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oopt-gnpy/gnpy/core/network.py
Jonas Mårtensson 44f8cdbf20 Fix span loss calculation for auto-design 
I believe a previous commit, 3ac08f5, changed the behaviour of span
loss calculation in an unintended way, since now it adds the loss of
consecutive fiber elements even when there is no fused element in
between. This means for example that no padding is added when the loss
of consecutive fibers is higher than the padding specified in the
equipment file even though inline amplifiers will be added between the
fibers in a later step. This patch changes the conditions in the next_
and prev_node_generator so that they stop when two consecutive fibers
are found.

Signed-off-by: Jonas Mårtensson <jonas.martensson@ri.se>
Change-Id: I42c9188c789a98a9b3d7e51d5aae15774d40dde7
2021-05-12 09:19:05 +02:00

547 lines
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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
'''
gnpy.core.network
=================
Working with networks which consist of network elements
'''
from operator import attrgetter
from gnpy.core import ansi_escapes, elements
from gnpy.core.exceptions import ConfigurationError, NetworkTopologyError
from gnpy.core.utils import round2float, convert_length
from collections import namedtuple
def edfa_nf(gain_target, variety_type, equipment):
amp_params = equipment['Edfa'][variety_type]
amp = elements.Edfa(
uid='calc_NF',
params=amp_params.__dict__,
operational={
'gain_target': gain_target,
'tilt_target': 0
}
)
amp.pin_db = 0
amp.nch = 88
return amp._calc_nf(True)
def select_edfa(raman_allowed, gain_target, power_target, equipment, uid, restrictions=None):
"""amplifer selection algorithm
@Orange Jean-Luc Augé
"""
Edfa_list = namedtuple('Edfa_list', 'variety power gain_min nf')
TARGET_EXTENDED_GAIN = equipment['Span']['default'].target_extended_gain
# for roadm restriction only: create a dict including not allowed for design amps
# because main use case is to have specific radm amp which are not allowed for ILA
# with the auto design
edfa_dict = {name: amp for (name, amp) in equipment['Edfa'].items()
if restrictions is None or name in restrictions}
pin = power_target - gain_target
# create 2 list of available amplifiers with relevant attributes for their selection
# edfa list with:
# extended gain min allowance of 3dB: could be parametrized, but a bit complex
# extended gain max allowance TARGET_EXTENDED_GAIN is coming from eqpt_config.json
# power attribut include power AND gain limitations
edfa_list = [Edfa_list(
variety=edfa_variety,
power=min(
pin
+ edfa.gain_flatmax
+ TARGET_EXTENDED_GAIN,
edfa.p_max
)
- power_target,
gain_min=gain_target + 3
- edfa.gain_min,
nf=edfa_nf(gain_target, edfa_variety, equipment))
for edfa_variety, edfa in edfa_dict.items()
if ((edfa.allowed_for_design or restrictions is not None) and not edfa.raman)]
# consider a Raman list because of different gain_min requirement:
# do not allow extended gain min for Raman
raman_list = [Edfa_list(
variety=edfa_variety,
power=min(
pin
+ edfa.gain_flatmax
+ TARGET_EXTENDED_GAIN,
edfa.p_max
)
- power_target,
gain_min=gain_target
- edfa.gain_min,
nf=edfa_nf(gain_target, edfa_variety, equipment))
for edfa_variety, edfa in edfa_dict.items()
if (edfa.allowed_for_design and edfa.raman)] \
if raman_allowed else []
# merge raman and edfa lists
amp_list = edfa_list + raman_list
# filter on min gain limitation:
acceptable_gain_min_list = [x for x in amp_list if x.gain_min > 0]
if len(acceptable_gain_min_list) < 1:
