Synchronisation Report Fron Bsnl

SYNCHRONIZATION REPORT OF

COMMITTEE

TERMS OF REFERENCE To review existing Synchronization plan. To study current problems in synchronization of network and reasons thereof. To suggest a new Synchronization plan in accordance with international practices but keeping in view the rollout of BSNL HQ and its interconnection with other operators.

TERMS OF REFERENCE To suggest actions to be taken in the short term as well as long term. To identify requirement of additional hardware and instruments needed to implement the full synchronization network. To formulate a Synchronization Audit and Monitoring strategy.

TERMS OF REFERENCE To formulate the role of every unit (Regions, Circles, SSAs) in the process as an ongoing activity.

EXISTING SYNCHRONIZATION PLAN • Separate Synchronization Plans for I. SWITCHING NETWORK : II. TRANSMISSION NETWORK:

SYNCHRONIZATION OF SWITCHING NETWORK This plan envisages to National Reference Clock.

SYNCHRONIZATION OF SWITCHING NETWORK 1. Main National Reference Clock (MNRC) At Mumbai established by VSNL. 2. BackUp National Reference Clock (BNRC) At Delhi . MNRC (Mumbai)

BNRC (Delhi)

SYNCHRONIZATION OF SWITCHING NETWORK MNRC will normally control the entire network. BNRC will be with dedicated and duplicated links with MNRC.

MNRC (Mumbai)

BNRC (Delhi)

SYNCHRONIZATION OF SWITCHING NETWORK The Clock Hierarchy follows natural telecom traffic hierarchy.

SYNCHRONIZATION OF SWITCHING NETWORK MNRC & BNRC forms Layer-1. MNRC (Mumbai)

BNRC (Delhi)

Layer-1

Timing reference is transported over traffic E1-links from MNRC/BNRC. Except Four Metros where these will be dedicated links.

SYNCHRONIZATION OF SWITCHING NETWORK MNRC & BNRC forms Layer-1. MNRC (Mumbai)

BNRC (Delhi)

Layer-1

SYNCHRONIZATION OF SWITCHING NETWORK Level-1 TAXs forms Layer-2. MNRC (Mumbai) Level-1 TAXs

BNRC (Delhi)

Layer-1

Layer-2

SYNCHRONIZATION OF SWITCHING NETWORK Level-1 TAXs will have timing I/Ps throw ‘M’ & ‘S’ links. MNRC (Mumbai)

BNRC (Delhi)

Layer-1

M links Level-1 TAXs

Layer-2

SYNCHRONIZATION OF SWITCHING NETWORK Level-1 TAXs will have timing I/Ps thr ‘M’ & ‘S’ links. MNRC (Mumbai) ‘M’ links Level-1 TAXs

BNRC (Delhi)

Layer-1 ‘S’ links

Layer-2

In addition, they may also receive Third reference I/P from another Level-1 TAX.

SYNCHRONIZATION OF SWITCHING NETWORK Level-1 TAXs will have timing I/Ps thr ‘M’ & ‘S’ links. MNRC (Mumbai) ‘M’ links Level-1 TAXs

BNRC (Delhi)

Layer-1 ‘S’ links

Layer-2

In addition, they may also receive Third reference I/P from another Level-1 TAX.

SYNCHRONIZATION OF SWITCHING NETWORK Level-2 TAXs forms Layer-3 . MNRC (Mumbai) ‘M’ links

BNRC (Delhi)

Layer-1 ‘S’ links

Level-1 TAXs

Layer-2

Level-2 TAXs

Layer-3

SYNCHRONIZATION OF SWITCHING NETWORK Level-2 TAXs will have three timing I/Ps . MNRC (Mumbai) ‘M’ links

BNRC (Delhi)

Layer-1 ‘S’ links

Level-1 TAXs

Layer-2

Level-2 TAXs

Layer-3

One from its own parent Level-1 TAX. Second from one of non-parent Level-1 TAX. Third from one of the designated Level-2 TAX.

SYNCHRONIZATION OF SWITCHING NETWORK All other Exges will have upto 3 timing I/Ps. MNRC (Mumbai) ‘M’ links

BNRC (Delhi)

Layer-1 ‘S’ links

Level-1 TAXs

Layer-2

Level-2 TAXs

Layer-3

Exchanges

SYNCHRONIZATION OF SWITCHING NETWORK All other Exges will have upto 3 timing I/Ps. MNRC (Mumbai) ‘M’ links

BNRC (Delhi)

Layer-1 ‘S’ links

Level-1 TAXs

Layer-2

Level-2 TAXs

Layer-3

Exchanges

One from its parent Lev-2 TAX. Second from non-parent Lev-2 TAX. Third from one of the Exchange.

