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<TITLE>RE: [openib-general] Unicast ARP</TITLE>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Roland Dreier [<A HREF="mailto:roland@topspin.com">mailto:roland@topspin.com</A>] </FONT>
<BR><FONT SIZE=2>> Sent: Monday, November 29, 2004 9:04 PM</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Michael> Currently it also seems that by just bringing the</FONT>
<BR><FONT SIZE=2>> Michael> interface up and down the hw address will change. Unless</FONT>
<BR><FONT SIZE=2>> Michael> I am doing something wrong, this inconvenience seems to</FONT>
<BR><FONT SIZE=2>> Michael> be caused by a different QP number being assigned. Cant</FONT>
<BR><FONT SIZE=2>> Michael> this be solved e.g. by assigning a fixed QP number for IP</FONT>
<BR><FONT SIZE=2>> Michael> over IB?</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> It seems you are doing something wrong. The QP is allocated </FONT>
<BR><FONT SIZE=2>> when the interface is created and remains the same when the </FONT>
<BR><FONT SIZE=2>> interface is brought up and down:</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> # ip addr show dev ib0</FONT>
<BR><FONT SIZE=2>> 7: ib0: <BROADCAST,MULTICAST,UP> mtu 2044 qdisc </FONT>
<BR><FONT SIZE=2>> pfifo_fast qlen 128</FONT>
<BR><FONT SIZE=2>> link/[32] </FONT>
<BR><FONT SIZE=2>> 00:02:04:04:fe:80:00:00:00:00:00:00:00:05:ad:00:00:01:82:06 </FONT>
<BR><FONT SIZE=2>> brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff</FONT>
<BR><FONT SIZE=2>> # ifconfig ib0 down</FONT>
<BR><FONT SIZE=2>> # ifconfig ib0 up</FONT>
<BR><FONT SIZE=2>> # ip addr show dev ib0</FONT>
<BR><FONT SIZE=2>> 7: ib0: <BROADCAST,MULTICAST,UP> mtu 2044 qdisc </FONT>
<BR><FONT SIZE=2>> pfifo_fast qlen 128</FONT>
<BR><FONT SIZE=2>> link/[32] </FONT>
<BR><FONT SIZE=2>> 00:02:04:04:fe:80:00:00:00:00:00:00:00:05:ad:00:00:01:82:06 </FONT>
<BR><FONT SIZE=2>> brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>Roland, </FONT>
<BR><FONT SIZE=2>You're right, it takes more than "ifconfig down" for the QPN to change.</FONT>
<BR><FONT SIZE=2>If you take the module down after doing ifconfig down, then the QPN</FONT>
<BR><FONT SIZE=2>may change.</FONT>
<BR><FONT SIZE=2>Assigning specific QPN for ipoib requires allocation of QPN space which</FONT>
<BR><FONT SIZE=2>is beyond IB spec verbs. Current verbs do not allow it. I don't have any</FONT>
<BR><FONT SIZE=2>objection for that, except that you have to hold a set of preallocated QPs</FONT>
<BR><FONT SIZE=2>with specific numbers and hand them over to privileged consumer when</FONT>
<BR><FONT SIZE=2>requested to. I wouldn't commit that it will work on any HCA architecture.</FONT>
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<P><FONT SIZE=2>-Dror</FONT>
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