# do not take this empty list into account for the rest of the code
# but issue a warning to the user and do not consider Raman
# Raman below min gain should not be allowed because i is meant to be a design requirement
# and raman padding at the amplifier input is impossible!
if len(edfa_list) < 1:
raise ConfigurationError(f'auto_design could not find any amplifier \
to satisfy min gain requirement in node {uid} \
please increase span fiber padding')
else:
# TODO: convert to logging
print(
f'{ansi_escapes.red}WARNING:{ansi_escapes.reset} target gain in node {uid} is below all available amplifiers min gain: \
amplifier input padding will be assumed, consider increase span fiber padding instead'
)
acceptable_gain_min_list = edfa_list
# filter on gain+power limitation:
# this list checks both the gain and the power requirement
# because of the way .power is calculated in the list
acceptable_power_list = [x for x in acceptable_gain_min_list if x.power > 0]
if len(acceptable_power_list) < 1:
# no amplifier satisfies the required power, so pick the highest power(s):
power_max = max(acceptable_gain_min_list, key=attrgetter('power')).power
# check and pick if other amplifiers may have a similar gain/power
# allow a 0.3dB power range
# this allows to chose an amplifier with a better NF subsequentely
acceptable_power_list = [x for x in acceptable_gain_min_list
if x.power - power_max > -0.3]
# gain and power requirements are resolved,
# =>chose the amp with the best NF among the acceptable ones:
selected_edfa = min(acceptable_power_list, key=attrgetter('nf')) # filter on NF
# check what are the gain and power limitations of this amp
power_reduction = round(min(selected_edfa.power, 0), 2)
if power_reduction < -0.5:
print(
f'{ansi_escapes.red}WARNING:{ansi_escapes.reset} target gain and power in node {uid}\n \
is beyond all available amplifiers capabilities and/or extended_gain_range:\n\
a power reduction of {power_reduction} is applied\n'
)
return selected_edfa.variety, power_reduction
def target_power(network, node, equipment): # get_fiber_dp
if isinstance(node, elements.Roadm):
return 0
SPAN_LOSS_REF = 20
POWER_SLOPE = 0.3
dp_range = list(equipment['Span']['default'].delta_power_range_db)
node_loss = span_loss(network, node)
try:
dp = round2float((node_loss - SPAN_LOSS_REF) * POWER_SLOPE, dp_range[2])
dp = max(dp_range[0], dp)
dp = min(dp_range[1], dp)
except IndexError:
raise ConfigurationError(f'invalid delta_power_range_db definition in eqpt_config[Span]'
f'delta_power_range_db: [lower_bound, upper_bound, step]')
return dp
_fiber_fused_types = (elements.Fused, elements.Fiber)
def prev_node_generator(network, node):
"""fused spans interest:
iterate over all predecessors while they are either Fused or Fibers succeeded by Fused"""
try:
prev_node = next(network.predecessors(node))
except StopIteration:
if isinstance(node, elements.Transceiver):
return
raise NetworkTopologyError(f'Node {node.uid} is not properly connected, please check network topology')
if ((isinstance(prev_node, elements.Fused) and isinstance(node, _fiber_fused_types)) or
(isinstance(prev_node, _fiber_fused_types) and isinstance(node, elements.Fused))):
yield prev_node
yield from prev_node_generator(network, prev_node)
def next_node_generator(network, node):
"""fused spans interest:
iterate over all predecessors while they are either Fused or Fibers preceded by Fused"""
try:
next_node = next(network.successors(node))
except StopIteration:
if isinstance(node, elements.Transceiver):
return
raise NetworkTopologyError(f'Node {node.uid} is not properly connected, please check network topology')
if ((isinstance(next_node, elements.Fused) and isinstance(node, _fiber_fused_types)) or
(isinstance(next_node, _fiber_fused_types) and isinstance(node, elements.Fused))):
yield next_node
yield from next_node_generator(network, next_node)
def span_loss(network, node):
"""Total loss of a span (Fiber and Fused nodes) which contains the given node"""
loss = node.loss if node.passive else 0
loss += sum(n.loss for n in prev_node_generator(network, node))
loss += sum(n.loss for n in next_node_generator(network, node))
return loss
def find_first_node(network, node):
"""Fused node interest:
returns the 1st node at the origin of a succession of fused nodes
(aka no amp in between)"""
this_node = node
for this_node in prev_node_generator(network, node):
pass
return this_node
def find_last_node(network, node):
"""Fused node interest:
returns the last node in a succession of fused nodes
(aka no amp in between)"""
this_node = node
for this_node in next_node_generator(network, node):
pass
return this_node
