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[mininet-discuss] DOT: A Distributed OpenFlow Testbed

Philip Wette wette at
Wed May 13 12:16:51 PDT 2015

Hi PhiHo,

if you plan to distribute a Mininet emulation across multiple physical 
machines you may take a look at MaxiNet.

MaxiNet lets you control and setup a distributed emulation without 
having to worry about your distributed resources. MaxiNet uses GRE 
tunnels to interconnect switches emulated at different machines. So you 
do not need any routing between the different mininet instances.



Am 13.05.15 um 21:08 schrieb Phiho Hoang:
> Hi Nick,
> Thank you for sharing your experience.
> I am not as much concerned with the through put as with how to handle 
> the massive number of hosts, sub-nets and datapaths in the emulation 
> using Mininet.
> (I plan to use dozens of cheap CHIP, the Raspberry Pi Killer ;-)
> Did you find any need for DHCP, DNS, routers... when you work with 
> Mininet at a massive scale across multiple servers so that all Mininet 
> hosts in the emulation can communicate with one another conveniently?
> Some sample codes would be much appreciated.
> Again, thank you for sharing.
> Regards,
> PhiHo
> On Tue, May 12, 2015 at 7:37 PM, Nicholas Bastin 
> <nick.bastin at <mailto:nick.bastin at>> wrote:
>     On Tue, May 12, 2015 at 6:55 PM, Phiho Hoang <hohoangphi at
>     <mailto:hohoangphi at>> wrote:
>         Are they described in some research paper?
>     No, it's work, not research.. :-)
>         Would you be able to share the custom topologies used in these
>         mininet ebvironments?
>     Most of the test topologies are proprietary, as they mirror
>     customer environments, but I can elaborate a bit about the
>     structure of the testbed. We have a small cluster of Dell C6100
>     servers (4-node 2U chassis - unavailable now but you can get them
>     on the surplus market or a newer variant from supermicro). 
>     They're 12 core each with quad-channel memory (very important) and
>     then we put multiport 10G cards (2-4 ports) in each node for the
>     distributed interconnection.  These function as the leaf of an
>     infrastructure that then has custom-built 1U servers with 12x10G
>     interfaces to serve as the core interconnection fabric between the
>     leaf nodes (you could also of course use hardware OF 10G switches
>     for this purpose, but we provision datapaths and network functions
>     on this hardware, do packet analysis, etc. so it's more than just
>     moving packets around).
>     This is more of a systems design problem than anything special
>     about mininet - mininet itself is unmodified in this environment
>     (although you must obviously tweak the OS for open file handles,
>     etc.).  The real question is not so much about the number of
>     datapaths, but the amount of traffic.  The amount of traffic the
>     system can handle is fixed by the amount of memory bandwidth
>     available - each leaf node in our system has a little over
>     40GBytes/sec of memory bandwidth and as such if you're doing
>     packet copies to move your packets around you have to consider
>     your data rate multiplied by the number of copies in a
>     representative average path to estimate rough max throughput per
>     node.  For large scale failover studies and such where you're not
>     really running traffic but want to see controller or switch
>     behaviour ripple throughout your topology, you can safely run high
>     hundreds of datapaths per core (given sufficient memory of course).
>     I would not necessarily try to bring up 50k datapaths on a single
>     node (you probably really start to run into OS resource issues
>     here, and maybe would have to do it using multiple VMs on the same
>     metal -  checking /proc/sys/fs/file-max on a newer system shows
>     over 2.5 million so maybe it'd be possible, although there are
>     also limits on the number of non-patch interfaces you can have),
>     but I'd wager on big modern hardware you could probably do it with
>     2 nodes (particularly considering the absolutely absurd number of
>     cores you can get per node these days).
>     --
>     Nick
> _______________________________________________
> mininet-discuss mailing list
> mininet-discuss at

Philip Wette, M.Sc.             E-Mail: wette at
University of Paderborn         Tel.:   05251 / 60-1716
Department of Computer Science
Computer Networks Group
Warburger Straße 100            Room:   O3.152
33098 Paderborn

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