[c-nsp] Layer 2 question

[Mike Johnson]

Agreed, but is there a device that will do just that. The reason I ask is
because that is exactly
what is needed in a GPON network architecture.

mike


On 7/29/08, Brett Frankenberger
<rbf+cisco-nsp at panix.com<rbf%2Bcisco-nsp at panix.com>>
wrote:
>
> On Tue, Jul 29, 2008 at 12:43:10PM -0400, Mike Johnson wrote:
> >
> > What happens if a layer 2 switch receives a frame that needs to be
> > forwarded out the same port that the incoming frame was received on?
>
> It will discard it.
>
> Back when Layer 2 switches were typically used to connect multiple
> shared-media Ethernet segments, this happened all the time -- every
> time two nodes on the same shared-media Ethernet segment communicated.
>
> These days, most switch ports connect only to a single device, but the
> operation of Layer 2 switching (which is just bridging) hasn't changed.
>
> > Im realize that a typical layer 2 switch would never forward that
> > packet upstream in the first place. However, If it did in fact happen
> > what does the upstream L2 switch do?
>
> Consider the case of a hub (not a switch) connected to a switch port,
> and multiple devices on that hub communicating with each other.  The
> switch sees all the packets, and doesn't forward them.
>
>     -- Brett
>