Re: switch flow control
Chuck - Pause frame is implemented with Gig-E over fiber, which Cisco has blades for for the Cat 4000, 6500, and above. There was a thread somewhere referring to it as either 802.1z or 802.3z. (Not sure which; I haven't looked it up) Sun's gig-e cards support pause frames, I know. I can't speak for any other cards. Joel ""Chuck Larrieu"" [EMAIL PROTECTED] wrote in message 000101c07c59$73636040$[EMAIL PROTECTED]">news:000101c07c59$73636040$[EMAIL PROTECTED]... Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ 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 s
RE: switch flow control
Hi, I don't know if my input got through on Friday or when ever. I understand there is a clocking type pulse that exists between the port and the nic. If this does not match then you will get no link and therefore no comms. In a nutshell a 100Meg port will not see a 10 Meg port. OK so we get to Autonegotiate. This works in a similar manner to a modem retrain and will attempt to train to the best and/or a preset speed. Unfortunately not all manufacturers agree on how this is to be acheived and therefore autoneg is not always a good option. Some devices do not correctly identify hard set ports. Just a thought. A clocking type pulse sets up the link, once the link is up then comms can take place. Teunis, Hobart, Tasmania Australia On Saturday, January 13, 2001 at 06:06:58 PM, Chuck Larrieu wrote: Just wanted to put this discussion into a summary form. Hoping that I have learned something. Hoping to help others learn something. The original question can be generalized to this: Host_1--Device---Host_2 Host one is transmitting at 100 mbs and host two can only receive at 10 mbs The question is "what happens to the excess packets when Device is overloaded like this?" S wrote out the following table: If Device is: what happens is: Repeater just does what it's told. If the wire is full it is higher layers that deal with it Ethernet CSMA/CD determines what goes onto the wire in the first place. Collisions will occur. Or bits won't get onto the wire in the first place because the medium is saturated. Medium MTU effects Host_1 transmission rate as well. Token ringpossession of the token determines a stations ability to transmit data. Medium MTU is a factor here as well. Frame relay if a frame switch is saturated, packets are dropped and FECN's and BECN's are generated ATM I believe that the admissions control process limits the acceptance of cells into the ATM switch. Correct me if I am wrong here. I find I am a bit shaky on 100VG, X.25 ( like I care, since it isn't on the Lab any more :- ), and HDLC Lastly, the issue the original post raised - a switch. In the reading of the this thread, and the reading of some of the references, what I am determining is that if there is some kind of flow control mechanism, it comes probably in the form of the switch creating false collisions on the port of the sender, so as to stop it from overflowing the switch buffers. The point being that in terms of layer two, the general means of dealing with too much input and not enough output is still generally speaking, massive dropping of excess packets, or some limitation of the medium itself to limit acceptance of new packets onto the medium. Which is as it should be, I would think. Any comments? Does this make sense? Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject: RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject:Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Guhh
RE: switch flow control
Chuck , I agree that if you don't have an input buffer you simply drop the packet . This is so with a router and this is so with a switch . You can use any queueing mechanisme you like but in the end if you have no buffers you drop the packet . In the thread someone came up with the existence of 'pause' frames . This is actually an annex to the gigabit spec that defines a means of flow control by using those pause frames . Like an send/no send mechanisme . Certainly not all hardware in the Cisco switches and available NIC's supports this mechanisme. This is gigabit , the original pause was about 100Mb. Is this 'pause' frame also implemented on 100Mb links ? Besides if you think of it ; PC/100MB switch 10Mb Lets consider a point to point links between PC and switch. The switch can handle the 100Mb comming from the PC. The switch is capable of switching the 100Mb stream to the 10Mb port . So the output buffers on the 10Mb switch port are suffering , in keeping up with the traffic coming from the 100Mb port. So were do you drop the packets ?? On the output queue at the 10Mb port . This makes it more difficult to implement the pause mechanisme on the 100Mb port . Infact the 10Mb should signal the 100Mb port that it cannot handle the packets otherwise the 100Mb port will never know and never send a pause frame to begin with . Imaging now that there are other ports switching frames to the same 10Mb port . What to do now ? Pc1 100Mbswitch 10Mb Pc2 100Mb Lets say PC1 one is streaming like hell to the 10Mb port . Lets say Pc2 behaves and is sending packets in a moderate fashion to the 10Mb port . How to implement the 'pause frame' mechanisme ? Real live switch is immense more complicated than the senarios above . This 'pause' thing makes sense if you have a one to one connection with similar speeds . I fail to see how this mechanisme can solve the 100Mb---10Mb buffer problem . I do not think that is was indendent to solve this type of problems in the first place . Thats what I make of it , flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Just wanted to put this