Introduction to Open vSwitch (OVS)

An Introduction to Open vSwitch (OVS).
Twitter: @davidmahler
LinkedIn: / davidmahler
Links:
Intro to OpenFlow: • Introduction to OpenFlow
Open vSwitch project page: openvswitch.org
OVS Deep Dive Presentation : • Open vSwitch Deep Dive...
OVS FAQs: openvswitch.org...
OVS Official Documentation: openvswitch.org...
Brent Salisbury's Blog: networkstatic.net/
Commands used in this video:
#show ovs current config summary
ovs-vsctl show
#add a bridge
ovs-vsctl add-br mybridge
#turn up mybridge interface
ifconfig mybridge up
#add eth0
ovs-vsctl add-port mybridge eth0
#remove eth0's IP addressing
ifconfig eth0 0
#make mybridge interface get a DHCP IP
dhclient mybridge
#add tap interfaces
ip tuntap add mode tap vport1
ip tuntap add mode tap vport 2
#add tap interfaces to mybridge
ovs-vsctl add-port mybridge vport1 -- add-port mybridge vport2
#view forwarding table (mac address table)
ovs-appctl fdb/show
#see mapping of OpenFlow ports to system ports
ovs-ofctl show mybridge
#see flow entries (OpenFlow) on mybridge
ovs-ofctl dump-flows mybridge
#see records in ovsdb-server tables
ovs-vsctl list Bridge
ovs-vsctl list Port
ovs-vsctl list Interface

[@JayLooney]

I feel like it's important to explain that all the commands are just abbreviations of what they are for 'ovs-vsctl' is for Open vSwitch Virtual Switch Control. I think it helps people to remember better and also helps provide some intuition and insight as to what certain commands might do based on what they are called.

[@DavidMahler]

+Jay Looney Great suggestion, thanks!

[@JayLooney]

+David Mahler no problem, thanks for the videos. I have spent the past few days trying to engineer a non-trivial home network with physical and virtual subnets and this video was super helpful.

[@JayLooney]

+David Mahler no problem, thanks for the videos. I have spent the past few days trying to engineer a non-trivial home network with physical and virtual subnets and this video was super helpful.

[@JayLooney]

+David Mahler no problem, thanks for the videos. I have spent the past few days trying to engineer a non-trivial home network with physical and virtual subnets and this video was super helpful.

[@PetterBruland]

Thank you for taking the time to create this video and share it with us. Excellent brief explanation, and now I understand why I lost connectivity to my remote box when setting up OVS.

[@DavidMahler]

+Petter Bruland You're welcome. Ah, yes I first learned that from Brent Salisbury's blog networkstatic.net/ it was confusing for me too at first.

[@cbaxtermusic]

dude you are making this too easy to understand, GREAT VIDEOS!!!!!!

[@DavidMahler]

C Bax Thanks, I'm glad they are useful for you!

[@matscloud]

THE best OVS intro I've seen so far... right now I see that I was confusing some cocepts, it just all came together now... Thanks!

[@DavidMahler]

You're welcome, thanks for the comment!

[@GRAFFDEMON]

This video helped me so much. HOURS I looked for guides thinking I installed it wrong, configured the bridge wrong. But nope. I forgot to add the tap ports to the virtual bridge. Thank you a ton for this video. I'd hug you if I could.

[@DavidMahler]

Motör Punx HA, I'm glad I could help via the video, thanks for the comments!

[@H3cJP]

this is the best explanation i have seen so far, already known some stuff but the way you explained it was excelent, still helping people 10 years later so thanks

[@DavidMahler]

ty!

[@steveinbox8771]

I am completely new to this but I wanted to say thank you so much for making this great easy to digest video. Explaining the the disconnect part was huge. I also wanted to add this in case someone else new needed it. To configure the mybridge with a static ip. You will should use the below. 1. Assign static ip to mybridge - #sudo ip addr add / dev mybridge 2. Set the default gateway to via mybridge - #sudo route add default gw mybridge 3. You may need to remove the eth0/ens default gateway route to ensure the only default route uses mybridge to go to the gateway * I found this because I am trying to learn how to configure openvswitch for lacp with some vm's in vmware. If anyone has any videos like this showing how to do this that would be great *Also if anyone knows offhand how to configure the settings I posted so that they persist upon reboot that would be cool (I am using ubuntu 20.04). vport1 and vport2 also don't persist reboot