def set_amplifier_voa(amp, power_target, power_mode):
VOA_MARGIN = 1 # do not maximize the VOA optimization
if amp.out_voa is None:
if power_mode and amp.params.out_voa_auto:
voa = min(amp.params.p_max - power_target,
amp.params.gain_flatmax - amp.effective_gain)
voa = max(round2float(voa, 0.5) - VOA_MARGIN, 0)
amp.delta_p = amp.delta_p + voa
amp.effective_gain = amp.effective_gain + voa
else:
voa = 0 # no output voa optimization in gain mode
amp.out_voa = voa
def set_egress_amplifier(network, this_node, equipment, pref_ch_db, pref_total_db):
""" this node can be a transceiver or a ROADM (same function called in both cases)
"""
power_mode = equipment['Span']['default'].power_mode
next_oms = (n for n in network.successors(this_node) if not isinstance(n, elements.Transceiver))
this_node_degree = {k: v for k, v in this_node.per_degree_pch_out_db.items()} if hasattr(this_node, 'per_degree_pch_out_db') else {}
for oms in next_oms:
# go through all the OMS departing from the ROADM
prev_node = this_node
node = oms
# if isinstance(next_node, elements.Fused): #support ROADM wo egress amp for metro applications
# node = find_last_node(next_node)
# next_node = next(n for n in network.successors(node))
# next_node = find_last_node(next_node)
if node.uid not in this_node_degree:
# if no target power is defined on this degree or no per degree target power is given use the global one
# if target_pch_out_db is not an attribute, then the element must be a transceiver
this_node_degree[node.uid] = getattr(this_node.params, 'target_pch_out_db', 0)
# use the target power on this degree
prev_dp = this_node_degree[node.uid] - pref_ch_db
dp = prev_dp
prev_voa = 0
voa = 0
visited_nodes = []
while not (isinstance(node, elements.Roadm) or isinstance(node, elements.Transceiver)):
# go through all nodes in the OMS (loop until next Roadm instance)
try:
next_node = next(network.successors(node))
except StopIteration:
raise NetworkTopologyError(f'{type(node).__name__} {node.uid} is not properly connected, please check network topology')
visited_nodes.append(node)
if next_node in visited_nodes:
raise NetworkTopologyError(f'Loop detected for {type(node).__name__} {node.uid}, please check network topology')
if isinstance(node, elements.Edfa):
node_loss = span_loss(network, prev_node)
voa = node.out_voa if node.out_voa else 0
if node.delta_p is None:
dp = target_power(network, next_node, equipment)
else:
dp = node.delta_p
if node.effective_gain is None or power_mode:
gain_target = node_loss + dp - prev_dp + prev_voa
else: # gain mode with effective_gain
gain_target = node.effective_gain
dp = prev_dp - node_loss - prev_voa + gain_target
power_target = pref_total_db + dp
if isinstance(prev_node, elements.Fiber):
max_fiber_lineic_loss_for_raman = \
equipment['Span']['default'].max_fiber_lineic_loss_for_raman
raman_allowed = prev_node.params.loss_coef < max_fiber_lineic_loss_for_raman
else:
raman_allowed = False
if node.params.type_variety == '':
if node.variety_list and isinstance(node.variety_list, list):
restrictions = node.variety_list
elif isinstance(prev_node, elements.Roadm) and prev_node.restrictions['booster_variety_list']:
# implementation of restrictions on roadm boosters
restrictions = prev_node.restrictions['booster_variety_list']
elif isinstance(next_node, elements.Roadm) and next_node.restrictions['preamp_variety_list']:
# implementation of restrictions on roadm preamp
restrictions = next_node.restrictions['preamp_variety_list']
else:
restrictions = None
edfa_variety, power_reduction = select_edfa(raman_allowed, gain_target, power_target, equipment, node.uid, restrictions)
extra_params = equipment['Edfa'][edfa_variety]
node.params.update_params(extra_params.__dict__)
dp += power_reduction
gain_target += power_reduction
elif node.params.raman and not raman_allowed:
print(f'{ansi_escapes.red}WARNING{ansi_escapes.reset}: raman is used in node {node.uid}\n but fiber lineic loss is above threshold\n')
else:
# if variety is imposed by user, and if the gain_target (computed or imposed) is also above
# variety max gain + extended range, then warn that gain > max_gain + extended range
if gain_target - equipment['Edfa'][node.params.type_variety].gain_flatmax - \
equipment['Span']['default'].target_extended_gain > 1e-2:
# 1e-2 to allow a small margin according to round2float min step
print(f'{ansi_escapes.red}WARNING{ansi_escapes.reset}: '
f'WARNING: effective gain in Node {node.uid} is above user '
f'specified amplifier {node.params.type_variety}\n'
f'max flat gain: {equipment["Edfa"][node.params.type_variety].gain_flatmax}dB ; '
f'required gain: {gain_target}dB. Please check amplifier type.')
