Introduction to OpenFlow

[@markh12891]

This video is one of the best I've seen on the subject. You seem to have scripted the narrative so it does not ramble, is precise and to the point which I really like. It delivers both detail and clarity which is typically difficult to achieve simultaneously. From your Linkedin your time as a trainer helps to explain the above. I really hope you'll do more videos on SDN.

[@eliav3]

it's 2020 and you still have the best tutorials about this topic in the web. thank you so much David Mahler!

[@DavidMahler]

Thank you!

[@DavidMahler]

Thanks so much for that detailed feedback. That was my goal so very happy to hear this.

[@gthaker]

Very good quality videos. I like the compact style, no waste of time and packed w/ well constructed content. Thank you very much.

[@DavidMahler]

Thank you for the feedback!

[@garfielddunn5240]

Just absolutely outstanding!!! Thank you for investing the time and effort into producing a great video. The content is crystal clear.

[@DavidMahler]

+Garfield Dunn Thanks! Thanks for ack'ing the time too ;-).

[@FinboySlick]

Exactly the information I was looking for. Any network admin wondering what OpenFlow is about should watch this.

[@DavidMahler]

FinboySlick That's a nice comment, thanks!

[@parthadutta9073]

Your tutorials are nice, it has balanced switching of slides and hands-on screen, you have great voice, diagrams are helping to identify the things easily.

[@DavidMahler]

+Partha Dutta Thanks Partha, I try to present the videos how I would learn best.

[@brianhaverty4160]

These videos are great. Thank you for making them!

[@DavidMahler]

My pleasure!

[@kbnumber24]

Excellent series of videos David. I'm now on the SDN bandwagon thanks to you.

[@DavidMahler]

Thanks Bernard, glad to hear it!

[@azharinamdar597]

Hi David, Thanks for these videos on open flow and intro to SDN. I am really excited about this new era of networking. Your videos are very well understood.

[@DavidMahler]

Azhar Inamdar Thanks!

[@ytbish]

Super descriptive, detailed and understandable. Thank you!

[@DavidMahler]

Георги Алипиев - You're welcome! I'm glad you thought that.

[@PETAJOULE543]

Openflow concept well explained. It is about controlling the switches by utilizing flow tables and their entries. If no entry is matched in the switch, controller is then utilized to make new entry. Also, some wireshark example how to understand the openflow 'packets'

[@DavidMahler]

Thanks for the comment!

[@EngTHUNDER]

Thank you!! Your introduction videos are great, easy to follow and understand.

[@DavidMahler]

EngTHUNDER Thanks for those comments, I'm glad you like them

[@nomayor1]

Thank you very much for this, as well as your other videos David.

[@DavidMahler]

You are very welcome!

[@DavidMahler]

Sanjeev Shrivastava I think good sources of information are www.coursera.org/course/sdn (great online SDN course) the links from there: An attempt to motivate and clarify Software-Defined Networking (SDN) , and How SDN will Shape Networking - Nick McKeown Also lot's of more detail on the ONS (Open Networking Summit) KZbin page: kzbin.info/door/Ho2uqQqpmE_Cg5b4qiUpUg

[@danrtseyppgz7445]

this video is without any subtitles, it's little difficult to understand, may i know if u have the video with subtitiles? my E-mail address is [e-mail], many thanks!

[@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 going forward.

[@santoshsridhar]

Excellent video! clear and precise info I was looking for as a beginner in SDN/OpenFlow.

[@DavidMahler]

santosh sridhar Thanks!

[@ppvshenoy]

Thanks for a splendid video on OpenFlow.

[@DavidMahler]

You are welcome!

[@maildpak]

Very well explained David, this was very helpful

[@DavidMahler]

Deepak Sharma Great!

[@behnamgheysari6850]

such worthful videos to watch,thank you so much for sharing them

[@DavidMahler]

Thanks!

[@erintoc]

Nice to see some OpenFlow details. Great video, thanks!

[@moshtaqramazan437]

thank you so much, it' help me a lot to explain my presentation well tomorrow

[@DavidMahler]

Great!