SYNCHRONIZATION OF SWITCHING NETWORK All other Exges will have upto 3 timing I/Ps. MNRC (Mumbai) ‘M’ links

BNRC (Delhi)

Layer-1 ‘S’ links

Level-1 TAXs

Layer-2

Level-2 TAXs

Layer-3

Exchanges

SYNCHRONIZATION OF SWITCHING NETWORK In present Scenario, The Clock is extended from Level-1 TAX at Mumbai/Delhi to other TAXs via E1s over TX n/w. Lev-1 TAX in each T/Circle will be the source for reference clock for the entire Switching Network in that Circle. Private operators in that Circle should also take the reference clock from designated Lev-1 TAX of that Circle.

SYNCHRONIZATION OF TRANSMISSION NETWORK Till PDH Systems were in use, Synchronization of Transmission N/W was not an issue.

After deployment of SDH Systems, Synchronization of Transmission N/W has become essential. “A separate guideline has been issued from TEC/DOT for synchronizing all the SDH Rings with PRC(MNRC) at Mumbai.

SYNCHRONIZATION OF REAL TIME CLOCK Elements in standalone mode – OMC NMS LCT These are not synchronized to show the same time everywhere.

Need for Review of ‘Synchronization plan’.

RECOMMENDATIONS of COMMITTEE SHORT TERM MEASURES LONG TERM MEASURES

SHORT TERM MEASURES  BSNL HQRS should issue guidelines for synchronizing all the switches with the 2MHz clocks from the SSU’s/ADM’s.

SHORT TERM MEASURES  1. The SDH equipment procured from SIEMENS (HTL) has the capability to resynchronize the E1’s at its output by configuring the E1’s to the retimed mode with the software. It has been tried by the committee and found to improve the clock quality of the traffic PCM. The results of the experiment on a traffic PCM after retiming in the Siemens system can be seen at Annexure3. Instructions may be issued that wherever the SIEMENS system is deployed, all the E1’s should be configured to the Resync mode. This will improve the data services delivered from the RLU’s, RSU’s. It will also benefit the BTS and improve the mobile services.

SHORT TERM MEASURES  Instructions for synchronizing the MSC’s, BTS can be issued to reduce the call drop rates.  Guidelines for synchronizing the DLC, MLLN, NIB with clock from SDH system/SSU also must be issued.

SHORT TERM MEASURES o In case of DLC, the parent exchange should be synchronized with the SDH clock and the DLC (COT) should be synchronized with the exchange. S D H

CLOCK SIG

E X G E

D L C

The experiment done at Bangalore in BGTD has shown encouraging result by bringing down the slips in data circuits to zero

SHORT TERM MEASURES o The DXC & V-MUX of MLLN should be synchronized using the external clock input taken from the SSU/ADM in that building. CLOCK SIG

SSU/ ADM

MLLN

Clear instructions need to be issued from BSNL HQRs to the vendor, QA, A/T, and field units since there seems to be some confusion amongst the engineers working on behalf of ITI.

SHORT TERM MEASURES o NIB nodes should be synchronized with the clock derived from the STM signal, or SSU, or SDH system whichever is applicable. o Similarly, equipment of VPN and other broadband services should be synchronized with the clock from SSU, ADM as per availability.

SHORT TERM MEASURES  Synchronization of real time clocks: Immediate action is required for synchronizing the clocks of the NMS, OMCs etc so that the time exhibited by them is matching with others. This is required for coherence of performance data and billing information.

SHORT TERM MEASURES  In order to gauge the effectiveness of synchronization, Sync Audit need to be carried out at strategically important stations immediately (This may require the purchase of 2 Nos of GPS clock urgently). Measuring the true clock quality will provide the true picture of the synchronization of the network.

SHORT TERM MEASURES  The SSUs deployed in the network should be used properly. Measurement and recording of the MTIE graph of all the input clocks at specified time intervals regularly. This will give data regarding the deterioration in the clock as it flows through the network and also the section which may be adding errors on the clock.

SHORT TERM MEASURES  The A/T of the SSU’s needs to be carried out. In the long run, these must also be tested once every year for the accuracy of the clock output. This can be carried out by the Sync Audit team.  The A/T schedule of all telecom equipments should include the compliance of synchronization requirements and this should be tested thoroughly before deployment in the network.

SHORT TERM MEASURES  Expert guidance may be sought for initial planning. ALTTC may be asked to conduct seminars with foreign experts for the select officers and sync audit team for effective synchronization of the network.

