RE: Portfast
yes, but only if he then connects another link to another hub / switch and causes a bridging loop. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:08 To: [EMAIL PROTECTED] Subject: Portfast In the below website it says not to have portfast on if you connect switches, hubs, or routers. I understand that point but what if a user connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he could connect multiple computers. Would this cause any problems? Thank you! http://www-1.cisco.com/warp/public/473/12.html Note: The portfast feature should never be used on switch ports that connect to other switches, hubs, or routers. These connections may cause physical loops and it is very important that spanning tree go through the full initialization procedure in these situations. A spanning tree loop can bring your network down. If portfast is turned on for a port that is part of a physical loop, it can cause a window of time where packets could possibly be continuously forwarded (and even multiply) in such a way that the network cannot recover. _ 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: Portfast
No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure in these situations. A spanning tree loop can >bring your network down. If portfast >is turned on for a port that is part of a physical loop, it can cause a >window of time where packets could possibly be continuously forwarded (and >even multiply) in >such a way that the network cannot recover. > >_ >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: Portfast
John, It should not cause any problems provided that the device in question is not using any kind of dual uplinks. Basically, all portfast does is allow that port to skip through a majority of the Spanning Tree protocol checking process. Obviously this is okay for end stations and servers. We have portfast turned on all the ports in our closet switches and we have wirless hubs on all floors as well as users who have mini hubs at their desks and we have not experienced any problems thus far. Heather - CCNA -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 9:08 AM To: [EMAIL PROTECTED] Subject: Portfast In the below website it says not to have portfast on if you connect switches, hubs, or routers. I understand that point but what if a user connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he could connect multiple computers. Would this cause any problems? Thank you! http://www-1.cisco.com/warp/public/473/12.html Note: The portfast feature should never be used on switch ports that connect to other switches, hubs, or routers. These connections may cause physical loops and it is very important that spanning tree go through the full initialization procedure in these situations. A spanning tree loop can bring your network down. If portfast is turned on for a port that is part of a physical loop, it can cause a window of time where packets could possibly be continuously forwarded (and even multiply) in such a way that the network cannot recover. _ 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: Portfast
If you are not going to form the loops you can turn the Spanning Tree off. But if you connect a hub or a switch or something you are not going to switch on/off very often, there's no point. You connect the hub to the switchport, you wait 30 seconds, you forget about it forever. Conecting/disconnecting stations to the hub doesn't bother the switch's spanning tree, the switch port is still sniffing the hub's heartbeat and stays in the forwarding state. /felis John Chang wrote: > > In the below website it says not to have portfast on if you connect > switches, hubs, or routers. I understand that point but what if a user > connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) > or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he > could connect multiple computers. Would this cause any problems? Thank you! > > http://www-1.cisco.com/warp/public/473/12.html > > Note: The portfast feature should never be used on switch ports that > connect to other switches, hubs, or routers. These connections may cause > physical loops > and it is very important that spanning tree go through the full > initialization procedure in these situations. A spanning tree loop can > bring your network down. If portfast > is turned on for a port that is part of a physical loop, it can cause a > window of time where packets could possibly be continuously forwarded (and > even multiply) in > such a way that the network cannot recover. > > _ > 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: Portfast