[@yajuvendra15]

for the first time i got the feel of openflow.... if i will write my blog the first link about how to learn openflow will be this.... thanks again

[@DavidMahler]

Thanks for that sir!

[@jacko646697]

I cant thank you enough for this very informative video! Helped me out a lot

[@DavidMahler]

Thanks Eric!

[@zulu123-x2d]

Great video with key missing details on packet flows... Thanks

[@DavidMahler]

Thanks for the feedback Rohit

[@pekkajaske]

Very clearly explained, thanks !

[@DavidMahler]

Pekka Jaske You're welcome Pekka!

[@asmaelmabrouk783]

Very informative tuto as an introduction I highly encourge you !

[@DavidMahler]

Thanks for the comment!

[@dipunjgupta8082]

Excellent video David! Cleared up a lot of my doubts. Just one question at 3:20 When the initial SYN packet arrives at the switch, how does the switch know which controller to send it to. As OpenFlow controllers could be implemented by different people, how does an intermediary switch identify which controller to talk to for a particular packet?

[@debashispanigrahi676]

Loved the explanation ! Just to the point

[@DavidMahler]

Glad it helped!

[@Elittttt2545]

Hi David, Thanks for this and other great videos. Do you have any video on using the ODL APIs to re-actively modify the routes? I am interested in service chaining using SDN and looking for a tutorial or video that explains how an application on top of SDN controller can manipulate routes on the fly.

[@DavidMahler]

+Elittttt2545 Hi - no I don't have any ODL video at the moment. My next ones are OpenStack ones and perhaps containers after that....

[@andrewniti]

Hi... Its very simple to understand.. Thank you... I have a small clarification... Please clarify... How the controller know that a particular host is connected to this specific port in the open flow switch?-- inorder to push the flow with action.. Thanks in advance...

[@DavidMahler]

Hi Andrew - well the first packet from a host is sent to the controller in a packet-in message from the ingress switch, so it is then 'aware' of the host

[@andrewniti]

David Mahler Thank you... Okay... then how controller will identify the outgoing port (where the destination host is connected)?

[@DavidMahler]

Andrew Niteesh Ah - up to the implementation of the different controllers and how they are programmed. But for example they can do flooding unknown unicast destination and learning the same way a traditional switch does (learn from source MAC/Port of a frame) or say if there is an orchestration platform involved that already knows where VMs are (because it put them there) stuff can be pre-populated.... Hope that helps....

[@sujeevkumar]

Pretty informative, thank you David Mahler.

[@DavidMahler]

You're welcome!

[@AhmedShabib92]

Very nicely explained thanks David

[@DavidMahler]

Thanks Ahmed and You're welcome!

[@amulgurav5409]

Thanks a lot David...appreciated very nicely explain what is openflow? how http openflow trace in wireshark.

[@DavidMahler]

You're welcome Amul! Thanks for commenting!

[@annonybro6908]

Hey David, great video.

[@DavidMahler]

Hey Annony thanks!

[@樱桃小弹弓]

hi, I want to know if the buffer ID in the video has a value, but when OVS creates the bridge, n_buffer=0, which means the buffer is turned off. I would like to ask how it is turned on here.

[@MahimaVuppuluri]

How can I capture traffic on wireshark, if I have done native installation of mininet?

[@aireadytaken3005]

press the button capture (should help :))

[@testcricket1000]

Great explanation, thanks David

[@DavidMahler]

Anytime!

[@AdnanShahidOpi]

Really nice video... Very helpful for starters...

[@DavidMahler]

Thanks Adnan!

[@kamalkumarmukiri4267]

Very useful video for the beginners... thank you.

[@DavidMahler]

You're welcome!

[@tolosricardos2111]

This is wonderful. I thank you very much this explanation. 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏

[@DavidMahler]

You're most welcome

[@dieganga]

Hey David , great videos. Im wondering as I saw your linkedIn profile and the great amount of experience you have in networking especially on Cisco. I just started working at the IT department of a company and we are currently building the network infrastructure for two buildings that are going to be interconnected (24 story building-79 condos, 33 story-130 condos). This infrastructure should support video, voice, data, BAS, etc. We are trying to decide what vendor product should purchase, we have proposals for Alcaltel Lucent, Cisco and Avaya. What input can you give me on this? Thanks in advance.

