def route_table(node):
# include global variables
global link1_flag, link2_flag # Flags to check link status of the current node
link1_flag = Link.routing_flag1()
link2_flag = Link.routing_flag2()
links = node.GetLinks() # Links of the current node
tabl = node.linkTable # Link table of the topology
print "Destination NID Cost/Metrix Next Hop\n"
for k in tabl.keys(): # Traverse through the Link Table
# If the node is not the current node
if (k!=int(node.nid)):
# Since there are maximum two links per node, only two possible routes to the destination
# exists. This portion of the code calculates the costs and next hop values for both of these
# routes, one by one
metrix1 = 1
tn1 = int(node.nid) # Source (current) NID
tn2 = links[0][0] # One of the connected nodes' NID
while tn2!=k:
for key, value in tabl.items():
if key==tn2:
# If end of path occurs
if len(filter(bool, value))==1:
metrix1 = 100
break
# Else, continue traversing, by updating values of tn1 and tn2
else:
if value[0]==tn1:
tn1 = tn2
tn2 = value[1]
metrix1 += 1
else:
tn1 = tn2
tn2 = value[0]
metrix1 += 1
break
if metrix1>10:
break
metrix2 = 1
tn1 = int(node.nid) # Source (current) NID
tn2 = links[1][0] # Other connected nodes' NID
while tn2!=k:
for key, value in tabl.items():
if key==tn2:
# If end of path occurs
if len(filter(bool, value))==1:
metrix2 = 100
break
# Else, continue traversing, by updating values of tn1 and tn2
else:
if value[0]==tn1:
tn1 = tn2
tn2 = value[1]
metrix2 += 1
else:
tn1 = tn2
tn2 = value[0]
metrix2 += 1
break
if metrix2>10:
break
if metrix2>metrix1:
metrix = metrix1
nhop = links[0][0]
if metrix2<metrix1:
metrix = metrix2
nhop = links[1][0]
if metrix2==metrix1:
metrix = metrix1
nhop = max(int(links[0][0]), int(links[1][0]))
if node.upL1==False and node.upL2==False:
metrix = "inf"
nhop = "not reachable"
if node.upL1==False and node.upL2==True:
metrix = metrix2
nhop = links[1][0]
if node.upL1==True and node.upL2==False:
metrix = metrix1
nhop = links[0][0]
print '{0:^14}{1:^21}{2:^3}\n'.format(k, metrix, nhop)
# print state of flags (for testing)
print "Link 1 flag is ", link1_flag
print "Link 2 flag is ", link2_flag
raw_input("press enter to continue...")
def next_hop(node, last_nid): # include global variables global link1_flag, link2_flag link1_flag = Link.routing_flag1() link2_flag = Link.routing_flag2() links = node.GetLinks() tabl = node.linkTable #print "in routing", last_nid; for k in tabl.keys(): if (k==int(last_nid)): metrix1 = 1 tn1 = int(node.nid) tn2 = links[0][0] while tn2!=k: for key, value in tabl.items(): if key==tn2: if len(filter(bool, value))==1: metrix1 = 100 break else: if value[0]==tn1: tn1 = tn2 tn2 = value[1] metrix1 += 1 else: tn1 = tn2 tn2 = value[0] metrix1 += 1 break if metrix1>10: break metrix2 = 1 tn1 = int(node.nid) tn2 = links[1][0] while tn2!=k: for key, value in tabl.items(): if key==tn2: if len(filter(bool, value))==1: metrix2 = 100 break else: if value[0]==tn1: tn1 = tn2 tn2 = value[1] metrix2 += 1 else: tn1 = tn2 tn2 = value[0] metrix2 += 1 break if metrix2>10: break if metrix2>metrix1: metrix = metrix1 nh = links[0][0] if metrix2<metrix1: metrix = metrix2 nh = links[1][0] if metrix2==metrix1: metrix = metrix1 nh = max(int(links[0][0]), int(links[1][0])) if node.upL1==False and node.upL2==False: metrix = "inf" nh = "not reachable" if node.upL1==False and node.upL2==True: metrix = metrix2 nh = links[1][0] if node.upL1==True and node.upL2==False: metrix = metrix1 nh = links[0][0] return nh