I don't know if I'd call this a bug or a feature but here's the scoop.
Originally, the source IP address was on S0.17. Then, S0.17 was
shutdown and this IP address was placed on S0.18. Things ran like this
for weeks.
Today, I went in and shutdown S0.18, moved the IP address to S0.19 and
then deleted S0.17 and S0.18.
The output of 'show run' and 'show ip int brief' showed that all was as
I expected it to be. As you can see from the debugging output, the
router *reported* that all five pings were leaving S0.19. However, I
think that internally the router was hopelessly confused and it was
doing a round-robin between the working subinterface and one or more of
the previous but-now-non-existent subinterfaces.
While awaiting a call back from Qwest I said "To Heck with it" and
reloaded the darn thing. The result?
All is well. :-) Let that be a lesson to you! As I mentioned
previously, this is 12.2(3) on a 2600.
John
>>> "John Neiberger" 2/27/02 4:00:47 PM
>>>
I'm starting to think this might be a bug in 12.2(3). I brought up a
new PVC from our hub router to one of our branches. I was noticing
really high round trip times, usually over one second when it should
be
averaging 10ms.
After playing around for a while I noticed that I was only having
problems with _every other_ packet. If I only sent one ping it would
succeed in about 12 ms. The second ping would get dropped. The third
ping would succeed, the fourth would get dropped. To completely bake
your noodle, I'll include the output of debug ip packet detail:
RNRTH#ping 10.12.10.70
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.12.10.70, timeout is 2 seconds:
!.!.!
Success rate is 60 percent (3/5), round-trip min/avg/max = 12/12/12 ms
RNRTH#un all
All possible debugging has been turned off
RNRTH#sho log
Syslog logging: enabled (0 messages dropped, 0 messages rate-limited,
0
flushes, 0 overruns)
Console logging: disabled
Monitor logging: level debugging, 67 messages logged
Buffer logging: level debugging, 539 messages logged
Logging Exception size (4096 bytes)
Trap logging: level informational, 283 message lines logged
Log Buffer (15000 bytes):
6w5d: IP: s=10.12.10.75 (local), d=10.12.10.70 (Serial0/0.19), len
100,
sending
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.70 (Serial0/0.19), d=10.12.10.75 (Serial0/0.19),
len 100, rcvd 3
6w5d: ICMP type=0, code=0
6w5d: IP: s=10.12.10.75 (local), d=10.12.10.70 (Serial0/0.19), len
100,
sending
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.75 (Serial0/0.19), d=10.12.10.70 (Serial0/0.19),
len 100, rcvd local pkt
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.75 (local), d=10.12.10.70 (Serial0/0.19), len
100,
sending
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.70 (Serial0/0.19), d=10.12.10.75 (Serial0/0.19),
len 100, rcvd 3
6w5d: ICMP type=0, code=0
6w5d: IP: s=10.12.10.75 (local), d=10.12.10.70 (Serial0/0.19), len
100,
sending
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.75 (Serial0/0.19), d=10.12.10.70 (Serial0/0.19),
len 100, rcvd local pkt
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.75 (local), d=10.12.10.70 (Serial0/0.19), len
100,
sending
6w5d: ICMP type=8, code=0
6w5d: IP: s=10.12.10.70 (Serial0/0.19), d=10.12.10.75 (Serial0/0.19),
len 100, rcvd 3
6w5d: ICMP type=0, code=0
As you can see, the first ping succeeds as you'd expect. But the
weird
thing is that the next packet we received *is* the packet we just sent!
Basically, it appears that somehow, somewhere in the frame cloud my
router is having _every other_ packet looped back to itself. Is that
not one of the weirdest things you've ever seen??
I'm awaiting a call back from Qwest. They probably won't believe me.
I asked someone else here who is more senior than I and he said he's
never seen anything like this either. The reason I think it might be
a
bug is that the local IP address--10.12.10.75--was originally on a
different subinterface. I deleted that subinterface and put the IP
address on the new interface. I'm wondering if internally it is
confused. I'm tempted to reboot it just to find out but I'd really
rather not since it's a production router.
Okay, back to work. I'll let you all know what I find out.
John
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=36742&t=36736
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