[@DavidMahler]

+Diego Gallegos Hi Diego, like you said I'm working for Cisco ;-)

[@alexkaouris6755]

Rich and to the point! thanx! one question: would you recommend the approach to implement link aggregation on the packet level with multiple links of different characteristics (latency, badwitdh, loss) using openflow with openv-switch?

[@DavidMahler]

Thanks Alex! Sorry, no specific recommendation.

[@pisitpongv]

I wonder how controller know that h4 is connected to switcH ON PORT 4, since that are no packet out of h4 yet in the first place?

[@EasyEnglish503]

I also have the same question from David Mahler

[@DavidMahler]

It's been a little since I set this up - but IIRC, its from the ARP request and reply which came before the TCP 3 way handshake. Those are punted to the controller which records (learns) IP, MAC and port mappings that way.

[@Ratnateja]

Why didn't the switch had an entry if there was an ARP packet sent out?

[@Codiac300]

Ratna teja I guess because the SDN Controller differinciates between Protocols. You can see in this example, that even for a new HTTP session the SDN Controller would have given out a new rule. But I think you could generalize those rules. (I am still new to SDN)

[@marahshehabat3843]

I've tried this but there were no OpenFlow packets being captured why ??

[@afroskywalker]

Same

[@guduriprathyusha8509]

Hello David Mahler Thanks alot for this video which clearly explains the basics. But my doubt is- Open Flow sits on top of TCP and controller listens on tcp port 6653 for switches which would like to connect. Now here how the switch to controller channel is established??? Controller listens on port 6653 but switch doesn't have any port ( L2 or L3 ). How is this network channel established then??? Is it like any other switch to host connection using the MAC address, in that case why would a controller listen to switch on the specified port??? Please David help me as soon as possible. I just cant go forward without this basic clarity. Thanks in advance

[@DavidMahler]

This post by Ivan Peplnjak will probably help: blog.ipspace.net/2013/12/control-plane-in-openflow-networks.html Easiest way is that the control network is 'out of band' and doesn't intermingle with the network it is controlling...the link has more detail and other links to dive into

[@guduriprathyusha8509]

David Mahler Thanks for a quick response. I checked the blog and went through all the related posts, but my main doubt is how a switch connects to a controller???? Switch doesn't have transport layer in it, so how a normal tcp connection is established between a switch and a controller?? Any kind of help will be appreciated, thank you

[@guduriprathyusha8509]

David Mahler It seems to me that the openflow switch is a multi layer switch, for the proper connection establishment between switch and the controller. Is that so???

[@DavidMahler]

Guduri Prathyusha OK - I THINK you may be getting hung up on the data plane versus the control plane and management plane. I'd suggest reading more about that concept. You are focusing on the data plane - how network nodes handle packets passing through them. However this packet handling behavior originates in the control plane using protocols like BGP, OSPF, MPLS and now OpenFlow. It's the control plane that handles a connection to a controller this is a separate 'plane' or construct from the data plane that I think you are focusing on. Also when you said there is no "transport layer" in a switch - how do you SSH into one - that uses TCP - when you do that you are connecting into the "management plane" I have a intro to SDN video coming up that may enlighten on this concept.

[@feedbrain6257]

kzbin.info/www/bejne/Y4Cqp6Vml894obc. U will have better understanding urself at 1:00:25 I think.

[@jarasuarezdepuga8710]

Hey, maybe is stupid question but, Can you capture mininet traffic from wireshark outside the VM?

[@DavidMahler]

I think you could set up a SPAN port in open vswitch to mirror traffic to a port the host can see....

[@TheBirdMan]

how did you created these figures ? and on which software you designed this presentations ?

[@shaiksunine1634]

Thanks for these videos. But can u please explain how to understand the packet flow path followed like h1->S1->S2->h2 in a tree topology without s3 used up to send packets. How to understand the dump-flows result if using controller.java to set switch flows.

