DSLAM Configuration in a Cabinet

1
DSLAM Configuration in a Cabinet

• Heat and Noise testing
• December 2008

2
DSLAM Configuration in a Cabinet

• What we propose to demonstrate is
• what heat testing involves
• our results to date in terms of what can fit into
  the cabinet and
• what the overall process needs to cover.
• This process is still at a very early stage of
  establishment. There will be consultation on
  various aspects of the details as we go forward.

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What Sets the Heat Dissipation Limit

• The following factors set the heat dissipation
  limit
• the overriding factor is ensuring that the
  external noise levels remain within the RMA/NES
  limits
• heat exchanger design and associated fans
• the temperature the equipment bay is maintained
  at, currently set to 45oC and
• maximum outside temperature and solar gain.

4
Heat Testing and Cabinet Configuration

• Certification of a particular combination of
  DSLAMs in a cabinet comprises two processes
• Sub rack configuration testing
• This is the work currently carried out at Eaton
  industries and
• Card configuration
• This is a modeled exercise based on manufacturing
  specifications.
• Supported where possible by in-the-field
  measurements.

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Sub Rack Configuration Testing

• The aim is establish a layout of all the proposed
  equipment in the cabinet to
• avoid hot spots within the equipment chamber
• establish the maximum heat loading for the
  cabinet with this configuration (the aim is to
  maintain the cabinets rating, e.g. 1200 watts)
  and
• confirm that the noise level associated with the
  cabinet is still within allowable limits.
• The DSLAM and cards cannot be fully loaded at
  Eaton. Therefore, to achieve the heat loading,
  we
• power up all DSLAMs and
• add additional heat loadings to bring the total
  heat load up to the cabinet rating.

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Sub Rack Testing - Method

• All DSLAMs involved are fully carded to create
  maximum resistance to air flow.
• An initial configuration is proposed and mounting
  iron work arranged.
• The test cabinet is then installed in a heat
  chamber with about 19 probes, which
• measure temperature at critical points and
• monitor the cabinet fan voltages.
• The cabinet is cycled through the temperature
  range with continual measurement recording.
• The cabinet is then taken to a quiet location to
  test for noise.

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Sub Rack Testing Method (cont)

• If a problem is encountered with this
  configuration, then alternative configurations
  are tried.
• If an alternative can not be established then
  Eaton will advise both the applicant and Chorus,
  and provide recommendations.
• These recommendations could include de-rating the
  cabinet for this configuration, raising the
  ambient temperature etc.
• The exact process is yet to be established and
  further consultation on this is required.

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Sub Rack Testing Results
Alcatel 7302
Alcatel 7356 DSLAM
Huawei 5603T DSLAM
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Sub Rack Testing Results

• The bottom two DSLAMs are mounted
• further back into the cabinet than the
• Alcatel 7302.
• This serves the following functions
• - allows some clear air into the 7302
• vents some of the other DSLAMs
• warm air up the back of the
• cabinet behind the 7302 and
• provides cable management room
• in front of the lower DSLAMs.

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Sub Rack Testing - Output

• The following are the deliverables from the
  testing
• a test report showing the heat and noise results
• a comparison against standard configuration
• configuration pictures
• required mounting metal work highlighted
• any remedial action required to achieve
  configuration revealed
• problems encountered and actions taken and
• heat rating for the cabinet for this particular
  configuration is identified.

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Card Configuration Certification

• Having established the cabinet heat capacity for
  this configuration, the allowable card
  combinations can be derived.
• The process for certifying card configuration is
  yet to be confirmed, following consultation.
• The following is a summary of how we expect the
  process will operate
• certification will be based on the manufacturers
  power rating for each type of card and DSLAM with
  input from in-the-field measurements
• the assumption is that the card is fully
  utilised and
• The results of each combination will be modeled
  in Excel.

12
Card Configuration Modeled output for a Single
Bay

• Based on known specifications, the table below
  has been calculated from the model to show the
  heat loading for the maximum possible subscribers
  as the technology progresses.

The cabinet heat capacity for this configuration
is 1,200 Watts
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Card Configuration Modeled output for a Single
Bay (continued)

• VDSL and Voice emulation represents the highest
  heat loading
• 384 is the absolute maximum number of customers
  per cabinet, average is 210 and normal targeted
  maximum is 330
• For ADSL 2 only, the maximum capacity for this
  combination of DSLAMs is 384 192 96 672
  ports. This is 75 above the maximum lines and
  over three times the average cabinet size.
• This is at the limit, but on the basis that this
  may only be a problem on maximum temperature
  days, it would be satisfactory
• No specialised cards included in this modeling.

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Card Configuration Modeled output for a Double
Bay

• Double Bay two DSLAMs Alcatel 7302 and Huawei
  5603T330 lines split 264/66
• All cards are VDSL
• Telecom Wholesale using Nokia Voice Mux
• 2nd provider has voice emulation cards used for
  80 of the lines
• No specialised cardsCabinet heat loading
  1,184 watts
• 330 is the absolute maximum lines on a double bay
• For ADSL 2 only, the maximum capacity for this
  combination of DSLAMs and Nokia voice Mux is 336
  128 464 ports. This is 21 above the maximum
  lines and over twice the average cabinet size.

15
Problem Resolution

• There are a number of ways that problem
  configurations can be addressed and, in some
  cases, solved.
• These should be treated on a case-by-case basis
  which allows for flexibility our aim is to
  satisfy as many of our customers as we can.
• Solutions may involve
• allowing the internal temperature to increase by
  a few degrees
• recognising that while the cabinet design is for
  a maximum outside temperature of 35oC, the
  cabinet may not be located in an area where this
  temperature is expected and
• checking the DSLAM manufacturers heat
  specifications against real world scenarios.
• Need to reiterate that this process is at an
  early stage of establishment.

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Double Bay Cabinet Layout

• A trial layout to house two DSLAMs plus Voice Mux
  in a Double Bay.
• Aim is to achieve an even heat load on either
  side of the equipment chamber

Space for Additional DSLAM Shown housing an
Alcatel 7356
Alcatel 7302
Voice Mux