Transport of 64 kbit/s transparent data service over IP
ETSI STQ Workshop
Martin Brand TELEKOM AUSTRIA
World Class Standards ISDN 64 kbit/s transparent data applications
• • • • • • •
Video conferencing systems (conventional) Radio and TV Channels Transmission Secure data transfer between banks Data transfer between hospitals ISDN Fax group 4 Remote maintenance of PBX LEONARDO (Apple) 2
World Class Standards
IWF in Network
3
World Class Standards
Timing requirements at edge and in core networks for 64 kbit/s transparent data The jitter and wander network limits currently specified in the relevant ITU-T Recommendations i.e. G.822, G.823, G.824, G.825, G.826
4
World Class Standards
Timing and synchronization requirements in packet networks for 64 kbit/s transparent data To ensure the timing requirements the packet network (access and core) must be synchronized according the ITU-T Recommendation G.8261/Y.1361
5
World Class Standards
Timing recovery for constant bit rate services transported over packet networks Timing recovery operating methods: • Network synchronous operation • Differential methods • Adaptive methods • Reference clock available at the TDM end systems
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World Class Standards
Outcome of the synchronization requirements in packet networks As the DSL access (IAD) is usually not synchronized, 64 kbit/s transparent data can not be offered on DSL access lines As the data channels are transmitted over an packet network the end-to-end association of bundled channels must be ensured Synchronisation of jitter buffers for the transmission of bundled 64 kbit/s transparent data channels is needed
7
World Class Standards Bundling of n x 64 kbit/s channels (1) TDM Channel 1 Channel 2
JB 1
TDM Channel 1
Channel 3 CLOCK
Channel 4
Channel 2
JB 2
Channel 5
… … … Channel n
IWF
Packet network
IWF
CLOCK
JB 3
Channel 3
CLOCK
JB n
Channel n
CLOCK
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World Class Standards
Bundling of n x 64 kbit/s channels (2) The network suppliers are synchronizing each RTP channel separately or a complete PCM The clock for the synchronization is located after the jitter buffer The loss of frame synchronization is caused due two events: Loss of frame synchronization due different queuing delay Loss of frame synchronization due packet loss
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World Class Standards Loss of frame synchronization due different queuing delay PCM Frame 256 µs
30
31
0
1a
2a
1a
16a 17a 18a 19a
1b
1c
1d
29
1e
30
31
1b
2b
3b
1f The packet was too early to be synchronized
2a
2b
2c
2d
2e
2f
Queing delay 1a
2a
256 µs
1b
2b
1c
2c
1d
2d
1e
2f
256 µs 256 µs Beating between regular rate packet streams
10
World Class Standards Loss of frame synchronization due packet loss PCM Frame 256 µs
30
Stream 1
31
0
1a
2a
1a
16a 17a 18a 19a
1b
2a
Stream 2
1a
2a
256 µs
1c
2b
1b
2b
256 µs
1d
2c
1c
2c
29
1e
2d
1d
31
1b
2b
3b
1f
2e
1e
30
2f
2f
256 µs 11
World Class Standards Summary of requirements for transport of 64 kbit/s transparent data service over IP
Forward error correction Synchronisation jitter buffers for the transmission of bundled 64 kbit/s transparent data service channels End-to-end association of channels Synchronisation of the access points and destination points Constant jitter buffer for all synchronized channels
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World Class Standards IP Requirements to carry 64 kbit/s transparent data service The basis of the objective is to use as base the ITU-T Recommendation G.826 Parameter
Objective
2,75 × 10-7 9,0 × 10-8 1,5 × 10-6 1,0 × 10-8
IP packet loss ratio for national connections IP packet loss ratio for each operator's network end-to-end probability IP packet loss ratio IP packet error ratio for each operator's network
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World Class Standards Network QoS Classes for Voice Applications QoS Classes
Network Performance Parameter
Nature of Network Performance Objective
Class 0
Class 1
IPTD
Upper bound on the mean IPTD
100 ms
400 ms
IPDV
Upper bound on the 1-10-3 quantile of IPTD minus the minimum IPTD
