add example and test for multiple links

examples/multiLink.py

+#!/usr/bin/python
+
+"""
+This is a simple example that demonstrates multiple links
+between nodes.
+"""
+
+from mininet.cli import CLI
+from mininet.log import lg, info
+from mininet.net import Mininet
+from mininet.topo import Topo
+    
+def runMultiLink():
+    
+    topo = simpleMultiLinkTopo( n=2 )
+    net = Mininet( topo=topo )
+    net.start()
+    CLI( net )
+    net.stop()
+
+class simpleMultiLinkTopo( Topo ):
+
+    def __init__( self, n, **kwargs ):
+        Topo.__init__( self, **kwargs )
+
+        h1, h2 = self.addHost( 'h1' ), self.addHost( 'h2' )
+        s1 = self.addSwitch( 's1' )
+        
+        for _ in range( n ):
+            self.addLink( s1, h1 )
+            self.addLink( s1, h2 )
+
+if __name__ == '__main__':
+    lg.setLogLevel( 'info' )
+    runMultiLink()

examples/test/test_multiLink.py

+#!/usr/bin/env python
+
+'''
+Test for multiple links between nodes
+validates mininet interfaces against systems interfaces
+'''
+
+import unittest
+import pexpect
+
+class testMultiLink( unittest.TestCase ):
+
+    prompt = 'mininet>'
+
+    def testMultiLink(self):
+        p = pexpect.spawn( 'python -m mininet.examples.multiLink' )
+        p.expect( self.prompt )
+        p.sendline( 'intfs' )
+        p.expect( 's(\d): lo' )
+        intfsOutput = p.before
+        # parse interfaces from mininet intfs, and store them in a list
+        hostToIntfs = intfsOutput.split( '\r\n' )[ 1:3 ]
+        intfList = []
+        for hostToIntf in hostToIntfs:
+            intfList += [ intf for intf in 
+                          hostToIntf.split()[1].split(',') ]
+
+        # get interfaces from system by running ifconfig on every host
+        sysIntfList = []
+        opts = [ 'h(\d)-eth(\d)', self.prompt ]
+        p.expect( self.prompt )
+        
+        p.sendline( 'h1 ifconfig' )
+        while True:
+            p.expect( opts )
+            if p.after == self.prompt:
+                break
+            sysIntfList.append( p.after )
+
+        p.sendline( 'h2 ifconfig' )
+        while True:
+            p.expect( opts )
+            if p.after == self.prompt:
+                break
+            sysIntfList.append( p.after )
+
+        failMsg = ( 'The systems interfaces and mininet interfaces\n'
+                    'are not the same' )
+
+        self.assertEqual( sysIntfList, intfList, msg=failMsg )
+        p.sendline( 'exit' )
+        p.wait()
+
+if __name__ == '__main__':
+        unittest.main()