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As promised on the ad hoc call, here is my understanding of Stefan Buntz’s multidrop topologies:
Assume: ‘head node’ is as discussed in EPON – this is the node that controls the multipoint protocol. All other nodes are clients.
Stub length < 100mm
Overall length, including < 25m
Minimum spacing between nodes: 500mm
Maximum spacing between nodes: 7900mm (8 m including 2 100mm stubs)
Maximum number of nodes: 8 (including head node)
No other constraints on node placement (no constraint on granularity)
David Brandt variation for industrial: 45mm shortest between nodes on linear topology.
- Does minimum spacing include the stub lengths?
- It appears from slide 4 that there may be minimums on overall length (8m) and stub length (50mm) – is this true?
- Would a terminator be placed at the far-end, or at the head-node?
- Is the ‘head node’ always at one end?
Head stub length (head node to passive star center) < 100mm
Maximum star branch length – 7900m (8m including head-node stub)
Minimum star branch length – 1000mm
Maximum number of nodes – 8 (including head node)
One node per branch
No constraint on the granularity of branch length
Is the minimum head stub length > 50mm
Maximum total cable length – is this constrained? 7900 x 7 + 100 = 55400 mm (~55m) – is this correct?
Placement of termination – at head end, distributed, or on one end of a linear
What MDI return loss might be assumed at the branch ends? (100BASE-T1?)
George Zimmerman, Ph.D.
President & Principal
CME Consulting, Inc.
Experts in Advanced PHYsical Communications