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Hi,
I guess this is generic problem, but I could not find information about
it on newsgroup. Any information regarding this problem would be
helpfull.
I have LAN segment of 2 switches interconnected in between. Each switch
has one router connected. Routers acts as redundant running HSRP and
has OSPF with default timers configured. Problems ocurs when one switch
is turned off and after while turned on again. Router connected to that
switch will add route to its routing table as soon as link is up, but
switch is not ready with startup yet and does not proccess traffic.
This creates time window when router sends out route update while that
link is not available. In my case it is 40 seconds. Switches has STP
turned off.
switches: Catalyst 2950-12
routers: C2801


Robertas

In article < .com>,
"Robertas" <> wrote:

> Hi,
> I guess this is generic problem, but I could not find information about
> it on newsgroup. Any information regarding this problem would be
> helpfull.
> I have LAN segment of 2 switches interconnected in between. Each switch
> has one router connected. Routers acts as redundant running HSRP and
> has OSPF with default timers configured. Problems ocurs when one switch
> is turned off and after while turned on again. Router connected to that
> switch will add route to its routing table as soon as link is up, but
> switch is not ready with startup yet and does not proccess traffic.
> This creates time window when router sends out route update while that
> link is not available. In my case it is 40 seconds. Switches has STP
> turned off.
> switches: Catalyst 2950-12
> routers: C2801

Since the router sees carrier on the interface, it has no way to know
that the network is not usable.

--
Barry Margolin,
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Robertas wrote:

> Hi,
> I guess this is generic problem, but I could not find information
> about it on newsgroup. Any information regarding this problem would be
> helpfull.
> I have LAN segment of 2 switches interconnected in between. Each
> switch has one router connected. Routers acts as redundant running
> HSRP and has OSPF with default timers configured. Problems ocurs when
> one switch is turned off and after while turned on again. Router
> connected to that switch will add route to its routing table as soon
> as link is up, but switch is not ready with startup yet and does not
> proccess traffic. This creates time window when router sends out
> route update while that link is not available. In my case it is 40
> seconds. Switches has STP turned off.
> switches: Catalyst 2950-12
> routers: C2801

Why do you have have STP turned off? Also, which switch port is not
processing traffic? The uplink port to the router? Also, you should
turn off FEC and Trunk negotiations on the uplink port to the routers.

--

hsb


"Somehow I imagined this experience would be more rewarding" Calvin
**************************ROT13 MY ADDRESS*************************
Due to the volume of email that I receive, I may not not be able to
reply to emails sent to my account. Please post a followup instead.
************************************************** ******************

Hansang Bae wrote:
> Robertas wrote:
>
> > Hi,
> > I guess this is generic problem, but I could not find information
> > about it on newsgroup. Any information regarding this problem would
be
> > helpfull.
> > I have LAN segment of 2 switches interconnected in between. Each
> > switch has one router connected. Routers acts as redundant running
> > HSRP and has OSPF with default timers configured. Problems ocurs
when
> > one switch is turned off and after while turned on again. Router
> > connected to that switch will add route to its routing table as
soon
> > as link is up, but switch is not ready with startup yet and does
not
> > proccess traffic. This creates time window when router sends out
> > route update while that link is not available. In my case it is 40
> > seconds. Switches has STP turned off.
> > switches: Catalyst 2950-12
> > routers: C2801
>
> Why do you have have STP turned off? Also, which switch port is not
> processing traffic? The uplink port to the router? Also, you should
> turn off FEC and Trunk negotiations on the uplink port to the
routers.
>
> --
>
> hsb
>
>
> "Somehow I imagined this experience would be more rewarding" Calvin
> **************************ROT13 MY ADDRESS*************************
> Due to the volume of email that I receive, I may not not be able to
> reply to emails sent to my account. Please post a followup instead.
> ************************************************** ******************

STP is turned off because I am not using it and not planning to use.
Actually, I thought it would take longer to startup if switch is using
STP. Yes, it is uplink port that takes 40 seconds from power on to
become usable. Port is set to static access mode and no negotiations.
Is there any way to shorten this time window or I do have to live with
it?
I believe that some one had the same problem and solve it in some way.


Robertas

My recommendation is not to turn the switch off.

Robertas wrote:
> STP is turned off because I am not using it and not planning to use.
> Actually, I thought it would take longer to startup if switch is using
> STP. Yes, it is uplink port that takes 40 seconds from power on to
> become usable. Port is set to static access mode and no negotiations.
> Is there any way to shorten this time window or I do have to live with
> it?
> I believe that some one had the same problem and solve it in some way.


You're not planning on using it but what if someone plugs in a wrong
cable? It's cheap insurance.

But it looks like you are negotiating something. Configs might help.


--

hsb


"Somehow I imagined this experience would be more rewarding" Calvin
**************************ROT13 MY ADDRESS*************************
Due to the volume of email that I receive, I may not not be able to
reply to emails sent to my account. Please post a followup instead.
************************************************** ******************

Or configures a dual connected windows server to bridge.

In a recent case the network would have died forever and
not only 'til portfast kicked out. Yes, it should have had this
and that guard set too but it didn't.

Can anyone point me to the right way to do
dual homed windows devices? I will raise a thread on it.

Back to the topic.
As already alluded, to turn _off_ trunking, channel,
and ethernet speed/duplex negotiation on the relevant ports.

There is a paper on this on the cisco web site, I was
astonished at the time outs for these phases.

Where is located this paper on the cisco web site?

Sorry, I don't know. It was a set of recommended
configuration parameters for connecting end stations
to switches and covered various models 6500, 4500,
29xx, 35xx. I had a quick look but it didn't pop out.