ATM Cross-Connect AXU

ATM Cross-connect (AXU) UnitDescription

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# Nokia CorporationNokia Proprietary and Confidential

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469693A.2_0Nokia UltraSite WCDMA BTS SupremeOutdoor, Rel2

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ATM Cross-connect (AXU) Unit Description

Contents

Contents 3

1 ATM cross-connect unit (AXU) unit operation and main blocks 51.1 Operation 61.2 Main blocks 7

2 AXU unit power requirements 11

3 AXU unit dimensions and weight 13

4 AXU unit interfaces 15

5 AXC LED indications 17

6 AXU traffic capacity 19

7 AXC units mean time between failures 21

8 AXC delays 23



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Contents

1 ATM cross-connect unit (AXU) unitoperation and main blocks

The ATM cross-connect unit (AXU) is the master unit of the AXC node and itcontrols the node within the Nokia WCDMA BTS. It cross-connects ATM trafficwithin the BTS, and connects the BTS to other BTSs or to the Nokia RadioNetwork Controller (RNC). The AXU unit is always installed in the first slot ofthe AXC.

There are two AXU units available: AXUA and AXUB. AXUB provides thecentralised BTS AAL2 multiplexing feature. It is enabled by the ATM AdaptationModule (AAM) of the AXUB unit.



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ATM cross-connect unit (AXU) unit operation and main blocks

Figure 1. AXU unit

1.1 Operation

The following features are available with the AXU units:

. semi-permanent ATM cross-connections on Virtual Path (VP) and VirtualChannel (VC) level providing connections between Wideband ApplicationManager (WAM) units and thus interconnecting different sectors inside theBTS, and providing a connection from the BTS to the RNC through the Iubinterface and further connections between other base stations and the RNC.

. reference clock recovered either from a physical interface, or received froman external timing source, or from an internal reference source andprovided for all the transmission interface units, and for BTSsynchronisation and BTS clock unit (WSC).

LED

LMP

Q1

ERC2

Lever

Lever

ERC1

Microcontrollermodule

Powermodule

AAM-Module (AXUB)




. management functionality of the AXC node for passing networkmanagement system information to the base station and vice versa. TheLocal Management Port (LMP) is available on the AXU front panel forlocal management of AXC and BTS or remote management of othernetwork elements.

. up to 1.2 Gbit/s ATM switching capacity

. 1000 simultaneous connections supported

. BTS AAL2 multiplexing of the AXUB unit for multiplexing AAL2connections between WAMs and RNC into one or several VCCs

1.2 Main blocks

The AXU unit includes the following functional blocks:

. Control Unit

. Clock Distribution Circuit

. ATM Switch Fabric

. AAM (in AXUB)

. Backplane Bus Adaptation

. DC/DC Converter

The Functional blocks of the AXU unit figure shows the block diagram of theAXU unit.



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Figure 2. Functional blocks of the AXU unit

Control Unit

The Control Unit consists of the Microcontroller and other necessary circuitry. Itis compiled on a module that is the same in each AXC unit. The module type is sogeneric that it meets all the requirements of each AXC unit.

The Microcontroller runs all unit control software on the AXC.

The Control Unit also features an IP router. Thus it provides a routing path forremote BTS management and enables the local management of the BTS via theLMP of the AXC. Management of other BTSs via the IP router is also possible.In addition the Control Unit features a Q1 management support function whichcan be used to manage Q1 network elements remotely. The Q1 network elementscan be connected to the Q1 management support function by means of a cableconnected to the Q1 interface at the front panel of the AXU or by means ofoperation channels (EOC) embedded in some transmission signals. The Q1management support function can be connected via the backplane to AXCembedded Q1 network elements (IFUE).

Clock Distribution Circuit

The Clock Distribution Circuit provides a reference clock for all IFUs and theWSC.

LED

LMP

Q1

ERC1/2

To/fromIFUX

To/fromWAM

DC input

ATMSwitchFabric

ControlUnit

ClockDistr.Circuit

BackplaneBus

Adapt.

DC/DCConverter Inter-unit

communication andQ1 bus

Clock distribution

Q1supportfunction AAM

(AXUB)




The reference clock can either be recovered from a physical interface or receivedfrom an external timing source, or from an internal reference source. The internalclock is used if no external reference is available. In this case the AXC does notprovide a reference clock for the BTS, but the BTS's WSC provides the clock forthe BTS. The AXU features two dedicated interfaces for external timing sourceinput.

