On Tue, 18 Jun 2002, Jing Shen wrote:
> If I don't misunderstand your situation, you interconnects all
> linux-based core router by a switch and some edge equipment / traffic
> source to 100Mbps switch.
>
> Under this situation, I think it not desirable to set up "core" switch
> to be one with only 10Mbps ports, as most of current switches are
> capable to autonegotiate its work switch according to computer's NIC
> speed. So do those NICs available from the market.
So you are suggesting changing the NICs in the routers to 10Mbit, right?
I dont even know if 10Mbit NICs are available anymore :)
> And, if all core routers interconnects through a same "switch backbone "
> in one box, some of p2p communication will cut-across directly if ip
> redirect is enabled. I means, if you want to experiment with Packet
> labeling/routing/queueing in routers, I don't think you need to consider
> much about Layer2 switch backbone as it act just like a crosswire and
> interface card determine how fast equipment can communicate.
Thats an interesting point. So if there are redundant routes in the core
network, then its not necessary that the "explicity specified" route will
be chosen, correct?
I think i DO need to consider Layer 2 switch backbone speed because
otherwise I would have to generate a LOT of data to ensure that queuing
takes place in the core routers.
e.g. On a all-100 Mbit network, i would have to generate close to
saturation traffic so that the queuing mechanisms work in the core.
Generating so much traffic in itself becomes a problem, especially if the
traffic has to follow a certain distribution (Poisson, exponential..)
because of the 10ms jiffy limit of Linux.
Dont you agree?
On a related note, I was playing with mii-tool and trying to throttle down
the 100Mbit cards on the routers to 10Mbit full duplex. What I see then
is that although my switch now detects the 10Mbit link, there are too many
collisions on the switch leading to a great performace hit.
Could any body comment on this phenomena?
TIA.
ciao,
Amit
--
I'm an angel!!! Honest!
The horns are just there to hold the halo up straight.
^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^
Amit Kucheria
EECS Grad. Research Assistant
University of Kansas @ Lawrence
(R): +1-785-830-8521 ||| (C): +1-785-760-2871
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