Check out the new portfast bpdu guard feature. It can shut down ports that have portfast enabled when detecting bpdus on the line. Keith -Original Message- From: McCallum, Robert [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 10:44 AM To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure in these situations. A spanning tree loop can >bring your network down. If portfast >is turned on for a port that is part of a physical loop, it can cause a >window of time where packets could possibly be continuously forwarded (and >even multiply) in >such a way that the network cannot recover. > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body containing: unsubscribe ccielab _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Portfast
If this bdpu guard works as it supposed to, I'll definitely use it. Windows 2000 machines seem to need portfast for DHCP, and almost all Windows machines need it for IPX. I've always pointed out to the customer about NEVER connecting other layer 2 devices to the ports I configured portfast on. This is good insurance. Chuck Church CCNP, CCDP, MCNE, MCSE Sr. Network Engineer Magnacom Technologies 140 N. Rt. 303 Valley Cottage, NY 10989 845-267-4000 x218 -Original Message- From: Latimer, Keith [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 11:13 AM To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast Check out the new portfast bpdu guard feature. It can shut down ports that have portfast enabled when detecting bpdus on the line. Keith -Original Message- From: McCallum, Robert [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 10:44 AM To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure in these situations. A spanning tree loop can >bring your network down. If portfast >is turned on for a port that is part of a physical loop, it can cause a >window of time where packets could possibly be continuously forwarded (and >even multiply) in >such a way that the network cannot recover. > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body containing: unsubscribe ccielab ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body containing: unsubscribe ccielab _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Portfast
We use it on all of our L2 and L3 Cat6509's... greatest thing since sliced bread. We were having a SEVERE problem with Win98 clients not being able to log on because of timing issues (AutoIPconfiguration feature of Win98 ) that portfast could correct. Before BPDU GUARD it was a manual config for each affected port. BPDU Guard allows you to do it globally. Philip G. Virnoche CCNA Network Engineer - AT&T Wireless phone: 425.580.5239 cell: 206.601.3134 "HAM AND EGGS - A day's work for a chicken; A lifetime commitment for a pig." -Original Message- From: Chuck Church [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 1:22 PM To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast If this bdpu guard works as it supposed to, I'll definitely use it. Windows 2000 machines seem to need portfast for DHCP, and almost all Windows machines need it for IPX. I've always pointed out to the customer about NEVER connecting other layer 2 devices to the ports I configured portfast on. This is good insurance. Chuck Church CCNP, CCDP, MCNE, MCSE Sr. Network Engineer Magnacom Technologies 140 N. Rt. 303 Valley Cottage, NY 10989 845-267-4000 x218 -Original Message- From: Latimer, Keith [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 11:13 AM To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast Check out the new portfast bpdu guard feature. It can shut down ports that have portfast enabled when detecting bpdus on the line. Keith -Original Message- From: McCallum, Robert [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 10:44 AM To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure in these situations. A spanning tree loop can >bring your network down. If portfast >is turned on for a port that is part of a physical loop, it can cause a >window of time where packets could possibly be continuously forwarded (and >even multiply) in >such a way that the network cannot recover. > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure viol
RE: Portfast
It's not specific to Windows 2000 machines... Any machine that needs DHCP and boots up with any speed (less than 50 seconds), or any machine running a novell client where it would try a GetNearestServer and find nothing Scott -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Chuck Church Sent: Thursday, March 01, 2001 4:22 PM To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast If this bdpu guard works as it supposed to, I'll definitely use it. Windows 2000 machines seem to need portfast for DHCP, and almost all Windows machines need it for IPX. I've always pointed out to the customer about NEVER connecting other layer 2 devices to the ports I configured portfast on. This is good insurance. Chuck Church CCNP, CCDP, MCNE, MCSE Sr. Network Engineer Magnacom Technologies 140 N. Rt. 303 Valley Cottage, NY 10989 845-267-4000 x218 -Original Message- From: Latimer, Keith [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 11:13 