RE: STP Question: Root Bridge placement load balancing [7:46703]
Well, I don't have that book but let me go off went you sent. ___ Assumptions made: All 3 switches carry both VLAN's and all 3 switchs have members in both VLAN's. The links between Switches are setup for VLAN trunking ___ Cat-C will have traffic that needs to access servers in both VLANS. Cat-A would be the root bridge for VLAN2 and all traffic would flow through it for this VLAN. Same for Cat-B and VLAN3.However, lets assume that the link between Cat-C and Cat-A fails. Now Cat-C can't send traffic directly to Cat-A, but It can however send to Cat-B which can send traffic across the link between them to get to Cat-A. Reverse the process for VLAN3. Traffic by default will flow towards the root bridge. That being said Traffic for VLAN 2 will always go across the VLAN2 link to Cat-A because that is the shorts distance to the Root bridge. A secondary route exists to Cat-A, via Cat-B, but since its not the shortest, that ports would be in a blocking mode (1/2 on Cat-C) for VLAN2. Only when Cat-C detects a failure, would a new STP algorithm be run, at which point Cat-C would detect that the shortest route to Cat-A would be through Cat-B. Once that happens traffic for that VLAN would begin going across the VLAN3 link even if it is for VLAN2. Now Cat-C has the same scenario for VLAN3 but this time, the shortest route to the Root Bridge for VLAN3 is across the VLAN3 link and the path (port 1/1) would be in a blocking mode for VLAN3. For this to work, the link between Cat-B and Cat-C would need to be a trunk port that carries VLAN2&3. This would provide the failover path for the VLAN's in the event of a link failure between Cat-C and one of the other Cat switches. In the case of a failure of either Cat-B or C, your out of luck for those servers connected to it. I suggest A quick call to TAC ! What I think might be confusing you ( if I haven't!) is that your thinking that if someone on Cat-C needs access to a server in VLAN2 that is physically plugged into Cat-B you might think that traffic would go across the link from Cat-C to Cat-B. Well, it doesn't, it would go from Cat-C to Cat-A to Cat-B. Ok, portion 2. Techically this is load sharing not load balancing BTW. Lets also assume that 2 servers plugged into Cat-A are hogging the BW. One server(SRV2) is in VLAN2 and the other is in VLAN3(SRV3). The traffic for SRV2 would go from Cat-C out port 1/1 directly to Cat-A. The traffic for SRV3 however would go out port 1/2 on Cat-C to Cat-B then from Cat-B across the link to Cat-A. If all links are 100Mbs, both servers would have a dedicated 100Mbs of BW to Cat-C,since each follows a different path to Cat-C. Hope I have not confused you any. I have retyped about 3 times trying to simply but point out the important parts. If you would like me to clear anything up let me know. Hope it helps. Thanks Larry -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Saturday, June 15, 2002 9:16 PM To: [EMAIL PROTECTED] Subject: STP Question: Root Bridge placement load balancing [7:46701] Hi, Studying Cisco LAN Switching,(by Hamilton & Clark), I didn't get how exactly this method (Root Bridge placement load balancing)works. He provides such an example (Figure 7-10): ___ |Cat-C (IDF)| |___| 1/1 /\ 1/2 / \ VLAN2 /\ VLAN3 / \ /\ 1/1 / \ 1/1 __/____\ |Cat-A(MDF)|__|Cat-B(MDF)| |__|1/21/2|__| || || Server Farm Server Farm Assuming that CAT-A is the Root bridge for VLAN2 and CAT-B is the Root bridge for VLAN 3, I don't get how this method provides load balancing and redundancy for CAT-C to the server farms. He doen't say anything about the third segment (the segment between CAT-A and CAT-B) Could anyone clearify please ? Thanks in advance, Hamid Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=46703&t=46703 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
