def linkhandler1(linkid, newcost):
'''called when cost from 0 to linkid changes from current value to newcost
You can leave this routine empty if you're an undergrad. If you want
to use this routine, you'll need to change the value of the LINKCHANGE
constant definition in prog3.c from 0 to 1
'''
global edges, node_dv, dt
print("rt%d: link to rt%d changed from %d to %d" %
(node_id, linkid, edges[linkid], newcost))
for i in range(4):
dt.costs[i][linkid] = dt.costs[i][linkid] - edges[linkid] + newcost
dt.costs[linkid][node_id] = newcost
print("rt%d: distance table changed to" % node_id)
printdt1(dt)
edges[linkid] = newcost
new_dv = [min([dt.costs[i][j] for j in range(4)]) for i in range(4)]
if node_dv != new_dv:
node_dv = new_dv
for i in neighbor_id:
packet = Rtpkt(node_id, i, node_dv)
tolayer2(packet)
print("rt%d: distance vector changed to %s and sent to neighbors\n" %
(node_id, node_dv))
else:
print("rt%d: distance vector not changed, no packets sent\n" % node_id)
def rtupdate1(rcvdpkt):
global node_dv
src_id, dst_id, src_dv = rcvdpkt.sourceid, rcvdpkt.destid, rcvdpkt.mincost
print("rt%d: received packet from rt%d with distance vector %s" %
(node_id, src_id, src_dv))
if src_id not in neighbor_id:
print("WARNING: illegal src id in received packet, ignoring packet!\n")
return
if dst_id != node_id:
print("WARNING: illegal dst id in received packet, ignoring packet!\n")
return
dt_update = False
for i in range(4):
cost = src_dv[i] + edges[src_id]
if cost > 999:
cost = 999
if dt.costs[i][src_id] != cost:
dt_update = True
dt.costs[i][src_id] = cost
if (dt_update):
print("rt%d: distance table changed to" % node_id)
printdt1(dt)
else:
print("rt%d: distance table not changed" % node_id)
new_dv = [min([dt.costs[i][j] for j in range(4)]) for i in range(4)]
if node_dv != new_dv:
node_dv = new_dv
for i in neighbor_id:
packet = Rtpkt(node_id, i, node_dv)
tolayer2(packet)
print("rt%d: distance vector changed to %s and sent to neighbors\n" %
(node_id, node_dv))
else:
print("rt%d: distance vector not changed, no packets sent\n" % node_id)
def rtinit1():
for i in range(4):
if i == node_id:
continue
dt.costs[i][i] = edges[i]
printdt1(dt)
tolayer2(Rtpkt(node_id, 0, edges))
tolayer2(Rtpkt(node_id, 2, edges))
def rtinit1():
for i in range(4):
for j in range(4):
if j == node_id:
dt.costs[i][j] = edges[i]
else:
dt.costs[i][j] = 999
for i in neighbor_id:
packet = Rtpkt(node_id, i, node_dv)
tolayer2(packet)
print("rt%d: initializing, distance vector %s sent to neighbors\n" %
(node_id, node_dv))
def rtupdate3(rcvdpkt):
change = False
srcid = rcvdpkt.sourceid
table = rcvdpkt.mincost
for i in range(4):
tmp = edges[srcid] + table[i]
dt.costs[i][srcid] = min(dt.costs[i][srcid], tmp)
if tmp < cost[i]:
change = True
cost[i] = tmp
printdt3(dt)
if change:
tolayer2(Rtpkt(node_id, 0, cost))
tolayer2(Rtpkt(node_id, 2, cost))
