RE: a question from lan switching book [7:23764]
thanks all kindly answers, :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23822&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
i am clear now, and thank you very very much for explain this point to me Leigh Anne Chisholm wrote: > > Think of it like this. Shared is as many people in a 10 foot > by 10 foot > room as you can stuff. The size of the room can be an analogy > for the > bandwidth of the network and the number of people in the room > are analogous > to PC's connected to the shared bandwidth. > > The rules of conversation are this: You can only talk if you > perceive that > no one else is talking. If you hear someone else talking, you > must stop > immediately, and wait a random period until you are able to try > speaking > again. Of course, before you begin speaking, you must > determine whether > someone else is speaking. That's shared bandwidth. In this > environment > where only 1 PC can speak at a time, that PC is able to use the > entire > bandwidth of the pipe to send one frame. That frame travels at > 10 Mbps. > Each PC however must pause briefly between sending frames in an > effort to > let others talk... > > Now just because you have 10 PC's, each PC won't necessarily > have traffic to > send when all 9 others do. Thus, never make the comparison > that if you have > 10 PC's, on a shared 10 Mbps link, that each PC has 1 Mbps of > bandwidth. > Not true. Each PC has the ability to use 10 Mbps of bandwidth > just like > each person has the ability to speak in our 10 foot by 10 foot > room--but as > the number of people in that room increase in their desire to > speak, the > ability of others to "get a word in edgewise" decreases. The > more PC's, the > more difficult to utilize that shared bandwidth. > > Now the term "switched" is also known as "dedicated". Switched > is a > point-to-point link between the connected device and the > switch. Think of > it like our telephone system. I'm able to pick up my phone and > dial > whomever I like. When I lift the receiver, I have a dialtone. > I couldn't > care less if my neighbor is on the phone--I have a link to the > telephone > company's central office. I don't care who my neighbors are > talking to. I > don't hear that conversation. I can use as much of my > bandwidth as I have > available because I've got a dedicated, point-to-point link > between myself > and the telephone exchange (aka in networking terms, PC and LAN > Switch > port). > > Now let me throw a bit of a curve into this discussion. > > In a half-duplex switched environment, just because I'm able to > use the full > bandwidth between myself and the telephone company's central > office, that in > itself doesn't guarantee that my call will get through. > Switched networks > operating in half-duplex mode are able to suffer from > collisions. If I try > and phone my mom at the same time some goofy telemarketer does, > our phone > calls collide. Likely, I get a busy signal. > > In a full-duplex environment, this type of collision won't > occur. One of us > will get the "answering service" which will take a message, > forwarding it > when the line becomes free. In the full-duplex switching world, > the switch > buffers the traffic, forwarding it when the destination port is > available. > > > > To go on a bit of a tangent here... > > Now of course, the telephone company only has a limited number > of circuits > that it can carry at one time. In networking terms, this is > known as the > capacity of the backplane of the switch. The switch is not > able to forward > unlimited traffic rates. For example, the Catalyst 5000 series > switch can > only forward 1.2 Gbps of traffic at any given time. > > > -Original Message- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > > Sent: Monday, October 22, 2001 9:57 AM > > To: [EMAIL PROTECTED] > > Subject: RE: a question from lan switching book [7:23764] > > > > > > is shared means that there is a 10M ethernet, if there are 10 > station in > > this network, every station has the 1M? > > > > or is shared means that there is a 10M ethernet, if there are > 10 > > station in > > this network every station has the 10M bandwidth when you > transmisstion, > > (csma/cd) after this station trasmisted, another can transmit > and has 10M > > bandwidth. > > > > which is right? > > > > thanks for answered :) > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23821&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: a question from lan switching book [7:23764]
In this environment > where only 1 PC can speak at a time, that PC is able to use the entire > bandwidth of the pipe to send one frame. That frame travels at 10 Mbps. Specifically, the frame doesn't actually travel at 10mbs. The frame travels at the speed of electrical current on a medium. This speed is the same for 10mb ethernet, 100mb ethernet, GigE, etc. The frame is copied to the medium at 10mbs... Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23801&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
At 10:14 AM 10/22/01, Mike Sweeney wrote: >Shared is your basic hub Hub or cabling, i.e. 10Base2 or 10Base 5. All stations hear each other's frames. They all contend for and share the bandwidth. They are affected by each other's collisions. >or bridge.. A bridge divides up collision domains. Stations on opposites of the bridge do not share bandwidth and do not see each other frames, unless forwarded by the bridge. The bridge forwards to a specific device (and floods broadcasts and unknown unicasts) just like a switch. Stations on opposite sides of a bridge are not affected by each other's collisions. >layer two.. no switching.. what one >workstation/host/device sees, all will see. > >MikeS Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23798&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: a question from lan switching book [7:23764]
