[Beowulf] Mutiple IB networks in one cluster
Alan Louis Scheinine
alscheinine at tuffmail.us
Thu Feb 6 19:51:10 PST 2014
When I wrote "the number of nonblocking connections is typically
much less than the number of nodes" I had in mind the telephone
network (in the age of copper wires). Are you sure that "1/2 the
nodes can make a single call to the other 1/2 of the nodes" is
typical of a computer interconnect? I thought that the typical
cross-sectional bandwidth was less, or am I mistaken?
Greg Lindahl wrote:
> In the usual Clos network, 1/2 of the nodes can make a single call to
> the other 1/2 of the nodes. That's what's non-blocking. Nothing else
> is. Running any real code, every node talks to more than one other
> node, and the network is not non-blocking.
> It makes perfect sense in a telephone network. In the real world, a
> Clos network is good but not non-blocking.
> On Wed, Feb 05, 2014 at 06:31:11PM -0600, Alan Louis Scheinine wrote:
>> Clos is non-blocking up to a certain number of completed connections.
>> The number of nonblocking connections is typically much less than
>> the number of nodes for which the Clos network provides service.
>> Anybody can make a telephone call to anybody else, up until the
>> maximum number of completed connections is reached.
>>> At least that is what Chuck Seitz drove into our heads whenever we said that a Clos was non-blocking. :-)
>> Alan Scheinine
>> 200 Georgann Dr., Apt. E6
>> Vicksburg, MS 39180
>> Email: alscheinine at tuffmail.us
>> Mobile phone: 225 288 4176
>> Beowulf mailing list, Beowulf at beowulf.org sponsored by Penguin Computing
>> To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
200 Georgann Dr., Apt. E6
Vicksburg, MS 39180
Email: alscheinine at tuffmail.us
Mobile phone: 225 288 4176
More information about the Beowulf