discussion into a summary form. Hoping that I have learned something. Hoping to help others learn something. The original question can be generalized to this: Host_1--Device---Host_2 Host one is transmitting at 100 mbs and host two can only receive at 10 mbs The question is "what happens to the excess packets when Device is overloaded like this?" S wrote out the following table: If Device is: what happens is: Repeater just does what it's told. If the wire is full it is higher layers that deal with it Ethernet CSMA/CD determines what goes onto the wire in the first place. Collisions will occur. Or bits won't get onto the wire in the first place because the medium is saturated. Medium MTU effects Host_1 transmission rate as well. Token ringpossession of the token determines a stations ability to transmit data. Medium MTU is a factor here as well. Frame relay if a frame switch is saturated, packets are dropped and FECN's and BECN's are generated ATM I believe that the admissions control process limits the acceptance of cells into the ATM switch. Correct me if I am wrong here. I find I am a bit shaky on 100VG, X.25 ( like I care, since it isn't on the Lab any more :- ), and HDLC Lastly, the issue the original post raised - a switch. In the reading of the this thread, and the reading of some of the references, what I am determining is that if there is some kind of flow control mechanism, it comes probably in the form of the switch creating false collisions on the port of the sender, so as to stop it from overflowing the switch buffers. The point being that in terms of layer two, the general means of dealing with too much input and not enough output is still generally speaking, massive dropping of excess packets, or some limitation of the medium itself to limit acceptance of new packets onto the medium. Which is as it should be, I would think. Any comments? Does this make sense? Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject: RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do
RE: switch flow control
Chuck , I agree that if you don't have an input buffer you simply drop the packet . This is so with a router and this is so with a switch . You can use any queueing mechanisme you like but in the end if you have no buffers you drop the packet . In the thread someone came up with the existence of 'pause' frames . This is actually an annex to the gigabit spec that defines a means of flow control by using those pause frames . Like an send/no send mechanisme . Certainly not all hardware in the Cisco switches and available NIC's supports this mechanisme. This is gigabit , the original pause was about 100Mb. Is this 'pause' frame also implemented on 100Mb links ? Besides if you think of it ; PC/100MB switch 10Mb Lets consider a point to point links between PC and switch. The switch can handle the 100Mb comming from the PC. The switch is capable of switching the 100Mb stream to the 10Mb port . So the output buffers on the 10Mb switch port are suffering , in keeping up with the traffic coming from the 100Mb port. So were do you drop the packets ?? On the output queue at the 10Mb port . This makes it more difficult to implement the pause mechanisme on the 100Mb port . Infact the 10Mb should signal the 100Mb port that it cannot handle the packets otherwise the 100Mb port will never know and never send a pause frame to begin with . Imaging now that there are other ports switching frames to the same 10Mb port . What to do now ? Pc1 100Mbswitch 10Mb Pc2 100Mb Lets say PC1 one is streaming like hell to the 10Mb port . Lets say Pc2 behaves and is sending packets in a moderate fashion to the 10Mb port . How to implement the 'pause frame' mechanisme ? Real live switch is immense more complicated than the senarios above . This 'pause' thing makes sense if you have a one to one connection with similar speeds . I fail to see how this mechanisme can solve the 100Mb---10Mb buffer problem . I do not think that is was indendent to solve this type of problems in the first place . Thats what I make of it , flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Just wanted to put this discussion into a summary form. Hoping that I have learned something. Hoping to help others learn something. The original question can be generalized to this: Host_1--Device---Host_2 Host one is transmitting at 100 mbs and host two can only receive at 10 mbs The question is "what happens to the excess packets when Device is overloaded like this?" S wrote out the following table: If Device is: what happens is: Repeater just does what it's told. If the wire is full it is higher layers that deal with it Ethernet CSMA/CD determines what goes onto the wire in the first place. Collisions will occur. Or bits won't get onto the wire in the first place because the medium is saturated. Medium MTU effects Host_1 transmission rate as well. Token ringpossession of the token determines a stations ability to transmit data. Medium MTU is a factor here as well. Frame relay if a frame switch is saturated, packets are dropped and FECN's and BECN's are generated ATM I believe that the admissions control process limits the acceptance of cells into the ATM switch. Correct me if I am wrong here. I find I am a bit shaky on 100VG, X.25 ( like I care, since it isn't on the Lab any more :- ), and HDLC Lastly, the issue the original post raised - a switch. In the reading of the this thread, and the reading of some of the references, what I am determining is that if there is some kind of flow control mechanism, it comes probably in the form of the switch creating false collisions on the port of the sender, so as to stop it from overflowing the switch buffers. The point being that in terms of layer two, the general means of dealing with too much input and not enough output is still generally speaking, massive dropping of excess packets, or some limitation of the medium itself to limit acceptance of new packets onto the medium. Which is as it should be, I would think. Any comments? Does this make sense? Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject: RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do
