I have the following topology set on AWS where there are 4 CSR 1000v Routers deployed and Segment Routing enabled in which the Segment Routing Headend is R1 and the destination is R3.

I aim to send iperf traffic from Endpoint1(Client) to Endpoint2 (Server) with the following SR path = {R1, R2, R3, R4, R3, R2, R1, R2, and R3}. enter image description here First of all, the traffic generated by iperf from Endpoint1 a linearly increasing UDP traffic until I stop manually. Using SNMP and Cacti I could get throughput across the links (GRE Tunnels) which are summarized below.

I set all tunnels' bandwidth as 10Mbps, I was expecting to see packet loss but I didn't. It is obvious from the plots that the throughput has exceeded the tunnels' bandwidth. However, no packet loss is recorded.

enter image description here enter image description here

here's the tunnel's configuration:

interface Tunnel0
 bandwidth 10000
 ip flow monitor NTAMonitor input
 ip flow monitor NTAMonitor output
 ip address
 ip router isis aws
 load-interval 30
 mpls traffic-eng tunnels
 keepalive 2 3
 tunnel source GigabitEthernet1
 tunnel destination
 tunnel path-mtu-discovery
 isis metric 1

it is basically the same as the other tunnels' configuration except for the name, address and destination address.

the show platform hardware throughput level shows 200000000 kb/s

1 Answer 1


The bandwidth command sets the reported bandwidth and is used for metric calculation only. It does not affect the actual interface bandwidth.

If you want to limit bandwidth, you will need to implement traffic shaping/policing.

  • Thanks! would implement traffic shaping/policing help to record packet loss that happens over the tunnel? Aug 9, 2019 at 17:17
  • You would see drop information in the policy you apply to the interface, not the tunnel itself.
    – Ron Trunk
    Aug 9, 2019 at 17:19
  • What about the tunnel? I am actually interested to see losses on tunnels. Aug 9, 2019 at 17:21
  • Sorry, that's not how things work.
    – Ron Trunk
    Aug 9, 2019 at 17:23
  • Okay! Thanks Ron! One question, when I set the policies, am I able to see the loss using SNMP ? Aug 9, 2019 at 17:38

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