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This is the kind of situation that I think screams for OpenFlow[1]. It seems issues like this would be easier to avoid and faster to troubleshoot. 1. http://ww

by dkhenry 14y ago

This is the kind of situation that I think screams for OpenFlow[1]. It seems issues like this would be easier to avoid and faster to troubleshoot. 1. http://www.openflow.org/ http://www.openflow.org/

ChuckMcM 14y ago
Can you say more about this? I'm quite familiar with OpenFlow but I've not seen anything that would help with problems like "I need to increase the cross sectional bandwidth of this collection of 1000 machines by 50%, and keep those machines running and serving data."
- wmf 14y ago
  I am building an OpenFlow-based fabric where the switches have no configuration; all decisions are made by the controller and pushed down to the switches as soft state. STP is not used, so no ports are ever blocked and all forwarding is shortest-path. The goal is to be fully dynamic so that adding links or switches triggers hitless path recomputation as necessary. This technically doesn't come out until Tuesday, but here's a peek: http://conferences.sigcomm.org/co-next/2012/eproceedings/conext/p49.pdf http://conferences.sigcomm.org/co-next/2012/eproceedings/con...
  - ChuckMcM 14y ago
    Ohh, that is very nice, thanks for the link. We happen to have G8264's at the center of our network ...
  - imbriaco 14y ago
    That is super interesting, thanks for the pointer. Looking forward to reading over the paper.
- dkhenry 14y ago
  The biggest advantage I think they would get is a central configuration through all their routers. No need to have a complex interdependent configuration on a dozen routers. One controller can forward the changes to everyone when their made. Also my knowledge here is limited, but I was under the impression that if I added additional routing bandwidth the system would learn about that and automatically make changes to the routing tables to utilize the additional bandwidth ?
deleted 14y ago
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arjun85 14y ago
I don't fully agree :). Openflow would make use of the same hardware table, and for a full Openflow implementation would presumably have to rely on hardware based MAC learning to scale. The switch software would still use some API to program the chip. Sounds like in this case, there was an interaction between the hardware and chip API, which would have been exactly the same case with Openflow. I think this problem would have probably occurred even with a centralized controller
- nixgeek 14y ago
  I believe that's a very rational conclusion and is likely correct.

by dkhenry 14y ago

This is the kind of situation that I think screams for OpenFlow[1]. It seems issues like this would be easier to avoid and faster to troubleshoot. 1. http://www.openflow.org/ http://www.openflow.org/

ChuckMcM 14y ago

Can you say more about this? I'm quite familiar with OpenFlow but I've not seen anything that would help with problems like "I need to increase the cross sectional bandwidth of this collection of 1000 machines by 50%, and keep those machines running and serving data."

wmf 14y ago
I am building an OpenFlow-based fabric where the switches have no configuration; all decisions are made by the controller and pushed down to the switches as soft state. STP is not used, so no ports are ever blocked and all forwarding is shortest-path. The goal is to be fully dynamic so that adding links or switches triggers hitless path recomputation as necessary. This technically doesn't come out until Tuesday, but here's a peek: http://conferences.sigcomm.org/co-next/2012/eproceedings/conext/p49.pdf http://conferences.sigcomm.org/co-next/2012/eproceedings/con...
- ChuckMcM 14y ago
  Ohh, that is very nice, thanks for the link. We happen to have G8264's at the center of our network ...
- imbriaco 14y ago
  That is super interesting, thanks for the pointer. Looking forward to reading over the paper.
dkhenry 14y ago
The biggest advantage I think they would get is a central configuration through all their routers. No need to have a complex interdependent configuration on a dozen routers. One controller can forward the changes to everyone when their made. Also my knowledge here is limited, but I was under the impression that if I added additional routing bandwidth the system would learn about that and automatically make changes to the routing tables to utilize the additional bandwidth ?

deleted 14y ago

[deleted]

arjun85 14y ago

I don't fully agree :). Openflow would make use of the same hardware table, and for a full Openflow implementation would presumably have to rely on hardware based MAC learning to scale. The switch software would still use some API to program the chip. Sounds like in this case, there was an interaction between the hardware and chip API, which would have been exactly the same case with Openflow. I think this problem would have probably occurred even with a centralized controller

nixgeek 14y ago
I believe that's a very rational conclusion and is likely correct.