def solve(self, topo, requirement_dags):
# a list of tuples with info on the node to be attracted,
# the forwarding address, the cost to be set in the fake LSA,
# and the respective destinations
self.fake_ospf_lsas = []
self.reqs = requirement_dags
self.igp_graph = topo
self.igp_paths = ShortestPath(self.igp_graph)
# process input forwarding DAGs, one at the time
for dest, dag in requirement_dags.iteritems():
log.info('Solving DAG for dest %s', dest)
self.dest, self.dag = dest, dag
log.debug('Checking dest in dag')
ssu.add_dest_to_graph(dest, dag)
log.debug('Checking dest in igp graph')
ssu.add_dest_to_graph(dest,
topo,
edges_src=dag.predecessors,
spt=self.igp_paths,
metric=self.new_edge_metric)
ssu.complete_dag(dag,
topo,
dest,
self.igp_paths,
skip=self.reqs.keys())
# Add temporarily the destination to the igp graph and/or req dags
if not ssu.solvable(dag, topo):
log.warning('Skipping requirement for dest: %s', dest)
continue
for node in dag:
nhs = self.nhs_for(node, dest, dag)
if not nhs:
continue
for req_nh in nhs:
log.debug('Placing a fake node for %s->%s', node, req_nh)
for i in xrange(get_edge_multiplicity(dag, node, req_nh)):
self.fake_ospf_lsas.append(
ssu.LSA(node=node,
nh=req_nh,
cost=(-1 - i),
dest=dest))
# Check whether we need to include one more fake node to handle
# the case where we create a new route from scratch.
for p in dag.predecessors_iter(dest):
if not is_fake(topo, p, dest):
continue
log.debug(
'%s is a terminal node towards %s but had no prior '
'route to it! Adding a synthetic route', p, dest)
self.fake_ospf_lsas.append(
ssu.GlobalLie(dest, self.new_edge_metric, p))
return self.fake_ospf_lsas
def solve(self, graph, requirements):
"""Compute the augmented topology for a given graph and a set of
requirements.
:type graph: IGPGraph
:type requirements: { dest: IGPGraph }
:param requirements: the set of requirement DAG on a per dest. basis
:return: list of fake LSAs"""
self.reqs = requirements
log.info('Preparing IGP graph')
self.g = prepare_graph(graph, requirements)
log.info('Computing SPT')
self._p = ShortestPath(graph)
lsa = []
for dest, dag in requirements.iteritems():
self.dest, self.dag = dest, dag
self.ecmp.clear()
log.info('Evaluating requirement %s', dest)
log.info('Ensuring the consistency of the DAG')
self.check_dest()
ssu.complete_dag(self.dag,
self.g,
self.dest,
self._p,
skip=self.reqs.keys())
log.info('Computing original and required next-hop sets')
for n, node in self.nodes():
node.forced_nhs = set(self.dag.successors(n))
node.original_nhs = set(
[p[1] for p in self._p.default_path(n, self.dest)])
if not ssu.solvable(self.dag, self.g):
log.warning('Consistency check failed, skipping %s', dest)
continue
log.info('Placing initial fake nodes')
self.place_fake_nodes()
log.info('Initializing fake nodes')
self.initialize_fake_nodes()
log.info('Propagating initial lower bounds')
self.propagate_lb()
log.debug('Fake node bounds: %s',
[n for _, n in self.nodes() if n.has_any_fake_node()])
log.info('Reducing the augmented topology')
self.merge_fake_nodes()
self.remove_redundant_fake_nodes()
log.info('Generating LSAs')
lsas = self.create_fake_lsa()
log.info('Solved the DAG for destination %s with LSA set: %s',
self.dest, lsas)
lsa.extend(lsas)
return lsa
def solve(self, graph, requirements):
"""Compute the augmented topology for a given graph and a set of
requirements.
