def create_vnf_processes(self):
'''
Create a process for each assigned VNF
:return: processes dict
'''
for v in self.attached_vnfs:
p = self.processes[v.id] = Process(v, self)
env.process(p.process())
def main():
'''
The main control flow to run the simulation
:return: None
'''
TOTAL_SERVICE_CHAIN_NUM = 4
TOTAL_SIM_TIME = 1000
random.seed(4)
# step1: create network topology
t = Topology()
t.load_network_graph(path='./topology/topology.txt')
t.create_network_topology()
for link in t.links.values():
env.process(link.run())
paths = cal_shortest_path(t.topology, t.links)
# step2: initialize servers
servers = Server.init_servers(t.get_nodes(), t.get_links())
# step3: create service chains
service_chains = [
ServiceChain.random_gen() for _ in range(TOTAL_SERVICE_CHAIN_NUM)
]
# step4: place service chains. single instance... multiple instance...
for chain in service_chains:
best_fit(servers, chain)
# launch server processes
for server in servers.values():
server.run()
# step5: generate a packet pool
packet_pool = Packet.gen_packet_pool(servers, paths, service_chains)
# step6 create a packet from the packet pool and simulate routing process.
# env.process(flow_generator(packet_pool, servers, t.links))
# single packet test
# packet = random.choice(packet_pool)
# print(packet.routing_path)
# print(packet.vnf_server_addr)
# packet.forward()
# generating traffic flow
env.process(flow_generator(packet_pool))
env.run(TOTAL_SIM_TIME)
def flow_generator(packet_pool):
'''
randomly generate a packet from the packet pool, and make it go through the placed service chain.
:param packet_pool:
:param servers:
:param links:
:return: None
'''
# todo: consider to find a Poisson distribution for the packet generation or to use the wiki traffic trace.
while True:
yield env.timeout(1)
packet = Packet.random_gen(packet_pool)
packet.create_time = env.now
env.process(packet.forward())
def run(self):
while True:
with self.forwarder.request() as req:
packet = yield self.buffer.get()
yield req
# forwarding the packet. KB / MB
forward_time = packet.get_size() / self.bandwidth / 1000
yield env.timeout(forward_time)
# print('link from {} to {} forwards the packet {} at time {}'.format(self.from_node.id, self.to_node.id,
# packet.id, env.now))
env.process(packet.forward(self.propagation_latency))
def run(self):
env.process(self.in_packet_proc())
env.process(self.out_packet_proc())
self.create_vnf_processes()