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Ater Compression Transmission Feature Parameter Description
Copyright Huawei Technologies Co., Ltd. 2010. All rights
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The information in this document is subject to change without
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Huawei Proprietary and Confidential Copyright Huawei
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BSS Ater Compression Transmission Contents
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Copyright Huawei Technologies Co., Ltd.
i
Contents 1 Introduction to This Document
.............................................................................................1-1
1.1 Scope
............................................................................................................................................
1-1 1.2 Intended Audience
........................................................................................................................
1-1 1.3 Change
History..............................................................................................................................
1-1
2 Overview
.....................................................................................................................................2-1
3 Technical Description
..............................................................................................................3-1
3.1 Network Topologies
.......................................................................................................................
3-1
3.1.1 Network Topology in Non-TC Pool Mode
.............................................................................
3-1 3.1.2 Network Topology in TC Pool Mode
.....................................................................................
3-1
3.2 Technologies in Ater Compression Transmission
.........................................................................
3-3 3.2.1 Speech Frame Processing
...................................................................................................
3-3 3.2.2 Packet
Multiplexing...............................................................................................................
3-5 3.2.3 Reliability
..............................................................................................................................
3-5
4 Engineering
Guidelines...........................................................................................................4-1
5 Parameters
.................................................................................................................................5-1
6
Counters......................................................................................................................................6-1
7 Glossary
......................................................................................................................................7-1
8 Reference Documents
.............................................................................................................8-1
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BSS Ater Compression Transmission 1 Introduction to This
Document
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1-1
1 Introduction to This Document 1.1 Scope This document
describes the network topologies on the Ater interface and the
technologies in Ater compression transmission.
1.2 Intended Audience It is assumed that users of this document
are familiar with GSM basics and have a working knowledge of GSM
telecommunication.
This document is intended for:
z Personnel working on Huawei GSM products or systems z System
operators who need a general understanding of this feature
1.3 Change History The change history provides information on
the changes between different document versions.
There are two types of changes, which are defined as
follows:
z Feature change Feature change refers to the change in the Ater
compression transmission feature of a specific product version.
z Editorial change Editorial change refers to changes in wording
or the addition of information that was not described in the
earlier version.
Document Issues The document issues are as follows:
z 02(2009-09-30) z 01(2009-06-30)
02(2009-09-30) This is the second commercial release of
GBSS9.0.
Compared with issue 01 (2009-06-30), issue 02 (2009-09-30)
incorporates the changes described in the following table.
Change Type
Change Description Parameter Change
Feature change
None. None.
Editorial change
The structure of the document is optimized.
None.
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1 Introduction to This Document BSS
Ater Compression Transmission
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Technologies Co., Ltd.
Issue 02 (2009-09-30)
01(2009-06-30) This is the first commercial release of
GBSS9.0.
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BSS Ater Compression Transmission 2 Overview
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2 Overview Ater Compression Transmission is a technology in
which the TransCoder Subrack (TCS) of the BSC is located remotely
and the IP over PPP over Ch-STM-1 transmission mode is used to
carry signals when the Ater interface is in TDM transmission mode.
Meanwhile, the techniques such as Ater MUX, PPP MUX, and IP header
compression are used for data compression on the Ater interface to
increase the transmission efficiency on the Ater interface.
Ater Compression Transmission has the following features:
z The remote location of the TCS can save the transmission
bandwidth by 75%. After the Ater compression transmission function
is enabled, an additional 30% transmission bandwidth on the Ater
interface can be saved.
z IP over PPP enables the IP packets to be transmitted over the
traditional TDM network. This protects the legacy investment of the
operator who owns the TDM transmission resources.
z If the Abis interface uses the IP/HDLC transmission mode, the
Ater compression transmission function does not require a
coding/decoding board to convert the Transcoder & Adaptor Unit
(TRAU) speech frames to packets. This saves the cost of board
configuration.
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BSS Ater Compression Transmission 3 Technical Description
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3 Technical Description About This Chapter The TRAU frames are
used to carry speech signals in a TDM network; packet TRAU (pTRAU)
frames are used to carry signals in IP/HDLC transmission mode.
When the Ater compression transmission function is enabled, IP
over PPP is used for data transmission. The Ater compression
transmission is applied only to the speech signals over the Ater
interface whereas the signaling and OM signals are still
transmitted in TDM mode.
To enable the Ater compression transmission function, set Ater
Interface Transfer Mode to IP.
3.1 Network Topologies 3.1.1 Network Topology in Non-TC Pool
Mode In the network topology in non-TC pool mode, the speech
services between the MPS(Main Processing Subrack)/EPS(Extended
Processing Subrack) and the TCS of a BSC are carried in IP over PPP
over Ch-STM-1 mode, as shown in Figure 3-1.