[@sshrivastava1]

Thanks David for providing information on openflow. Could you please inform on how openflow would add value to what is available right now ?

[@pritesh_chandaliya]

Do you have a playlist where I can get all the videos of OVS and OpenFlow?

[@DavidMahler]

+Pritesh Chandaliya Not at the moment - but I only have 13 videos so far :-)

[@pavanramisetty1900]

What fields does the open flow table have ? only inport and out port or anything else ?

[@brianchambers3255]

Great video and very helpful - I am taking the SDN class on Coursera and thought this was a good video to help get a head start. One question - do you know of any other good technical videos that might give a good/quick overview of network basics (without being overly simple)?

[@DavidMahler]

Hello Brian, I haven't looked at more than a few of the videos from them but the course at Stanford online looks like it might be really good. f12.class2go.stanford.edu/networking/Fall2012 You have to register for the links to work.... Thanks for the comments! Dave

[@gstankevix]

Hi David, I'd like to know if there's a framework to make a conection between the SDN and an IDS (Snort)?

[@DavidMahler]

Hi Gabriel. I know there are different Vendors with solutions. For example : h17007.www1.hp.com/us/en/networking/products/network-management/Network_Protector_SDN_Application_Series/index.aspx and www.inmon.com/products/sFlow-RT.php and www.radware.com/Solutions/SDN/ There are some in startup/stealth mode focused on this as well. I don't know what's out there for Open Source specific to integrating say an SDN controller application for IDS. Hope that's at least some good jumping off points.

[@pavanomanwar1389]

Great video for understanding fundamental principle , i want to ask one thing , i am doing mini project in my college in domain of computer networks , i want to implement open flow network simulation using ns3.Can you advice me how to start or anything worth knowing related to this or which sites to refer , please help

[@DavidMahler]

Hi Pavan - sorry I don't have any information about that, although looking a bit - let me know what you come up with.

[@ramawidipradita5207]

Is it possible to modify the timeout and the priority?? If it's yes how to do it??

[@rahulk8537]

so what message does the controller actually send to the switch?? whether it is a packet out message or flow modification message??

[@amelouferhat3428]

Can i create a sdn topology without using mininet (i have a reason for that) ? Perhaps there is a way to add openflow protocol to a switch or a linux machine? Can you help?

[@BrianThomas]

I know this was 6 years ago, but something doesn't make sense. Back in the early days of networking, we had bridges which performed frame switching via software. This was a bit slow so frame switching was performed via the ASIC (ASIC - application-specific intergraded circuit). This allows frames to be processed at wire speed. Now we're back to a software implementation of switching. Don't get me wrong I fully understand the benefits, but how has switching via software improved with respect to speed vs switching via ASIC

[@DavidMahler]

Emphasis on the 6 years ago, I'm not working with OpenFlow anymore - but programable ASICs - e.g. sites.google.com/view/iu-whitebox-project/home/programmable-asics-and-p4

[@rinksshah]

Nice and informative video. Thanks!!!

[@DavidMahler]

Rinku Shah You're weolcome!

[@sabotocki]

Question - when h1 sent a ARP BROADCAST to ff:ff:ff:ff:ff:ff there was no flow_mod packet. Why is there no flow modification for ARP broadcasts?

[@DavidMahler]

It's been a while so I don't remember the context - maybe I just skipped ARP process to focus on core points if I recall correctly....

[@sabotocki]

Right the video is about the TCP SYN and TCP SYN ACK. This was a question about the functionality of Openflow mod packets and ARP. ARP was not shown in the video but I replicated it in my lab and just wanted to understand how Openflow handles ARP broadcasts.

[@DavidMahler]

Well it's not how "OpenFlow" handles broadcasts, it's what a controller decides to do with them and pushes down in the form of flow entries. For example, in OpenStack you can enable a feature so that broadcasts only go to where they are needed instead of flooding the whole l2 domain. On the switch itself this is seen as flow entries directing broadcasts only out via certain tunnels. I did this video a while ago but I assume a flow modification is pushed down here just to treat it like a normal l2 switch broadcast (everywhere out but the input port). The default on OVS is just to act like a normal switch which would mean normal broadcast (if there are no specific OpenFlow entries to override that behavior that came from a controller, etc.) Hope that helps?

