SIU Functionality

Offe, Richard

© 2008 Mobile Telephone Networks. All rights reserved.

SIU Functionality

Upon completion of this knowledge sharing, you will be able to:

• Understand the functionality of SIU

• Optimize/Troubleshoot the Lower Abis of an IP RAN site

• Grasp the need for you to master IP RAN technology.

© 2008 Mobile Telephone Networks. All rights reserved. Page 3

Chapter 1 SIU UnitChapter 1 SIU Unit

Chapter 2 SIU FunctionalityChapter 2 SIU Functionality

Chapter 3 Lower Abis Optimization Chapter 3 Lower Abis Optimization

© 2008 Mobile Telephone Networks. All rights reserved.

SIU UNIT

Power Source

Console – The interface is used for connection of a Local Maintenance Terminal (LMT).

E1/T1 TX Interfaces - The SIU has eight connectors for the sixteen E1/T1 transmission interfaces. Each connector supports two E1 or T1 transmission interfaces.

Ethernet Interfaces – Connectivity to WAN

SFP (small form factor pluggable)- adaptor for connectivity to fibre interface.

Clock Interface – for synchronization

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Chapter 1 SIU UnitChapter 1 SIU Unit

Chapter 2 SIU FunctionalityChapter 2 SIU Functionality

Chapter 3 Lower Abis OptimizationChapter 3 Lower Abis Optimization

© 2008 Mobile Telephone Networks. All rights reserved.

SIU IN IPRAN ARCHITECTURE

The feature Packet Abis over IP uses IP technology for transmission between BSC and BTS, instead of a TDM network.

New HW required to terminate IP on both the BSC and BTS. In BSC, PGWs are required . On the BTS side of Abis, STNs are required, either SIU or TCU or RBS 2409. A Security Gateway (SEGW) is needed for the recommended level of safety.

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SIU FUNCTIONALITY

Routing

IP/TDM Conversion

Bundling

Synchronization (Highly Stable Oven Controlled Crystal Oscillator _HS-OCXO)

ACL (Abis Local Connectivity)

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STN CAPABILITY

HARDWARE TG TRX ERLANG INTERFACE SUPPORT COMMENT

1 x SIU 6 36 - 72 700 - 900 IP over E1/T1, Ethernet (1Gb/100Mb)

1 x TCU 6 36 - 72 700 - 900 IP over E1/T1, Ethernet (1Gb/100Mb) TG limited with IP over E1/T1Supported from G12B

1 x RBS2409 1 2 30 Ethernet (10Mb/100Mb)

© 2008 Mobile Telephone Networks. All rights reserved.

LOWER ABIS – BASIC TERMS

Abis PathNo more the physical 64 kbps path between BSC and BTS but a virtual path end-to-end where some parts are still 64 kbps but others have higher rate.

Super Channel SIU connects to the RBS using the SC concept - a set of contiguous timeslots on a PCM link that terminate in one BTS port. The timeslots are used to create a single high-speed link using the HDLC protocol. The relationship between TRXs and SCs is fixed. One TRX cannot transmit over different SCs. One TG can communicate via up to four SCs, and the SCs connected to one TG are grouped into a SCGR.

BundlingBundling is the concept of packing of several frames into a single IP packet with the objective of reducing protocol overhead. Default, any LAPD frames are bundled in a packet, but it is possible to bundle for example one single traffic type [RSL, CS, PS, OML] into one bundling group. A LAPD Bundling Group is called LBG and is used as a profile by all TGs. The traffic type of a LAPD frame is defined by its SAPI value.

JitterVariation in the delay of received packets. At the sending side, packets are sent in a continuous stream with the packets spaced evenly apart. Due to network congestion, improper queuing, or configuration errors, this steady stream can become lumpy, or the delay between each packet can vary instead of remaining constant.

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SC DATA

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SCGR DATA

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SIU CONNECTION

SAPI LBG PACKET

0 0 RSL

10 1 Speech

11 2 CS Data

12 2 GPRS/EGPRS

62 3 OML

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Chapter 1 SIU UnitChapter 1 SIU Unit

Chapter 2 SIU FunctionalityChapter 2 SIU Functionality

Chapter 3 Lower Abis OptimizationChapter 3 Lower Abis Optimization

© 2008 Mobile Telephone Networks. All rights reserved.

Optimization Prerequisites.

IP Networks Concept:1.Delay2.Jitter [Elastic & Inelastic traffic]3.DiffServ4.Bundling

Parameters:1.Bundling Group2.Super Channel 3.LAPD4.Load Regulation5.P-GSL Timing Advance6.Packing Algorithm7.STN 8.Jitter & Delay

Counters:1.ABISIP2.SUPERCH3.CLTCH

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Optimization Problem

RCA:1.Congestion2.Configuration Errors3.Complexity4.New Technology

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ABISIP COUNTERS

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SUPERCH COUNTERS

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CLTCH COUNTERS

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O&M

CLI provided via SSHv2 [communication protocol] & SFTP [file transfers]Both local [LMT] and remote [OSS] connectivity available.

Syntax Eg: OSmon> command ParameterValue1 ParameterValue2 ...

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References

BSS G12B_User Description, Packet Abis over IP

SIU T12A Library

© 2008 Mobile Telephone Networks. All rights reserved.

MERCI