[@Javier_FH]

Hi Steve, did you ever find answers to your questions? The truth is that I was also trying to follow the demo with a Ubuntu 20.04 VM instantiated in Openstack, but when I redirect eth0 towards the mybridge all goes down. I tried dhclient mybridge and takes forever, but I am afraid it didn't do anything and then when i try to see the routes everything is empty. Did you manage to get a more up to date list of steps. I would love to be able to complete the whole exercise and what David did, feels so easy when he does it :)

[@sanshrestha08]

Thanks for a great tutorial David. To all the viewers following this tutorial, just want to inform that you will encounter a problem if you try to assign wireless interface instead of wired interface(eth0) to open vswitch. When you start the VM, you will lost internet connectivity. Try using wired interface to make it work.

[@DavidMahler]

sandesh shrestha Thanks Sandesh!

[@pranaypallavtripathi2460]

This was brilliant. Even though my knowledge of networking is very basic, I could understand everything except the openflow and kernel module part. Thank you so much. Please keep making videos like this. Subscribed 👍

[@DavidMahler]

Thank you Pranay!!!

[@sivan111in]

Awesome explanation.... I was actually struggling for a working example to make use of OVS to throttle internet traffic for end user VMS. You just gave it... Many thanks...

[@DavidMahler]

Viswa K.S.P You're welcome!

[@srinivaspithani7645]

What a way to explain such a complex concept for a newbie like me .. can't expect more than this. Thanks for sharing Dave ...well done.

[@DavidMahler]

Thank you Srinivas! You are very welcome.

[@Akshatha512]

Thank you, David. Immense respect for your presentation technique and eloquence. You inspire me to learn more and dig deeper to understand the core concepts behind these awesome technologies. I cannot stress the importance of the inspiration you provide. As an intern who wishes to excel in the networking field, it is deeply valuable.

[@DavidMahler]

That's, great Akshata. Thanks so much for the kind words! The networking field is definitely about digging deeper into everything.

[@ReubenUrRahman]

I am new to networking domain, But your video is very helpful and easy to understand for target audiences like me. Thank you for sharing !

[@DavidMahler]

Great, I'm glad its was helpful. Thanks Reuben.

[@Javier_FH]

Thanks a lot for the explanation David. I love the way explain such a complex subject (at least for me). I wish there would be a revisited version, since many of the commands have changed, but I also understand it is a huge effort. Anyway, once more thank you very much for your clear explanations. Now if the whole exercise works in my machine, I'll be the happiest man in the world :P

[@pubdigitalix]

This is because they change cosmetics things every time to time but the core concepts are the same. man pages are your friend.

[@PrayingForYourWellBeing]

One of the excellent informational videos i have ever found with such great vocational and presentation skills. Great clarity. Thanks David !!!

[@DavidMahler]

Rohan Shah Thanks Rohan! Quite the complement!

[@davidcaughey9205]

Excellent work, well presented by someone who has an obvious passion for what they do. I really appreciate these David. Well done hats of to ya

[@DavidMahler]

David Caughey I'm glad you like them, thanks for the comment!

[@wanderer-1986]

Very good video. Easy to follow and put in terms most people can understand. Well done, and thank you for making it.

[@DavidMahler]

Hey Joseph, thanks for commenting! You're welcome!!

[@PETAJOULE543]

Open vSwitch explained well (it is Switch that utilize OpenFlow concepts) and also practical implementation with these command lines. As default implementation, it work like regular layer 2 switch. But we can modify it further to get SDN capabilities.

[@vinayaksharma280]

Amazing Very easy to understand explaination..thank you so much

[@DavidMahler]

yw!

[@e.hunter9427]

phenomenal explanation and tutorial!

[@DavidMahler]

Thank you! I appreciate this comment!

[@dyveshmahadea2728]

Did vport 1 and vport 2 appeared for selection of bridge interface?

[@nathanfarrar]

Thank you so much for this video. So helpful for a beginner.

[@DavidMahler]

***** You're welcome Nathan!

[@pwu2007]

great video, simple and strait forward, easy to understand, thank you.

[@DavidMahler]

You're welcome Ping!

[@sreenivasaraju4988]

Excellent demo, makes me easy to understand.

[@DavidMahler]

Great!

