```
"""
Rocketfuel topology and traffic matrix
======================================
This example shows how to import a topology from RocketFuel, configure it
(assign capacities, weights and delays), generate a traffic matrix and
save topology and traffic matrix to XML files.
"""
import fnss
import random
# Import RocketFuel topology
# Replace the filename with the actual location of the file you want to parse
topology = fnss.parse_rocketfuel_isp_map("rocket-fuel-topo-file.cch")
# add capacities
capacities = [1, 10, 40]
capacity_unit = 'Gbps'
fnss.set_capacities_edge_betweenness(topology, capacities, capacity_unit,
weighted=False)
# add weights proportional to inverse of capacity
fnss.set_weights_inverse_capacity(topology)
# add constant link delays of 2 ms
fnss.set_delays_constant(topology, 2, delay_unit='ms')
# generate cyclostationary traffic matrix (period 7 days, 24 samples per day)
tmc = fnss.sin_cyclostationary_traffic_matrix(
topology,
mean=0.5, # average flow in TM is 0,5 Gbps
stddev=0.05, # this is the std among average flows of different OD pairs
gamma=0.8, # gamma and log_psi are parameters for fitting the std of
log_psi=-0.33, # volume fluctuations over time. Look at Nucci et al. paper
delta=0.2, # traffic variation from period max and avg as fraction of average
n=24, # number of samples per each period
periods=7, # number of periods
max_u=0.9, # max link utilization desired
origin_nodes=None, # Specify origin and destination nodes. If None,
destination_nodes=None # all nodes of the topology are both
) # origin and destination nodes of traffic
# now we generate a static traffic matrix, but this time instead of generating
# a matrix where all nodes are both origin and destinations, we pick up only
# few nodes as sources and destinations of traffic.
# Let's select 5 sources and 5 destinations
nodes = topology.nodes()
origins = random.sample(nodes, 5)
destinations = random.sample(nodes, 5)
# generate traffic matrix
tms = fnss.static_traffic_matrix(topology, mean=0.5, stddev=0.05, max_u=0.9,
origin_nodes=origins,
destination_nodes=destinations)
# save topology on a file
fnss.write_topology(topology, 'topology.xml')
# save traffic matrices on files
fnss.write_traffic_matrix(tmc, 'cyclostationary-traffic-matrix.xml')
fnss.write_traffic_matrix(tms, 'static-traffic-matrix.xml')
```