two GbE interfaces and maximum bandwidth achievable

Hello all,

I have been posed the following question: "A PC motherboard has two GbE
interfaces, and is acting as a bridge. The theoretical maximum bandwidth
achievable across the bridge is 2Gbps. In practice only about one half of
this is achieved. Why might this be?"

First of all, I cant really understand if the term bridge means layer 2
switching or its just a misuse of the term and means in reality layer 3
routing. Can you give me some pointers regarding the reasons why only half
the theoritical bw can be achieved?

(in case bridge means in reality layer 3 routing, inefficient scheduling on
a perhaps loaded systems may slow down the routing process).

TIA

On Thu, 11 Aug 2005 20:27:57 GMT, "jimjim" <(E-Mail Removed)>
wrote:

>Hello all,
>
>I have been posed the following question: "A PC motherboard has two GbE
>interfaces, and is acting as a bridge. The theoretical maximum bandwidth
>achievable across the bridge is 2Gbps. In practice only about one half of
>this is achieved. Why might this be?"
>
>First of all, I cant really understand if the term bridge means layer 2
>switching or its just a misuse of the term and means in reality layer 3
>routing. Can you give me some pointers regarding the reasons why only half
>the theoritical bw can be achieved?
>
>(in case bridge means in reality layer 3 routing, inefficient scheduling on
>a perhaps loaded systems may slow down the routing process).


Many times, these open ended questions are not meant to get a precise
answer but to seek your knowledge behind your answer. Except when the
question is asked at the end of a chapter for example, then they are
looking for a precise answer that was treated in the chapter.

In general, a generic PC Mobo is a very inefficient platform for a
bridge. The answer could be as simple as 'cuz it's running half
duplex!







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> Many times, these open ended questions are not meant to get a precise
> answer but to seek your knowledge behind your answer.
>
true..

> In general, a generic PC Mobo is a very inefficient platform for a
> bridge. The answer could be as simple as 'cuz it's running half
> duplex!
>
hmm, he said the bw is halved across the bridge!

TIA