From: Bob Ciotti <Bob.Ciotti-NSQ8wuThN14@public.gmane.org>
To: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: changing subnet ID
Date: Wed, 13 Apr 2011 15:18:31 -0700 [thread overview]
Message-ID: <20110413221831.GA20946@nas.nasa.gov> (raw)
Question with regard to changing the subnet prefix in OpenSM.
We want to uniquely identify individual subnets via changing the
subnet prefix in OpenSM:
/etc/ofa/opensm-ib0.conf:subnet_prefix 0xfe80000000000000
to something like
/etc/ofa/opensm-ib0.conf:subnet_prefix 0xfe80000000000100
Then an application can make some sense of what ib subnets it has access to, particularly on multi-homed
or multi interfaced hosts that can be on any combination of ib subnets.
The RFC on ipv6 addressing (http://tools.ietf.org/html/rfc4291#section-2.5.6) says those bits should
be 0. I'm unclear if FE80/10 or FE80:0:0:0/64 is link local.
Does anyone know if this will break things or a better way to do this, and keep the host address part
private (not unique) between subnets? I suppose it could break routing ::))
host A - multi if on
ib0 - 0xfe80000000000000
ib1 - 0xfe80000000000001
host B - multi if on
ib0 - 0xfe80000000000001
ib1 - 0xfe80000000000000
host C - multi if on
ib0 - 0xfe80000000000100
ib1 - 0xfe80000000000001
host D - multi if on
ib0 - 0xfe80000000000100
ib1 - 0xfe80000000000001
host E - multi homed and multi if on
ib0 - 0xfe80000000000000
ib1 - 0xfe80000000000001
ib2 - 0xfe80000000000100
ib3 - 0xfe80000000000100
An application that spans all 5 hosts wants to know which hosts it can *expect* to connect to over what
interfaces, without actually making the connection.
909
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next reply other threads:[~2011-04-13 22:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-13 22:18 Bob Ciotti [this message]
[not found] ` <20110413221831.GA20946-2Ww08eqqtp6fRvmTrFJqzg@public.gmane.org>
2011-04-13 23:25 ` changing subnet ID Jason Gunthorpe
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