[@sabotocki]

I think I understand now, the default OVSSwitch doesn't need a flow entry from the controller on to handle broadcast traffic, that behavior is already built in the switch by default?

[@prince.kmr1]

I m undergraduate student and new to sdn. I hav a question How to do port mirroring functionality in openflow? As you said about group table.Will it be helpful in doing port mirroring?

[@DavidMahler]

Try docs.openvswitch.org/en/latest/faq/configuration/ there is a section "How do I configure a port as a SPAN port, that is, enable mirroring of all traffic to that port?"

[@worzelhund]

Very good explanation, thank you.

[@DavidMahler]

worzelhund Anytime worzelhund!

[@worzelhund]

David Mahler would you mind doing some segment on NFV?

[@DavidMahler]

worzelhund I do have that on my list of topics I'd like to cover, but honestly its behind a few others - so might not be anytime soon.

[@muhammedroshantnoushad8342]

Well Explained. Thanks David

[@DavidMahler]

Muhammed Roshan You're welcome!

[@eliav3]

could you please make a tutorial about interacting with ovs without the command line?(I mean like adding and removing flow entries without using ovs-ofctl)

[@georgepapathanail8933]

Hello how can I use bitmask to match only the appropriate bits on eth_src?

[@ha11odri]

Really great tutorial. Thank you very much!!!

[@DavidMahler]

You're welcome Florian!

[@KanishkkaKeshav]

I tried capturing the packets with wireshark. i am using two VMs one with cbench and other with the controller. It captures all the packets but doesnt mark anything as OFP wireshark v1.8.10 in use. can anyone help

[@gregormax10]

You have to use: 1. RawCap.exe -f dump.pcap to create pcap file 2. the Wireshark development release 1.13.x, available at: www.wireshark.org/download/automated Make the catpure with RawCap and then load the pcap by Wireshark. Then enable openflow protocol by Wireshark menu: "Analyze - Decode As", scroll down right listbox to select openflow, then click on Apply and you will see openflow protocol be highlighted in the capture window. If your capture stores openfow packet, then you should have TCP packets using srcport 6633.

[@gregormax10]

gregormax10 dstPort 6633

[@DavidMahler]

gregormax10 Thanks Gregor!

[@Malx0re]

Great video, very helpful! please, how to create diagrams like in the video ? thanks

[@DavidMahler]

Thanks! Visio.

[@ujjalsamanta5841]

Best of Best lecture .thank you sir..... sir, my FLOW modification packet does not show out port number .it is showing 0.what is the problem

[@rabbymustafa3792]

hi ....can you tell me how do u capture OFP in wireshark???? in my wireshark it does not showing OFP packets?

[@AttiDavidson]

Thank you very much! Really great video!

[@DavidMahler]

you're welcome!

[@DavidMahler]

Thanks a lot Clécio!

[@MarcioMarconi]

Outstanding video, thanks a lot!

[@DavidMahler]

You're quite welcome!

[@SuganShakya]

Very excellent video. Thank you

[@DavidMahler]

+Sugan Shakya You're welcome! Thanks for the comment!

[@user-hx6xu8jj9s]

Honestly, it is indeed painful for not having more videos from you on SDN. So many years have passed and I am still waiting if you come up with a new video on networking 😪😪

[@DavidMahler]

Thanks a lot! I am thinking of starting them up again!

[@noficoh]

Hi David, I am working on an SDN project in which I use a physical router Linksys WRT54gl and burned an openWRT OS with openFlow 1.0 from the pantou project. I tried to connect two routers to some controller (openmul, floodlight) as following: r1->r2->c1 . I am having a problem in configuring the ports to allow traffic from hosts connected to r1 to hosts connected to r2. I'm having some issues when trying capture traffic on wireshark, so I was wondering if you could supply me some information about my problem. I was wondering if when r1 gets a tcp packet and encapsulate it with openFlow, and forward it to r2, does r2 encapsulate it as well or does it recognizes that it is an openFlow packet and just forward it as is to the controller? would appreciate any help on the matter, Thanks

[@MohammadImran-rn1vg]

Thanks for the Amazing Video.