RE: switch flow control
Just wanted to put this discussion into a summary form. Hoping that I have learned something. Hoping to help others learn something. The original question can be generalized to this: Host_1--Device---Host_2 Host one is transmitting at 100 mbs and host two can only receive at 10 mbs The question is "what happens to the excess packets when Device is overloaded like this?" S wrote out the following table: If Device is: what happens is: Repeaterjust does what it's told. If the wire is full it is higher layers that deal with it EthernetCSMA/CD determines what goes onto the wire in the first place. Collisions will occur. Or bits won't get onto the wire in the first place because the medium is saturated. Medium MTU effects Host_1 transmission rate as well. Token ring possession of the token determines a stations ability to transmit data. Medium MTU is a factor here as well. Frame relay if a frame switch is saturated, packets are dropped and FECN's and BECN's are generated ATM I believe that the admissions control process limits the acceptance of cells into the ATM switch. Correct me if I am wrong here. I find I am a bit shaky on 100VG, X.25 ( like I care, since it isn't on the Lab any more :- ), and HDLC Lastly, the issue the original post raised - a switch. In the reading of the this thread, and the reading of some of the references, what I am determining is that if there is some kind of flow control mechanism, it comes probably in the form of the switch creating false collisions on the port of the sender, so as to stop it from overflowing the switch buffers. The point being that in terms of layer two, the general means of dealing with too much input and not enough output is still generally speaking, massive dropping of excess packets, or some limitation of the medium itself to limit acceptance of new packets onto the medium. Which is as it should be, I would think. Any comments? Does this make sense? Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject: RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick H __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ ___
Re: Subject: RE: switch flow control
I believe what everybody is trying to reference is actually the subspec contained in 802.3x, which is generally dealing with Full Duplex transmission. An optional subcomponent deals with flow control using "pause" frames. This appears in these links (watch wrap): http://www.ieng.com/univercd/cc/td/doc/cisintwk/ito_doc/ethernet .htm Search on "flow control" and here: http://www.cisco.com/warp/public/cc/so/neso/lnso/lnmnso/fesol_wp .htm The actual configuration steps can be found here for a CAT 1900: http://www.cisco.com/univercd/cc/td/doc/product/lan/28201900/192 8v9x/cli/part1.htm#xtocid1592737 a 2900/3500XL: http://www.cisco.com/univercd/cc/td/doc/product/lan/c2900xl/29_3 5xp/cmdref/macrcli.htm#xtocid397620 a 6500/XDI interface: http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_ 6_1/cmd_ref/set_po_r.htm#30647 HTH, Paul Werner Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: switch flow control
--- Chuck Larrieu [EMAIL PROTECTED] wrote: Besides which. Isn't 802.3Z gigabit? Not relevant to most switches or switch ports? It is gigabit ethernet but there are annex that specify this kind of flow control . I would say that gigabit ethernet is *only* relevant for trunk ports on switches and high speed routers . Certainly not to the question of a fast port sending data to a slow port. Nope . Queuing is extremely difficult and congestion on switches involves more than sending a few pause packets to end stations. And re-reading, yeah I guess I was confused a bit by the summary, which I may have misinterpreted as autoconfig -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject: RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject:Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick H __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: switch flow control
A switch recieves data in it's port buffer at 100 mbps, as the frame travels the switches backplane it is copied to all ports, when it arrives at an ASIC chip (I forget if it's the Earl or what)in the SUP module, the module looks in it's table and decides what port it should go out of and tells all other ports but that one to flush their buffers and the forwarding port to forward. So you see the frame arrives at the port at 100, but travels the backplane at a constant speed as it is traveling the backplane it is copied to the 10 meg port (all ports actually), after the asic decides who flushes and who forwards, the forwarding port tells the 10 meg port to forward. This is my understanding of what happens. Corrections and additions welcome!! -Original Message- From: Rick Holden [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 11, 2001 8:34 PM To: [EMAIL PROTECTED] Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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]
Re: switch flow control
