Transmit Exess defer frames and Output packet Drops

[Mr dum]

Hi all
I have some problem on my switch 
I have Topology like this :

CoreSW ---> MainSW ---> WLC5520 -- APs ---> Client

and when my switch got this packet excess defer frames

and this Output Drops

I have no Internet Access on my APs
maybe someone can explain me why this happend on my switch
thankyou

[Leo Laohoo]

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@Mr dum wrote:
CoreSW ---> MainSW ---> WLC5520 -- APs ---> Client

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That topology is so wrong in so many places.

The link from the switch to the WLC is only a single link?  Not an Etherchannel?  And it is on a 1 Gbps link? 

[Mr dum]

I think real topologi like this

Uplink --- CoreSw (port24) --- wlc

CoreSw (port11)--- APs 

Yes only single link

And I used 1Gbps Sfp

Is it the problem?

[Leo Laohoo · Accepted solution]

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@Mr dum wrote:
And I used 1Gbps Sfp
Is it the problem?

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A 5520 with a single 1 Gbps back to the network?  Yes, I smell the problem right there.  

A single 1 Gbps might be OK for the "mini" controllers like the 2504/3504/9800-L but expect the switch to get overwhelmed from the traffic coming from the 5520.

[Mr dum · Accepted solution]

thankyou @Leo Laohoo for your information
I will change my ethernet port to 10gig
is it solved the problem? 

[Joseph W. Doherty]

Although I fully agree with @Leo Laohoo that a 5520 WLC can be limited by a single gig link, unclear how inadequate bandwidth would just preclude wireless Internet access.  Unless wireless only provides Internet access?  If, that's the case, insufficient bandwidth usually doesn't cause "no access", but degraded service, to various degrees.

Regardless, if you can easily migrate to 10g, that's still a good recommendation, and if it actually solves your issue (which we don't yet know, correct?), it's a great recommendation.  Please let us know actual result.

[Joseph W. Doherty]

I'm puzzled by your Excess Defer frames.  Cisco documentation on that stat, that I found, explains little.  Further, my impression was it had meaning under half duplex.  With full duplex seems to imply hardware cannot keep up with load.

In any case, your posted stats show a busy interface.

What's the IOS and hardware specifics?

As to why no wireless Internet access, we would need much, much more information.

[Mr dum]

My ethernet run on Full duplex
and you can see that's my WLC Spesification