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6 votes

How does SDN Controller know the IP address from a packet?

We've always said that SDN Controllers are "Protocol-less", they don't need to know the packet's encoding to switch it. Or, controllers can route packets by the IP Address. And the IP Address used ...
Ron Trunk's user avatar
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4 votes
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how openflow messages get routed from switch to controller? (SDN)

When the network is set up, the controller on recognizing the switch has been added to the network will install the default rule to ensure it gets messages from that switch that are not resolved by ...
Matt Stevens's user avatar
4 votes

Forwarding to multiple output ports using SDN

Yes, the openflow protocol supports the creation of flows with multiple actions, and each action can be to send a frame/packet out a certain port. However, whether or not your openflow switch ...
hertitu's user avatar
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4 votes
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Scaling VXLAN tunnels in openvswitch

You could solve this by running VXLAN on the hypervisor using software like FRR. That would imply that you run a full mesh BGP setup between your hypervisors, or use route reflectors. Then, you can ...
Teun Vink's user avatar
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3 votes

Direct packet forwarding by controller

An SDN controller generally doesn't forward user data (at least not with OpenFlow). It often only gets a digest from an unmatched packet (the essential data extracted), so there might even be nothing ...
Zac67's user avatar
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3 votes
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Finding the difference between flow tables in SDN and routing tables in traditional network

First note that all of these technical terms are subject to distortion by Marketing, so sometimes you have to read between the lines. The term switch refers to a layer-2 device, so it is forwarding ...
MAP's user avatar
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2 votes
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OpenFlow takes some seconds to apply rule

Ingress policing on OVS is not implemented using OpenFlow, but is implemented as a Token Bucket, according to the OVS manual. The size of the bucket corresponds to ingress_policing_burst. ...
ederlf's user avatar
  • 111
2 votes

Software defined system

If by Ethernet, you mean Ethernet 'frames' then that packet is sent to the Controller. The Controller then instructs the Switch about packet modification and actions for output port. Alternatively, ...
Pratik Lotia's user avatar
2 votes

What does this flow mean? (SDN)

It is the default flow that sends all packets to the controller. The controller can then install new flows, or process the packets via PACKET_OUT messages. I believe that if you use the -m or --more ...
nik's user avatar
  • 217
2 votes
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Forwarding to multiple output ports using SDN

I found that using Group Tables that is supported in OpenFlow since version 1.1 of the standard, it is possible to replicate and process a packet through multiple buckets of actions. If a group table ...
mnmp's user avatar
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2 votes
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The communication among multiple controllers

One of the characteristics of SDN is that the controllers are not in the forwarding path. So, s1 and s2 need a path between them, not the controllers.
Ron Trunk's user avatar
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2 votes

How to manipulate Openflow data packet to change IP adresses?

The function you are looking for is Network Address Translation (NAT), which you would most likely need to use the misc.nat tool. The usage is documented in nat.py located here: https://github.com/...
Benjamin Dale's user avatar
1 vote

How does a new switch know how to reach the controller in an SDN?

Now how would the new switch know how to reach the controller? And how did the first switches know how to reach the controller in the first place? Most often, SDN switches are added to the controller ...
Zac67's user avatar
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1 vote

In an SDN (OpenFlow), are all switches directly connected to controller?

The quoted answer is not quite correct. Switches have a logical connection to the controller, but not a physical one -- at least not in a network of any size. Openflow protocol uses TCP/IP (port 6653)...
Ron Trunk's user avatar
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1 vote
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Are Openconfig and Openflow trying to address same problem .?

In part. OpenConfig is an initiative to use a vendor-neutral, common set of command and data models across a mixed-vendor network. OpenFlow allows forwarding-plane control and is normally used in ...
Zac67's user avatar
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1 vote

Is there a method to modify bits in IP packets with OpenFlow?

