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New Member

Weird 8510 problem... HELP!

Hi all, I posted this problem before, but didn't get any replies. Here it is again with some additional info; hopefully one of you can help. :) I've searched CCO without any luck either.

I'm seeing this error message on our Catalyst 8510CSR switch-router:

00:15:01: %AAL5-3-NOBUFFER: No reassembly buffers to receive pkt , vpi 0, vci 36

Show proc cpu shows cpu usage around 75-85% continually. There isn't nearly enough of traffic on the network to generate this, and I confirmed by checking the loads on all the interfaces (ALL are at 1/255 except Controller0). So I assume its something isolated to this router.

Show proc cpu (possible interesting items shown):

43 0 1 0 0.00% 0.00% 0.00% 0 IMAPAM Onesec

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

44 0 1 0 0.00% 0.00% 0.00% 0 IMAPAM Config Ma

45 0 1 0 0.00% 0.00% 0.00% 0 IMAPAM Mailbox M

46 308 231 1333 0.00% 0.00% 0.00% 0 CDP Protocol

47 707880 79294 8927 29.47% 27.66% 26.18% 0 IP Input

I'm thinking this is an ATM problem of some kind, but we don't run any ATM nor have any ATM interfaces in the 8510. While looking through the interfaces, i saw this:

Controller0 is up, line protocol is up

Hardware is ATM Swi/Proc

MTU 4470 bytes, sub MTU 4470, BW 155520 Kbit, DLY 0 usec,

reliability 147/255, txload 1/255, rxload 5/255

Encapsulation ATM, loopback not set

Keepalive not supported


8192 maximum active VCs, 0 current VCCs

VC idle disconnect time: 300 seconds

Signalling vc = 35, vpi = 128, vci = 37

UNI Version = 3.0, Link Side = user

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue :0/40 (size/max)

5 minute input rate 3577000 bits/sec, 4522 packets/sec

5 minute output rate 570000 bits/sec, 1333 packets/sec

4753676 packets input, 469607611 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

18427 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

1384921 packets output, 73400813 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

I imagine the reliabiltiy indicated in this output can't be good! Also, why is there any load at all when we aren't running ATM? Anyway, is this the source of the problem or not? If not, what could it be? Any help is greatly appreciated. Thanks!


- Sean

New Member

Re: Weird 8510 problem... HELP!

Isn't it amazing how often after posting a problem in a public forum, you figure out the problem on your own? D'oh!

Anyway, the source of all the troubles was an apparently bad Extreme Summit switch. No matter how the speed and duplex was configured on both ends, thousands of collisions and errors were occuring on the link; cable's good too, tested that. As soon as I shut down the connection, cpu usage dropped to normal levels and all was happy and merry. However, I am still curious why I was receiving the "%AAL5-3-NOBUFFER: No reassembly buffers to receive pkt , vpi 0, vci 36" error-- as that is definitely an ATM error. I would think the error have been something along the lines of no buffer as this is, but without mention of the ATM stuff... would anyone with more experience care to comment?

- Sean

New Member

Re: Weird 8510 problem... HELP!

The internal architecture of 8500 switches is through ATM backplane. Your packets are converted to ATM cells and forwarded on the backplane and then cells are coverted back to packets. So eventhough you don't have physical ATM interfaces, you would see ATM related messages.

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