Jason wrote:

> What happens if the SM reprograms the pkey table later?
> 
> I'm not sure this is the right approach.. See the recent dicussion
> about using pkey indexes at all.
> 
> Each ipoib interface is assigned a pkey, by number, not index. If the
> SM has not supplied that pkey to the port then the ipoib should not
> come up. If the SM adds it later then it should come up, if it the SM
> removes it later then it should go down.
> 
> The default ipoib interface uses the default pkey. If your network
> need ipoib to use a different pkey then you have to change the pkey
> number assignment when the ipoib interface is created, not magically
> attempt to autoconfigure.
> 
> I believe you cannot safely change the broadcast GID once the ipoib
> interface has started.

The goal for IPoIB should be a mechanism which can mimic the ease of setting up 
VLANs in Ethernet.  In Ethernet a default VLAN can be programmed into a switch 
in which case no configuration of the server is needed.  Ethernet switch 
vendors often provide centralized tools for setting up VLANS in all the 
switches.  It is only when you want a given server to participate in multiple 
VLANs that you need to setup specific configuration on the server to do so.

For IB, the centralized tool is the SM and a "VLAN" is an IB Partition.  The 
present capability of using the 1st PKey table entry is a nice simple and 
powerful way to mimic the ease of use of Ethernet VLANs.  Only when a user 
wants IPoIB to run on two different partitions (which is rare) is a server 
specific configuration needed.

When IPoIB sees a PKey table change, it will reregister with the broadcast GID. 
 PKey table changes typically also involve a restart of the SM and hence a 
reregistration request is necessary anyway.

Todd Rimmer
Chief Architect 
QLogic Network Systems Group
Voice: 610-233-4852     Fax: 610-233-4777
[email protected]  www.QLogic.com
 

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