I used NXM_NX_IPV6_DST field and load action to resolve this problem on openvswitch bridge by adding a flow as follows ovs-ofctl -O openflow13 add-flow br0 "priority=60000,ipv6,ipv6_dst=2020::/16,...
stoner's user avatar
  • 11
1 vote

What is the difference between meters and queues in Openflow?

On the one hand, OpenFlow Queues: Guarantee minimum and maximum bandwidth for egress traffic. Are applied per port. Apply both traffic policing and traffic shaping, by dropping traffic exceeding the ...
Christos Dalamagkas's user avatar
1 vote

SDN switch: packet forwarding use of transport-layer headers

There are many possible uses - load balancing, fail-over, ... For instance, you could forward based on a (virtual) web server's IP address and TCP port 80 to one host in a cluster - based on current ...
Zac67's user avatar
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1 vote
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dpctl: OpenFlow packet receive failed: unexpected end of file

Found good advice about your case: https://mailman.stanford.edu/pipermail/openflow-discuss/2013-April/004537.html Also see this part of man ovs-dpctl: This program works only with datapaths that ...
Ivan Gurzhiy's user avatar
1 vote
Accepted

Direct packet forwarding by controller

Yes, it is possible to deliver the packet directly. From the most recent OpenFlow Specification, (It is 1.5 but it is also valid for 1.3 and 1.4), page 94. /* Action structure for OFPAT_OUTPUT, ...
ederlf's user avatar
  • 111
1 vote

What does this flow mean? (SDN)

If you are familiar with the concept of forwarding table in conventional networking. 'Flows' has a similar role in software defined networks. The switch under use appears to be OVS. OVS is a software ...
john 's user avatar
  • 1,237
1 vote

FloodLight OpenFlow controller - ACLs, Firewall, static rules - what is the difference between them?

The difference between an ACL and a firewall is keyword stateful. A firewall keeps a state table whereas a basic ACL simply filters based on layer 3/4 properties. In a router, firewall functionality ...
Ronnie Royston's user avatar
1 vote
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What is the difference in OpenVSwitch and openswitch?

Good question. The 5 second, and facetious answer is that OpenSwitch needs real wires and ports whereas OpenVswitch doesn't. In more detail: OpenSwitch is switching software that you ultimately ...
AlwaysLearning's user avatar
1 vote
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Openflow-based Switch Action set

Yes. To be more precise, the openflow protocol defines the set-field action, but it depends on the switch implementation whether or not it supports this, and which fields can be modified if it does. ...
hertitu's user avatar
  • 2,658
1 vote

Problem with an n-host, zero-switch topology in mininet

There are 2 problems here based on the fact that Mininet considers one interface in a host as the "default" interface for the node. In a host with many interfaces, mininet assigns an IP only to the ...
Amedeo's user avatar
  • 111
1 vote

Problem with an n-host, zero-switch topology in mininet

Perhaps the first two hosts get an IP assigned in the same subnet. Hence, they may be communicating over traditional network. Since, you didn't add a switch, the question of loops shouldn't arise. ...
Pratik Lotia's user avatar
1 vote
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Delete flow by cookie match in Pox?

No. According to the OpenFlow 1.0 specification (since you are using POX, I can assume that is the version you are using.) the cookie field is only used to identify a flow retrieved via flow stats ...
ederlf's user avatar
  • 111
1 vote
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Why OpenFlow allows L4 features to be included in match structure

Short answer: because merely routing isn't enough. In modern enterprise or service provider networks, there is usually a requirement to treat certain types of traffic differently than others. For ...
Ron Trunk's user avatar
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1 vote

How firewalls differ between traditional networks and SDN

The architecture of SDN prevents stateful in-line processing of packet flows (ignoring using firewall hardware, NFV or experimental stateful switches). Therefore anything that monitors the state of a ...
Matt Stevens's user avatar
1 vote
Accepted

What does the load balancer shall have the ability to serve traffic over a static IP address mean?

There are applications and appliances which can perform load balancing as you described, but it may be for resources other than servers. The load balancer will have a fixed, known IP address, and that ...
Ron Maupin's user avatar
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