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here's a FECN question for the network techs in the room...

 
 
Dood
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      12-21-2004
I've got a router with a full T-1 plugged in. I've configured traffic
shaping and FULL CIR. I've confirmed with Bell South that they are set
to FULL CIR on there side also. So supposedly both sides are set for
full T-1 CIR. My problem is the fact that my router is seeing approx
5000 FECNs per hour, even when I show 30 to 40 percent utilization on
my line. I've configured my router to throttle back when it recieves
FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
link inbetween my CSU and my router. I've run captures and history
samples and benchmark utilization. I've tasked Bell South to tell me
which frame switch is sending my router the FECN's, but so far no
luck. Has anyone else experienced anything like this? I could be
wrong, but if both sides are set to FULL CIR, I don't think I should
see FECNs even if I oversubsribe my circuit. Both sides should be
transmitting and recieving at the same speed.

Any input is greatly appriciated, Peace.

Network Dood.
 
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donnie
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      12-21-2004
On Tue, 21 Dec 2004 00:14:04 GMT, http://www.velocityreviews.com/forums/(E-Mail Removed) (Dood) wrote:

>I've got a router with a full T-1 plugged in. I've configured traffic
>shaping and FULL CIR. I've confirmed with Bell South that they are set
>to FULL CIR on there side also. So supposedly both sides are set for
>full T-1 CIR. My problem is the fact that my router is seeing approx
>5000 FECNs per hour, even when I show 30 to 40 percent utilization on
>my line. I've configured my router to throttle back when it recieves
>FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
>link inbetween my CSU and my router. I've run captures and history
>samples and benchmark utilization. I've tasked Bell South to tell me
>which frame switch is sending my router the FECN's, but so far no
>luck. Has anyone else experienced anything like this? I could be
>wrong, but if both sides are set to FULL CIR, I don't think I should
>see FECNs even if I oversubsribe my circuit. Both sides should be
>transmitting and recieving at the same speed.
>
>Any input is greatly appriciated, Peace.
>
>Network Dood.

#####################
What router are you using? Athough it appears to be a telco problem,
you might want to hear what the router manufacturer has to say.
donnie.
 
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Michael J. Pelletier
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      12-21-2004
Dood wrote:

> I've got a router with a full T-1 plugged in. I've configured traffic
> shaping and FULL CIR. I've confirmed with Bell South that they are set
> to FULL CIR on there side also. So supposedly both sides are set for
> full T-1 CIR. My problem is the fact that my router is seeing approx
> 5000 FECNs per hour, even when I show 30 to 40 percent utilization on
> my line. I've configured my router to throttle back when it recieves
> FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
> link inbetween my CSU and my router. I've run captures and history
> samples and benchmark utilization. I've tasked Bell South to tell me
> which frame switch is sending my router the FECN's, but so far no
> luck. Has anyone else experienced anything like this? I could be
> wrong, but if both sides are set to FULL CIR, I don't think I should
> see FECNs even if I oversubsribe my circuit. Both sides should be
> transmitting and recieving at the same speed.
>
> Any input is greatly appriciated, Peace.
>
> Network Dood.


First a couple of things. If you are using Frame Relay on a T1 (physical)
you can NOT over subscribe (over 1.54 Mbs). Remember you can only go as
fast as the physical layer permits. In other words try to get more than
1.54 Mbs on a T1 is NOT possible.

Second, you should look at the stats on the physical (T1) and data link
(Frame Relay) layers. Look for errors on both. It is posssible that you
have some sort of error that is causing packet loss.

Michael

 
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Dood
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      12-22-2004
On Mon, 20 Dec 2004 22:58:11 -0800, "Michael J. Pelletier"
<(E-Mail Removed)> wrote:

>Dood wrote:
>
>> I've got a router with a full T-1 plugged in. I've configured traffic
>> shaping and FULL CIR. I've confirmed with Bell South that they are set
>> to FULL CIR on there side also. So supposedly both sides are set for
>> full T-1 CIR. My problem is the fact that my router is seeing approx
>> 5000 FECNs per hour, even when I show 30 to 40 percent utilization on
>> my line. I've configured my router to throttle back when it recieves
>> FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
>> link inbetween my CSU and my router. I've run captures and history
>> samples and benchmark utilization. I've tasked Bell South to tell me
>> which frame switch is sending my router the FECN's, but so far no
>> luck. Has anyone else experienced anything like this? I could be
>> wrong, but if both sides are set to FULL CIR, I don't think I should
>> see FECNs even if I oversubsribe my circuit. Both sides should be
>> transmitting and recieving at the same speed.
>>
>> Any input is greatly appriciated, Peace.
>>
>> Network Dood.

>
>First a couple of things. If you are using Frame Relay on a T1 (physical)
>you can NOT over subscribe (over 1.54 Mbs). Remember you can only go as
>fast as the physical layer permits. In other words try to get more than
>1.54 Mbs on a T1 is NOT possible.
>
>Second, you should look at the stats on the physical (T1) and data link
>(Frame Relay) layers. Look for errors on both. It is posssible that you
>have some sort of error that is causing packet loss.
>
>Michael


Thanks for the input guys. I've had the router vendor, Nortel,
conferenced with Bell South, and according to Nortel, my router is
configured correctly for full CIR on a T-1. According to Bellsouth I'm
not oversubscribing my circuit. Most of the day the router sits at 30
to 40 percent utilization. I'm not seeing errors increment anywhere I
look. I'm using Sniffer and Ethereal to look, and both are reporting
the same data as far as utilization on the pipe goes. I just keep
seeing FECNs from the cloud which tells my router to throttle back.
Bell South has run stress tests and found "nothing wrong". One
Bellsouth guy even told me the FECNs must be coming from my router. I
had to very calmly explain to him that I don't own a piece of hardware
capable of generating FECNs, Frame switches generate FECNs. Sometimes
you wonder where they get there techs from. I wonder how much they
pay? I'm gonna swap the router out as soon as I can to rule out that
possibilty, even though I really don't think my routers the issue. I
think there is congestion somewhere in the frame cloud that Bell south
needs to fix.
 
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donnie
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      12-22-2004
On Wed, 22 Dec 2004 00:33:57 GMT, (E-Mail Removed) (Dood) wrote:

> I'm gonna swap the router out as soon as I can to rule out that
>possibilty, even though I really don't think my routers the issue. I
>think there is congestion somewhere in the frame cloud that Bell south
>needs to fix.

##########################
You're probably right, but I thought I would mention the router anway.
Swaping the router is a good test.
donnie
 
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