Geat explanation! And one of the best analogies I've seen yet. If you're not an instructor you ought to be... Leigh Anne Chisholm wrote: > Think of it like this. Shared is as many people in a 10 foot by 10 foot > room as you can stuff. The size of the room can be an analogy for the > bandwidth of the network and the number of people in the room are analogous > to PC's connected to the shared bandwidth. > > The rules of conversation are this: You can only talk if you perceive that > no one else is talking. If you hear someone else talking, you must stop > immediately, and wait a random period until you are able to try speaking > again. Of course, before you begin speaking, you must determine whether > someone else is speaking. That's shared bandwidth. In this environment > where only 1 PC can speak at a time, that PC is able to use the entire > bandwidth of the pipe to send one frame. That frame travels at 10 Mbps. > Each PC however must pause briefly between sending frames in an effort to > let others talk... > > Now just because you have 10 PC's, each PC won't necessarily have traffic to > send when all 9 others do. Thus, never make the comparison that if you have > 10 PC's, on a shared 10 Mbps link, that each PC has 1 Mbps of bandwidth. > Not true. Each PC has the ability to use 10 Mbps of bandwidth just like > each person has the ability to speak in our 10 foot by 10 foot room--but as > the number of people in that room increase in their desire to speak, the > ability of others to "get a word in edgewise" decreases. The more PC's, the > more difficult to utilize that shared bandwidth. > > Now the term "switched" is also known as "dedicated". Switched is a > point-to-point link between the connected device and the switch. Think of > it like our telephone system. I'm able to pick up my phone and dial > whomever I like. When I lift the receiver, I have a dialtone. I couldn't > care less if my neighbor is on the phone--I have a link to the telephone > company's central office. I don't care who my neighbors are talking to. I > don't hear that conversation. I can use as much of my bandwidth as I have > available because I've got a dedicated, point-to-point link between myself > and the telephone exchange (aka in networking terms, PC and LAN Switch > port). > > Now let me throw a bit of a curve into this discussion. > > In a half-duplex switched environment, just because I'm able to use the full > bandwidth between myself and the telephone company's central office, that in > itself doesn't guarantee that my call will get through. Switched networks > operating in half-duplex mode are able to suffer from collisions. If I try > and phone my mom at the same time some goofy telemarketer does, our phone > calls collide. Likely, I get a busy signal. > > In a full-duplex environment, this type of collision won't occur. One of us > will get the "answering service" which will take a message, forwarding it > when the line becomes free. In the full-duplex switching world, the switch > buffers the traffic, forwarding it when the destination port is available. > > To go on a bit of a tangent here... > > Now of course, the telephone company only has a limited number of circuits > that it can carry at one time. In networking terms, this is known as the > capacity of the backplane of the switch. The switch is not able to forward > unlimited traffic rates. For example, the Catalyst 5000 series switch can > only forward 1.2 Gbps of traffic at any given time. > > > -Original Message- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > > Sent: Monday, October 22, 2001 9:57 AM > > To: [EMAIL PROTECTED] > > Subject: RE: a question from lan switching book [7:23764] > > > > > > is shared means that there is a 10M ethernet, if there are 10 station in > > this network, every station has the 1M? > > > > or is shared means that there is a 10M ethernet, if there are 10 > > station in > > this network every station has the 10M bandwidth when you transmisstion, > > (csma/cd) after this station trasmisted, another can transmit and has 10M > > bandwidth. > > > > which is right? > > > > thanks for answered :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23795&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: a question from lan switching book [7:23764]
> is shared means that there is a 10M ethernet, if there are 10 station in > this network, every station has the 1M? > > or is shared means that there is a 10M ethernet, if there are 10 station in > this network every station has the 10M bandwidth when you transmisstion, > (csma/cd) after this station trasmisted, another can transmit and has 10M > bandwidth. > is mean that all station fight for bandwith of that 10mb. Only 1 station can send packet each time, so is not true that each station have the 1mb. Is true that one station at time has all 10mb. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23793&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
You're closer to being correct on your first answer, but each station won't get exactly 1MB. Ethernet is shared medium. In CSMA/CD, the MA means Multiple Access. All stations on that link are competing for bandwidth on the link. If 9 of the stations are idle and one station wants to transmit it will have a lot of the bandwidth available. If more stations transmit then less bandwidth will be available per station. This doesn't mean that each station gets the same amount of bandwidth, though. Link usage in ethernet is very dynamic depending on traffic patterns. HTH, John >>> "xie rootstock" 10/22/01 9:56:57 AM >>> is shared means that there is a 10M ethernet, if there are 10 station in this network, every station has the 1M? or is shared means that there is a 10M ethernet, if there are 10 station in this network every station has the 10M bandwidth when you transmisstion, (csma/cd) after this station trasmisted, another can transmit and has 10M bandwidth. which is right? thanks for answered :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23789&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
