>>>SNIP
Also, it's
pretty clear that the question is about who
retransmits the original frame,
>>>>END SNIP
I didn't think that the question was that clear, and
produced my previous response from the argument that
who transmits the next frame on segment B is
independent of the conversation taking place i.e from
comp 1 to 2.
If we define "original" frame as the first frame
transmitted from computer 1 then obviously this cannot
be the same frame as that which would exist on segment
B (different CRC), therefore the "original" frame
could not be re-transmitted. If however, the
"original" frame is the first frame from router B then
the answer is more obvious and I agree.
Regards,
Phil.
--- Priscilla Oppenheimer <[EMAIL PROTECTED]> wrote:
> At 07:08 PM 9/19/00, Phil Barker wrote:
> >I havn't read this thread so apologies if this has
> >been done already.
> >
> >Computer 1 sends to Computer 2.
> >
> >Router B relays a valid frame to computer 2.
> >Assume no other devices on Segment B for clarity,
>
> Why should we assume that? The question doesn't
> assume that.
> not who retransmits the frame that collided with it.
> The answer is
> obviously the router. This is fundamental Ethernet
> 101 stuff. It's so
> basic, we should move this question to the CCNA
> list! %-)
>
> Priscilla
>
> >computer 2 must be transmitting a frame on this
> >segment in order for the collision to occur.
> >
> >Therefore router B and computer 2 do a random
> back-off
> >
> >before attempting to re-transmit. So shouldn't the
> >answer to which device re-transmits be "either"
> >depending on which device can respond the fastest ?
> >
> >i.e Router B's frame is totally independent from
> >Computer 2's frame.
> >
> >Regards,
> >
> >Phil.
> >
> >PS : hope thats not a real CCIE question or I think
> >I'll be throwing tantrums on the day .......
> >
> >
> >
> >
> >--- Priscilla Oppenheimer <[EMAIL PROTECTED]>
> wrote:
> > > Where did these questions come from? Please
> specify
> > > the source (book, etc.)
> > > so that we know we aren't disobeying the NDA and
> > > giving you answers from an
> > > actual test. These sure sound like questions
> from
> > > the CCIE written. Also, I
> > > think it would be best to limit each e-mail
> message
> > > to one topic. It makes
> > > discussions easier to follow.
> > >
> > > Despite all that, I can't resist giving you my
> > > answers! &;-) See below.
> > >
> > > At 05:18 AM 9/17/00, Derek Chung wrote:
> > > >Question 1:
> > > >Router A and Router B are configured to route
> IP to
> > > each other over a serial
> > > >line. Host A is connected to Router A and Host
> B is
> > > connected to Router B. A
> > > >packet is sent from Host A to host B. A hit on
> the
> > > serial line causes an
> > > >error in the packet. Retransmission is sent by:
> > >
> > > Host A retransmits the packet. The data-link
> layer
> > > protocols in use today
> > > on serial lines, including PPP, Frame Relay, and
> > > Cisco HDLC, detect errors
> > > but are not responsible for error correction or
> > > retransmission.
> > >
> > >
> > > >Question 2:
> > > >During the middle of a TCP conversion across a
> > > routed backbone, the network
> > > >receives a voltage spike and several of the
> packets
> > > are damaged. Where are
> > > >the packets retransmitted from?
> > >
> > > The TCP sender. This is almost a repeat of the
> last
> > > question.
> > >
> > >
> > > >Question 3:
> > > >Computer1 --------[Segment
> > >
> >
>
>A]-------RouterA--------------RouterB----------[SegmentB]--------------Compu
> > > >ter2
> > > >A packet is sent to Computer 2 from Computer 1.
> A
> > > collision occurs on
> > > >Segment B. Which device will retransmit the
> frame
> > > and what will the source
> > > >MAC address be (when the packet actually
> reaches
> > > Segment B)?
> > >
> > > Router B senses the collision and retransmits at
> the
> > > MAC layer. The MAC
> > > address is Router B's Ethernet address.
> > >
> > >
> > > >Question 4:
> > > >When computer A sends a frame to computer B
> across
> > > many routers, how will
> > > >the source and destination layer 3 addresses
> > > change? How will the source and
> > > >destination layer 2 addresses change?
> > >
> > > Layer 3 addresses won't change (unless you have
> NAT
> > > or tunnelling or
> > > something else bizarre.) The Layer 2 addresses
> > > change each time a router
> > > re-encapsulates the packet in a data-link-layer
> > > header than includes
> > > layer-2 addresses.
> > >
> > > Priscilla
> > >
> > > ________________________
> > >
> > > Priscilla Oppenheimer
> > > http://www.priscilla.com
> > >
> > > **NOTE: New CCNA/CCDA List has been formed. For
> more
> > > information go to
> > > http://www.groupstudy.com/list/Associates.html
> > > _________________________________
> > > UPDATED Posting Guidelines:
> > > http://www.groupstudy.com/list/guide.html
> > > FAQ, list archives, and subscription info:
> > > http://www.groupstudy.com
> > > Report misconduct and Nondisclosure violations
> to
> >[EMAIL PROTECTED]
> >
> >
>
>____________________________________________________________
> >Do You Yahoo!?
> >Get your free @yahoo.co.uk address at
> http://mail.yahoo.co.uk
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>
>
> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
> **NOTE: New CCNA/CCDA List has been formed. For more
> information go to
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> _________________________________
> UPDATED Posting Guidelines:
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> Report misconduct and Nondisclosure violations to
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____________________________________________________________
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**NOTE: New CCNA/CCDA List has been formed. For more information go to
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