[@ramprasvm]

to the point and very practical approach.. thanks a lot for the great presentation

[@DavidMahler]

No problem! Thanks Rampras.

[@mohamedel-demery3006]

Excellent Job , please keep going

[@DavidMahler]

probably going to post a few more OVS videos next....when I find the time beyond my real job :-). Thanks Mohamed.

[@vitalysibichenkov7202]

Thanks for great explanation! I've added script in autostart and all is running well.

[@DavidMahler]

You're welcome!

[@wdxgy136]

非常好的ovs指导视频，感谢作者！

[@DavidMahler]

You're welcome! Thanks for the comment.

[@ffp3]

Thank you for this video, very useful, brief and to the point with example. Great job.

[@DavidMahler]

Thanks!

[@manickamdhayalan]

Great David. Awesome video.

[@DavidMahler]

Thanks Dhayalan!

[@rraj7491]

Expectation well set and great presentation! Thanks and well done David!

[@DavidMahler]

Thanks!

[@RohitVerma-wh1ki]

Thanks David.. this video was very useful

[@DavidMahler]

Great, glad it was useful Rohit.

[@undeaddutch]

Very clear explanation! Would like to see more :)

[@Oswee]

Would be really great to have updated 2021 version of this very same video. :)

[@DavidMahler]

I agree ha.

[@timmy610387]

Awesome video

[@DavidMahler]

Thanks!

[@srinivaspithani7645]

Nice video David, helped me to learn OVS , a good start for me ... Thanks for uploading .

[@DavidMahler]

+Srinivas Pithani Anytime!

[@rathisoft]

As always, very informative and helpful.

[@DavidMahler]

+Bharathi Athinarayanan Thanks for taking the time to comment!

[@singar1976]

Great video to get started on OVS. Thank you for your effort.

[@DavidMahler]

Singaravelu Shanmugam yw!

[@k6eep593]

I had to do "ifconfig vport1 up" and "ipconfig vport2 up" also. Thanks for video!

[@DavidMahler]

Thanks!

[@TheLastBabyBoomer]

Great introduction. My network is starting to sing now. Thanks!

[@DavidMahler]

Oh great John, I see you have OpenFlow 2.0 installed whose flow actions include singing, dancing and foolin' around. Thanks!

[@SeePatPlay]

Super helpful video! Thanks

[@DavidMahler]

So glad!

[@tiskanto]

Excellent Job ...!!!! need more videos like these please !

[@paraffin333]

Hey David, that's a great video with perfect explanation. Was so helpful that I earnestly request you to make another video illustrating the internal design of ovs. :)

[@DavidMahler]

Thanks Bushra! Thanks for the feedback!

[@IncensedCeasar7]

Helps me a lot. Thanks David

[@DavidMahler]

yw!

[@richardmurphy7101]

Makes sense now. :-) Thanks from a fellow HPer.

[@DavidMahler]

:-) You're quite welcome!

[@EmreSeyyidhanoglu]

Nice explanation and demonstration but it's outdated when you try to attach you VM's in Ubuntu.

[@wamosalis26]

Great video. It really helps me

[@DavidMahler]

Great!

[@tolosricardos2111]

Very helpful. Thank you very much. 🙏🙏🙏🙏🙏🙏🙏

[@DavidMahler]

Most welcome 😊

[@dyveshmahadea2728]

You have been able to configure this?

[@SharnavBanik]

Excellent tutorial. Thank you.

[@DavidMahler]

You're welcome!

[@ParvizKermani]

Great & easy to understand video. Thank you!

[@DavidMahler]

Thanks!

[@Bagga4u]

Very well explained. Thanks !!

[@DavidMahler]

You're welcome Prabhjit!

[@lifeisbeautiful7882]

Great explanation, thanks

[@DavidMahler]

YW!

[@dyvm3180]

Did vport 1 and vport 2 appeared for selection of bridge interface?

[@richardwang1480]

very good introduction course!!

[@DavidMahler]

Thanks Richard

[@loipan1891]

Thanks David. That's nice.

[@DavidMahler]

You're welcome Loi!

[@parisonravalomanda7670]

Simple and clear! Thank you

[@DavidMahler]

Thanks for the comment Parison. You're welcome!

[@mconran69]

Very good david

[@DavidMahler]

+Matthew Conran Thanks Matt! Thought I recognized your name - checking out your blog right now..looks awesome! network-insight.net/

[@anandanviv1]

It was great listening..Neat presentation

[@DavidMahler]

Thanks Vivekanandan

[@rohan2726]

Thank You david. Great video.

