ex07_flowbased.py

# Definitions from the exercise
avg_packet_size = 400

edge_def = """
Edge	Dist	C_bps
AB	1	20000
BC	3	10000
AD	2	20000
BE	5	20000
CE	2	30000
AF	3	15000
CH	1	20000
DF	2	10000
DG	4	25000
EH	2	20000
FG	6	40000
GH	3	25000"""

traffic_def = """
AB 3 ABC 7 AD 4 ADE 2 AF 5 ADG 2 ADEH 5
BC 3 BAD 7 BE 3 BAF 4 BADG 3 BCH 4
CED 7 CE 5 CEDF 3 CHG 5 CH 3
DE 2 DF 9 DG 2 DEH 9
EDF 3 EHG 1 EH 2
FG 1 FDEH 9
GH 1
"""

# parse the traffic specification
import re
traffic = []
for m in re.finditer(r"([A-Z]+) ([0-9])", traffic_def):
  # add the forward traffic
  traffic.append((m.group(1), int(m.group(2))))

# parse the edges
edges = []
for line in edge_def.split("\n")[2:]:
  edge, dist, cap = line.split("\t")
  edge_rev = edge[::-1]
  avg_load_packets = 0
  for traf_path, traf_packets in traffic:
    if edge in traf_path or edge_rev in traf_path:
      avg_load_packets += traf_packets
  cap_packets = float(cap) / avg_packet_size
  avg_delay = 1 / (cap_packets - avg_load_packets)
  edges.append([edge, dist, avg_load_packets, float(cap), cap_packets, avg_delay, 0])

# calculate weight
all_lines_traffic = sum(e[2] for e in edges)
all_avg_delay = 0
print("Edge Dist Load  CapBits  CapPkgs  AvgDelay  Weight") 
for i in range(len(edges)):
	edge, dist, avg_load_packets, cap, cap_packets, avg_delay, weight = edges[i]
	weight = edges[i][6] = avg_load_packets / all_lines_traffic
	all_avg_delay += weight * avg_delay
	print("%s   %s   %4d   %0.01f  %7.01f   %0.04f   %0.04f"%tuple(edges[i]))

print("All lines avg delay: ", all_avg_delay)