openflow | OpenFlow Reference
kandi X-RAY | openflow Summary
kandi X-RAY | openflow Summary
OpenFlow is a flow-based switch specification designed to enable researchers to run experiments in live networks. OpenFlow is based on a simple Ethernet flow switch that exposes a standardized interface for adding and removing flow entries. An OpenFlow switch consists of three parts: (1) A "flow table" in which each flow entry is associated with an action telling the switch how to process the flow, (2) a "secure channel" connecting the switch to a remote process (a controller), allowing commands and packets to be sent between the controller and the switch, and (3) an OpenFlow protocol implementation, providing an open and standard way for a controller to talk to the switch.
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QUESTION
I have the following to first create relationship between nodes (the nodes already created in a previous step)
...ANSWER
Answered 2021-May-07 at 16:23If you want to find a :connect relationship between the nodes (you don't care what the properties are to match upon) and then update the properties, then only MERGE the relationship, do not include the properties in the pattern. Then use SET to set the properties to the new values:
QUESTION
I have the following list in python:
...ANSWER
Answered 2021-Apr-27 at 19:29out = {"data": [{"{#NAPP}": i.split(":")[-1]} for i in napps_list]}
from pprint import pprint
pprint(out)
QUESTION
I just finished reading sections 1-6.2 of the OpenFlow specification here.
Section 6.1.2 says:
Packet-in events can be configured to buffer packets. For packet-in generated by an output action in a flow entries or group bucket, it can be specified individually in the output action itself (see 7.2.6.1), for other packet-in it can be configured in the switch configuration (see 7.3.2). If the packet-in event is configured to buffer packets and the switch has sufficient memory to buffer them, the packet-in event contains only some fraction of the packet header and a buffer ID to be used by a controller when it is ready for the switch to forward the packet. Switches that do not support internal buffering, are configured to not buffer packets for the packet-in event, or have run out of internal buffering, must send the full packet to controllers as part of the event. Buffered packets will usually be processed via a Packet-out or Flow-mod message from a controller, or automatically expired after some time
This makes it sound like for every packet that hits the OpenFlow switch, an asynchronous message must be sent to the controller to make a forwarding decision. However Chapter 5 makes it sound like a switch has a set of OpenFlow flows and at the end of that generates an action set which determines what should be done with a packet and the packet is only forwarded to the controller when there is a flow table miss.
Under what conditions is a packet sent to the controller for a decision? Is it always? Or is it only circumstantial?
...ANSWER
Answered 2020-Apr-27 at 00:01Packets will be sent to the OpenFlow controller any time the out port is set to be the controller.
PACKET_IN events occur when a flow wasn't matched on the switch and are then sent to the controller. Otherwise no event is created - the switch simply forwards the packet according to the flow rules and the controller is none the wiser.
QUESTION
For the uninitiated - I am asking a Python/SDN question. It is a programming question.
There isn't much literature on this and I didn't see it in the specification. I have built a Ryu controller based on the documentation and have it all working, but I have a rather simple problem:
How do you map the in_port numbers to actual port numbers? In my case, it is saying I have an in_port of 5. However, it's actually coming in to physical port 1/1/2 on my Dell 4112F-ON. There doesn't seem to be any correlation between the two.
If I want to control traffic on a per port basis, how do I know from which physical port the traffic came?
Edit: I know how to convert to a MAC address, but I haven't figured out a clean way to programatically determine the port # from the MAC address.
...ANSWER
Answered 2020-Apr-24 at 13:54I discovered that in Ryu, the name of the physical port is inside the dpset data structure which is part of ryu.controller. In dpset there is an attribute called port_state which is a dictionary of type {: }. You can extract the data with the following code:
QUESTION
When I used the ONOS Controller, which uses the OpenFlow Discovery Protocol, each switch had send a PacketIN encapsulated LLDP message back to the controller. These PacketINs are answering the LLDP messages the controller has send to discover the network. This was checked using wireshark. I wanted to check if OpenDayLight had the same behaviour, but there were no PacketINs.
Thats why I wanted to know how ODL gets topology information without receiving any LLDP packages ?
...ANSWER
Answered 2020-Apr-17 at 16:39Try installing these three features:
QUESTION
I'm trying to complete the mininet topology exercise from this website https://github.com/mininet/openflow-tutorial/wiki/Advanced-Topology. Basically I have to create a topology like this:
h1-----s1---s2----h3
(there is also another host attached to s1 called h2)
and program a POX controller to install flows to the switches so that the pingall and iperf commands work.
Everything works fine except for the iperf command which fails when it runs from h1 to h3 or from h2 to h3.
This is the code I have, and I believe the problem has to do with communicating to the right switch what to do with packets of a type different than arp or icmp, but I've been stuck too long on this problem and have decided to ask for help here.
...ANSWER
Answered 2020-Mar-22 at 11:57EDIT:
I solved this by flooding IP_packets directed to h3, to all ports except the in_port
QUESTION
My questions is a flow doesn't hit the OpenFlow flow table although its property matches the table perfectly.
I did a small experiment by using mininet,ONOS, Iperf.
I want to see flow routing according to srcIP, dstIP, UDP, dstPort.
Therefore, I generated a UDP flow (srcIP=10.0.0.3, dstIP=10.0.0.2, dstPORT=50000)
and I add flow rules to each mininet switch by using ONOS REST api.
You can see two flow rules below the raw flow rules.
...ANSWER
Answered 2020-Jan-04 at 03:03I solve this problem. the problem is related with UDP fragmentation
As I write the comment, I found only the small UDP datagram hit the flow table properly.
In other words, It is because the UDP datagram is so large.
I set the UDP datagram 63k. Then it is fragmented at IP layer.
Then the only first packet has UDP header information and only the packet hit the flow table properly, as I expected.
For solve this problem, I use the Jumbo frame which means OVS can handle the packet with larger MSS.
We should also set NIC MSS. (http://docs.openvswitch.org/en/latest/topics/dpdk/jumbo-frames/)
And we update OVS version above 2.6.0 (it will be better to use http://docs.openvswitch.org/en/latest/intro/install/general/ than other sites that we can google)
After setting Jumbo frame, we can see the flow table hitting works properly for larger UDP datagram.
QUESTION
I running basic html and json file to visualize nodes and links using vis.js. Json files contain list of nodes and links/edges. I refer to SO sample here to run it... example . I test using the examples and it does work and show all the nodes and links. I replace the json file with my own data and when i execute the code... it just show the nodes without any link.
My Json file
...ANSWER
Answered 2019-Nov-24 at 21:56as you say edges are not structured as { id, source, target } but as { id, from, to }. The same applies to options.edges.arrows.
This also seems problematic (two variables named data in the same scope, more like bad practice though):
QUESTION
How to get the port number from a log (Splunk) by regular expressions:
...ANSWER
Answered 2019-Oct-28 at 15:40To match the different formats, you might use:
QUESTION
I just started play-around with flask and html.
I have a python file that make a request to a url and return the output in json. The output is printed on the terminal. Now, I want to get the output to be shown in html page. I have gone with few tutorial..but difficult to understand and to adopt it based on my own data.
Python file without any flask/html
...ANSWER
Answered 2019-Oct-02 at 12:32Here is a possible approach:
PYTHON'S SIDE:
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