From: hadek.el-ayachi@nsn.com
Date: Tue Oct 30 2007 - 10:12:48 ART
Hi,
In the document "Using PortFast and Other Commands to Fix Workstation
Startup Connectivity Delays", it is stated that:
"STP dictates that the port starts out blocking, and then immediately
moves through the listening and learning phases. By default, the port
spends approximately 15 seconds listening and 15 seconds learning.
During the listening state, the switch tries to determine where the port
fits in the spanning tree topology. The switch especially wants to know
whether this port is part of a physical loop. If the port is part of a
loop, the port can be chosen to go into blocking mode. The blocking mode
means that the port does not send or receive user data in order to
eliminate loops. If the port is not part of a loop, the port proceeds to
the learning state, in which the port learns which MAC addresses live
off this port. This entire STP initialization process takes about 30
seconds.
"
This means that at startup, port start in bloking state and moves
"immediately" to listning where he stays 15s, learning stay 15s and
forwarding. This means that startup need 2*fwddelay.
I made also some debugs in my switch using access and then trunk port:
*Mar 2 01:39:27.438: set portid: VLAN0001 Fa0/1: new port id 8003 *Mar
2 01:39:27.438: Created spanning tree port Fa0/1 (2D3F560) for tree
VLAN00
01 (2D3F8E0)
*Mar 2 01:39:27.438: Enabling spanning tree port: FastEthernet0/1
(2D3F560) *Mar 2 01:39:27.438: STP: VLAN0001 Fa0/1 -> listening *Mar 2
01:39:29.434: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state t
o up *Mar 2 01:39:29.434: Returning spanning tree port stats:
FastEthernet0/1 (2D3F560) *Mar 2 01:39:29.434: Returning spanning tree
port stats: FastEthernet0/1 (2D3F560) *Mar 2 01:39:29.434: Returning
spanning tree port stats: FastEthernet0/1 (2D3F560) *Mar 2
01:39:30.441: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthern
et0/1, changed state to up *Mar 2 01:39:44.441: STP: VLAN0001 Fa0/1 ->
learning *Mar 2 01:39:49.634: Returning spanning tree port stats:
FastEthernet0/1 (2D3F560) *Mar 2 01:39:49.634: Returning spanning tree
port stats: FastEthernet0/4 (36D7430) *Mar 2 01:39:49.634: Returning
spanning tree port stats: FastEthernet0/11 (3510988) *Mar 2
01:40:01.445: STP: VLAN0001 sent Topology Change Notice on Fa0/23 *Mar
2 01:40:01.445: STP: VLAN0001 Fa0/1 -> forwarding
Hence, port startup need 30 seconds.
This is my understanding
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ext ccielab-owner@groupstudy.com
Sent: lundi 29 octobre 2007 15:44
To: gary.duncanson@googlemail.com; scott_ccie_list@it-ag.com
Cc: ccielab@groupstudy.com
Subject: RE: Getting a por to be in forwarding state in 14 seconds ....
It was my question and Scott Moriss s answer was that startup time is
(maxage + 2*fwddelay) = 50s In your case, auusuming you are using STP
(in RSTP where is no listing), you can use maxage= 10s and fwddelay = 2s
Is it true Scott?
thanks
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ext Gary Duncanson
Sent: samedi 27 octobre 2007 23:12
To: Scott Vermillion
Cc: ccielab@groupstudy.com
Subject: Re: Getting a por to be in forwarding state in 14 seconds ....
Hi Scott
I have no idea how the archives work. I guess what Im saying is check
about this recently. I think the 14 second thing on switches was covered
by Scott Morris just a week or two ago.
Regards
Gary
----- Original Message -----
From: "Scott Vermillion" <scott_ccie_list@it-ag.com>
To: "'Gary Duncanson'" <gary.duncanson@googlemail.com>; "'ccie1101'"
<ccie1101@gmail.com>
Cc: <ccielab@groupstudy.com>
Sent: Saturday, October 27, 2007 6:42 PM
Subject: RE: Getting a por to be in forwarding state in 14 seconds ....
> OK all, I have a question:
>
> How are you searching the archives?? Because when I try to search the
> CCIE
> list, the most recent results I get range anywhere from late 2004 to
early
> 2007! We used to have a very nice search function on the professional
> board
> but Paul had to disable it because it was apparently crashing the
server.
> But there must be something more effective than what I'm doing, which
is
> going here:
>
> http://www.groupstudy.com/cgi-bin/search
>
> So just as an example, I just plugged "Frame Relay" into the CCIE R&S
list
> and sorted by date in reverse order. The most recent result I get is
a
> post
> on 3/07/2007. I suppose we've had one or two FR posts between now and
> that
> time, wouldn't you say? What am I doing wrong?
>
> Thx,
>
> Scott
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Gary
> Duncanson
> Sent: Saturday, October 27, 2007 4:06 AM
> To: ccie1101
> Cc: ccielab@groupstudy.com
> Subject: Re: Getting a por to be in forwarding state in 14 seconds
....
>
> Check recent archives. I believe our friend Scott Morris covered this
one.
>
> HTH
>
> Gary
> ----- Original Message -----
> From: "ccie1101" <ccie1101@gmail.com>
> To: "Cisco certification" <ccielab@groupstudy.com>
> Sent: Friday, October 26, 2007 6:18 PM
> Subject: Re: Getting a por to be in forwarding state in 14 seconds
....
>
>
>> GS,
>> The question asks a total link startup delay of 14 seconds, at
fist
>> instance I just did the following,
>> spanning-tree vlan 30 forward-time 14 but the TOTAL LINK delay is
Hello +
>> Forward Delay + Max Age.
>>
>> So therefore to get the port to be up in 14 seconds, would it be
:-
>> spanning-tree vlan 30 forward-delay 6 spanning-tee vlan 30 max-age 6
>>
>> and 2 seconds is for BPDU which gives us 14 seconds in total for
the
>> link to be up. Would this logic be
>> correct ?
>>
>> Pls advice,
>>
>> ccie1101.
>>
>>
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