Changes between Version 16 and Version 17 of OpenFlow/FOAM/AdminIntro


Ignore:
Timestamp:
01/30/14 15:44:39 (6 years ago)
Author:
Josh Smift
Comment:

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  • OpenFlow/FOAM/AdminIntro

    v16 v17  
    1919A physical !OpenFlow switch has one or more "datapaths", each of which connects to one !OpenFlow controller. Each datapath has a unique identifier ("DPID"), often including the MAC address of the management interface on the switch, and on VLAN-hybrid switchs, the VLAN ID corresponding to that datapath.
    2020
     21Some physical switches have more than one datapath, and some datapaths are "VLAN-hybrid" datapaths, which typically means that (a) on the switch itself, datapaths are set up using the switch's native mechanisms for setting up VLANs, and each datapath corresponds to a VLAN; (b) traffic within the datapath is not tagged by VLAN, because the switch is already using VLAN to differentiate datapaths. The InstaGENI racks use VLAN-hybrid switches; the ExoGENI racks use port-hybrid switches (in which each physical port on the switch is either part of the !OpenFlow datapath, or managed by the switches normal native logic; the !OpenFlow ports are a essentially a pure-!OpenFlow datapath, from a FOAM point of view at least).
     22
    2123To allow multiple GENI experimenters to use a datapath, we use !FlowVisor to slice traffic into multiple "flowspaces", based on criteria that match various characteristics of the traffic ("flowspace rules" in FV terms). For example, the flowspace rules for a FV slice might match any traffic on VLAN 1755 (`dl_vlan=1755`), or IP subnet 10.42.15.0/24 (`dl_type=0x800,nw_dst=10.42.109.0/24,nw_src=10.42.109.0/24`), etc.
    2224
    2325(Note that a "!FlowVisor slice" isn't a slice in the GENI sense; they're very different, they just happen to use the same term. There's typically a one-to-one relationship between a FOAM sliver and a FV slice, so it may be helpful to think of a FV slice as the resources that have been allocated to a FOAM sliver.)
    24 
    25 Some physical switches have more than one datapath, and some datapaths are "VLAN-hybrid" datapaths, which typically means that (a) on the switch itself, datapaths are set up using the switch's native mechanisms for setting up VLANs, and each datapath corresponds to a VLAN; (b) traffic within the datapath is not tagged by VLAN, because the switch is already using VLAN to differentiate datapaths. The InstaGENI racks use VLAN-hybrid switches; the ExoGENI racks use port-hybrid switches (in which each physical port on the switch is either part of the !OpenFlow datapath, or managed by the switches normal native logic; the !OpenFlow ports are a essentially a pure-!OpenFlow datapath, from a FOAM point of view at least).
    2626
    2727!FlowVisor has a command-line interface that the FV admin can use to configure and interact with it (called "fvctl"), but in GENI, each !FlowVisor is generally completely controlled by FOAM. It can sometimes be useful to use fvctl to examine !FlowVisor state, but you typically won't need (or want) to change FV state with fvctl.