node.delta_p = dp if power_mode else None
node.effective_gain = gain_target
set_amplifier_voa(node, power_target, power_mode)
prev_dp = dp
prev_voa = voa
prev_node = node
node = next_node
# print(f'{node.uid}')
if isinstance(this_node, elements.Roadm):
this_node.per_degree_pch_out_db = {k: v for k, v in this_node_degree.items()}
def add_roadm_booster(network, roadm):
next_nodes = [n for n in network.successors(roadm)
if not (isinstance(n, elements.Transceiver) or isinstance(n, elements.Fused) or isinstance(n, elements.Edfa))]
# no amplification for fused spans or TRX
for next_node in next_nodes:
network.remove_edge(roadm, next_node)
amp = elements.Edfa(
uid=f'Edfa_booster_{roadm.uid}_to_{next_node.uid}',
params={},
metadata={
'location': {
'latitude': roadm.lat,
'longitude': roadm.lng,
'city': roadm.loc.city,
'region': roadm.loc.region,
}
},
operational={
'gain_target': None,
'tilt_target': 0,
})
network.add_node(amp)
network.add_edge(roadm, amp, weight=0.01)
network.add_edge(amp, next_node, weight=0.01)
def add_roadm_preamp(network, roadm):
prev_nodes = [n for n in network.predecessors(roadm)
if not (isinstance(n, elements.Transceiver) or isinstance(n, elements.Fused) or isinstance(n, elements.Edfa))]
# no amplification for fused spans or TRX
for prev_node in prev_nodes:
network.remove_edge(prev_node, roadm)
amp = elements.Edfa(
uid=f'Edfa_preamp_{roadm.uid}_from_{prev_node.uid}',
params={},
metadata={
'location': {
'latitude': roadm.lat,
'longitude': roadm.lng,
'city': roadm.loc.city,
'region': roadm.loc.region,
}
},
operational={
'gain_target': None,
'tilt_target': 0,
})
network.add_node(amp)
if isinstance(prev_node, elements.Fiber):
edgeweight = prev_node.params.length
else:
edgeweight = 0.01
network.add_edge(prev_node, amp, weight=edgeweight)
network.add_edge(amp, roadm, weight=0.01)
def add_inline_amplifier(network, fiber):
next_node = next(network.successors(fiber))
if isinstance(next_node, elements.Fiber) or isinstance(next_node, elements.RamanFiber):
# no amplification for fused spans or TRX
network.remove_edge(fiber, next_node)
amp = elements.Edfa(
uid=f'Edfa_{fiber.uid}',
params={},
metadata={
'location': {
'latitude': (fiber.lat + next_node.lat) / 2,
'longitude': (fiber.lng + next_node.lng) / 2,
'city': fiber.loc.city,
'region': fiber.loc.region,
}
},
operational={
'gain_target': None,
'tilt_target': 0,
})
network.add_node(amp)
network.add_edge(fiber, amp, weight=fiber.params.length)
network.add_edge(amp, next_node, weight=0.01)
def calculate_new_length(fiber_length, bounds, target_length):
if fiber_length < bounds.stop:
return fiber_length, 1
n_spans2 = int(fiber_length // target_length)
n_spans1 = n_spans2 + 1
length1 = fiber_length / n_spans1
length2 = fiber_length / n_spans2
if (bounds.start <= length1 <= bounds.stop) and not(bounds.start <= length2 <= bounds.stop):
return (length1, n_spans1)
elif (bounds.start <= length2 <= bounds.stop) and not(bounds.start <= length1 <= bounds.stop):
return (length2, n_spans2)
elif target_length - length1 < length2 - target_length:
return (length1, n_spans1)
else:
return (length2, n_spans2)
def split_fiber(network, fiber, bounds, target_length, equipment):
new_length, n_spans = calculate_new_length(fiber.params.length, bounds, target_length)
if n_spans == 1:
return
try:
next_node = next(network.successors(fiber))
prev_node = next(network.predecessors(fiber))
except StopIteration:
raise NetworkTopologyError(f'Fiber {fiber.uid} is not properly connected, please check network topology')
network.remove_node(fiber)
fiber.params.length = new_length
xpos = [prev_node.lng + (next_node.lng - prev_node.lng) * (n + 0.5) / n_spans for n in range(n_spans)]
