From: Bob Sinclair (bsin@xxxxxxxxx)
Date: Sat Feb 23 2002 - 13:08:04 GMT-3
Annu,
The 30 seconds is caused by the STP forward delay timer. The timer is 15 secon
ds by default, and it is used once as STP goes through listening state and agai
n as STP goes through learning state. No way to avoid this that I know of. Yo
u can speed up the process by getting aggressive with the forward delay timer f
or each vlan.
>From what I understand of your setup, you could use the Spantree root macro wi
th a diameter of 3 to automatically set a more aggressive forward delay. I wou
ld definitely suggest testing first, and also close study of Kennedy Clark's Ci
sco LAN Switching book.
-Bob
----- Original Message -----
From: "Annu Roopa" <annu_roopa@yahoo.com>
To: "John Mistichelli" <jmistichelli@yahoo.com>
Cc: <ccielab@groupstudy.com>
Sent: Saturday, February 23, 2002 8:46 AM
Subject: RE: Uplinkfast issues
> John,
> Thanks for replying.here is how its connected.Let me
> try textual explanation.
>
> 1.Access layer switch is where hosts are.
> 2.Uplink fast on the access layer switch.
> 3.The connection to 6509 is layer 2 without
> channeling.
> 4. Access layer connected to 2 core switches which
> have the CSM( load balancing blade in 6509).
> 5. Link to left switch fails (this is Spantree Root
> now).
> 6. Due to UPlinkfast the Right core switch becomes
> Root.
> 7.When link comes back up agian the Root flips to left
> core switch and we loose flows for around 20 seconds.
>
> hope this helps.thanks in advance for ur answers.
> Bye
> Annu
>
>
> --- John Mistichelli <jmistichelli@yahoo.com> wrote:
> > I am not sure we have a clear picture of how you
> > are wired. Is Uplinkfast configured on the switch
> > you expect to be the root bridge (and backup to the
> > root)? If so, its not designed for that. Uplinkfast
> > is for access layer switches.
> > John
> > Rich <rmallory@enteract.com> wrote: Question(s):
> >
> > Are the uplinks from the closet switches single
> > connections to the 2 core
> > switches or are you using Etherchannel on the
> > uplinks to each core switch?
> > How many VLAN's are being used in the closet switch?
> > Are the root bridges
> > for the VLAN's placed on the core switches to enable
> > spanning tree load
> > balancing? If not, which core is root for the VLAN
> > you are testing from, and
> > does it matter which of the links drops? In other
> > words does the problem
> > occur if the link which comes back up is connected
> > to the root bridge?
> >
> > Thanks,
> >
> > Rich
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com]On Behalf Of
> > Annu Roopa
> > Sent: Friday, February 22, 2002 2:10 PM
> > To:
> > Cc: annu_roopa@yahoo.com
> > Subject: OT:Uplinkfast issues
> >
> >
> > Group,
> >
> > I have a issue with one of the setups hopefully
> > someone has come across this or has some ideas ?
> >
> > My setup is as follows:
> >
> > Firewall1 Firewall2
> > | |
> > | |
> > Cat6509(with CSM) Cat6509 (with CSM)
> > Primary Backup
> > | |
> > | <--Uplinkfast -->| Layer2
> > ---- ----- conn
> > | |
> > |----------|
> > | Switch |
> > ============
> > PC Hosts
> >
> > My issue is when link to Cat6509 which is primary
> > (with CSM blade) fails the Uplinkfast fails over to
> > secondary and traffic goes thru Backup Cat6509 and
> > goes well.
> >
> > The PROBLEM IS WHEN THE LINK TO OLD PRIMARY comes
> > back...upkink fast takes around 30 seconds and
> > meanwhile traffic in terms of flows is lost.
> >
> > Is there a way to speed up this process in any way ?
> >
> > Let me know the connection between access switch and
> > Cat6509 is Layer 2 and cannot be Layer 3 connection
> > as
> > per requirements.
> >
> > Thanks in advance for ur answers.
> > Annu
> >
This archive was generated by hypermail 2.1.4 : Thu Jun 20 2002 - 13:46:31 GMT-3