Cisco 881 WAN port - consumption/traffic

[Scott Saunders]

TL;DR: Something's not right here. Do the in/out byte counts on the WAN port rollover at a certain number?

I've been monitoring the traffic coming in on an asymmetric broadband connection because a new potential ISP wants to know how many GBps the branch office consumes in a billing cycle. I don't have NetFlow, or anything else for monitoring, just the simple router statistics. But I see this:

Last clearing of "show interface" counters 04:33:30

 . .

5 minute input rate 804.0 kilobits , 76 pps
5 minute output rate 151.0 kilobits , 53 pps
4,275,047 packets input, 938,363,820 bytes
 . . 
3,282,535 packets output, 543,728,095 bytes, 0 underruns

The input byte count 2.5 hours earlier was 2,604,945,049. 

Simple question, hopefully a simple answer. Thanks.

[Francesco Molino · Accepted solution]

Hi

Yes there's a roll over on interfaces.
At least 3 methods to clear counters:
- at reload
- issuing manually clear command
- auto roll over. If I recall it rolls over at 4 billion (you can do some search on Cisco IOS docs to validate that number)