[@DavidMahler]

You're welcome rohan!

[@Neven1986]

Really great introduction on OVS. :)

[@DavidMahler]

+Neven Vrenko Thanks for the comment!

[@tawakaleezz1993]

Thank you and waiting for more Great Videos

[@DavidMahler]

tawakal eezz :-) I'll try.....

[@mikee5306]

Thanks so much for this. Turns out I don't even need the bridge-utils package.

[@张豪-t7e]

It‘s very useful, thank you a lot.

[@DavidMahler]

You're welcome, thanks for commenting.

[@normanmeinzer6698]

Thanks for this awesome example! Unfortunately I did run into a problem that may fit to multiple comments here: The VirtualBox VMs are not able to communicate with the virtual bridge. In my case, all packets have been dropped by the tuntap interface. Also, doing a `netstat -i`, I've seen exclusively TR-ERRs on the internal bridge port and exclusively TX-OVRs on the tuntaps. The root cause is that VirtualBox seems to require hardware virtualization for communicating with a virtual bridge or a tuntap interface. Don't know exactly. However, no warning is produced anywhere. So if you have the same problem, then check if VT-x or AMD-V is available on your host machine. E.g. with `egrep -c '(vmx|svm)' /proc/cpuinfo`. If this returns 0, then you may be able to fix it by enabling one of the features in your BIOS. In my case, the situation was a little bit weirder. I'm using nested VMs. I have a Mac that runs a VM in which I'm using openvswich. Within this VM I have a bunch of other VMs that connect to the vswitch/bridge. This means that the first level VM needs to emulate a CPU that supports hardware virtualization. In VMWare it can be enabled under the advanced settings of the virtual CPU. Didn't find the same option in VirtualBox. By default it is not enabled.

[@DavidMahler]

Thanks so much for commenting on this

[@raajkr6762]

Very useful talk

[@DavidMahler]

Thanks!

[@donmccoy20]

Brilliant video, thanks so much

[@DavidMahler]

Thank you!

[@antonioskoulouris2111]

Hi! If you would like, an installation video for mac mini would be very useful as there is no official installation guide for mac... Very handy video indeed... Thanks a lot

[@rexagon7945]

Love the demo part.

[@DavidMahler]

Thanks, Visuals help me to learn a lot

[@derekchamorro78]

Great video David!!!

[@srijit999]

Thanks for the demo

[@DavidMahler]

Anytime :-)

[@bsudhakoushik]

Perfect Intro to OVS. :-)

[@DavidMahler]

Sudha Koushik Thanks!

[@srinivasanrao4593]

This is so so so so so GOOOd!!! thank you!!!

[@DavidMahler]

You're so welcome!

[@yanandre7352]

excellent video! thanks!

[@DavidMahler]

You're welcome Yan! Thank You!

[@vinllenchen9964]

nice vedio! thank you David

[@DavidMahler]

Vinllen Chen You're welcome!

[@bmachkour]

Why does the laptop loose internet connectivity when eth0 is attached as port of the bridge ? Not sure to understand

[@bboyfaja]

Cool video, but to get mapping: port number (from ovs-appctl fdb/show BRIDGE) interface name you should use ovs-dpctl show (especially when you have > 1 ovs bridge in your system) cheers

[@DavidMahler]