Figure 3-1 Network topology in non-TC pool mode
In Ater compression transmission mode, the MPS/EPS (regarded as
the BSC) and TCS are adjacent nodes to each other.
You need to configure the adjacent BSC of the TCS by setting
Adjacent Node Type to BSC(Ater Interface on BSC) and BSC ID to 0.
Meanwhile, configure the adjacent TCS of the BSC by setting
Adjacent Node Type to TC(Ater Interface on TC).
3.1.2 Network Topology in TC Pool Mode Figure 3-2 shows the
network topology in TC pool mode when the user plane on the Ater
interface is in IP over PPP mode.
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3 Technical Description BSS
Ater Compression Transmission
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Figure 3-2 Network topology in TC pool mode (IP over PPP on the
Ater user plane)
Figure 3-3 shows the network topology when both TDM and IP over
PPP are used on the user plane of the Ater interface.
Figure 3-3 Network topology in TC pool mode (TDM and IP over PPP
on the Ater user plane)
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BSS Ater Compression Transmission 3 Technical Description
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In the network topology in TC pool mode, the MPS/EPS (regarded
as the BSC) and TCS that support Ater compression transmission are
adjacent nodes.
You need to configure all the BSCs in the TC pool as the
adjacent nodes of the TCS by setting Adjacent Node Type of each BSC
to BSC(Ater Interface on BSC) and setting BSC ID of the primary BSC
to 0 and BSC ID of every secondary BSC to a non-zero value.
Meanwhile, configure the adjacent TCS of each BSC by setting
Adjacent Node Type to TC(Ater Interface on TC).
3.2 Technologies in Ater Compression Transmission 3.2.1 Speech
Frame Processing The timeslots on the Ater interface consist of
timeslots for the Ater signaling link, timeslots for the Ater OML,
timeslots for the Ater speech service, and timeslots for the A SS7
signaling link. On the Ater interface, the IP over PPP mode is used
to carry speech signals whereas the TDM mode is retained to carry
signaling and OM signals. Figure 3-4 shows the timeslots on the
Ater interface.
Figure 3-4 Timeslots on the Ater interface
In Ater compression transmission mode, the speech signals can be
processed in the following ways:
z Direct transmission of pTRAU frames from the Abis interface
board to the Ater interface board When the Abis interface uses the
HDLC or IP transmission mode, the pTRAU frames are directly sent
from the Abis interface board to the Ater interface board without
further processing of the DPUc board. This reduces the delay of
frame processing. Figure 3-5 shows the signal flow.
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3 Technical Description BSS
Ater Compression Transmission
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Figure 3-5 Signal flow in the MPS/EPS (Abis over HDLC/IP)
z Frame format conversion between the Abis interface board and
the Ater interface board When the Abis interface uses the TDM
transmission mode, the DPUc board in the MPS/EPS processes the TRAU
frames on the Abis interface and the pTRAU frames on the Ater
interface. In addition, the DPUc board can eliminate the jitter and
delay in packet arrival when IP/HDLC transmission is used on the
Ater interface. Figure 3-6 shows the signal flow.
Figure 3-6 Signal flow in the MPS/EPS (Abis over TDM)
z Frame format conversion between the Ater interface board and
the A interface board In Ater compression transmission mode, the
Ater interface board sends the pTRAU frames to the DPUc board for
converting the pTRAU frames to PCM frames used on the A interface.
In addition, the DPUc board can eliminate the jitter and delay in
packet arrival when IP/HDLC transmission is used on the Ater
interface, support the downlink DTX function, and compress the
silence frames. This improves the transmission efficiency on the
Ater interface. Figure 3-7 shows the signal flow.
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BSS Ater Compression Transmission 3 Technical Description
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Figure 3-7 Signal flow in the TCS
3.2.2 Packet Multiplexing In Ater compression transmission mode,
the POUc board works as the Ater interface board in the MPS/EPS/TCS
and supports the following packet multiplexing functions:
z Ater multiplexing The speech signals on the Ater interface are
encapsulated in the same format of pTRAU frames used on the Abis
interface. Multiple pTRAU frames are multiplexed into a UDP packet
through the Frame Protocol (FP) multiplexing technology, thus
improving the transmission efficiency.
z IP header compression The UDP/IP header can be compressed to
decrease the packet header overhead, reduce the packet loss, and
shorten the period of packet response.
z PPP multiplexing Multiple pTRAU frames are multiplexed into a
PPP packet to decrease the packet header overhead and thus improve
the transmission efficiency.
