class HashrouteSymmetric(BaseStrategy):
"""Hashroute with symmetric routing
"""
def __init__(self, topology, log_dir, scenario_id, params=None):
'''
Constructor
'''
super(HashrouteSymmetric, self).__init__(topology, log_dir, scenario_id)
# map id of content to node with cache responsibility
self.cache_assignment = self.assign_caches(topology, self.cache_size, replicas=1)
self.stretch_logger = StretchLogger(path.join(log_dir, 'RESULTS_%s_STRETCH.txt' % scenario_id))
def handle_event(self, time, event):
# get all required data
receiver = event['receiver']
content = event['content']
log = event['log']
source = self.content_location[content]
cache = self.cache_assignment[self.content_hash(content)]
# handle (and log if required) actual request
if log: self.log_transfer(time, receiver, cache, PACKET_TYPE_INTEREST, content)
has_content = self.caches[cache].has_content(content)
if has_content and log:
self.cache_logger.log_cache_info(time, EVENT_CACHE_HIT, content, receiver, cache, source)
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content)
return
else:
if log:
self.log_transfer(time, cache, source, PACKET_TYPE_INTEREST, content)
self.cache_logger.log_cache_info(time, EVENT_SERVER_HIT, content, receiver, cache, source)
self.log_transfer(time, source, cache, PACKET_TYPE_DATA, content) # pass via cache
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content)
optimal_path_len = len(self.shortest_path[source][receiver]) - 1
actual_path_len = len(self.shortest_path[source][cache]) + len(self.shortest_path[cache][receiver]) - 2
self.stretch_logger.log_stretch_info(time, receiver, source, content, optimal_path_len, actual_path_len)
self.caches[cache].store(content) # insert content
return
def close(self):
super(HashrouteSymmetric, self).close()
self.stretch_logger.close()
class HashrouteHybridSymmMCast(BaseStrategy):
"""
Hashroute implementation with hybrid delivery of Data packets.
In this implementation, the edge router receiving a DATA packet decides
whether to deliver the packet using Multicast or asymmetric hashroute
based on the total cost for delivering the Data to both cache and receiver
in terms of hops.
"""
def __init__(self, topology, log_dir, scenario_id, params=None):
'''
Constructor
'''
super(HashrouteHybridSymmMCast, self).__init__(topology, log_dir, scenario_id)
# map id of content to node with cache responsibility
self.cache_assignment = self.assign_caches(topology, self.cache_size, replicas=1)
self.stretch_logger = StretchLogger(path.join(log_dir, 'RESULTS_%s_STRETCH.txt' % scenario_id))
self.scenario_id = scenario_id
self.symm_count = 0
self.mcast_count = 0
def handle_event(self, time, event):
# get all required data
receiver = event['receiver']
content = event['content']
log = event['log']
source = self.content_location[content]
cache = self.cache_assignment[self.content_hash(content)]
# handle (and log if required) actual request
if log: self.log_transfer(time, receiver, cache, PACKET_TYPE_INTEREST, content)
has_content = self.caches[cache].has_content(content)
if has_content and log:
self.cache_logger.log_cache_info(time, EVENT_CACHE_HIT, content, receiver, cache, source)
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content)
else:
if log:
self.log_transfer(time, cache, source, PACKET_TYPE_INTEREST, content)
self.cache_logger.log_cache_info(time, EVENT_SERVER_HIT, content, receiver, cache, source)
if cache in self.shortest_path[source][receiver]:
self.caches[cache].store(content) # insert content
if log:
self.log_transfer(time, source, cache, PACKET_TYPE_DATA, content) # pass via cache
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content) # pass via cache
path_len = len(self.shortest_path[source][receiver])
self.stretch_logger.log_stretch_info(time, receiver, source, content, path_len, path_len)
return
else:
#do multicast here
cache_path = self.shortest_path[source][cache]
recv_path = self.shortest_path[source][receiver]
# find what is the node that has to fork the DATA packet
for i in range(1, min([len(cache_path), len(recv_path)])):
if cache_path[i] != recv_path[i]:
fork_node = cache_path[i-1]
break
else: fork_node = cache
optimal_path_len = len(self.shortest_path[source][receiver])
symmetric_path_len = len(self.shortest_path[source][cache]) + \
len(self.shortest_path[cache][receiver]) - 2
multicast_path_len = len(self.shortest_path[source][fork_node]) + \
len(self.shortest_path[fork_node][cache]) + \
len(self.shortest_path[fork_node][receiver]) - 3
# insert content in cache
self.caches[cache].store(content)
# decide if use symmetric or multicast depending on total costs
if symmetric_path_len < multicast_path_len: # use symmetric delivery
if log:
self.symm_count += 1
self.log_transfer(time, source, cache, PACKET_TYPE_DATA, content)
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content)
self.stretch_logger.log_stretch_info(time, receiver, source, content, optimal_path_len, symmetric_path_len)
else: # use multicast delivery
if log:
self.mcast_count += 1
self.log_transfer(time, source, fork_node, PACKET_TYPE_DATA, content)
self.log_transfer(time, fork_node, receiver, PACKET_TYPE_DATA, content)
self.log_transfer(time, fork_node, cache, PACKET_TYPE_DATA, content)
self.stretch_logger.log_stretch_info(time, receiver, source, content, optimal_path_len, multicast_path_len)
def close(self):
super(HashrouteHybridSymmMCast, self).close()
self.stretch_logger.close()
class HashrouteHybridStretch(BaseStrategy):
"""
Hashroute implementation with hybrid delivery of Data packets.