AM To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast Check out the new portfast bpdu guard feature. It can shut down ports that have portfast enabled when detecting bpdus on the line. Keith -Original Message- From: McCallum, Robert [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 10:44 AM To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure in these situations. A spanning tree loop can >bring your network down. If portfast >is turned on for a port that is part of a physical loop, it can cause a >window of time where packets could possibly be continuously forwarded (and >even multiply) in >such a way that the network cannot recover. > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body containing: unsubscribe ccielab ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body co
RE: Portfast
One of my customers had a problem only with W2K machines and DHCP. His NT4.0 and 98 machines didn't need port fast. Possibly W2K has less of a delay between loading the lan driver (and activating the link) and looking for a DHCP server? Or maybe they were just faster machines. Or maybe W2K has a shorter timeout for the DCHP lease request? Anyway, I've been using portfast on almost all workstation ports for the past few months. Thanks, Chuck Church CCNP, CCDP, MCNE, MCSE Sr. Network Engineer Magnacom Technologies 140 N. Rt. 303 Valley Cottage, NY 10989 845-267-4000 x218 -Original Message- From: Scott Morris [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 4:44 PM To: 'Chuck Church'; ''Ccielab' (E-mail)'; 'Cisco@Groupstudy. Com (E-mail)' Subject: RE: Portfast It's not specific to Windows 2000 machines... Any machine that needs DHCP and boots up with any speed (less than 50 seconds), or any machine running a novell client where it would try a GetNearestServer and find nothing Scott -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Chuck Church Sent: Thursday, March 01, 2001 4:22 PM To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast If this bdpu guard works as it supposed to, I'll definitely use it. Windows 2000 machines seem to need portfast for DHCP, and almost all Windows machines need it for IPX. I've always pointed out to the customer about NEVER connecting other layer 2 devices to the ports I configured portfast on. This is good insurance. Chuck Church CCNP, CCDP, MCNE, MCSE Sr. Network Engineer Magnacom Technologies 140 N. Rt. 303 Valley Cottage, NY 10989 845-267-4000 x218 -Original Message- From: Latimer, Keith [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 11:13 AM To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast Check out the new portfast bpdu guard feature. It can shut down ports that have portfast enabled when detecting bpdus on the line. Keith -Original Message- From: McCallum, Robert [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 01, 2001 10:44 AM To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) Subject: RE: Portfast No, The problem occurs if he creates a loop i.e. you have a main switch a cable from the main switch goes to user A. User A decides to connect a hub and a few terminals - Outcome fine. User B then says hey user A can you access those terminals and the main network. User A says yeah how do you want to connect? User A says yes and inadvertently patches his own pc and the original connection that was from him to the main switch outcome is now main switch has 2 connections to the minihub. NOW spanning tree goes oh my and recalculates - outcome 30 second outage for everyone on that vlan. Then the users go home, switch off their kit and go to the pub. Next day. The mini hub is switched back on - because portfast is enabled the ports go whoosh straight into forwarding mode - result - spanning tree goes oh my!! and recalculates. Outcome -- You and every other support member run about like loonies trying to find this fault which occurs only when the user decides to switch on his equipment. -----Original Message- From: John Chang [mailto:[EMAIL PROTECTED]] Sent: 01 March 2001 15:34 To: McCallum, Robert Subject: RE: Portfast Let me see if I got this correct. If he only connects one mini-hub or mini-switch it is OK to have portfast on on the main switch. If he then connects another mini-hub or mini-switch onto the first mini-hub or mini-switch than there will be a problem. But when you connect 2 mini-hubs aren't you just extending the amount of ports and in a sense there is only one virtual mini-hub? At 03:24 PM 3/1/2001 +, you wrote: >yes, but only if he then connects another link to another hub / switch and >causes a bridging loop. > >-Original Message- >From: John Chang [mailto:[EMAIL PROTECTED]] >Sent: 01 March 2001 15:08 >To: [EMAIL PROTECTED] >Subject: Portfast > > >In the below website it says not to have portfast on if you connect >switches, hubs, or routers. I understand that point but what if a user >connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub) >or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he >could connect multiple computers. Would this cause any problems? Thank >you! > > >http://www-1.cisco.com/warp/public/473/12.html > >Note: The portfast feature should never be used on switch ports that >connect to other switches, hubs, or routers. These connections may cause >physical loops >and it is very important that spanning tree go through the full >initialization procedure
