Build protocol mechanism in twisted Site - twisted

Question

I am trying to understand how and when the protocols are created for http requests in Site factory. Though I have a basic understanding of working of factory and protocols,My confusion arises because I see multiple protocols are created for single requests from browser. Following are sample code and the output .
import sys
from twisted.web.server import Site
from twisted.web.static import File
from twisted.internet import reactor
from twisted.python import log
log.startLogging(sys.stdout)
class GFactory(Site):
protmade = 0
def __init__(self,resource):
Site.__init__(self,resource)
def buildProtocol(self, addr):
GFactory.protmade +=1
print "Building Protocol in factory" + str(GFactory.protmade)
print addr
p = Site.buildProtocol(self, addr)
return p
resource = File('./temp')
factory = GFactory(resource)
reactor.listenTCP(8888, factory)
reactor.run()
Log from a single request of http://localhost:8888/ through chrome
2016-05-02 01:38:07+0530 [-] Log opened.
2016-05-02 01:38:07+0530 [-] GFactory starting on 8888
2016-05-02 01:38:07+0530 [-] Starting factory <__main__.GFactory instance at 0x11bac75f0>
2016-05-02 01:38:19+0530 [-] Building Protocol in factory1
2016-05-02 01:38:19+0530 [-] IPv4Address(TCP, '127.0.0.1', 64913)
2016-05-02 01:38:19+0530 [-] Building Protocol in factory2
2016-05-02 01:38:19+0530 [-] IPv4Address(TCP, '127.0.0.1', 64914)
2016-05-02 01:38:19+0530 [-] Building Protocol in factory3
2016-05-02 01:38:19+0530 [-] IPv4Address(TCP, '127.0.0.1', 64915)
2016-05-02 01:38:19+0530 [-] "127.0.0.1" - - [01/May/2016:20:08:19 +0000] "GET / HTTP/1.1" 200 800 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36"
Following are my queries
1) As shown above there are 3 different protocols created for requests from 3 different ports. Is this an expected behaviour? Shouldn't there be one protocol for each request?
2) If I have to take some actions when the request expire or protocol is closed, which protocol should I be looking into?