Traffic was capped to half of bandwidth

[peter.zhu]

We faced a situation that the inbound traffic was capped to 25Mbis out of total 50Mbis BW ordered from supplier. We have removed QoS, no change at all. The supplier has confirmed no restriction on the BW. I perform ping test with giant packet, it would reach full BW in short time, but it resume to 25Mbits after the test. It could prove link itself is fine.

Router is 4331 and throughput is 100bits.

Did anyone face similar issue and shed some light on this.

SKFSVERIGEAB_DASHIJUTOWN1_CN#sho platform hardware throughput level
The current throughput level is 100000 kb/s

SKFSVERIGEAB_DASHIJUTOWN1_CN#sh int gi0/0/1
GigabitEthernet0/0/1 is up, line protocol is up
Hardware is ISR4331-3x1GE, address is 4c71.0c62.dda1 (bia 4c71.0c62.dda1)
Description: BTCM: ***** WAN interface *****
Internet address is 60.12.102.14/30
MTU 1500 bytes, BW 50000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 5/255, rxload 130/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 1000Mbps, link type is force-up, media type is RJ45
output flow-control is on, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:04, output 04:11:54, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 25546000 bits/sec, 2318 packets/sec <<<<<<<<<<<<,
30 second output rate 1107000 bits/sec, 892 packets/sec

[balaji.bandi]

Any other QOS configuraiton in the device which stopping your Pings with gian packets.

Try use Iperf of jperf to test.

[Joseph W. Doherty]

You have not described nature of ingress traffic that appears to be capped at 25 Mbps.

Assuming some traffic is using TCP, WAN transfer rates can often not be full link bandwidth due to various reasons.

For example, if TCP's receiver doesn't provide a large enough RWIN buffer for the end-to-end BDP (bandwidth delay product), TCP's transfer rate will be limited to less than link's bandwidth capacity.