RE: Portfast
Hello, If u r using c6500 in CatOS 5.4.2 or later, I think u have better to use another macro command, 'set port host' , it will diable ur port channel negoitation and trunking negoitation, turn the port fast on...it's quite suitable for the single host attached on it. Justin Fu > One of my customers had a problem only with W2K machines and DHCP. His > NT4.0 and 98 machines didn't need port fast. Possibly W2K has less of a > delay between loading the lan driver (and activating the link) and looking > for a DHCP server? Or maybe they were just faster machines. Or maybe W2K > has a shorter timeout for the DCHP lease request? Anyway, I've been using > portfast on almost all workstation ports for the past few months. > > Thanks, > > Chuck Church > CCNP, CCDP, MCNE, MCSE > Sr. Network Engineer > Magnacom Technologies > 140 N. Rt. 303 > Valley Cottage, NY 10989 > 845-267-4000 x218 > > > -Original Message- > From: Scott Morris [mailto:[EMAIL PROTECTED]] > Sent: Thursday, March 01, 2001 4:44 PM > To: 'Chuck Church'; ''Ccielab' (E-mail)'; 'Cisco@Groupstudy. Com > (E-mail)' > Subject: RE: Portfast > > > It's not specific to Windows 2000 machines... Any machine that needs DHCP > and boots up with any speed (less than 50 seconds), or any machine running a > novell client where it would try a GetNearestServer and find nothing > > Scott > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Chuck Church > Sent: Thursday, March 01, 2001 4:22 PM > To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) > Subject: RE: Portfast > > > If this bdpu guard works as it supposed to, I'll definitely use it. Windows > 2000 machines seem to need portfast for DHCP, and almost all Windows > machines need it for IPX. I've always pointed out to the customer about > NEVER connecting other layer 2 devices to the ports I configured portfast > on. This is good insurance. > > Chuck Church > CCNP, CCDP, MCNE, MCSE > Sr. Network Engineer > Magnacom Technologies > 140 N. Rt. 303 > Valley Cottage, NY 10989 > 845-267-4000 x218 > > > -Original Message- > From: Latimer, Keith [mailto:[EMAIL PROTECTED]] > Sent: Thursday, March 01, 2001 11:13 AM > To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail); > Cisco@Groupstudy. Com (E-mail) > Subject: RE: Portfast > > > Check out the new portfast bpdu guard feature. It can shut down ports that > have portfast enabled when detecting bpdus on the line. > Keith > > -Original Message- > From: McCallum, Robert [mailto:[EMAIL PROTECTED]] > Sent: Thursday, March 01, 2001 10:44 AM > To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail) > Subject: RE: Portfast > > > No, > > The problem occurs if he creates a loop i.e. you have a main switch a cable > from the main switch goes to user A. User A decides to connect a hub and a > few terminals - Outcome fine. User B then says hey user A can you access > those terminals and the main network. User A says yeah how do you want to > connect? User A says yes and inadvertently patches his own pc and the > original connection that was from him to the main switch outcome is now main > switch has 2 connections to the minihub. NOW spanning tree goes oh my and > recalculates - outcome 30 second outage for everyone on that vlan. Then the > users go home, switch off their kit and go to the pub. > Next day. The mini hub is switched back on - because portfast is enabled > the ports go whoosh straight into forwarding mode - result - spanning tree > goes oh my!! and recalculates. > > Outcome -- You and every other support member run about like loonies > trying to find this fault which occurs only when the user decides to switch > on his equipment. > > -Original Message- > From: John Chang [mailto:[EMAIL PROTECTED]] > Sent: 01 March 2001 15:34 > To: McCallum, Robert > Subject: RE: Portfast > > > Let me see if I got this correct. If he only connects one mini-hub or > mini-switch it is OK to have portfast on on the main switch. If he then > connects another mini-hub or mini-switch onto the first mini-hub or > mini-switch than there will be a problem. But when you connect 2 mini-hubs > aren't you just extending the amount of ports and in a sense there is only > one virtual mini-hub? > > At 03:24 PM 3/1/2001 +, you wrote: > >yes, but only if he then connects another link to another hub / switch and > >causes a bridging loop. > > > >-Original M
Re: Portfast ???
