into STM-N signal according to the SONET/SDH multiplexing structure. When the bridged TU-12 is to be sent over the microwave link, El is demapped from the TU12 on the egress card and transmitted as PDH El signal. Both these signals are carried to the other end-points through a series of equipments (kindly mention the equipments that are used). The other end monitors the two receive signals for failures and/or degradation.

The receive 1+1 protection logic chooses the better of the two copies of the signal e.g.

1. If one copy is good and other copy is degraded or failed, good copy is chosen.

2. If one copy is degraded and another copy is failed, the degraded copy is selected.

Traditionally, only E1s carried in VC12 inside STM-N optical ports are considered as candidates for working/protection path pair. The change is to have protection scheme where working and protecting port types are decoupled. What really matters is that ports/paths objects representing equivalent BW act as working/protect entities with no restrictions e.g. VC12 and El, VC11 and DS1, VC3 and E3/DS3.

The capability provides for all the following options where working are protecting entities are paired without any restrictions.

a) VC12 and VC12, VC12 and El, El and VC12, El and El.

b) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1.

c) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3.

d) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3.

e) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4.

For PDH signals carries inside optical ports, the signal fail criteria are LOS/LOF/MS-AIS at Section and Line layers, LOP/AIS/UNEQ at higher order path layer and LOP/AIS/UNEQ at lower order path layers. The signal degradation criteria are typically threshold-crossing error based on monitoring performed using B2 counts at Line, B3 counts at higher order path and BIP-2 counts at lower order path layer.

For the PDH ports, the failure and degradation triggers can be line and/or path alarms and performance counter thresholds depending on the application e.g. in case of El used as either working or protect channel, LOS/AIS/LOF/LOM and high CRC/LCV error (say 10e-3 to 10e-5) rate can be treated as SF (Signal Fail) trigger. Lower CRC/LCV error (say 10e-6 to 10e-8) can be used to deduce SD (Signal Degrade) trigger. Poor weather or something similar might result in path failure/degradation for the El. Power failure or some other failure of the microwave equipment or poor wiring might result in Line failure/degradation for the El.

We Claim:

1. A method to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure by transmitting client signal through plurality of dissimilar communication links and choosing receive of the signal through appropriate link.

2. The method as claimed in claim 1, wherein the protection means protecting one link with another to provide high service availability to the client signal.

3. The method as claimed in claim 1, wherein the transmit signal at one end is bridged to working as well as protection path and said signals are monitored at other end for failure and/or degradation.

4. The method as claimed in claim 3, wherein the signal failure and/or degradation criteria for PDH ports are line and/or path alarms and performance counter thresholds depending on the application.

5. The method as claimed in claim 1, wherein the method enables the protection in which working and protecting port types are decoupled.

6. The method as claimed in claim 6, wherein the ports or paths objects representing equivalent bandwidth acts as working and/or protect entities with no restrictions.

7. The method as claimed in claims 1 and 7, wherein the method is applicable to all combinations that the working and the protecting entities are paired without any restrictions is selected from a group comprising

f) VC12 and VC12, VC12 and El, El and VC12, El and El;

g) VC11 and VC11, VC11 and DS1, DS1 and VC11, DS1 and DS1;

h) VC3 and VC3, VC3 and E3, E3 and VC3, E3 and E3;

i) VC3 and VC3, VC3 and DS3, DS3 and VC3, DS3 and DS3; and j) VC4 and VC4, VC4 and E4, E4 and VC4, E4 and E4.

8. The method as claimed in claim 1, wherein the dissimilar link is that the communication link or medium of working and protecting path is different from each other.

9. An Apparatus to provide protection to equivalent payload bandwidth independent of physical media and/or multiplexing structure, said apparatus comprises

i. transmitter for transmitting client signal;

ii. plurality of dissimilar communication links to carry the transmitted signal;
and

iii. receiver with receive protection logic for receiving the signal and to
monitor failure and/or degradation of the received signal.

10. A method and an apparatus to provide protection to equivalent payload bandwidth
independent of physical media and/or multiplexing structure.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=/etc1Qo/vnb92NZt7atAqw==&loc=egcICQiyoj82NGgGrC5ChA==

« Previous Patent

Next Patent »

Patent Number

272536

Indian Patent Application Number

102/CHE/2008

PG Journal Number

15/2016

Publication Date

08-Apr-2016

Grant Date

07-Apr-2016

Date of Filing

10-Jan-2008

Name of Patentee

TEJAS NETWORKS LIMITED

Applicant Address

#58 1ST MAIN ROAD, J.P. NAGAR, 3RD PHASE, BANGALORE-560 078.

Inventors:

#	Inventor's Name	Inventor's Address
1	HIREN DESAI	58, 1ST MAIN ROAD, J.P. NAGAR, 3RD PHASE, BANGALORE-560 078, KARNATAKA, INDIA
2	GOVINDAN KUTTY THRITHALA	58, 1ST MAIN ROAD, J.P. NAGAR, 3RD PHASE, BANGALORE-560 078, KARNATAKA, INDIA

PCT International Classification Number

H04J

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA