[c-nsp] 2821 and my HWIC-1FE again

Bernd Ueberbacher noc at mynet.at
Thu Aug 2 08:59:24 EDT 2007


Hi there!

I posted a question about the HWIC-1FE some time ago and also wrote that 
everything is working fine, but I wrote that so soon :-(

Right now I got a running config with a 3640 and a 2924XL-EN behind 
(don't laugh, they are old but they work! ;-)
One port of the 3640 is the uplink and the second port is connected to 
the trunk of the switch. Five subinterfaces for five VLANs with /30 subnets.
Here everything works perfect!

The CPU load of the 3640 is about 40% and there should be some policing 
etc, so I wanted to "upgrade" to a 2821 and a 2950 behind.
Gi0/0 is an uplink and Gi1/0 is a backup uplink. The HWIC-1FE connects 
to the trunk of the 2950. Same VLANs, same config.
If I ping the uplink ports everything is perfect. If I ping the HWIC (no 
matter if it's the fastethernet0/0/0 or one of the subifs 
fastethernet0/0/0.123) everything works fine, too. If I'm going to ping 
one of the computers on one of the VLANs (in the /30 subnet, all 100mbit 
full, locally connected), I ALWAYS get a 2-3% packet loss...
If I change the 2950 to the 2924 (old config or new manual config) I 
have the same problem. Ports (switch an router) are fixed to 100 full. 
If I configure the interface on my FreeBSD Laptop as VLAN ID 123, plug 
it into the HWIC-1FE and ping the subinterface on the router, everything 
is PERFECT.
If I plug everything back as desired and ping from one VLAN to an other 
VLAN (over the router), I get about 4-6% packet loss. Still no 
difference if I use the 2924 or 2950. I changed the cable, configured 
everything from scratch, went to church, ... nothing helps :-((((((((((( 
Logging etc shows nothing and no errors on the interfaces!


Can anybody explain this phenomenon?



Thanks,
Bernd

PS:
Router:
interface FastEthernet0/0/0
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/0/0.301
 encapsulation dot1Q 301
 ip address 10.50.50.2 255.255.255.252
 no cdp enable
!
.......


Switch:
interface FastEthernet0/1
 duplex full
 speed 100
 switchport access vlan 301
 spanning-tree portfast
.......
interface FastEthernet0/24
 description TRUNK to c2821
 duplex full
 speed 100
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 1,300-399,1002-1005
 switchport mode trunk







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