SimpleHTTPRequestHandler.client_address与keepalive客户端连接不一致

Question

以下是非常标准的HTTP服务器的一部分：

class ConnectionHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
    def do_GET(self, *args, **kwargs):
        print "client_address=", self.client_address
        data = "Some Text"
        self.send_response(200)
        self.send_header("Content-Type", "text/plain")
        self.send_header("Content-Length", len(data))
        self.end_headers()
        self.wfile.write(data)

class MyHttpServer(object):
    def __init__(self, Port=9999, ConnHandler=ConnectionHandler):
        self.Port = Port
        self.ConnHandler = ConnHandler
        self.Server = SocketServer.TCPServer(
            ('127.0.0.1', self.Port), self.ConnHandler)
        self.Server.serve_forever()

if __name__ == "__main__":
    DemoServer = MyHttpServer()

这是client.py。它使用urllib3进行keepalive会话：

from urllib3 import HTTPConnectionPool
pool = HTTPConnectionPool('127.0.0.1:9999', maxsize=1)
pool.request('GET', '/connect')
pool.request('GET', '/ping')
pool.request('GET', '/test')
print "pool.num_connections={} pool.num_requests={}".format(
    pool.num_connections, pool.num_requests)

当我运行客户端时，它显示pool.num_connections = 1 pool.num_requests = 3，正如预期的那样。但是当我运行服务器时，它显示的是：

client_address= ('127.0.0.1', 34858)
127.0.0.1 - - [09/Jul/2014 01:42:45] "GET /connect HTTP/1.1" 200 -
client_address= ('127.0.0.1', 34859)
127.0.0.1 - - [09/Jul/2014 01:42:45] "GET /ping HTTP/1.1" 200 -
client_address= ('127.0.0.1', 34860)
127.0.0.1 - - [09/Jul/2014 01:42:45] "GET /test HTTP/1.1" 200 -

我不应该在每次请求时都有相同的client_address端口号吗？要么我不理解keepalive连接的概念，要么我做错了。