Changes between Version 14 and Version 15 of OpenFlow/CampusTopology


Ignore:
Timestamp:
05/12/11 13:55:10 (13 years ago)
Author:
Josh Smift
Comment:

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  • OpenFlow/CampusTopology

    v14 v15  
    5959Note that the two ports don't have to be on the same switch. In particular, if there were already another campus switch in the path between this !OpenFlow switch and the regional, you could connect port 3 on this switch (still on VLAN 1750) to a port on that other campus switch (still on VLAN 3715), and accomplish the same effect. This would free up a port on this !OpenFlow switch, but use up a port on the other switch, so campuses should decide where to put the cross-connects based on where ports are scarce.
    6060
    61 VLAN 1750 is an !OpenFlow-controlled VLAN, shared by multiple experimenters via the FlowVisor. In addition to whatever other !OpenFlow programming each experimenter wishes to do with their sliver, the experimenter also uses !OpenFlow to direct outbound traffic to a physical port; the port they choose controls which inter-campus VLAN will be used for the outbound traffic. For example, an experiment that wanted to send inter-campus traffic via VLAN 3715 would use !OpenFlow to send that traffic out port 3. Example code to do this is available from Stanford and the GPO, contact us for more information. ''(FIXME: Replace the previous sentence with a link to a page with more information, download links, etc.)''
     61VLAN 1750 is an !OpenFlow-controlled VLAN, shared by multiple experimenters via the FlowVisor. In addition to whatever other !OpenFlow programming each experimenter wishes to do with their sliver, the experimenter also uses !OpenFlow to direct outbound traffic to a physical port; the port they choose controls which inter-campus VLAN will be used for the outbound traffic. For example, an experiment that wanted to send inter-campus traffic via VLAN 3715 would use !OpenFlow to send that traffic out port 3.
     62
     63Note that since VLAN 1750 is cross-connected to multiple intercampus VLANs, care must be taken to ensure that e.g. broadcast packets aren't flooded out to both VLAN 3715 and 3716. The simplest way to prevent this is for experimenters to never reserve a topology that includes more than one cross-connect port, and for campus Expedient admins to carefully check experimenter requests to make sure that they don't. If a particular experimenter wanted to do a particular experiment that did use multiple inter-campus VLANs, they would need to expressly confirm that they understand the risks and are confident that they won't accidentally flood broadcast traffic, ideally by testing and demonstrating their experiment in a staging environment first.
    6264
    6365Additional VLANs can be set up for physical translation, but they use two ports per VLAN, and they need to be physically connected by a campus network admin... So this can be done if needed, but should generally be minimized.