NT and 2000 will have major latency when connecting directly to a switch without portfast. There is a article on www.cisco.com about this problem. The problem is not cisco related it will happen on any switch. http://www.cisco.com/warp/public/473/12.html > I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it into portfast > mode. > > Has anyone done this before? Are there any problems you encountered or > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > ___ > 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] ___ 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]
RE: Portfast ???
Portfast is implemented on a per port basis. It is used (a) when spanning-tree is used on the switch and (b) on ports that have directly connected PCs. Without portfast spanning-tree can take up to 40 seconds to go to forwarding mode. This can be a major "O bleep!" for PCs trying to log onto a network at that time. While you're at the old command line might as well force speed and duplex for each port. Autonegotiation between switches and NIC cards is fine in theory but leaves something to be desired in practice. > -Original Message- > From: ed smith [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, September 06, 2000 8:33 AM > To: [EMAIL PROTECTED] > Subject: Portfast ??? > > > I'm swapping out a 2900XL with a 2924C XL to give us Fiber > capability. Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it > into portfast > mode. > > Has anyone done this before? Are there any problems you > encountered or > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > __ > ___ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ___ 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] ___ 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]
RE: Portfast ???
only use portfast on workstations or servers. it will prevent another switch or hub from participating in the spanning tree. I don't think I would enable portfast just to save users 20 seconds or so of startup one time while you swap switches. Unless you are in a 24x7 shop there must be some time when you can swap them without inconveniencing your users. Even if you are 24x7, if you are already committed to making the swap they probably won't notice if your downtime is ten minutes or only nine. Unless your servers or whatever the workstations are talking to are on the same switch you wait for spanning tree on your uplink port(s) anyway. If you notice problems logging in when you power up the workstations then portfast can help. I've seen situations where a win95/98 workstation can't log in immediately because the status light hasn't changed to green yet (spanning tree, autosensing speed and autosensing duplex can take a little while). They'll get a "do domain server found" message and then they try again they get in okay. It's kind of annoying. In addition to portfast you can specify speed and duplex (rather than autosense) to speed up that process. But you add to your management duties. daveh -Original Message- From: ed smith [mailto:[EMAIL PROTECTED]] Sent: Wednesday, September 06, 2000 9:33 AM To: [EMAIL PROTECTED] Subject: Portfast ??? I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since we have customers on the current switch I want to keep down time to a minimum. One suggestion has been to, on the new switch put it into portfast mode. Has anyone done this before? Are there any problems you encountered or things I should be aware of? Just a quick note today Thanks for any input. Ed CCNA _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ___ 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] ___ 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]
RE: Portfast ???
Title: RE: Portfast ??? Set portfast on any ports connecting to workstations..this will greatly improve the negotiation time when the station is coming up. Just do not set port fast on ports connecting to hubs or switches as it does not check for loops via spanning tree Patrick -Original Message- From: ed smith [mailto:[EMAIL PROTECTED]] Sent: Wednesday, September 06, 2000 9:33 AM To: [EMAIL PROTECTED] Subject: Portfast ??? I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since we have customers on the current switch I want to keep down time to a minimum. One suggestion has been to, on the new switch put it into portfast mode. Has anyone done this before? Are there any problems you encountered or things I should be aware of? Just a quick note today Thanks for any input. Ed CCNA _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ___ 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]
Re: Portfast ???
Patrick, I will check for loops, however the use of portfast is to put the port into the forwarding stage of the STP upon connectivity. The alogorithm will still run in the background, however you do run the risk of a loop until the port discovers this. If a loop is indeed introduced the port will eventually go into the blocking stage. Portfast has nothing to do with negotiation. It only allows the port to initially skip the listening and learning stages of the alogorithm, therefore the port goes to forwarding stage upon sensining connectivity. Joe "Greene, Patrick" wrote: > > > Set portfast on any ports connecting to workstations..this will > greatly improve the negotiation time when the station is coming up. > Just do not set port fast on ports connecting to hubs or switches as > it does not check for loops via spanning tree > > Patrick > > -Original Message- > From: ed smith [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, September 06, 2000 9:33 AM > To: [EMAIL PROTECTED] > Subject: Portfast ??? > > I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. > Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it into > portfast > mode. > > Has anyone done this before? Are there any problems you encountered or > > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > > > > Get Your Private, Free E-mail from MSN Hotmail at > http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > ___ > 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] ___ 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]
Re: Portfast ???
