- Purple, 4500 points or more
We have a 3745 that has a DS3 connection into a frame cloud. Yesterday we noticed that the serial interface had almost 100% of bandwidth being used outbound. I set up netflow to see what was using it, and it wasn't consistent. I tried to block ports and servers in an acl, and I applied it inbound on the serial interface, but that didn't make a difference. The configuration for the port is here and I've bolded the lines that we're concerned with:
Serial1/0 is up, line protocol is up
Hardware is DSXPNM Serial
Description: DS3 connection for the GO
MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
reliability 255/255, txload 92/255, rxload 8/255
Encapsulation FRAME-RELAY IETF, crc 16, loopback not set
Keepalive set (10 sec)
LMI enq sent 5539, LMI stat recvd 5539, LMI upd recvd 0, DTE LMI up
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 923/0, interface broadcasts 0
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 15:23:06
Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 10003
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 1521000 bits/sec, 494 packets/sec
30 second output rate 16042000 bits/sec, 3334 packets/sec
35238211 packets input, 2648515031 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
192251637 packets output, 1216186812 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DSU mode 0, bandwidth 44210, real bandwidth 44210, scramble 0
a.) The DSU line that we have is a 20mb connection, but the default is 44210. The line is in the running config as "dsu bandwidth 44210", but according to Cisco is the default. I think this is primarily for calculations, and that would mean that my "tx load" would be even higher than it shows now.
b.) The tx load is almost at 100% if we take into calculation that it's around 30% now, but it "thinks" it's a 45mb pipe. If we convert that to a 20mb calculation, then the transmit rate would naturally increase to something around 225/255. (Does that make sense?)
c.) The 30 second output is at 16mb, which means that there's 16mb of data going out CONSTANT out of a 20mb connection. This isn't normal for this connection.
d.) Do I need to be concerned with the dropped packets?
Also, when we're talking about output for this interface, is that output respective of the direction? I mean if I'm sending traffic through the router from one side and it's going into my network, does that register as output as well as sending traffic out of my network?
I'm at a loss as to why there's so much traffic, and where it's coming from and I hope you guys can give me some pointers as to what's going on. This is not a new connection either by the way; this just started happening yesterday morning.