Hello bboyfaja - at first I agreed with you but look at this: The ports are not mapping the same in the 2 commands, and the correct mapping looks to be in ovs-ofctl and not in ovs-dpctl..... See port '1' for example...(maps to OVS internal port on 'dpctl', but to s2-eth1 on 'ofctl'. root@mininet-vm:/home/mininet/mininet/examples# ovs-dpctl show system@ovs-system: lookups: hit:895 missed:41 lost:0 flows: 1 port 0: ovs-system (internal) port 1: s2 (internal) port 2: s2-eth1 port 3: s2-eth2 port 4: vxlan_sys_4789 (vxlan: df_default=false, ttl=0) root@mininet-vm:/home/mininet/mininet/examples# ovs-ofctl show s2 OFPT_FEATURES_REPLY (xid=0x2): dpid:0000000000000002 n_tables:254, n_buffers:256 capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP actions: OUTPUT SET_VLAN_VID SET_VLAN_PCP STRIP_VLAN SET_DL_SRC SET_DL_DST SET_NW_SRC SET_NW_DST SET_NW_TOS SET_TP_SRC SET_TP_DST ENQUEUE 1(s2-eth1): addr:5e:6c:cf:98:d1:0d config: 0 state: 0 current: 10GB-FD COPPER speed: 10000 Mbps now, 0 Mbps max 2(s2-eth2): addr:4a:01:f9:c5:1f:b5 config: 0 state: 0 current: 10GB-FD COPPER speed: 10000 Mbps now, 0 Mbps max 10(vtep): addr:a6:52:52:99:a4:bf config: 0 state: 0 speed: 0 Mbps now, 0 Mbps max LOCAL(s2): addr:ba:2a:a1:84:38:42 config: 0 state: 0 speed: 0 Mbps now, 0 Mbps max OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0

[@bboyfaja]

David Mahler Hi David, yes, you are right. Port mappings from 'ovs-dpctl show' and 'vs-ofctl show bridge_name' are different, and I'm not fully understand this, but what I've noticed is: if I print mac table using command: 'ovs-appctl fdb/show br-int' and want to know port->interface mapping I need to use 'ovs-dpctl show'. Please take a look: 1) I have 2 bridges # ovs-vsctl list-br br-int br-vm 2) mac table on one of them: # ovs-appctl fdb/show br-int port VLAN MAC Age 5 1 da:7a:51:f7:68:b1 124 5 1 86:85:ce:af:71:56 119 5 1 da:7a:51:f7:d2:2d 119 ... ... 4 1 fa:16:3e:bb:59:02 0 In mac table I have only ports: 4 and 5. 3) Ports in this bridge: # ovs-vsctl list-ports br-int int-br-vm tap48931a45-3d So the question is which one is port 4 and which one is port 5? Lets see what do 'ovs-dpctl show' and 'ovs-ofctl show' print: 4) ovs-dpctl show # ovs-dpctl show system@ovs-system: lookups: hit:134035999 missed:1701486556 lost:0 flows: 256 port 0: ovs-system (internal) port 1: br-int (internal) port 2: br-vm (internal) port 3: eth0 port 4: tap48931a45-3d (internal) port 5: int-br-vm port 6: phy-br-vm 5) ovs-ofctl show br-int # ovs-ofctl show br-int OFPT_FEATURES_REPLY (xid=0x2): dpid:00003aa578eb5a42 n_tables:254, n_buffers:256 capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP actions: OUTPUT SET_VLAN_VID SET_VLAN_PCP STRIP_VLAN SET_DL_SRC SET_DL_DST SET_NW_SRC SET_NW_DST SET_NW_TOS SET_TP_SRC SET_TP_DST ENQUEUE 1(tap48931a45-3d): addr:fa:16:3e:bb:59:02 config: 0 state: 0 speed: 0 Mbps now, 0 Mbps max 3(int-br-vm): addr:ee:22:7e:10:40:28 config: 0 state: 0 current: 10GB-FD COPPER speed: 10000 Mbps now, 0 Mbps max LOCAL(br-int): addr:3a:a5:78:eb:5a:42 config: 0 state: 0 speed: 0 Mbps now, 0 Mbps max OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0 So it looks like 'ovs-dpctl show' prints correct mappings. Cheers and thank you for your videos, they are great!

[@yasser_rafid]

great video!

[@DavidMahler]

Thanks!

[@vmejia1979]

Great video.

[@DavidMahler]

Thanks!

[@dyvm3180]

Hello, On my vm1 and vm2, the vport1 and vport2 does not appear. What are the steps? Thank you

[@MartynDavies]

Very useful, thanks

[@DavidMahler]

You're welcome!

[@guteusa]

Great video intro on ovsdb!

[@DavidMahler]

Gute Fernandes Thanks a lot.

[@vineetkapoor6950]

Hi David, Great Video! Please upload more tutorial videos on OVS. Thanks

[@DavidMahler]

+vineet kapoor Thanks Vineet! I have 2 ones on OpenStack on deck, the second one will get a bit into how OVS is used there for Neutron.

[@lordskyit]

Hello, thank you for your time! Did you take a video about setup fake vlan inside OVS? Thank you!

[@young-bosim8284]

Soooooooooooooooooooo useful for me!! Thank you so much.

