Transcript Slide 1
DSLAM Configuration in a Cabinet Heat and Noise testing December 2008 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. 2 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. 3 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. 4 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 cabinet’s 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. 5 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. 6 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. 7 Sub Rack Testing – Results Alcatel 7302 Alcatel 7356 DSLAM Huawei 5603T DSLAM 8 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. 9 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. 10 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 manufacturer’s 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. 11 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. Scenario 1 Scenario 2 Scenario 3 384 384 384 Customer split (%) 70/20/10 70/20/10 70/20/10 Broadband Service type ADLS 2+ VDSL 2 VDSL 2 Exchange tie cable Exchange tie cable 70% Voice emulation Alcatel 7302 Yes Yes Yes Huawei 5603T Yes Yes Yes Alcatel 7356 Yes Yes Yes Heat Loading (watts) 765 934 1,248 Active lines Voice Service delivery The cabinet heat capacity for this configuration is 1,200 Watts 12 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. 13 Card Configuration – Modeled output for a Double Bay Double Bay two DSLAMs– Alcatel 7302 and Huawei 5603T 330 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 cards Cabinet 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. 14 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. 15 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 16