ATM Switch Fabric

The ATM Switch Fabric performs all ATM layer functionalities of the AXC:

. Virtual Path and Virtual Channel cross-connection functionality for ATMcells between a certain number of IFUs and WAMs

. header translation functionality for ATM connections

. traffic management functions like policing or traffic shaping

. O&M functionality (operations, administration and maintenance)

The total switching capacity of the block is 1.2 Gbit/s.

AAM (in AXUB)

The AXUB unit with the working AAL type 2 module (AAM) multiplexes ordemultiplexes AAL type 2 connections between the WAMs and RNC into one orseveral VCCs.

Backplane Bus Adaptation

The Backplane Bus Adaptation provides serial payload backplane connectionsbetween the IFUs and the AXU by means of a bus, as well as the AXU and theWAMs.

DC/DC Converter

The DC/DC Converter transforms the input voltage of �48 V fed through thebackplane to the voltages required at unit level.



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2 AXU unit power requirements

The tables below lists the DC power supply value and typical and maximumpower consumption for AXUA and AXUB units.

Table 1. AXUA power supply and consumption

Property Property Value

DC power supply -37.5 to -60 V DC

Power consumption (typical) 35 W

Power consumption (max.) 40 W

Table 2. AXUB power supply and consumption

Property Property Value

DC power supply -37.5 to -60 V DC

Power consumption (typical) 38 W

Power consumption (max.) 43 W



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AXU unit power requirements

3 AXU unit dimensions and weight

The tables below define the dimensions and weight of AXUA and AXUB units

Table 3. AXUA dimensions

Property Value

Height 264 mm

Width 25 mm

Depth 285 mm (incl. front panel)

Weight 800 g

Table 4. AXUB dimensions

Property Value

Height 264 mm

Width 25 mm

Depth 285 mm (incl. front panel)

Weight 900 g



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AXU unit dimensions and weight

4 AXU unit interfacesAXUA and AXUB interfaces

Interface Connector

Local Management Port (LMP) 10baseT crossed Ethernet interface, RJ-45 connector

Ethernet standards IEEE 802.3 and ANSI8802.3, RFC 1483 (routed)

Q1 management port V.11 interface, D-sub 9 connector

External reference clock interface 1 (ERC1)

TQ connector (symmetrical), 110 ©

64 kHz + 8 kHz (AMI with 8 kHz bipolarviolation)

External reference clock interface 2 (ERC2)

Coaxial BT-43 connector, 75 ©

1.544 MHz, 2.048 MHz, 2 Mbit/s

Figure 3. ERC1 symmetrical interface

Local management port pinout (RJ-45 connector)

Pin Signal Explanation

1 TD+ Transmitted data +

2

341 Clock input -

2 Clock input +

3 nc

4 nc

1



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AXU unit interfaces


2 TD- Transmitted data -

3 RD+ Received data +

4 nc Not used by 10baseT




8 RD- Received data -


Nokia Q1 management interface pinout


1 Q1_OUT_N Transmitted data -

2 nc Not connected

3 GND Ground

4 GND Ground

5 Q1_IN_N Received data -

6 Q1_OUT_P Transmitted data +

7 nc Not connected

8 nc Not connected

9 Q1_IN_P Received data +




5 AXC LED indications

The LEDs of the Nokia AXC-ATM cross-connect unit (AXU) and Interface UnitsIFUA/IFUD, IFUB, IFUC and IFUE are presented in the following.

Front panel LEDs

Each of the Nokia AXC units has a 3-colour status LED located on the frontpanel. These indicators display the current state of the equipment. The LEDsindicate the following:

Table 5. LED indications (O/A/F1)

Colour Explanation

Stable red Major or critical alarm

or

Unit disabled

Blinking red Minor alarm

Stable yellow Unit starting up

Stable green Normal operation, power on

Blinking green Software download from LMT or networkduring operation

IFUE LEDs

The Interface Unit IFUE has two 3-colour status LEDs on the front panelindicating the operational status of the unit: O/A/F1 and O/A/F2 (O/A/F signifiesOperation/Alarm/Fail). The O/A/F1 LED indicates the operational status of theATM part and the O/A/F2 LED indicates the operational status of the Flexbuspart of the IFUE. In addition, each of the three Flexbus interfaces has a statusLED of its own (DC on).