:type graph: IGPGraph
:type requirements: { dest: IGPGraph }
:param requirements: the set of requirement DAG on a per dest. basis
:return: list of fake LSAs"""
self.reqs = requirements
log.info('Preparing IGP graph')
self.g = prepare_graph(graph, requirements)
log.info('Computing SPT')
self._p = ShortestPath(graph)
lsa = []
for dest, dag in requirements.iteritems():
self.dest, self.dag = dest, dag
self.ecmp.clear()
log.info('Evaluating requirement %s', dest)
log.info('Ensuring the consistency of the DAG')
self.check_dest()
ssu.complete_dag(self.dag, self.g, self.dest, self._p,
skip=self.reqs.keys())
log.info('Computing original and required next-hop sets')
for n, node in self.nodes():
node.forced_nhs = set(self.dag.successors(n))
node.original_nhs = set([p[1] for p in
self._p.default_path(n, self.dest)])
if not ssu.solvable(self.dag, self.g):
log.warning('Consistency check failed, skipping %s', dest)
continue
log.info('Placing initial fake nodes')
self.place_fake_nodes()
log.info('Initializing fake nodes')
self.initialize_fake_nodes()
log.info('Propagating initial lower bounds')
self.propagate_lb()
log.debug('Fake node bounds: %s',
[n for _, n in self.nodes() if n.has_any_fake_node()])
log.info('Reducing the augmented topology')
self.merge_fake_nodes()
self.remove_redundant_fake_nodes()
log.info('Generating LSAs')
lsas = self.create_fake_lsa()
log.info('Solved the DAG for destination %s with LSA set: %s',
self.dest, lsas)
lsa.extend(lsas)
return lsa
def solve(self, topo, requirement_dags):
# a list of tuples with info on the node to be attracted,
# the forwarding address, the cost to be set in the fake LSA,
# and the respective destinations
self.fake_ospf_lsas = []
self.reqs = requirement_dags
self.igp_graph = topo
self.igp_paths = ShortestPath(self.igp_graph)
# process input forwarding DAGs, one at the time
for dest, dag in requirement_dags.iteritems():
log.info('Solving DAG for dest %s', dest)
self.dest, self.dag = dest, dag
log.debug('Checking dest in dag')
ssu.add_dest_to_graph(dest, dag)
log.debug('Checking dest in igp graph')
ssu.add_dest_to_graph(dest, topo,
edges_src=dag.predecessors,
spt=self.igp_paths,
metric=self.new_edge_metric)
ssu.complete_dag(dag, topo, dest, self.igp_paths,
skip=self.reqs.keys())
# Add temporarily the destination to the igp graph and/or req dags
if not ssu.solvable(dag, topo):
log.warning('Skipping requirement for dest: %s', dest)
continue
for node in dag:
nhs = self.nhs_for(node, dest, dag)
if not nhs:
continue
for req_nh in nhs:
log.debug('Placing a fake node for %s->%s', node, req_nh)
for i in xrange(get_edge_multiplicity(dag, node, req_nh)):
self.fake_ospf_lsas.append(ssu.LSA(node=node,
nh=req_nh,
cost=(-1 - i),
dest=dest))
# Check whether we need to include one more fake node to handle
# the case where we create a new route from scratch.
for p in dag.predecessors_iter(dest):
if not is_fake(topo, p, dest):
continue
log.debug('%s is a terminal node towards %s but had no prior '
'route to it! Adding a synthetic route', p, dest)
self.fake_ospf_lsas.append(
ssu.GlobalLie(dest, self.new_edge_metric, p))
return self.fake_ospf_lsas
def solve(self, topo, requirement_dags):
# a list of tuples with info on the node to be attracted,
# the forwarding address, the cost to be set in the fake LSA,
# and the respective destinations
self.fake_ospf_lsas = []
self.reqs = requirement_dags
self.igp_graph = topo
self.igp_paths = ShortestPath(self.igp_graph)
log.debug('Original SPT: %s', self.igp_paths)
# process input forwarding DAGs, one at the time
for dest, dag in requirement_dags.iteritems():
log.debug('Solving DAG for dest %s', dest)
self.dest, self.dag = dest, dag
log.debug('Checking dest in dag')
ssu.add_dest_to_graph(dest, dag)
log.debug('Checking dest in igp graph')
ssu.add_dest_to_graph(dest,
topo,
edges_src=dag.predecessors,
spt=self.igp_paths,
metric=self.new_edge_metric)
ssu.complete_dag(dag,
topo,
dest,
self.igp_paths,
skip=self.reqs.keys())
# Add temporarily the destination to the igp graph and/or req dags
if not ssu.solvable(dag, topo):
log.warning('Skipping requirement for dest: %s', dest)
continue
for node in nx.topological_sort(dag, reverse=True)[1:]:
nhs, original_nhs = self.nhs_for(node, dag, dest)
if not self.require_fake_node(nhs, original_nhs):
log.debug('%s does not require a fake node (%s - %s)',
node, nhs, original_nhs)
continue
for req_nh in nhs:
log.debug('Placing a fake node for nh %s', req_nh)
self.fake_ospf_lsas.append(
ssu.LSA(node=node, nh=req_nh, cost=-1, dest=dest))
return self.fake_ospf_lsas
def solve(self, topo, requirement_dags):
# a list of tuples with info on the node to be attracted,
# the forwarding address, the cost to be set in the fake LSA,
# and the respective destinations
self.fake_ospf_lsas = []
self.reqs = requirement_dags
self.igp_graph = topo
self.igp_paths = ShortestPath(self.igp_graph)
log.debug('Original SPT: %s', self.igp_paths)
# process input forwarding DAGs, one at the time
for dest, dag in requirement_dags.iteritems():
log.debug('Solving DAG for dest %s', dest)
self.dest, self.dag = dest, dag
log.debug('Checking dest in dag')
ssu.add_dest_to_graph(dest, dag)
log.debug('Checking dest in igp graph')
ssu.add_dest_to_graph(dest, topo,
edges_src=dag.predecessors,
spt=self.igp_paths,
metric=self.new_edge_metric)
ssu.complete_dag(dag, topo, dest, self.igp_paths,
skip=self.reqs.keys())
# Add temporarily the destination to the igp graph and/or req dags
if not ssu.solvable(dag, topo):
log.warning('Skipping requirement for dest: %s', dest)
continue
for node in nx.topological_sort(dag, reverse=True)[1:]:
nhs, original_nhs = self.nhs_for(node, dag, dest)
if not self.require_fake_node(nhs, original_nhs):
log.debug('%s does not require a fake node (%s - %s)',
node, nhs, original_nhs)
continue
for req_nh in nhs:
log.debug('Placing a fake node for nh %s', req_nh)
self.fake_ospf_lsas.append(ssu.LSA(node=node,
nh=req_nh,
cost=-1,
dest=dest))
return self.fake_ospf_lsas
