Data transport architecture over fiber and/or copper Francesco Simeone INFN Sez. Roma

Detection Unit interface with the Optical Network … Tower 1 Tower 5 2 fibers redundancy can be implemented at connector level PJB SJB 1 2 fibers allow 100% redundancy MEOC … SJB 18 Slow control data sent to the DUs connected to the SJB as broadcast. Data from each DU is sent to the SJB over a different fiber using a specific color.

Data Transmission (1/3): Tower Backbone Backbone architecture: optical daisy chain “waterfall” scheme (1 B&W transceiver per node); data rate 1.25 Gb/s (easily expandable up to 2.5 Gb/s); accommodates up to 6 PMTs and 2 hydros per storey high optical power budget allows cheaper connectors; nodes are connected by backbone branches optical and electrical branches are separated; PRO: improved system reliability, lower cable complexity, shorter manufacture time and assembly time. 3

Data Transmission (1/3): Tower Backbone Backbone architecture: optical daisy chain “waterfall” scheme (1 B&W transceiver per node); data rate 1.25 Gb/s (easily expandable up to 2.5 Gb/s); accommodates up to 6 PMTs and 2 hydros per storey high optical power budget allows cheaper connectors; nodes are connected by backbone branches optical and electrical branches are separated; PRO: improved system reliability, lower cable complexity, shorter manufacture time and assembly time. F19 F17 F15 F3 F1 F20 F18 F16 F4 F0 F2 B&W BackBone 1 Fiber 1 color per direction 4

Data Transmission (2/3): BackBone Bypass Faulty nodes can be bypassed: use a splitter per node (10:90 ratio); use an active switch per node (controlled by the independent power control system); allowed by the high optical power budget available at each hop; bypass optical loss: pass 1.1 dB and tap 10 dB; total worst case loss 11 dB (10 nodes failure case); transceivers with about 15 dB power link budget can be used (wide availability) Low power transceivers electronics: <1W per floor 5

Data Transmission (3/3): the copper daisy chain Copper daisy chain architecture: stringent limitations between cable length and max data flux; double daisy chain: one going up, lower speed, carries the clock: the receiver recover and regenerates the clock one going down, carrying 1.2 Gb/s data at ~50m distance accommodates up to 6 PMTs and 2 hydros per storey; at the DU base an electronic board transfers the flux on optical fibre (one colour) to the optical network copper handling safer than fibre handling, with copper cheaper connectors and components data rate on copper limited bypassing a faulty storey not so easy as with optical backbone

Data Transmission (3/3): Tower JB Electronics Odd Back Bone (OBB) 400V/5V DC/DC converter V-I meter Power Monitor & Control, Data Mux & Demux, Floor Control Spread Spectrum Drivers Opto Tx Opto Rx DWDM TX/RX Even (EBB) Main DC 400 V Tower Single Fiber Copper