ypos = [prev_node.lat + (next_node.lat - prev_node.lat) * (n + 0.5) / n_spans for n in range(n_spans)]
for span, lng, lat in zip(range(n_spans), xpos, ypos):
new_span = elements.Fiber(uid=f'{fiber.uid}_({span+1}/{n_spans})',
type_variety=fiber.type_variety,
metadata={
'location': {
'latitude': lat,
'longitude': lng,
'city': fiber.loc.city,
'region': fiber.loc.region,
}
},
params=fiber.params.asdict())
if isinstance(prev_node, elements.Fiber):
edgeweight = prev_node.params.length
else:
edgeweight = 0.01
network.add_edge(prev_node, new_span, weight=edgeweight)
prev_node = new_span
if isinstance(prev_node, elements.Fiber):
edgeweight = prev_node.params.length
else:
edgeweight = 0.01
network.add_edge(prev_node, next_node, weight=edgeweight)
def add_connector_loss(network, fibers, default_con_in, default_con_out, EOL):
for fiber in fibers:
try:
next_node = next(network.successors(fiber))
except StopIteration:
raise NetworkTopologyError(f'Fiber {fiber.uid} is not properly connected, please check network topology')
if fiber.params.con_in is None:
fiber.params.con_in = default_con_in
if fiber.params.con_out is None:
fiber.params.con_out = default_con_out
if not isinstance(next_node, elements.Fused):
fiber.params.con_out += EOL
def add_fiber_padding(network, fibers, padding):
"""last_fibers = (fiber for n in network.nodes()
if not (isinstance(n, elements.Fiber) or isinstance(n, elements.Fused))
for fiber in network.predecessors(n)
if isinstance(fiber, elements.Fiber))"""
for fiber in fibers:
try:
next_node = next(network.successors(fiber))
except StopIteration:
raise NetworkTopologyError(f'Fiber {fiber.uid} is not properly connected, please check network topology')
if isinstance(next_node, elements.Fused):
continue
this_span_loss = span_loss(network, fiber)
if this_span_loss < padding:
# add a padding att_in at the input of the 1st fiber:
# address the case when several fibers are spliced together
first_fiber = find_first_node(network, fiber)
# in order to support no booster , fused might be placed
# just after a roadm: need to check that first_fiber is really a fiber
if isinstance(first_fiber, elements.Fiber):
first_fiber.params.att_in = first_fiber.params.att_in + padding - this_span_loss
def build_network(network, equipment, pref_ch_db, pref_total_db):
default_span_data = equipment['Span']['default']
max_length = int(convert_length(default_span_data.max_length, default_span_data.length_units))
min_length = max(int(default_span_data.padding / 0.2 * 1e3), 50_000)
bounds = range(min_length, max_length)
target_length = max(min_length, 90_000)
# set roadm loss for gain_mode before to build network
fibers = [f for f in network.nodes() if isinstance(f, elements.Fiber)]
add_connector_loss(network, fibers, default_span_data.con_in, default_span_data.con_out, default_span_data.EOL)
add_fiber_padding(network, fibers, default_span_data.padding)
# don't group split fiber and add amp in the same loop
# =>for code clarity (at the expense of speed):
for fiber in fibers:
split_fiber(network, fiber, bounds, target_length, equipment)
roadms = [r for r in network.nodes() if isinstance(r, elements.Roadm)]
for roadm in roadms:
add_roadm_preamp(network, roadm)
add_roadm_booster(network, roadm)
fibers = [f for f in network.nodes() if isinstance(f, elements.Fiber)]
for fiber in fibers:
add_inline_amplifier(network, fiber)
for roadm in roadms:
set_egress_amplifier(network, roadm, equipment, pref_ch_db, pref_total_db)
trx = [t for t in network.nodes() if isinstance(t, elements.Transceiver)]
for t in trx:
next_node = next(network.successors(t), None)
if next_node and not isinstance(next_node, elements.Roadm):
set_egress_amplifier(network, t, equipment, 0, pref_total_db)
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