I see no reason you cannot bring up both switches at the same time. Once the 2924C has been up for a minute or so you can start pulling the patch cables from the old switch and start putting them in the new one. Your switch over time will be essentially painless as long as the new switch is configured correctly. - Original Message - From: ed smith <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, September 06, 2000 6:32 AM Subject: Portfast ??? > I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it into portfast > mode. > > Has anyone done this before? Are there any problems you encountered or > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > ___ > 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] > ___ 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]
Re: Portfast ???
You have to enable it on an interface-by-interface basis and make sure the links only connect to workstations not to other network equipment. Duck - Original Message - From: ed smith <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, September 06, 2000 6:32 AM Subject: Portfast ??? > I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it into portfast > mode. > > Has anyone done this before? Are there any problems you encountered or > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > ___ > 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] ___ 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]
RE: Portfast ???
You can and should have links connected to other switches/hubs/routers that are portfast enabled. However you should leave portfast disabled when there is resiliency between 2 network devices which would cause a spanning tree loop. -Paul -Original Message- From: Donald B Johnson Jr [mailto:[EMAIL PROTECTED]] Sent: Thursday, September 07, 2000 9:07 PM To: ed smith; [EMAIL PROTECTED] Subject: Re: Portfast ??? You have to enable it on an interface-by-interface basis and make sure the links only connect to workstations not to other network equipment. Duck - Original Message - From: ed smith <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, September 06, 2000 6:32 AM Subject: Portfast ??? > I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since > we have customers on the current switch I want to keep down time to a > minimum. One suggestion has been to, on the new switch put it into portfast > mode. > > Has anyone done this before? Are there any problems you encountered or > things I should be aware of? > > Just a quick note today > > Thanks for any input. > > Ed > CCNA > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > ___ > 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] ___ 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] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associate-Announcement.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]
RE: portfast and router
Portfast simply allows the port to begin forwarding immedtiatly as opposed to going through the blocking, litening, learning, forwarding states that a spanning tree port goes through. It can safely be disabled if you do not have redundant paths. -Original Message- From: Chen, Scott [mailto:[EMAIL PROTECTED]] Sent: Friday, July 14, 2000 12:42 PM To: [EMAIL PROTECTED] Subject: portfast and router I have one port on a Catalyst 6500 connected to a router with fast ethernet. I also have spantree enable on the switches. Currently I have the spantree portfast feature disabled on that port on the Catalyst 6500 that connects to the router. Should that be enable or disable and why? ___ 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] ___ 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]
Re: portfast and router
Chen, You don't want to enable portfast on ANY port that hooks up to a multiport device. Switch, router, hub, even a multi-homed server. Only enable it on a device that has a SINGLE connection to the network. Even at that it would be a good idea to set up the portfast guard stuff unless you can guarantee that nobody can plug in a desktop hub or something. The reason is that it is far too easy for routing loops to creep into your network. Whether by accident on your part, or ignorance on the part of the users (or even someone in IS who may not realize the problem...). However, it will only happen with multiport devices. Karen E Young Network Engineer ELF Technologies, Inc [EMAIL PROTECTED] Desk: 425-369-5369 Fax: 425-391-1774 Pager: 206-994-4514 "Chen, Scott" cc: Sent by: Subject: portfast and router nobody@groups tudy.com 07/14/00 09:41 AM Please respond to "Chen, Scott" I have one port on a Catalyst 6500 connected to a router with fast ethernet. I also have spantree enable on the switches. Currently I have the spantree portfast feature disabled on that port on the Catalyst 6500 that connects to the router. Should that be enable or disable and why? ___ 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] ___ 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]
