期末作业

SDN期末作业——负载均衡

一．作业部分

１．负载均衡程序

• 代码链接

２．演示视频

• 视频链接

３．程序分工

• 小组：incredible five
• 构建拓扑：俞鋆
• 编写程序：陈绍纬、周龙荣
• 程序调试和视频录制：陈辉、林德望

４．个人工作

• 在期末作业中我和绍伟主要负责程序代码的编写，在做期末作业的过程中我们小组聚在一起开了两次会议，第一次确定要做的内容并分工，第二次将自己的部分和别人的对接。关于代码部分，我们参考了学长的代码，然后对于我们的拓扑结构进行了初步的构思，慢慢开始和队友合作一起编写代码。由于对python语言的不熟悉，编写代码的过程中还是查找了不少资料也和队友一起讨论了多次，最终完成了代码，并虚拟机上运行，和大家一起完成了验收。

• 程序思路
  场景二默认包从s1-s4路径发送，所以先给s2、s3下发流表，使之通行。（s2、s3流表链接）。我们小组没有去底层交换机收集信息，再对数据处理得到动态负载均衡，最后经过小组讨论，将s1-s4、s1-s2-s4、s1-s3-s4三条线路默认1：2：2的关系，以经历的线路为基准进行负载均衡，对s4下发流表，使用hardtime机制，让3条线路在一段时间内的占比为2:1:1以达到负载均衡。

• 拓扑图

• 拓扑代码

from mininet.topo import Topo

class MyTopo( Topo ):

    def __init__( self ):

        # Initialize topology
        Topo.__init__( self )

        # Add hosts and switches
        h1 = self.addHost( 'h1' )
        h2 = self.addHost( 'h2' )
        h3 = self.addHost( 'h3' )
        h4 = self.addHost( 'h4' )
        s1 = self.addSwitch( 's1' )
        s2 = self.addSwitch( 's2' )
        s3 = self.addSwitch( 's3' )
        s4 = self.addSwitch( 's4' )

        # Add links
        self.addLink( s1, h1, 1, 0 )
        self.addLink( s1, s2, 2, 1 )
        self.addLink( s1, s3, 3, 1 )
        self.addLink( s1, s4, 4, 1 )
        self.addLink( s2, s4, 2, 2 )
        self.addLink( s3, s4, 2, 3 )
        self.addLink( s4, h2, 4, 0 )
        self.addLink( s4, h3, 5, 0 )
        self.addLink( s4, h4, 6, 0 )


topos = { 'mytopo': ( lambda: MyTopo() ) }

• 流表代码

#!/usr/bin/python
# -*- coding:UTF-8 -*-
import httplib2
import time

class OdlUtil:
    http = httplib2.Http()	
    url = ''
    def __init__(self, host, port):
        self.url = 'http://' + host + ':' + port
    def install_flow(self, container_name='default',username="admin", password="admin"):
        self.http.add_credentials(username, password)
        flow_name = 'flow_' + str(int(time.time()*1000)) 

        h2_s4_s2_1 = '''
            {"flow-node-inventory:flow": [
            {"id": "1","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":4,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "2"}}]}}]},
            "priority": 1000,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "4",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        h2_s4_s1_1 = '''
            {"flow-node-inventory:flow": [
            {"id": "0","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":2,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "1"}}]}}]},
            "priority": 1005,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "4",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''      
 
        h2_s4_s3_1 = '''
            {"flow-node-inventory:flow": [
            {"id": "2","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":3,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "3"}}]}}]},
            "priority": 1002,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "4",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        h3_s4_s2_1='''
            {"flow-node-inventory:flow": [
            {"id": "4","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":4,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "2"}}]}}]},
            "priority": 1000,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "5",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        h3_s4_s1_1 = '''
            {"flow-node-inventory:flow": [
            {"id": "3","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":2,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "1"}}]}}]},
            "priority": 1005,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "5",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]}  '''