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AXC LED indications

. O/A/F1 (ATM part)

. O/A/F2 (Flexbus part)

. DC on (Flexbus 1)

. DC on (Flexbus 2)

. DC on (Flexbus 3)

The following table shows the indications of the O/A/F2 multi-colour LED forthe Flexbus part.

Table 6. IFUE O/A/F2 LED indications

Colour Status

Green The unit functions well, no alarms.

Yellow Alarms with low priority occur, e.g. �thenode clock is not set�

Red Some errors occur, e.g. �LOS of FB1� or�2M interface 3: Buffer overflow�

The following table shows shows the indications of the DC on Flexbus LEDs.

Table 7. IFUE Status of �DC on� LED indications

Indication Status

Off Normal status, no remote power feeding.

Blinking Try to find an Outdoor Unit (OU), remotepower feeding is temporarily on.

On OU found and remote power feeding ison.




6 AXU traffic capacity

Table 8. Capacity of AXUA

Property Value

Switching capacity 1.2 Gbit/s

Simultaneous connections 1000 (with any mix of VPs and VCs)

Supported ATM service categories Constant Bit Rate (CBR)

Unspecified Bit Rate (UBR)

ATM Forum af-0056.000

Supported cross-connections semi-permanent Virtual Path Connections(VPC)

semi-permanent Virtual ChannelConnections (VCC)

Table 9. Capacity of AXUB

Property Value

Switching capacity 1.2 Gbit/s

Simultaneous connections 1000 (with any mix of VPs and VCs)

Supported ATM service categories Constant Bit Rate (CBR)

Unspecified Bit Rate (UBR)

ATM Forum af-0056.000

Supported cross-connections semi-permanent Virtual Path Connections(VPC)

semi-permanent Virtual ChannelConnections (VCC)



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AXU traffic capacity

Table 9. Capacity of AXUB (cont.)

Property Value

Supported AAL2 connections 1736




7 AXC units mean time between failures

Table 10. Mean time between failures (years)

Unit MTBF

AXU 23 years

IFUA (symmetrical E1/JT1/T1) 28 years

IFUB (JT2) 28 years

IFUC (SDH/Sonet) 24 years

IFUD (E1 coaxial) 28 years

IFUE (Flexbus) 18 years



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AXC units mean time between failures

8 AXC delays

Table 11. Estimated intrinsic delays

Interface type Estimated intrinsic delay/interface

STM-1 16 µs

STM-0 24 µs

E1 260 µs

JT1 316 µs

JT2 69 µs

IMA (n x E1) 800 µs

IMA (n x JT1) 1000 µs

Flexbus 30 µs

CBR Cross-connection 350 µs

UBR Cross-connection 0 µs

Table 12. Estimated generated Cell Delay Variation (CDV)

Interface CDV for CBR CDV for UBR

STM-1 12 µs 12 µs

STM-0 12 µs 12 µs

E1 660 µs 220 µs

JT-1 828 µs 276µs

IMA (2xE1) 120 µs 120 µs



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AXC delays

Table 12. Estimated generated Cell Delay Variation (CDV) (cont.)

Interface CDV for CBR CDV for UBR

IMA (8xE1) 40 µs 40 µs

IMA (2xJT1) 160 µs 160 µs

IMA (4xJT1) 85 µs 85 µs

The following example illustrates how the estimated delay can be calculated forthe STM-1 - IMA (n x E1) connection shown in the figure below.

If the connection is of type UBR the mean Cell Transfer Delay can be calculatedwith the following formula: intrinsic STM-1 + intrinsic E1 + intrinsic IMA (n xE1) or 16 + 260 + 800 = 1076 µs.

If the connection is of type UBR the mean Cell Transfer Delay can be calculatedwith the following formula: intrinsic STM-1 + intrinsic E1 + intrinsic IMA (n xE1) or 16 + 260 + 800 = 1076 µs.

The maximum Cell Transfer Delay can be calculated with the following formula:CTD Max = CTDMean + CDV/2. Thus for this connection the maximum CTD isCTD Mean + CDV IMA (2xE1)/2, or for the UBR connection 1076 + 120/2 =1136 µs and for the CBR connection 1426 + 120/2 = 1486 µs.

The following table shows the Cell Transfer Delay (CTD) mean and maximumvalues for these UBR - UBR and CBR - CBR connections. The propagation delayof any layer on transport medium is not included.

Table 13. CTD for example connection

STM-1 - IMA (2XE1) CTD mean CTD max

UBR - UBR 1076 1136

CBR - CBR 1426 1486




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