title: How to set bandwidth on Mininet custom topology?
body: <p>I want to set bandwidth on Mininet custom topology.</p>
  
  <p>The python code is:</p>
  
  <pre><code>#!/usr/bin/python
  from mininet.topo import Topo
  from mininet.net import Mininet
  from mininet.node import CPULimitedHost
  from mininet.link import TCLink
  from mininet.util import dumpNodeConnections
  from mininet.log import setLogLevel
  
  class MyTopo( Topo ):
  "Simple topology example."
  
      def __init__( self, **opts):
          "Create custom topo."
  
          # Initialize topology
          Topo.__init__( self, **opts )
  
          # Add hosts and switches
          h1 = self.addHost('h1')        
          h2 = self.addHost( 'h2' )
  
          s3 = self.addSwitch( 's3' )
          s1 = self.addSwitch( 's1' )
          s2 = self.addSwitch( 's2' )
  
          # Add links
          self.addLink(h1,s1,bw=10)
          self.addLink(h2,s3,bw=20)
          self.addLink(s3,s2,bw=10)
          self.addLink(s1,s3,bw=10)
  
  topos = { 'mytopo': ( lambda: MyTopo() ) }
  </code></pre>
  
  <p>But it has error</p>
  
  <pre><code>------------------------------------------------------------------
  Caught exception. Cleaning up...
  TypeError: __init__() got an unexpected keyword argument 'bw'
  ------------------------------------------------------------------
  </code></pre>
  
  <p>What can I do?
  How to set bandwidth on Mininet custom topology?</p>