        h3_s4_s3_1 = '''
          {"flow-node-inventory:flow": [
            {"id": "5","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":3,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "3"}}]}}]},
            "priority": 1002,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "5",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        h4_s4_s2_1 = '''
          {"flow-node-inventory:flow": [
            {"id": "7","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":4,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "2"}}]}}]},
            "priority": 1000,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "6",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]}
         '''
        h4_s4_s1_1 = '''
          {"flow-node-inventory:flow": [
            {"id": "6","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":2,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "1"}}]}}]},
            "priority": 1005,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "6",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        h4_s4_s3_1 = '''
          {"flow-node-inventory:flow": [
            {"id": "8","flow-name": "s4_s2_1","cookie": 256,
            "hard-timeout":3,"instructions": {
            "instruction": [{"order": 0,"apply-actions": {
            "action": [{"order": 0,"output-action": {
            "output-node-connector": "3"}}]}}]},
            "priority": 1002,"table_id": 0,"match": {
            "ipv4-destination": "10.0.0.1/32","in-port": "6",
            "ethernet-match": {"ethernet-type": {"type": 2048}}}}]} '''

        headers = {'Content-type': 'application/json'}
        num=0
        while num < 4 :
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/0', body=h2_s4_s1_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/1', body=h2_s4_s2_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/2', body=h2_s4_s3_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/3', body=h3_s4_s1_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/4', body=h3_s4_s2_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/5', body=h3_s4_s3_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/6', body=h4_s4_s1_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/7', body=h4_s4_s2_1, method='PUT',headers=headers)
            response, content = self.http.request(uri='http://192.168.81.133:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:4/flow-node-inventory:table/0/flow/8', body=h4_s4_s3_1, method='PUT',headers=headers)
            print("success")
            time.sleep(4)
            print(content.decode())

if __name__=='__main__':
	
	odl = OdlUtil('192.168.81.133', '8181')
	odl.install_flow()

二．课程总结

个人总结

• 在上个学期选这门课的时候并没有对这门课有过多的了解，对于网络编程也是知之甚少，本着了解新的专业知识有一定的必要性的心态选了这门课。在课程开始后随着课程的不断深入，慢慢对于软件定义网络有了一定的深入认识，尤其是理论和实践结合的方式，在实践的过程中更能加深对于理论的理解。老师布置的关于SDN方面课外资料阅读的博客作业，也帮助扩展了我的知识面。回顾整个课程期间的点点滴滴，总的来说还是收获了不少。

关于SDN

• 软件定义网络（Software Defined Network, SDN ）,是一种集中控制的新型网络创新架构，是网络虚拟化的一种实现方式，SDN的核心技术OpenFlow通过将网络设备控制面与数据面分离开来，从而实现了网络流量的灵活控制，使网络作为管道变得更加智能

关于控制器

• Ryu控制器：
  Ryu是基于Python语言的开源SDN控制器，提供完备的API，支持多种网络管理设备协议如OpenFlow,Netconf,OF-CO NFIG等多种南向协议。
  Ryu构架分3层。最上层Quantum与OF Rest分别为OpenStack和Web提供编程接口；中间层为Ryu自行研发的应用组件；最下层为Ryu底层实现的基本组件。

• Floodlight控制器：
  Floodlight是基于Java语言的开源SDN控制器，当前支持的南向协议为OpenFlow1.0协议。Floodlight与Big Switch Networks开发的商用控制器Big Switch Controller的API接口完全兼容，具有较好的可移植性。也以其企业级别的优秀性能，开发效率更高的Java语言，模块化的设计等优点得到了喜欢Java语言的SDN研究者的青睐。

• ONOS控制器：
  ONOS控制器采用Java编写,由一系列功能模块组成,每个功能模块由一个或多个组件组成,对外提供一种特定服务,核心功能主要包含:北向接口抽象层/APIs,分布式核心,南向接口抽象层/APIs,软件模块化。
  ONOS控制器的服务对象是运营商，它具有高可靠性、高扩展性、高实时性以及高性能ONOS控制器的服务对象是运营商，它具有高可靠性、高扩展性、高实时性以及高性能。

• ODL控制器：
  OpenDaylight控制器采用Java编写，支持多种南向协议，包括OpenFlow(支持1.0和1.3版本）、Netconf和OVSDB等，是一个广义的SDN控制平台，而不是OpenFlow系的狭义SDN控制器。
  Opendayligh构架也分3层:顶层由控制器和监控网络行为的业务和网络逻辑应用构成；中间层是SDN控制器框架层，其南向协议接口可以支持不同南向协议插件，这些协议插件动态链接到SAL，SAL适配后再同意北向接口供上层应用调用；底层由物理或虚拟设备构成。

关于实践

• mininet的使用
• Floodlight的使用
• ＯＶＳ下发流表
• ＯＤＬ控制器
• 下发流表实现简单负载均衡