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oopt-gnpy/gnpy/core/network.py
Jonas Mårtensson 3d5b1fcf64 Fix calculation of power target for Edfa in gain mode 
See GitHub issue #368

The out_voa attenuation of the previous Edfa is currently not taken
into account when calculating power target for an Edfa in gain mode.
This makes the calculated gain target (in case of autodesign) for
the following Edfa in the chain incorrect and also impacts automatic
amplifier selection.

Change-Id: Idc473762ccf7b021a0885c7ce20de1abb66eb075
Signed-off-by: Jonas Mårtensson <jonas.martensson@ri.se>
2020-11-03 21:40:38 +01:00

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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
def prev_node_generator(network, node):
"""fused spans interest:
iterate over all predecessors while they are Fused or Fiber type"""
try:
prev_node = next(network.predecessors(node))
except StopIteration:
raise NetworkTopologyError(f'Node {node.uid} is not properly connected, please check network topology')
# yield and re-iterate
if isinstance(prev_node, elements.Fused) or isinstance(node, elements.Fused):
yield prev_node
yield from prev_node_generator(network, prev_node)
else:
StopIteration
def next_node_generator(network, node):
"""fused spans interest:
iterate over all successors while they are Fused or Fiber type"""
try:
next_node = next(network.successors(node))
except StopIteration:
raise NetworkTopologyError('Node {node.uid} is not properly connected, please check network topology')
# yield and re-iterate
if isinstance(next_node, elements.Fused) or isinstance(node, elements.Fused):
yield next_node
yield from next_node_generator(network, next_node)
else:
StopIteration
def span_loss(network, node):
"""Fused span interest:
return the total span loss of all the fibers spliced by a Fused node"""
loss = node.loss if node.passive else 0
try:
prev_node = next(network.predecessors(node))
if isinstance(prev_node, elements.Fused):
loss += sum(n.loss for n in prev_node_generator(network, node))
except StopIteration:
pass
try:
next_node = next(network.successors(node))
if isinstance(next_node, elements.Fused):
loss += sum(n.loss for n in next_node_generator(network, node))
except StopIteration:
pass
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 this_node_degree:
# find the target power on this degree
if node.uid in this_node_degree.keys():
prev_dp = this_node_degree[node.uid] - pref_ch_db
else:
# if no target power is defined on this degree use the global one
# if target_pch_out_db is not an attribute, then the element must be a transceiver
prev_dp = getattr(this_node.params, 'target_pch_out_db', 0) - pref_ch_db
this_node_degree[node.uid] = prev_dp
else:
# if 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
prev_dp = getattr(this_node.params, 'target_pch_out_db', 0) - pref_ch_db
this_node_degree[node.uid] = prev_dp
dp = prev_dp
prev_voa = 0
voa = 0
while not (isinstance(node, elements.Roadm) or isinstance(node, elements.Transceiver)):
# go through all nodes in the OMS (loop until next Roadm instance)
next_node = next(network.successors(node))
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
# implementation of restrictions on roadm boosters
if isinstance(prev_node, elements.Roadm):
if prev_node.restrictions['booster_variety_list']:
restrictions = prev_node.restrictions['booster_variety_list']
else:
restrictions = None
elif isinstance(next_node, elements.Roadm):
# implementation of restrictions on roadm preamp
if next_node.restrictions['preamp_variety_list']:
restrictions = next_node.restrictions['preamp_variety_list']
else:
restrictions = None
else:
restrictions = None
if node.params.type_variety == '':
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')
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_egress_amplifier(network, node):
next_nodes = [n for n in network.successors(node)
if not (isinstance(n, elements.Transceiver) or isinstance(n, elements.Fused) or isinstance(n, elements.Edfa))]
# no amplification for fused spans or TRX
for i, next_node in enumerate(next_nodes):
network.remove_edge(node, next_node)
amp = elements.Edfa(
uid=f'Edfa{i}_{node.uid}',
params={},
metadata={
'location': {
'latitude': (node.lat + next_node.lat) / 2,
'longitude': (node.lng + next_node.lng) / 2,
'city': node.loc.city,
'region': node.loc.region,
}
},
operational={
'gain_target': None,
'tilt_target': 0,
})
network.add_node(amp)
if isinstance(node, elements.Fiber):
edgeweight = node.params.length
else:
edgeweight = 0.01
network.add_edge(node, amp, weight=edgeweight)
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 + 1) / (n_spans + 1) for n in range(n_spans)]
ypos = [prev_node.lat + (next_node.lat - prev_node.lat) * (n + 1) / (n_spans + 1) 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)
amplified_nodes = [n for n in network.nodes() if isinstance(n, elements.Fiber) or isinstance(n, elements.Roadm)]
for node in amplified_nodes:
add_egress_amplifier(network, node)
roadms = [r for r in amplified_nodes if isinstance(r, elements.Roadm)]
for roadm in roadms:
set_egress_amplifier(network, roadm, equipment, pref_ch_db, pref_total_db)
# support older json input topology wo Roadms:
if len(roadms) == 0:
trx = [t for t in network.nodes() if isinstance(t, elements.Transceiver)]
for t in trx:
set_egress_amplifier(network, t, equipment, 0, pref_total_db)
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