Wireless Access

Hi,all

      I use the following command to calculate flow rate: 

echo -n `snmpwalk -v2c -c public 192.168.0.10 IF-MIB::ifHCOutOctets.1 | cut -d' ' -f4` > /tmp/result.tmp
echo -n `snmpwalk -v2c -c public 192.168.0.10 IF-MIB::ifHCInOctets.1 | cut -d' ' -f4` > /tmp/result1.tmp
echo -n " " >> /tmp/result.tmp
echo -n " " >> /tmp/result1.tmp
sleep 10
echo `snmpwalk -v2c -c public 192.168.0.10 IF-MIB::ifHCOutOctets.1 | cut -d' ' -f4` >> /tmp/result.tmp
awk '{printf "Cernet egress rate: %d mbps
",($2-$1)*8/10000000}' /tmp/result.tmp
echo `snmpwalk -v2c -c public 192.168.0.10 IF-MIB::ifHCInOctets.1 | cut -d' ' -f4` >> /tmp/result1.tmp
awk '{printf "Cernet ingress rate: %d mbps",($2-$1)*8/10000000}' /tmp/result1.tmp

But, I got the similar value,  can somebody tell me what's wrong?

Not so sure what you mean by 'got the similar value'.

I tried your script in a modified form (I removed the divide by 10M to get to bits per 10 seconds) and that produces something like this:

Cernet egress rate: 7102224 bps
Cernet ingress rate: 6233293 bps

Cernet egress rate: 9516807 bps
Cernet ingress rate: 8491288 bps

Cernet egress rate: 7189673 bps
Cernet ingress rate: 6194052 bps

If you want to know why the ingress and egress are similar in magnitude, that may be because traffic is tunneled. Most of the client traffic that comes in on the interface via the AP tunnel, will go out almost instantaneous as decrypted client traffic. So unless you have the client VLANs on a different physical interface than the APs, you will see this pretty symmetrical traffic pattern.

You will see similar on the controller itself:

(md-7005-01) #show interface counters


Port          InOctets     InUcastPkts     InMcastPkts     InBcastPkts
GE0/0/0     56111156670       331810222        46136913          258436

Port         OutOctets    OutUcastPkts    OutMcastPkts    OutBcastPkts
GE0/0/0     43991147096       302752988        43813062           13238

Will this be an answer to your question??