Somebody tell me if I have this wrongt. The STP algorithm is executed whenever a unexpected BPDU is recieved, or a number of expected BPDU's are NOT recieved. A BPDU is Layer-2 Multicast out of all ports on a switch at regular intervals. A port is placed in the blocking state if it recieves one of it's own BPDU's. In the blocking state, all frames except for BPDU's are ignored. BPDU's are still transmitted and recieved on a Blocking port. Original Message Follows From: "AUX0" <[EMAIL PROTECTED]> Reply-To: "AUX0" <[EMAIL PROTECTED]> To: "Leigh Anne Chisholm" <[EMAIL PROTECTED]>,"Jared Carter" <[EMAIL PROTECTED]>, "'Jon Mitchell'" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> Subject: Re: STP question Date: Mon, 2 Oct 2000 08:35:52 -0400 No, putting a pc on a switch port WILL cause the STP algorithm to execute. - Original Message - From: "Leigh Anne Chisholm" <[EMAIL PROTECTED]> To: "Jared Carter" <[EMAIL PROTECTED]>; "'Jon Mitchell'" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Friday, September 29, 2000 7:35 PM Subject: RE: STP question > Actually, Spanning Tree only runs if it detects the presence new or absence of expected BPDU's. Plugging a PC into a switch port will not cause the Spanning Tree Algorithm to execute. > > > -- Leigh Anne > > > -Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > > Jared Carter > > Sent: Friday, September 29, 2000 4:37 PM > > To: 'Jon Mitchell'; '[EMAIL PROTECTED]' > > Subject: RE: STP question > > > > > > Spanning Tree will run its algorithm every time a port is plugged > > in (unless > > Portfast is enabled...) and ensure a loop free topolgy. The first port up > > will not necessarily be the one that stays in forwarding, it depends on > > several variables... bridge ID, cost to root, port priority... > > all of which > > are sent out in STP BPDUs. > > > > I would recommend you get a copy of the Cisco Press book Cisco LAN > > Switching. The two chapters on STP (and the rest of the book, too) are > > probably the best written. Well worth the $60 or so. > > > > /Jared > > > > **NOTE: New CCNA/CCDA List has been formed. For more information go to > http://www.groupstudy.com/list/Associates.html > _ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ 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. **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
No, putting a pc on a switch port WILL cause the STP algorithm to execute. - Original Message - From: "Leigh Anne Chisholm" <[EMAIL PROTECTED]> To: "Jared Carter" <[EMAIL PROTECTED]>; "'Jon Mitchell'" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Friday, September 29, 2000 7:35 PM Subject: RE: STP question > Actually, Spanning Tree only runs if it detects the presence new or absence of expected BPDU's. Plugging a PC into a switch port will not cause the Spanning Tree Algorithm to execute. > > > -- Leigh Anne > > > -Original Message- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > > Jared Carter > > Sent: Friday, September 29, 2000 4:37 PM > > To: 'Jon Mitchell'; '[EMAIL PROTECTED]' > > Subject: RE: STP question > > > > > > Spanning Tree will run its algorithm every time a port is plugged > > in (unless > > Portfast is enabled...) and ensure a loop free topolgy. The first port up > > will not necessarily be the one that stays in forwarding, it depends on > > several variables... bridge ID, cost to root, port priority... > > all of which > > are sent out in STP BPDUs. > > > > I would recommend you get a copy of the Cisco Press book Cisco LAN > > Switching. The two chapters on STP (and the rest of the book, too) are > > probably the best written. Well worth the $60 or so. > > > > /Jared > > > > **NOTE: New CCNA/CCDA List has been formed. For more information go to > http://www.groupstudy.com/list/Associates.html > _ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
The spanning tree algorithm WILL execute if you plug a PC into a cAT switch. - Original Message - From: "Leigh Anne Chisholm" <[EMAIL PROTECTED]> To: "Jared Carter" <[EMAIL PROTECTED]>; "'Jon Mitchell'" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Friday, September 29, 2000 7:35 PM Subject: RE: STP question > Actually, Spanning Tree only runs if it detects the presence new or absence of expected BPDU's. Plugging a PC into a switch port will not cause the Spanning Tree Algorithm to execute. > > > -- Leigh Anne > > > -Original Message- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > > Jared Carter > > Sent: Friday, September 29, 2000 4:37 PM > > To: 'Jon Mitchell'; '[EMAIL PROTECTED]' > > Subject: RE: STP question > > > > > > Spanning Tree will run its algorithm every time a port is plugged > > in (unless > > Portfast is enabled...) and ensure a loop free topolgy. The first port up > > will not necessarily be the one that stays in forwarding, it depends on > > several variables... bridge ID, cost to root, port priority... > > all of which > > are sent out in STP BPDUs. > > > > I would recommend you get a copy of the Cisco Press book Cisco LAN > > Switching. The two chapters on STP (and the rest of the book, too) are > > probably the best written. Well worth the $60 or so. > > > > /Jared > > > > **NOTE: New CCNA/CCDA List has been formed. For more information go to > http://www.groupstudy.com/list/Associates.html > _ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
