mininet: Dynamically created Host cannot ping other Hosts, but Host can ping Switch

Question

I am trying to dynamically add Hosts and Links after Mininet Startup. I am using the py net.addHost,addLink commands.

Using the standard linear,3 Topology

The code is:

py net.addHost('h4')
py net.addLink(h4,s3)
py h4.setMAC("00:30:00:00:30:10")
py h4.configDefault(defaultRoute = h4.defaultIntf())

The last statement ensures h4 has a valid IP address. On running ifconfig on h4:

mininet> h4 ifconfig
h4-eth0   Link encap:Ethernet  HWaddr 00:30:00:00:30:10  
          inet addr:10.0.0.4  Bcast:10.255.255.255  Mask:255.0.0.0
          inet6 addr: fe80::230:ff:fe00:3010/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:25 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:4001 (4.0 KB)  TX bytes:1296 (1.2 KB)

Pinging h4 from h1 (part of the static topology):

mininet> h1 ping h4
PING 10.0.0.4 (10.0.0.4) 56(84) bytes of data.
From 10.0.0.1 icmp_seq=1 Destination Host Unreachable
From 10.0.0.1 icmp_seq=2 Destination Host Unreachable
From 10.0.0.1 icmp_seq=3 Destination Host Unreachable

Pinging between static topology nodes (h1 and h3):

mininet> h1 ping h3
PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.
64 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=2.14 ms
64 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.141 ms

Any help will be appreciated!

Answer 1

You were almost there! All you needed to do was:

mininet> py s1.attach('s3-eth3')

then:

mininet> h1 ping h4
PING 10.0.0.4 (10.0.0.4) 56(84) bytes of data.
64 bytes from 10.0.0.4: icmp_req=1 ttl=64 time=2.99 ms
64 bytes from 10.0.0.4: icmp_req=2 ttl=64 time=0.113 ms

Found the answer here .

Answer 2

Try adding this flag to your 'mn' command to make it use openflow v1.3. It could be using v1.0 by default.

--switch ovsk,protocols=OpenFlow13

ie Append the above line while running the mininet:

 sudo mn --switch ovsk,protocols=OpenFlow13

for custom topologies:

sudo mn --custom ~/<filename>.py --topo mytopo --link tc --switch ovsk,protocols=OpenFlow13