[@DavidMahler]

You're very welcome!!!! Thanks for commenting.

[@jianweiyan8642]

very good, thanks!

[@DavidMahler]

+Jianwei Yan Anytime!

[@easycollabDotNet]

Thanks man - this video helped a lot. I'm subscribing :)

[@DavidMahler]

Awesome!

[@anatoxin]

Clear presentation

[@DavidMahler]

Thanks a lot!

[@vinllenchen9964]

hi, David, i follow your way to start my vhost through the virtualbox, and i also use the bridge adpter, one vhost connect to vport1, and another connect to vport2. But, there is no ip address in the vhost after a start it. Do you konw the reason? Great appreciate for your reply

[@vinllenchen9964]

But when i connect to the eth0 instead of the vport1 and vport2, i can get the ip address

[@user.w18]

Probably missed to add eth0 to the bridge, using: `ovs-vsctl add-port mybridge eth0`

[@longnguyenhoang6735]

@@user.w18 I don't have eth0 but have wlp2s0, which is my wireless NIC, and I've already added to mybridge. However, I still face the problem of no ip for vport1 and vport2. Can you help me with this?

[@RebeliousSapien]

this was so incredibly well explained. thank you so much any chance of setting up vlan tagging on ovs switches in the future please ?

[@r1ckmav]

thanks David that was a good one

[@DavidMahler]

Ashish Jain You're welcome. Glad you liked it!

[@sergiogonzalez6597]

great job, awesome tutorial!!!!

[@DavidMahler]

sergio gonzalez Thanks Sergio!

[@heikoloewe1539]

Hi David, for my Fedora 21 distribution I had to add some routing commands to make it work. # route del default gw 192.168.1.1 enp0s25 default route was still pointing to the phys. interface # route add default gw 192.168.1.1 mybridge So I had to setup a new default route # route del -net 192.168.1.0 netmask 255.255.255.0 dev enp0s25 also I had 2 routes to the local net and had to delete the old route

[@DavidMahler]

Heiko Loewe Hmm OK thanks Heiko, I hadn't tried on Fedora, I'll check it out!

[@UdaySingh-im4hd]

How can I create internal and external bridge? Actually I wanted to connect 2 interfaces (network codr) to my KVM VMs, one for internal (hostonly/inter-vm traffic ) and other for internet. @david, could you please guide me here? It will be super helpful if you can create another similar video on this.

[@georgianmusat9958]

i cannot ping from VMs, they do not get IP address. i run Ubuntu on my PC and Lubuntu in the VMs any idea why?

[@Marco_Onyxheart]

Doesn't seem to work for me. When I assign eno1 to my bridge, I lose internet access, as expected. I then run "ifconfig eno1 0" and "dhclient mybridge". Still no internet. "route -n" shows eno1, instead of the bridge like in the tutorial.

[@Javier_FH]

Hi Marco, did you ever figured out how to solve that issue, I am pretty much at the same place as you. If you fixed it, do you remember how?

[@MaryamTanha40]

Awesome! Thanks.

[@DavidMahler]

You're welcome Maryam!

[@krskeshara]

great video to get understand. Thanks....

[@DavidMahler]

+Keshara Dorakumbura You're welcome, thanks for commenting!

[@RM-gm7lu]

Thanks for the great content!

[@DavidMahler]

Glad you enjoy it!

[@dillip4572]

Good intro stuff. Thanks

[@DavidMahler]

You're welcome!

[@PascalPETIT91]

Thanks for this videos. An idea: with subtitles, i will be easier for peoples not so fluent in english. It will allow people to submit foreign langage translation. It will be better for deaf people.

[@DavidMahler]

Hey Pascal, thanks for that feedback!

[@DavidMahler]

FYI on my last video "Introduction to Git" I added subtitles, I will be doing that from now on, thanks for the feedback - I made a process change to incorporate it now.

[@ChengyuFan]

useful tutorial to me

[@DavidMahler]

+Chengyu Fan Great!

[@chenoi]

Hi..very nice introduction. I still could not understand some of the idea of OVS....I hope you could clarify further...(1)does ovs is also an Ethernet switch? by default ovs also leveraging L2 addressing similar like any Ethernet switch... (2)If ovs leveraging L2 mac, whats the reason of having OF protocol? why not just totally OF.... Thanks