11-21-200211:50 PM - last edited on 03-25-201902:43 PM by ciscomoderator
we have a switch Catalyst 3524-XL-EN which is connected to a Cisco 827 ADSL router. This router has a 10Mb Ethernet port. So far we configured the port (0/1) where the router is connected to speed =10Mb and duplex = half. If I do a sh int after some period I can find a increased counter of deferred. Is this a normal behaviour on a half duplex Ethernet? In the command reference
I couldnt find some detailed information how its exactly work.
FastEthernet0/1 is up, line protocol is up
Hardware is Fast Ethernet, address is 0007.0eee.6241 (bia 0007.0eee.6241)
Description: to router r_lachauxd_1
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Half-duplex, 10Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:32, output 00:00:01, output hang never
The deferred counter counts the number of times the interface has tried to send a frame, but found the carrier busy at the first attempt (Carrier Sense). This does not constitute a problem, and is part of normal Ethernet operation.
Probably what is happening in your case is , users on 3524 are all trying to go out ADSL connection to internet thus large amount of traffic. 307 deferred packets for 3days isn't bad. I've seen the deferred counter go up by hundreds in a minutes time, thats when you have a problem.
Possible solutions / workarounds: On switch, make sure all devices are same speed/duplex therefore less chance of bottleneck causing defers (100meg to 10meg, etc). Remove/replace slow devices.