#mininet

Before we dive into the configuration first lets review the components needed to build the lab.

GNS3 is a software suite that simulates complex networks, providing an intuitive graphical user interface to design and configure virtual networks.

Virtualbox is a virtualization software package for x86 and AMD64/Intel64-based computers from Oracle Corporation. It can be integrated into the GNS3 software suite.

MiniNet is an OpenFlow testing platform consisting of a realistic virtual network, running real kernel, switch and application code, with a single command prompt.

Virtualbox / Mininet

Download Virtualbox HERE, and install (default settings are fine in most cases). Download Mininet HERE. After installing Virtualbox, and downloading Mininet.

Now create the Mininet VM in Virtualbox. To do this select NEW button from the toolbar and go through the wizard to install the Mininet VM. At step one select the name and operating system. Type is Linux and Version is Ubuntu. Click NEXT through the memory size configuration. At the Hard drive selection option, select 'Use an existing virtual hard drive file' and add the mininet vmdk file. Now click CREATE.

The Mininet VM is created. Now we need to add extra network adapters to Virtualbox. To do this open the File -> Preferences... menu item, and open the NETWORK tab. Within the NETWORK tab, select the 'Host-only Adapter' tab and click 'Add host-only network' icon, until there are at least three 'VirtualBox Host-Only Adapter's', then click OK.

Virtualbox is now configured.

GNS3

In GNS3 click Edit -> Preferences... and open the VirtualBox tab. Select the 'VirtualBox Guest' sub tab. Now select the 'Mininet' VM from the 'VM List' drop down list. Set the 'Number of NICs' to 3, and check the 'Reserve first NIC for VirtualBox NAT to host OS', the 'Enable Console Support', and the 'Enable Console Server' checkboxes. Add an 'Identifier name', I choose Mininet, click SAVE button and then click OK button.

Now we are ready the to build our first lab.

The lab

For demonstration purposes the lab will consist of two routers connected to the Mininet VM. The Mininet VM will be started in the standard configuration: one Openflow switch, one controller, and two virtual hosts.

After which I manually attached both the interfaces eth1 and eth2, to the switch s1.

Both routers are configured with in the IP range 10.0.0.0/24. The .1 and .2 are used by the two virtual hosts.

The result of a ping from R1 to R2, from the perspective of R2.

R2# *Mar  1 00:07:24.155: IP ARP: rcvd req src 10.0.0.3 c00d.2440.0000, dst 10.0.0.4 FastEthernet0/0 *Mar  1 00:07:24.155: IP ARP: sent rep src 10.0.0.4 c00e.2440.0000,                 dst 10.0.0.3 c00d.2440.0000 FastEthernet0/0 *Mar  1 00:07:24.159: IP ARP: rcvd rep src 10.0.0.3 c00d.2440.0000, dst 10.0.0.3 FastEthernet0/0 R2# *Mar  1 00:07:42.775: ICMP: echo reply sent, src 10.0.0.4, dst 10.0.0.3 *Mar  1 00:07:42.823: ICMP: echo reply sent, src 10.0.0.4, dst 10.0.0.3 *Mar  1 00:07:42.847: ICMP: echo reply sent, src 10.0.0.4, dst 10.0.0.3 *Mar  1 00:07:42.867: ICMP: echo reply sent, src 10.0.0.4, dst 10.0.0.3

*Mar  1 00:07:42.887: ICMP: echo reply sent, src 10.0.0.4, dst 10.0.0.3

Conclusion

Mininet provides a great tool to experiment with Software-defined networking (SDN), while providing an software switching platform within the GNS3 environment. Non of the routers available in the GNS3 (officially) support Openflow. Limiting the experimentation with Openflow to switching only.

References

Mininet Walkthrough

Virtualbox documentation

GNS3 documentation

以前、以下のような記事を書いた時は、Mininet で起動した Open vSwitch に OpenFlow 1.3 を喋らせるために ovs-vsctl コマンドを直接呼び出すというかなり無理やりな方法を取っていた。 OpenFlow の動作確認に便利な Mininet を OpenFlow 1.3 で使う あれから時は流れて、先日リリースされた Mininet 2.2.0 では、プロトコルバージョンの指定が Mininet から直接できるようになった。 今回は、その方法を試してみよう。 使用するプラットフォームは Ubuntu 14.04 LTS にした。

$ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION="Ubuntu 14.04.1 LTS" $ uname -r 3.13.0-24-generic

まずは Mininet 2.2.0 をインストールする。 インストールスクリプトのオプションには Mininet (-n) と Open vSwitch (-v) を指定する。

$ sudo apt-get install git build-essential -y $ git clone https://github.com/mininet/mininet.git $ cd mininet/ $ ./util/install.sh -nv

次に動作確認用の OpenFlow コントローラとして Ryu SDN Framework もインストールしておく。

$ sudo apt-get install python-dev libxslt-dev zlib1g-dev -y $ sudo easy_install pip $ sudo pip install ryu

早速起動…と思ったら何かエラーでた。 Python のサードパーティー製ライブラリ Six のバージョンが古いらしい。

$ ryu-manager ryu.app.simple_switch_13 Traceback (most recent call last): File "/usr/local/bin/ryu-manager", line 5, in <module> from pkg_resources import load_entry_point File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2749, in <module> working_set = WorkingSet._build_master() File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 446, in _build_master return cls._build_from_requirements(__requires__) File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 459, in _build_from_requirements dists = ws.resolve(reqs, Environment()) File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 632, in resolve raise VersionConflict(dist,req) # XXX put more info here pkg_resources.VersionConflict: (six 1.5.2 (/usr/lib/python2.7/dist-packages), Requirement.parse('six>=1.7.0'))

パッケージでインストールされているバージョンを見ると確かに古い。

$ dpkg-query -l | grep six ii python-six 1.5.2-1 all Python 2 and 3 compatibility library (Python 2 interface)

なので、一旦パッケージ版の Six はアンインストールしておく。

$ sudo apt-get remove python-six -y

PIP を使ってインストールし直す。

$ sudo pip install -U six

改めて Ryu で OpenFlow 1.3 版の L2 スイッチアプリケーションを起動する。

$ ryu-manager ryu.app.simple_switch_13 loading app ryu.app.simple_switch_13 loading app ryu.controller.ofp_handler instantiating app ryu.app.simple_switch_13 of SimpleSwitch13 instantiating app ryu.controller.ofp_handler of OFPHandler

ここからが今回の本題。 別のターミナルを使って Mininet を起動する。 --switch オプションに ovsk と protocols=OpenFlow13 を指定するのがキモ。 これで、スイッチの実装に Open vSwitch (Kernel) を、OpenFlow プロトコルのバージョンとして 1.3 が選択される。 トポロジ (--topo) はスイッチ 1 台にホスト 2 台が接続された 1 階層のツリー構造を指定しておく。

$ sudo mn --controller=remote,ip=127.0.0.1 --switch=ovsk,protocols=OpenFlow13 --topo tree,depth=1 *** Creating network *** Adding controller *** Adding hosts: h1 h2 *** Adding switches: s1 *** Adding links: (s1, h1) (s1, h2) *** Configuring hosts h1 h2 *** Starting controller c0 *** Starting 1 switches s1 *** Starting CLI: mininet>

無事接続できたようならホスト間の疎通を確認してみる。 ホスト h1 からホスト h2 に ping を打ってみる。

mininet> h1 ping h2 -c 3 PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data. 64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=1.20 ms 64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=0.063 ms 64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=0.076 ms --- 10.0.0.2 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2000ms rtt min/avg/max/mdev = 0.063/0.449/1.209/0.537 ms