Chuck,
It's pretty much an issue of semantics... Another station could send
to you, but the frame would be buffered by the switch until the
current frame had finished sending. It would be transmitted to you
afterward.
Also, to confirm Peter's statement that he's never seen a full-duplex
hub... Such an animal does not/can not exist. This is one of the key
differences between hubs and switches. A hub, by it's very nature,
cannot provide full-duplex operation. It has no means of bufferring
frames, nor of providing segmentation on a per node basis. A hub is
layer 1 device, and the network is provides is a shared medium.
Vijay, chances are that if it has a 1Gbps uplink, it is a switch, and
depending on the number of connected 100Mbps stations, and your
network traffic patterns, you very well might be able to saturate the
uplink connection, because a switch allows for multiple simultaneous
conversations. Under the right conditions, you could fill up
virtually any pipe, but unless your traffic demands are really
outlandish, you probably won't. If you do, you should examine the
reasons, and revise the design of your network accordingly.
Alan
----- Original Message -----
From: "Chuck Larrieu"
To:
Sent: Wednesday, May 30, 2001 11:14 AM
Subject: RE: elementary? [7:6359]
> Hhhmmmm....... Not so sure this is exactly right......
>
> With full duplex, you have effectively created two "directions" ---
there
> and back.
>
> I believe it is accurate to say that only one packet can be on the
wire per
> direction at one time.
>
> I can send to you at the same time you are sending to me. But
Someone else
> can not send to you at the time my packet is on the wire.
>
> Correct me if I'm wrong.
>
> Chuck
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf
Of
> Peter I. Slow
> Sent: Wednesday, May 30, 2001 7:40 AM
> To: [EMAIL PROTECTED]
> Subject: Re: elementary? [7:6359]
>
> Noooooooo.
> nononononono.
> CSMA/CD only gets used when you are not in full duplex. (/me ducks)
( i
> have NEVER seen a full-dup. hub) meaning that if i am using a switch
capable
> of full duplex (as most are) ..conversations, every station can
transmit as
> much as they want. this is what differentiates between a hub and a
switch.
> (but not the only thing)
> you are correct in that a 100 meg HUB with a gig uplink could never
fully
> utilize the link, but the case is completly different with a switch.
>
>
>
> ----- Original Message -----
> From: "Vijay Ramcharan"
> To:
> Sent: Wednesday, May 30, 2001 9:54 AM
> Subject: RE: elementary? [7:6359]
>
>
> > Thanks everyone for their replies. As I now understand it, the
1Gb
> > uplink just moves data faster than... say, a 100Mb uplink.
Correct?
> > Conversations between hosts on each switch still take place one at
a
> > time, thereby obeying Ethernet rules of one station transmitting
at a
> > time. Correct?
> > Okay my next question. Is there any point at which this 1Gb uplink
can
> > become saturated, since it's only handling station to station
sessions-
> > one at a time.
> > If a number of stations on each switch were doing large file
transfers
> > to each other via the uplink, would there be some point at which
the
> > uplink would be maxed out- in terms of bandwidth? Or is the only
> > limiting factor, the workstations inability to pump data out fast
enough
> > to max out the uplink when they're only running 100Mb?
> >
> > I'm thinking that it's really not possible to max out a 1Gb uplink
when
> > stations are only running 100Mb. If this is correct then I lay
this
> > question to rest.
> >
> > Thanks.
> >
> > Vijay Ramcharan
> >
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On
Behalf Of
> > Vijay Ramcharan
> > Sent: Wednesday, May 30, 2001 12:06 AM
> > To: [EMAIL PROTECTED]
> > Subject: elementary? [7:6359]
> >
> >
> > Forgive me if this sounds a little bit basic but this is what
happens
> > when you rush into things without understanding the fundamentals.
> > Suppose a 24 port 100Mbit switch called A is uplinked to another
24 port
> > 100Mb switch called B via a 1Gb connnection. Suppose hosts D
through N
> > are on switch A and hosts M through X are on Switch B. Would
> > conversations between the hosts from Switch A to Switch B occur
one at a
> > time or are multiple conversations multiplexed over the 1Gb
uplink?
> >
> > I'm just trying to find out if and how that 1Gb uplink is used up.
> > Thanks in advance. I'd put TIA but I hate those little acronyms.
No
> > flames please.
> >
> > Vijay Ramcharan
> > FAQ, list archives, and subscription info:
> > http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
> > FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
> FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
> FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=6468&t=6359
--------------------------------------------------
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