EXPERIENCE AFTER SYNCHRONIZATION  TAX Level II (e.g. JND) : Station AM (B) AM (BT) ANAND AMRELI BARODA BHARUCH BHAVNAGAR BHUJ MBI-FTN MBI-G’GAON MBI-PDI

July 11, 2003 36.47 46.83 43.32 44.75 45.32 44.44 44.03 39.63 4.052 44.75 35.87

Jan 23, 2003 40.17 48.89 45.55 52.89 41.65 48.85 51.65 42.45 45.34 38.12 50.38

Remark

EXPERIENCE AFTER SYNCHRONIZATION  TAX Level I & II : Station

July 11, 2003

Jan 23, 2003

JMN

46.96

49.85

MEHSANA

38.27

45.15

RJ BKT

46.25

50.86

SURAT

40.96

43.35

Remark

EXPERIENCE AFTER SYNCHRONIZATION  LOCAL EXCHANGES : • Vadodara SSA, Savil SDCC -Repeated Failure of dependent Exchanges -- Required to be reset After Synchronization with SDH Clock -- No such prolem -- CCR improves by 4 to 5%.

EXPERIENCE AFTER SYNCHRONIZATION  MSC : Rajkot, Surat and Ahmedabad – Earlier CCR was of the order 50%. After few months dropped to less than 40% After synchronization again improved to above 50%.

EXPERIENCE AFTER SYNCHRONIZATION  InterNet : • Earlier Frequent Problems of Disconnection. (Since Launch of Internet services) Very slow. • After Synchronization Both the problems are Solved • Examples: Umargaon SDCC of Valsad SSA.

EXPERIENCE AFTER SYNCHRONIZATION  ISDN : ∀ Waghodia SDCC – Apollo Tyre using ISDN for Video Conferencing.

** Before Synchronization -Freezing of images Low speed **After Synchronization -No freezing Full Speed

EXPERIENCE AFTER SYNCHRONIZATION  ISDN : ∀ Dholka SDCC (AM SSA)-ZS-Cadilla – ** Before Synchronization -Not able to commission ISDN connection High error rate **After Synchronization -Error free ISDN got commissioned.

EXPERIENCE AFTER SYNCHRONIZATION  Data Circuit (G3/G4) : ∀ For some of the MUX at Rajkot and Ahmedabad – ** Before Synchronization -Complaint of Slip/Error Every time it was required to JO/JI the control Card **After Synchronization – No slips observed. Speed improvement for circuits of Stock Exchange Rajkot .

LONG TERM MEASURES ITPRC  The is suggested BSNL should of VSNLthat (TATA’s) is beinghave usedits as the reference for at whole of BSNL Network. own PRC’s all the four Metros – Delhi, Mumbai, Chennai, Kolkata. ND CA BY CNI

LONG TERM MEASURES Each PRC should be connected to Three SSU’s located at three different places in each metro. ND CA BY CNI

LONG TERM MEASURES  Every station in the network should have access to all the three SSU’s to build redundancy in the clock distribution network. ND CA BY CNI

LONG TERM MEASURES  In all future procurements, the TM’s should have provision delivering Retimed E1’s. This can be used as clock source in addition to carrying traffic.

LONG TERM MEASURES  At location of RLU, BTS where Retimed E1’s cannot be provided, a separate Retiming unit can do the job of retiming the E1’s. The process of framing the GR can be initiated and at the same time alternate ways of procuring the same can be examined.

LONG TERM MEASURES  The detailed plan for carrying out the Sync Audit for BSNL network in long run may be chalked out .  In all future procurement of any telecom equipment, the synchronization aspect should be taken care of – provision of external clock input port, compatibility, etc.

Action To Be Taken Sl.No.

Action To Be Taken

Unit Concerned

Remarks

1.

Issue of orders/guidelines for NM cell, BSNL New Implementation by all synchronization of all TAXs Delhi circles and Maintenance and Switches with 2 MHz clock Regions.

2.

Configuration of 2 Mb tributary All territorial circles (TEX 1) cards in the Re-synch mode

Orders to be issued by HQRS

3.

Redeployment of already All territorial circles supplied Siemens TM’s in areas where RLUs/RSUs/BTS are to be connected.

Orders to be issued by HQRS

4.

Guidelines for Synchronization All territorial circles of DLC, MLLN with clock from SDH source

Orders to be issued by HQRS

Action To Be Taken Sl.No.

Action To Be Taken

Unit Concerned

Remarks

5.

Synchronization of NIB with clock taken from SDH.

Data Networks

6.

Synch Audit of Synchronization All Maintenance network of BSNL. Regions

Initially NTR and WTR may do it on top priority after procuring GPS clock ALTTC can be involved in the exercise

7.

Performance monitoring in the All Maintenance SSUs at regular intervalsRegions MRTIE, TDEV, FFOFF, SPREAD.

To be done at mutually agreed times and schedule in consultation with ALTTC.