As far as I know flow control is one of the functions of many data link layer protocols, besides framing, error correction, sync and control. ""Rick Holden"" [EMAIL PROTECTED] wrote in message 003001c07c37$b61d6880$[EMAIL PROTECTED]">news:003001c07c37$b61d6880$[EMAIL PROTECTED]... There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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]
Re: switch flow control
I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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]
RE: switch flow control
It doesn't. Layer 2 device buffers full = packets dropped. What should happen is that at the TCP level, the two end devices should through the TCP flow control mechanisms, agree to a reduced transmission on the part of the sender. UDP is another story - packets are bit-bucketed and no one is the wiser. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Rick Holden Sent: Thursday, January 11, 2001 5:34 PM To: [EMAIL PROTECTED] Subject:switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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]
Re: switch flow control
Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: switch flow control
Hi, Between the nic and the switch don't worry you won't even get a link if there is a speed mismatch. These things I think you will find do a little clocking if they don't get together there nothing will happen. Autonegotiate does something similar to modems training and will establish the best or a predefined rate. (this is not always very successful depending on how the manufacturers do it) Teunis, Hobart, Tasmania Australia On Thursday, January 11, 2001 at 09:43:48 PM, Circusnuts wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] -- www.tasmail.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: switch flow control
802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: switch flow control
802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: switch flow control
This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd/ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: switch flow control
Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits.pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd/ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: switch flow control
Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick Holden" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 11, 2001 11:33 PM Subject: switch flow control There is one thing that confuses me about switches. If you have a switch with a 100Mb port and 10Mb port and the 100 starts sending data to the 10 how does the sending station keep from overflowing the buffer on the switch since there in now flow control at layer 2? _ 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] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ 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]
RE: switch flow control
One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick H __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: switch flow control
Besides which. Isn't 802.3Z gigabit? Not relevant to most switches or switch ports? Certainly not to the question of a fast port sending data to a slow port. And re-reading, yeah I guess I was confused a bit by the summary, which I may have misinterpreted as autoconfig -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:56 PM To: Chuck Larrieu Cc: [EMAIL PROTECTED] Subject:RE: switch flow control One of us needs a pair of glasses ;-) I read ; minimal specification for asymetric flow control Has to do with flow control. If you say a device to pause , process the buffers and then release the pause is indeed a minimal form of flow control . I never played with set port flowcontrol so I getting impressed I loved the old style no buffer , drop packet . Things are really getting more complex is it not ? flem --- Chuck Larrieu [EMAIL PROTECTED] wrote: Guys, this "pause" frame does not appear to have anything whatsoever to do with flow control of data transmission. Unless I am blind as a bat I am reading the link below to be referencing auto negotiation of links between NIC and switch or any device on a port and switch.. Look, if a switch cannot output data as fast as it comes in, and the buffers fill, then packets get dropped. Same as with a router. or a PC. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Flem Sent: Thursday, January 11, 2001 9:17 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: switch flow control Or ; http://grouper.ieee.org/groups/802/3/z/public/presentations/jan1997/HFpsbits .pdf Written by a cisco guy ... you are rights cisco do implement it. flem --- Chris McCoy [EMAIL PROTECTED] wrote: This is true...sorry. I was reading a cisco document on the Cat 6000s where they explained flow control as being 802.3Z flow control. I screwed up...(see http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd /ether.htm#xtocid170110) Come to think of it...it's called 802.1x (http://www.ieee802.org/1/pages/802.1x.html). Cisco supports it with some exceptions (set port flowcontrol). Gu Chris M. --- Flem [EMAIL PROTECTED] wrote: 802.1Z ? or 802.3z ? This is gigabit stuff is it not ? Is cisco implementing 802.3z on his gigabit switches ? Don't think so . Switch will buffer , if no buffer , then drop packet. Do you know what vendor implements pause frames ? flem --- Chris McCoy [EMAIL PROTECTED] wrote: 802.1Z or 'pause frames' Chris M. --- Flem [EMAIL PROTECTED] wrote: Between NIC and switch ? What is the name of this handshaking ? flem --- Circusnuts [EMAIL PROTECTED] wrote: I believe there is a handshake going on with the switch NIC - Original Message - From: "Rick H __ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/ _ 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]
