It depends on what you're trying to model. If you're trying to model
an ethernet hub then the correct thing is to send the packet to all
the ethernet interfaces that are connected to the hub. If you are
trying to model a switch then you would need to create an MAC address
cache. The first 6 bytes of the packet is the destination MAC address
and the second 6 bytes is the source MAC address. In the case that
the destination address is FF:FF:FF:FF:FF:FF that is a broadcast
packet and should be sent to all devices, otherwise you should cache
source MAC addreseses/port pairs so given some destination MAC
address you could find the port to send it to.
Ali
On Jul 2, 2007, at 9:38 AM, Nikolas Galanis wrote:
Ali,
I have been looking into the EtherBus object and my approach would
be to have the EtherBus keep a list of the connected EtherInt
devices so, every time one of these devices wants to transmit to
another device a Link can be instantiated between the two EtherInts
and let it handle the transmission exactly the way EtherLink does.
I have taken the Link class outside the EtherLink definition and I
have created different classfiles "link.cc" and "link.hh" for it in
order to use it in the EtherBus as well.
However, in order to know between which 2 machines the Link should
be created, I need to know the destination of the transmition. Is
there a way to know that? From what I have seen the EtherPacket
objects don't appear to have any destination information. Nor does
the transmit() function of the ethernet adapter model.
Nikolas
Ali Saidi wrote:
Hi Nikolaos,
The EtherBus object was a work in progress to create an Ethernet
Hub, however I don't believe it was ever finished. You are correct
in saying that it can't be done with an Etherlink. The EtherBus
object was created before we had the level of python integration
we do now, so the only way you can probably connect them now is to
derive an object from EtherInt that requires a EtherBus pointer as
a parameter and then calls etherbus->reg(this) on it. At this
point there isn't any way to connect them in python directly but
there should be something like the way the ports are connected to
a Bus. If you use the Ports code as an example it shouldn't be
that difficult to implement similar functionality for the
EtherInts (it's where the port idea initially came from anyway).
Let us know what you end up doing and we'll try to help where we can.
Ali
On Jun 27, 2007, at 10:03 AM, Nikolas Galanis wrote:
Hi all,
I am trying to simulate a distributed system using m5 v2-b3 and
ALPHA_FS. I have been looking the example in fs.py where you
build a 2-machine system by connecting the etherint objects of
the two systems using an etherLink.
My goal is to connect the ethernet interfaces of more than two
systems, which as far as I understand cannot be done with
etherLink. There is an EtherBus class present that seems to be
the one to use to connect multiple EtherInt devices but I cannot
find out how to do it. The EtherBus has a devlist attribute and a
reg() function to add devices to the devlist but there doesn't
seem to be any way of registering devices using python.
I have tried the following in my configuration file:
/
ethBus = EtherBus()
Parent.testsys1.tsunami.etherint[0].peer = ethB/us
but the assignment is (obviously) not correct. I get the
following error:
/Traceback (most recent call last):
File "<string>", line 1, in <module>
File "build/ALPHA_FS/python/m5/main.py", line 326, in main
execfile(sys.argv[0], scope)
File "configs/myConf/myFS.py", line 120, in <module>
root = makeQuadRoot(m_test_sys[0], m_test_sys[1], m_test_sys
[2], drive_sys, options.etherdump)
File "/media/x3/m5-2.0b3/configs/common/FSConfig.py", line 119,
in makeQuadRoot
Parent.testsys1.tsunami.etherint[0].peer = ethBus
File "build/ALPHA_FS/python/m5/proxy.py", line 56, in __setattr__
"cannot set attribute '%s' on proxy object" % attr
AttributeError: cannot set attribute 'peer' on proxy object/
Shouldn't the EtherBus have some port attribute like the Bus()
class has in order to connect the various EtherInt objects?
Is there another way to make the interconnections for a
distributed memory system?
Thanks in advance,
Nikolas
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