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New Member

Ignored errors on PoS link

I have several OC-3 PoS links out to my service provider. I see input errors incrementing on some of the interfaces, but not all of them. The errors fall into the ignored category, but do not appear to be related to any queueing or buffering.

The unusual part is that they increment about every 10 seconds at a rate of 11 packets each time. I have confirmed that the config is the same on both circuits for the ISP and we can not find any reason that this would happen. The routes are the same for both - static from the ISP for the same block to both and default routes to both from my router. Does anyone have any idea of what this could be?

Here are two interfaces on my router which connect to two interfaces on the ISP router, same card for both. Notice that the ignored errors are on one but not the other.

POS3/1 is up, line protocol is up

Hardware is Packet over Sonet OC3 LC

Internet address is

MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,

reliability 255/255, txload 107/255, rxload 121/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Scramble disabled

Last input 00:00:02, output 00:00:00, output hang never

Last clearing of "show interface" counters 00:25:22

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 73651000 bits/sec, 74270 packets/sec

5 minute output rate 65591000 bits/sec, 66153 packets/sec

L2 Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes mcast

L3 out Switched: ucast: 0 pkt, 0 bytes

110800252 packets input, 848385420 bytes, 0 no buffer

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

0 parity

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

100897345 packets output, 3914595607 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

POS3/2 is up, line protocol is up

Hardware is Packet over Sonet OC3 LC

Internet address is

MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,

reliability 255/255, txload 109/255, rxload 71/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Scramble disabled

Last input 00:00:00, output 00:00:01, output hang never

Last clearing of "show interface" counters 00:25:24

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 43282000 bits/sec, 43629 packets/sec

5 minute output rate 66544000 bits/sec, 67107 packets/sec

L2 Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes mcast

L3 out Switched: ucast: 0 pkt, 0 bytes

63126917 packets input, 3534617620 bytes, 0 no buffer

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

0 parity

1529 input errors, 0 CRC, 0 frame, 0 overrun, 1529 ignored, 0 abort

99902279 packets output, 3792276475 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

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2 REPLIES
Silver

Re: Ignored errors on PoS link

Ignores are caused by a MEMD buffer shortage , O high speed interfaces thaey are caused by the traffic that is received on a high speed interface that has to wait to be transmitters on a low speed interface , The interfaces buffer pool can be tied up waiting for the transmit ring to free up some buffers.

One solution to this is to configure the same MTU size on all your interfaces , When all the interfaces has the same MTU size all the interfaces can share the same pool .

Another thing to keep in mind is the amount of ignores you are having in rlation to the amount of input trafiic is very low ,

New Member

Re: Ignored errors on PoS link

That does not seem to be the case. The OC-3 links that i showed above are on the same router to the same ISP. The traffic coming on those two was once all on one of the circuits, and had just recently been balanced across the two circuits. So currently, the traffic on both of these are going to the same outgoing interfaces of the router - some FastE and GigE interfaces. BTW, this is a 7609 router. One sees the ignores, but the other does not. Also, the fact that they are come 11 packets at a time at 10 second intervals leads me to believe tha they are something else. Are there any other causes that woudl increment the ignores.

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