Think of it like this. Shared is as many people in a 10 foot by 10 foot room as you can stuff. The size of the room can be an analogy for the bandwidth of the network and the number of people in the room are analogous to PC's connected to the shared bandwidth. The rules of conversation are this: You can only talk if you perceive that no one else is talking. If you hear someone else talking, you must stop immediately, and wait a random period until you are able to try speaking again. Of course, before you begin speaking, you must determine whether someone else is speaking. That's shared bandwidth. In this environment where only 1 PC can speak at a time, that PC is able to use the entire bandwidth of the pipe to send one frame. That frame travels at 10 Mbps. Each PC however must pause briefly between sending frames in an effort to let others talk... Now just because you have 10 PC's, each PC won't necessarily have traffic to send when all 9 others do. Thus, never make the comparison that if you have 10 PC's, on a shared 10 Mbps link, that each PC has 1 Mbps of bandwidth. Not true. Each PC has the ability to use 10 Mbps of bandwidth just like each person has the ability to speak in our 10 foot by 10 foot room--but as the number of people in that room increase in their desire to speak, the ability of others to "get a word in edgewise" decreases. The more PC's, the more difficult to utilize that shared bandwidth. Now the term "switched" is also known as "dedicated". Switched is a point-to-point link between the connected device and the switch. Think of it like our telephone system. I'm able to pick up my phone and dial whomever I like. When I lift the receiver, I have a dialtone. I couldn't care less if my neighbor is on the phone--I have a link to the telephone company's central office. I don't care who my neighbors are talking to. I don't hear that conversation. I can use as much of my bandwidth as I have available because I've got a dedicated, point-to-point link between myself and the telephone exchange (aka in networking terms, PC and LAN Switch port). Now let me throw a bit of a curve into this discussion. In a half-duplex switched environment, just because I'm able to use the full bandwidth between myself and the telephone company's central office, that in itself doesn't guarantee that my call will get through. Switched networks operating in half-duplex mode are able to suffer from collisions. If I try and phone my mom at the same time some goofy telemarketer does, our phone calls collide. Likely, I get a busy signal. In a full-duplex environment, this type of collision won't occur. One of us will get the "answering service" which will take a message, forwarding it when the line becomes free. In the full-duplex switching world, the switch buffers the traffic, forwarding it when the destination port is available. To go on a bit of a tangent here... Now of course, the telephone company only has a limited number of circuits that it can carry at one time. In networking terms, this is known as the capacity of the backplane of the switch. The switch is not able to forward unlimited traffic rates. For example, the Catalyst 5000 series switch can only forward 1.2 Gbps of traffic at any given time. > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > Sent: Monday, October 22, 2001 9:57 AM > To: [EMAIL PROTECTED] > Subject: RE: a question from lan switching book [7:23764] > > > is shared means that there is a 10M ethernet, if there are 10 station in > this network, every station has the 1M? > > or is shared means that there is a 10M ethernet, if there are 10 > station in > this network every station has the 10M bandwidth when you transmisstion, > (csma/cd) after this station trasmisted, another can transmit and has 10M > bandwidth. > > which is right? > > thanks for answered :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23788&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
is shared means that there is a 10M ethernet, if there are 10 station in this network, every station has the 1M? or is shared means that there is a 10M ethernet, if there are 10 station in this network every station has the 10M bandwidth when you transmisstion, (csma/cd) after this station trasmisted, another can transmit and has 10M bandwidth. which is right? thanks for answered :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23783&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
hehehe.. maybe *I* needed more coffee :) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23781&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
I'm coming in at the end of this thread so I apologize if I'm stating something that someone else already covered. I wanted to nitpick a little, perhaps because I need more coffee, as usual, A hub is a layer one technology since it's simply a multiport physical repeater. It is truly shared. As Mike mentions, what one device sees all others will see. A bridge is a layer two technology that limits the traffic seen on each port. A bridge--or switch--will forward broadcast/multicast traffic out all ports. It will also forward unicast traffic destined for unknown destinations. Once it has populated its bridge table, an endstation on a given port will only see broadcast/multicast traffic and traffic that is destined for it specifically. It will not see unicast traffic destined for hosts on other ports. Regards, John >>> "Mike Sweeney" 10/22/01 8:14:08 AM >>> Shared is your basic hub or bridge.. layer two.. no switching.. what one workstation/host/device sees, all will see. MikeS Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23773&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: a question from lan switching book [7:23764]
Shared is your basic hub or bridge.. layer two.. no switching.. what one workstation/host/device sees, all will see. MikeS Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23768&t=23764 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