In this strategy, if there is a cache miss, when DATA packets returns in
the domain, the packet is multicasted, one copy being sent to the
authoritative cache and the other to the receiver. If the cache is on the
path from source to receiver, this strategy behaves as a normal asymmetric
HashRoute
"""
def __init__(self, topology, log_dir, scenario_id, params=None):
'''
Constructor
'''
super(HashrouteHybridStretch, self).__init__(topology, log_dir, scenario_id)
# map id of content to node with cache responsibility
params = {'max_stretch': 0.2}
self.cache_assignment = self.assign_caches(topology, self.cache_size, replicas=1)
self.max_stretch = nx.diameter(topology) * params['max_stretch']
self.stretch_logger = StretchLogger(path.join(log_dir, 'RESULTS_%s_STRETCH.txt' % scenario_id))
def handle_event(self, time, event):
# get all required data
receiver = event['receiver']
content = event['content']
log = event['log']
source = self.content_location[content]
cache = self.cache_assignment[self.content_hash(content)]
# handle (and log if required) actual request
if log: self.log_transfer(time, receiver, cache, PACKET_TYPE_INTEREST, content)
has_content = self.caches[cache].has_content(content)
if has_content and log:
self.cache_logger.log_cache_info(time, EVENT_CACHE_HIT, content, receiver, cache, source)
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content)
else:
if log:
self.log_transfer(time, cache, source, PACKET_TYPE_INTEREST, content)
self.cache_logger.log_cache_info(time, EVENT_SERVER_HIT, content, receiver, cache, source)
if cache in self.shortest_path[source][receiver]:
self.caches[cache].store(content) # insert content
if log:
self.log_transfer(time, source, cache, PACKET_TYPE_DATA, content) # pass via cache
self.log_transfer(time, cache, receiver, PACKET_TYPE_DATA, content) # pass via cache
path_len = len(self.shortest_path[source][receiver])
self.stretch_logger.log_stretch_info(time, receiver, source, content, path_len, path_len)
return
else:
#do multicast here
cache_path = self.shortest_path[source][cache]
recv_path = self.shortest_path[source][receiver]
# find what is the node that has to fork the DATA packet
for i in range(1, min([len(cache_path), len(recv_path)])):
if cache_path[i] != recv_path[i]:
fork_node = cache_path[i-1]
break
else: fork_node = cache
optimal_path_len = len(self.shortest_path[source][receiver]) - 1
actual_path_len = len(self.shortest_path[source][fork_node]) + \
len(self.shortest_path[fork_node][cache]) + \
len(self.shortest_path[fork_node][receiver]) - 3
# multicast to cache only if stretch is under threshold
go_to_cache = ((actual_path_len - optimal_path_len) < self.max_stretch)
if go_to_cache:
self.caches[cache].store(content)
if log:
self.log_transfer(time, source, fork_node, PACKET_TYPE_DATA, content)
self.log_transfer(time, fork_node, receiver, PACKET_TYPE_DATA, content)
if go_to_cache:
self.log_transfer(time, fork_node, cache, PACKET_TYPE_DATA, content)
self.stretch_logger.log_stretch_info(time, receiver, source, content, optimal_path_len, actual_path_len)
def close(self):
super(HashrouteHybridStretch, self).close()
self.stretch_logger.close()