[@DavidMahler]

Glad you liked it!

[@NicholasAngelucci]

Hello, how can I connect a mininet host to the Internet network? that is: how can i send a wget from a virtual host of the mininet network to www.google.com? I use ryu controller and I'm able to turn a mininet switch into a router. Thank you

[@DavidMahler]

Hi Nicholas, please check here github.com/mininet/mininet/wiki/FAQ under "Why can't I ping Google from my Mininet hosts?" Also please search the mininet and ryu mailing list archives I'm sure it's come up as a question before that hopefully has the answer you need....

[@rezamashayekhi7614]

Thanks again davis.....,

[@DavidMahler]

Reza Mashayekhi Thanks for the comment!

[@DavidMahler]

Thanks Mauro

[@ashishneupane1457]

thanks. just what i was looking for.

[@chetannoginahal]

Great tutorial for a beginner like me.

[@DavidMahler]

Thanks Chetan!

[@curtisridenour4091]

This was extremely helpful!

[@DavidMahler]

Great, thanks for the comment Curtis!

[@RemiOYEKA-k5r]

you come where the week that is to come

[@dinahwobuyaga3890]

Thank you so much this is resourceful

[@DavidMahler]

Thanks!

[@RemiOYEKA-k5r]

you draw very well

[@alexiss6853]

Great videos, big thanks

[@DavidMahler]

you're welcome Alexis!

[@shellwhale8994]

Is OpenFlow still worth learning in 2020? I heard it is dead

[@DavidMahler]

It's not dead. Maybe not as ubiquitous as people thought it would be, depends on your interests :-).

[@shellwhale8994]

@@DavidMahler I asked the same question on /r/networking www.reddit.com/r/networking/comments/ibb0kd/is_openflow_worth_learning_in_2020/ 4 months ago. I got some replies saying that it's quite used by service providers. Is that something you notice as well? I would like to do some work at the ISP once I'm out of college.

[@selmison]

Excellent video!! Thanks!!

[@DavidMahler]

You're welcome!

[@GS31661]

really excellent. Thanks a lot.

[@yunshaojiang9016]

Really clear. Thanks.

[@DavidMahler]

You're welcome!

[@dmn1n]

excellent video !

[@DavidMahler]

dmn1n Thanks!

[@freddyfrancoisateba4419]

Thanks David

[@DavidMahler]

yw!

[@javiergf]

Great video!

[@DavidMahler]

+John Connor777 Thanks!

[@leonardnonde7593]

Just what I needed!!

[@DavidMahler]

+Leonard Nonde Great!

[@EngClecio]

Very good... thanks for video!!!

[@MauroLollo]

Excellent vid!

[@bingzhang8878]

Thanks for your share!

[@DavidMahler]

bing zhang You're welcome!

[@Mtech-kf4lu]

sir how to change host ip address

[@rathisoft]

Very informative.

[@DavidMahler]

+Bharathi Athinarayanan Thanks again!

[@columgaynor9254]

CG: David, One irksome question. Sorry! I tried to set up the environment on Windows 7 PC Using Virtual Box and the Mininet VM supplied at mininet.org. I ran the same commands as in the video and noticed one difference in the output of the dump command. See below.... Interestingly, on a seprate Ubuntu 14.10 machine with mininet packages installed directly from Ubuntu Software Centre, running the same topology produced the same "OVSController" identifier as in your video, for the dump command... Why am I getting Controller as opposed to the expected OVSController ON WIDOWS 7 PC Virtual Box - Mininet VM : ===================================== sudo mn --topo=single,4 : The usual output etc... : mininet> dump sh sudo service --status-all [ + ] apparmor [ ? ] console-setup [ + ] cron [ - ] dbus [ ? ] dns-clean [ + ] friendly-recovery [ - ] grub-common [ ? ] irqbalance [ ? ] killprocs [ ? ] kmod [ ? ] networking [ + ] ntp [ ? ] ondemand [ - ] openvswitch-controller