You're right... I was really just trying to say that STP runs more than just when the initial switch comes up. If I recall, I think it only runs the algorithm when it "hears" a "better" BPDU that the one it has currently, or would be currently sending out, not when it hears _any_ new BPDU. /Jared -Original Message- From: Leigh Anne Chisholm [mailto:[EMAIL PROTECTED]] Sent: Friday, September 29, 2000 7:36 PM To: Jared Carter; 'Jon Mitchell'; [EMAIL PROTECTED] Subject: RE: STP question Actually, Spanning Tree only runs if it detects the presence new or absence of expected BPDU's. Plugging a PC into a switch port will not cause the Spanning Tree Algorithm to execute. -- Leigh Anne > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Jared Carter > Sent: Friday, September 29, 2000 4:37 PM > To: 'Jon Mitchell'; '[EMAIL PROTECTED]' > Subject: RE: STP question > > > Spanning Tree will run its algorithm every time a port is plugged > in (unless > Portfast is enabled...) and ensure a loop free topolgy. The first port up > will not necessarily be the one that stays in forwarding, it depends on > several variables... bridge ID, cost to root, port priority... > all of which > are sent out in STP BPDUs. > > I would recommend you get a copy of the Cisco Press book Cisco LAN > Switching. The two chapters on STP (and the rest of the book, too) are > probably the best written. Well worth the $60 or so. > > /Jared > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
Actually, Spanning Tree only runs if it detects the presence new or absence of expected BPDU's. Plugging a PC into a switch port will not cause the Spanning Tree Algorithm to execute. -- Leigh Anne > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Jared Carter > Sent: Friday, September 29, 2000 4:37 PM > To: 'Jon Mitchell'; '[EMAIL PROTECTED]' > Subject: RE: STP question > > > Spanning Tree will run its algorithm every time a port is plugged > in (unless > Portfast is enabled...) and ensure a loop free topolgy. The first port up > will not necessarily be the one that stays in forwarding, it depends on > several variables... bridge ID, cost to root, port priority... > all of which > are sent out in STP BPDUs. > > I would recommend you get a copy of the Cisco Press book Cisco LAN > Switching. The two chapters on STP (and the rest of the book, too) are > probably the best written. Well worth the $60 or so. > > /Jared > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
Spanning Tree will run its algorithm every time a port is plugged in (unless
Portfast is enabled...) and ensure a loop free topolgy. The first port up
will not necessarily be the one that stays in forwarding, it depends on
several variables... bridge ID, cost to root, port priority... all of which
are sent out in STP BPDUs.
I would recommend you get a copy of the Cisco Press book Cisco LAN
Switching. The two chapters on STP (and the rest of the book, too) are
probably the best written. Well worth the $60 or so.
/Jared
-Original Message-
From: Jon Mitchell [mailto:[EMAIL PROTECTED]]
Sent: Friday, September 29, 2000 10:16 AM
To: Bradley J. Wilson
Cc: [EMAIL PROTECTED]
Subject: Re: STP question
On Fri, Sep 29, 2000 at 09:36:46AM -0400, Bradley J. Wilson wrote:
> Spanning Tree Protocol, which I'm assuming is what you're referring to,
> doesn't have anything to do with routing. If you were connecting bridges
> together in a loop, STP would break the loop and you'd be fine. In your
> case, the mechanism which will prevent routing loops is split horizon
> (assuming you're running RIP), which is on by default.
Sorry, I meant to say switch, wrote this too early in the morning
evidently. So you are saying that STP does not only negotiate at switch
startup, it will constantly detect new loops that are added? If so,
another question would be whether I could guarentee that it would be this
switch's port that would block to prevent the loop. Or would it just be
the first switch that detects the problem?
The network looks like this:
| Switch A |-| Switch B |
||
| <-- This is link I plugin.
| Switch C |-| Switch D |
So if switch D is then plugged in, will it start STP negotiation on the
port even though the switch has already booted? Or will one of the
switches randomly discover the loop after the link is already forwarding
traffic and disable it's interfaces?