Packet multiplexing can greatly improve the transmission
efficiency in Ater compression transmission mode when the timeslot
resources are limited.
For details of packet multiplexing, see IP Transport
Architecture Description.
3.2.3 Reliability Ater Compression Transmission can improve
transmission resource utilization; however, due to the inherent
characteristics of IP transmission, more bit errors, jitter, and
delay are generated. In addition, IP transmission has more protocol
layers than TDM transmission, thus higher reliability is
required.
Ater Compression Transmission provides high reliability at the
physical layer and the data link layer.
z At the physical layer, the active/standby switchover is
performed without disrupting services in the case of board fault or
optical port fault.
z At the data link layer, the MLPPP (Multilink PPP) group is
configured to achieve PPP link redundancy.
In the case of TC fault, the TC pool function can be
enabled.
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BSS Ater Compression Transmission 4 Engineering Guidelines
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4 Engineering Guidelines z If the core network supports IP
transmission, the A over IP mode is recommended. z If the core
network does not support IP transmission and the Abis interface
uses IP/HDLC
transmission, then the use of IP transmission on the Ater
interface can save the cost of board configuration and Ater
transmission resources. Hardware upgrade is required to implement
IP transmission on the Ater interface.
z If the Abis interface uses TDM transmission but the Ater
interface uses IP transmission, the configuration cost is increased
and the speech quality is degraded. In this case, Ater Compression
Transmission is not recommended.
z When the Ater interface uses IP transmission, the Abis and
Ater interfaces can be configured with the same type of interface
board to save transmission resources.
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BSS Ater Compression Transmission 5 Parameters
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5 Parameters This chapter describes the parameters related to
Ater compression transmission.
For the meaning of each parameter, see Table 5-1. For the
default value, value ranges, and MML commands of each parameter,
see Table 5-2.
Table 5-1 Parameter description (1)
Parameter Description
Ater Interface Transfer Mode
Transport mode of the Ater interface. The Ater interface can be
in TDM or in IP transport mode.
Adjacent Node Type Adjacent node type
BSC ID Unique ID of one BSC in the TC POOL scenario
Table 5-2 Parameter description (2)
Parameter Default Value
GUI Value Range
Actual Value Range
Unit
MML Command
Impact
Ater Interface Transfer Mode TDM
TDM(TDM), IP(IP) TDM, IP
None
SET BSCBASIC(Mandatory)
BSC6900
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5 Parameters BSS
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Parameter Defau GUI Value Actual Un MML Impaclt Value
Range Value Range
it Com t mand
Adjacent Node Type None
IUB(Iub Interface), IUR(Iur Interface), IUCS(Iu-CS Interface),
IUPS(Iu-PS Interface), UNI_AAL2SWITCH(the adjacent node of the ATM
switch on the Iub interface), NNI_AAL2SWITCH(the adjacent node of
ATM switch on Iur or Iu-CS interface), ABIS(Abis Interface), A(A
Interface), BSC(Ater Interface on BSC), TC(Ater Interface on
TC)
IUB, IUR, IUCS, IUPS, UNI_AAL2SWITCH, NNI_AAL2SWITCH, ABIS, A,
BSC, TC
None
ADD ADJNODE(Mandatory)
Adjacent node
BSC ID None 0~15 0~15 None
ADD ADJNODE(Mandatory)
Adjacent node
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BSS Ater Compression Transmission 6 Counters
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6 Counters None.
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BSS Ater Compression Transmission 7 Glossary
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7 Glossary For the acronyms, abbreviations, terms, and
definitions, see the Glossary.
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BSS Ater Compression Transmission 8 Reference Documents
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8 Reference Documents z RFC1661: The Point-to-Point Protocol
(PPP) z RFC1990: The PPP Multilink Protocol (ML-PPP) z RFC 2686:
The Multi-Class Extension to Multi-Link PPP z RFC 3153: PPP
Multiplexing z BSC6900 Feature List z BSC6900 Optional Feature
Description z GBSS Reconfiguration Guide z BSC6900 GSM Parameter
Reference z BSC6900 GSM MML Command Reference
1 Introduction to This Document 1.1 Scope 1.2 Intended Audience
1.3 Change History 2 Overview 3 Technical Description 3.1 Network
Topologies 3.1.1 Network Topology in Non-TC Pool Mode 3.1.2 Network
Topology in TC Pool Mode
3.2 Technologies in Ater Compression Transmission 3.2.1 Speech
Frame Processing 3.2.2 Packet Multiplexing 3.2.3 Reliability
4 Engineering Guidelines 5 Parameters 6 Counters 7 Glossary 8
Reference Documents