RE: portfast and router
Switch ports that connect to routers or other switches should have portfast disabled. Only enable portfast on switch ports that you are certain connect directly to workstations. NT workstations are prone to needing portfast enabled to make connections to the PDC at boot-up. Portfast places a port directly into the forwarding state. This could cause problems with spanning tree if you are not aware of what is connected to the switch port. HTH - Jon -Original Message- From: Chen, Scott [mailto:[EMAIL PROTECTED]] Sent: Friday, July 14, 2000 12:42 PM To: [EMAIL PROTECTED] Subject: portfast and router I have one port on a Catalyst 6500 connected to a router with fast ethernet. I also have spantree enable on the switches. Currently I have the spantree portfast feature disabled on that port on the Catalyst 6500 that connects to the router. Should that be enable or disable and why? ___ 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] ___ 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]
RE: portfast and router
Would this help a problem I have with a dhcp client timing out? DHCP works fine but between the switch and my laptops pcmia card it takes to long for the link to come up. By the time it does DHCP times out. On Fri, 14 Jul 2000, you wrote: > Portfast simply allows the port to begin forwarding immedtiatly as opposed > to going through the blocking, litening, learning, forwarding states that a > spanning tree port goes through. It can safely be disabled if you do not > have redundant paths. -- James Kavenaugh Computer Geek [EMAIL PROTECTED] 425-260-4067 ___ 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]
Re: PortFast and routers [7:71253]
Curious 6/24/03 10:25:25 AM >>> >Hello, > >I know that is a bad idea to configure a port with "portfast" when this port >connect with other switch (loops can be created), but the question is: could >I put a port connected to a router in portfast mode? A router is a layer 3 >device not a layer 2, so I think this is not a risk, am I right? This way >the port wakes up quickly, right? And the final question: If I configure a >portfast port with a trunk an connect it to a router? > >Thanks my friends. It's safe to turn on portfast on any port that you know will not be connected to another switch (or a hub that might get connected to another switch.) John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71259&t=71253 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: PortFast and routers [7:71253]
Sticking a router in a port fast port is probably okay, since there should be no Bpdu's generated by the router. Most Cisco switches don't allow the trunk function And the stp-portfast function on at the same time...you do not want the portfast Function enabled on trunks... Larry Letterman Cisco Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 24, 2003 8:48 AM To: [EMAIL PROTECTED] Subject: PortFast and routers [7:71253] Hello, I know that is a bad idea to configure a port with "portfast" when this port connect with other switch (loops can be created), but the question is: could I put a port connected to a router in portfast mode? A router is a layer 3 device not a layer 2, so I think this is not a risk, am I right? This way the port wakes up quickly, right? And the final question: If I configure a portfast port with a trunk an connect it to a router? Thanks my friends. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71268&t=71253 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: PortFast and routers [7:71253]
"" Curious"" wrote in message news:[EMAIL PROTECTED] > Hello, > > I know that is a bad idea to configure a port with "portfast" when this port > connect with other switch (loops can be created), but the question is: could > I put a port connected to a router in portfast mode? A router is a layer 3 > device not a layer 2, so I think this is not a risk, am I right? This way > the port wakes up quickly, right? And the final question: If I configure a > portfast port with a trunk an connect it to a router? My understanding of the reason for the existence of the portfast function in the first place had to do with startup times for protocols like IPX. I can recall in one production network I managed, where we ran IP and IPX, it was not uncommon for a machine to boot on the IP side but fail to boot on the IPX side - the IPX side timed out prior to establishing a connection with an IPX server. I could browse the internet, for example, but I was unable to log on to the Novell server. The solution was portfast on all the switchports to which servers and users connected. A router isn't going to care one way or another since it is not logging on to anything. So the answer is that it can't hurt. I'm curious - what is it you think will be gained? > > Thanks my friends. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71404&t=71253 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