--
Jon Mitchell
Systems Engineer, Subject Wills & Company
[EMAIL PROTECTED]
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
Or it could be Lamaze? The port starts breathing deeply, and as the traffic approaches is starts to contract, and then... No, on second thought, that's probably not what he meant... Dale [=`) >From: "Chuck Larrieu" <[EMAIL PROTECTED]> >Reply-To: "Chuck Larrieu" <[EMAIL PROTECTED]> >To: "McCallum, Robert" <[EMAIL PROTECTED]>,"'Jon >Mitchell'" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> >Subject: RE: STP question >Date: Fri, 29 Sep 2000 07:23:43 -0700 > >Check your spelling. I think you mean Le Mans, not lamens. The port goes >into racing mode, trying to beat the course time for creating a new tree, >without wrapping itself around one. I still like those Ferrari's the best >:-> > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of >McCallum, Robert >Sent: Friday, September 29, 2000 6:53 AM >To:'Jon Mitchell'; [EMAIL PROTECTED] >Subject: RE: STP question > >When you plug in your other port the port will go into listening, learning >states. In lamens terms the port sends out a frame and if it hears it back >it will block - if it doesnt it will forward. Please see link below:- > >http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_5_2/config/s >pantree.htm > >-Original Message- >From: Jon Mitchell [mailto:[EMAIL PROTECTED]] >Sent: 29 September 2000 14:03 >To: [EMAIL PROTECTED] >Subject: STP question > > > >Does STP only stop loops when the router boots? If I am building a loop >network, and then I boot up the final router with only one interface >plugged in (so it is not yet a loop), and then plug in the other interface >after the fact, what will happen? Will the other interface start in >blocking or forwarding mode? The book I am using does not seem clear on >this. > >-- >Jon Mitchell >Systems Engineer, Subject Wills & Company >[EMAIL PROTECTED] > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associates.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associates.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associates.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ 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. **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
Spanning tree runs on pretty much all Cisco internetworking devices Brad, not just bridges. >From: "Bradley J. Wilson" <[EMAIL PROTECTED]> >Reply-To: "Bradley J. Wilson" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Subject: Re: STP question >Date: Fri, 29 Sep 2000 09:36:46 -0400 > >Spanning Tree Protocol, which I'm assuming is what you're referring to, >doesn't have anything to do with routing. If you were connecting bridges >together in a loop, STP would break the loop and you'd be fine. In your >case, the mechanism which will prevent routing loops is split horizon >(assuming you're running RIP), which is on by default. > >Hope this helps - > >Bradley Wilson >CCNA, CCDA, MCSE, NNCSS, CNX-A, MCT, CTT > > >- Original Message - >From: Jon Mitchell >To: [EMAIL PROTECTED] >Sent: Friday, September 29, 2000 9:02 AM >Subject: STP question > > > >Does STP only stop loops when the router boots? If I am building a loop >network, and then I boot up the final router with only one interface >plugged in (so it is not yet a loop), and then plug in the other interface >after the fact, what will happen? Will the other interface start in >blocking or forwarding mode? The book I am using does not seem clear on >this. > >-- >Jon Mitchell >Systems Engineer, Subject Wills & Company >[EMAIL PROTECTED] > > > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associates.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ 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. **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
If you are routing you are not concerned with stp or if you are bridging then it will shut down the loop no matter when you activate the interface Duck - Original Message - From: Jon Mitchell <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, September 29, 2000 6:02 AM Subject: STP question > > Does STP only stop loops when the router boots? If I am building a loop > network, and then I boot up the final router with only one interface > plugged in (so it is not yet a loop), and then plug in the other interface > after the fact, what will happen? Will the other interface start in > blocking or forwarding mode? The book I am using does not seem clear on > this. > > -- > Jon Mitchell > Systems Engineer, Subject Wills & Company > [EMAIL PROTECTED] > > **NOTE: New CCNA/CCDA List has been formed. For more information go to > http://www.groupstudy.com/list/Associates.html > _ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
No no no, he clearly meant Lamaze. "Keep pushing, yes, you're dilated to 100mb, I can see the preamble now..." - Original Message - From: Chuck Larrieu To: McCallum, Robert ; 'Jon Mitchell' ; [EMAIL PROTECTED] Sent: Friday, September 29, 2000 10:23 AM Subject: RE: STP question Check your spelling. I think you mean Le Mans, not lamens. The port goes into racing mode, trying to beat the course time for creating a new tree, without wrapping itself around one. I still like those Ferrari's the best :-> -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of McCallum, Robert Sent: Friday, September 29, 2000 6:53 AM To: 'Jon Mitchell'; [EMAIL PROTECTED] Subject: RE: STP question When you plug in your other port the port will go into listening, learning states. In lamens terms the port sends out a frame and if it hears it back it will block - if it doesnt it will forward. Please see link below:- http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_5_2/config/s pantree.htm -Original Message- From: Jon Mitchell [mailto:[EMAIL PROTECTED]] Sent: 29 September 2000 14:03 To: [EMAIL PROTECTED] Subject: STP question Does STP only stop loops when the router boots? If I am building a loop network, and then I boot up the final router with only one interface plugged in (so it is not yet a loop), and then plug in the other interface after the fact, what will happen? Will the other interface start in blocking or forwarding mode? The book I am using does not seem clear on this. -- Jon Mitchell Systems Engineer, Subject Wills & Company [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
Check your spelling. I think you mean Le Mans, not lamens. The port goes into racing mode, trying to beat the course time for creating a new tree, without wrapping itself around one. I still like those Ferrari's the best :-> -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of McCallum, Robert Sent: Friday, September 29, 2000 6:53 AM To: 'Jon Mitchell'; [EMAIL PROTECTED] Subject: RE: STP question When you plug in your other port the port will go into listening, learning states. In lamens terms the port sends out a frame and if it hears it back it will block - if it doesnt it will forward. Please see link below:- http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_5_2/config/s pantree.htm -Original Message- From: Jon Mitchell [mailto:[EMAIL PROTECTED]] Sent: 29 September 2000 14:03 To: [EMAIL PROTECTED] Subject: STP question Does STP only stop loops when the router boots? If I am building a loop network, and then I boot up the final router with only one interface plugged in (so it is not yet a loop), and then plug in the other interface after the fact, what will happen? Will the other interface start in blocking or forwarding mode? The book I am using does not seem clear on this. -- Jon Mitchell Systems Engineer, Subject Wills & Company [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
On Fri, Sep 29, 2000 at 09:36:46AM -0400, Bradley J. Wilson wrote:
> Spanning Tree Protocol, which I'm assuming is what you're referring to,
> doesn't have anything to do with routing. If you were connecting bridges
> together in a loop, STP would break the loop and you'd be fine. In your
> case, the mechanism which will prevent routing loops is split horizon
> (assuming you're running RIP), which is on by default.
Sorry, I meant to say switch, wrote this too early in the morning
evidently. So you are saying that STP does not only negotiate at switch
startup, it will constantly detect new loops that are added? If so,
another question would be whether I could guarentee that it would be this
switch's port that would block to prevent the loop. Or would it just be
the first switch that detects the problem?
The network looks like this:
| Switch A |-| Switch B |
||
| <-- This is link I plugin.
| Switch C |-| Switch D |
So if switch D is then plugged in, will it start STP negotiation on the
port even though the switch has already booted? Or will one of the
switches randomly discover the loop after the link is already forwarding
traffic and disable it's interfaces?
--
Jon Mitchell
Systems Engineer, Subject Wills & Company
[EMAIL PROTECTED]
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
>From your diagram here, it looks like you don't have a loop - it looks like
Sw B is plugged into Sw A, A to C, then C to D in series. If this is
accurate, then you don't have a loop and won't have any problems.
As far as STP works, each switch will send out BPDUs every two seconds on
all interfaces. If a switch receives two BPDUs from the same switch on two
different interfaces, it will start the election process and you'll have a
few seconds of downtime (not exactly sure how much - 15 or so?). But again,
from this diagram it doesn't look like you have a loop, so you should be
okay.
- Original Message -
From: Jon Mitchell
The network looks like this:
| Switch A |-| Switch B |
| |
| <-- This is link I plugin.
| Switch C |-| Switch D |
So if switch D is then plugged in, will it start STP negotiation on the
port even though the switch has already booted? Or will one of the
switches randomly discover the loop after the link is already forwarding
traffic and disable it's interfaces?
--
Jon Mitchell
Systems Engineer, Subject Wills & Company
[EMAIL PROTECTED]
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: STP question
When you plug in your other port the port will go into listening, learning states. In lamens terms the port sends out a frame and if it hears it back it will block - if it doesnt it will forward. Please see link below:- http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_5_2/config/s pantree.htm -Original Message- From: Jon Mitchell [mailto:[EMAIL PROTECTED]] Sent: 29 September 2000 14:03 To: [EMAIL PROTECTED] Subject: STP question Does STP only stop loops when the router boots? If I am building a loop network, and then I boot up the final router with only one interface plugged in (so it is not yet a loop), and then plug in the other interface after the fact, what will happen? Will the other interface start in blocking or forwarding mode? The book I am using does not seem clear on this. -- Jon Mitchell Systems Engineer, Subject Wills & Company [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: STP question
Spanning Tree Protocol, which I'm assuming is what you're referring to, doesn't have anything to do with routing. If you were connecting bridges together in a loop, STP would break the loop and you'd be fine. In your case, the mechanism which will prevent routing loops is split horizon (assuming you're running RIP), which is on by default. Hope this helps - Bradley Wilson CCNA, CCDA, MCSE, NNCSS, CNX-A, MCT, CTT - Original Message - From: Jon Mitchell To: [EMAIL PROTECTED] Sent: Friday, September 29, 2000 9:02 AM Subject: STP question Does STP only stop loops when the router boots? If I am building a loop network, and then I boot up the final router with only one interface plugged in (so it is not yet a loop), and then plug in the other interface after the fact, what will happen? Will the other interface start in blocking or forwarding mode? The book I am using does not seem clear on this. -- Jon Mitchell Systems Engineer, Subject Wills & Company [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
