Merge pull request #7218 from kuldeepkash/multicast_pim_bsm

tests: Add multicast-pim-bsm-topo1 suite

diff --cc doc/developer/topotests.rst
index 16901c08aba5b832214095091dc5784e8ac1a206,865f0481dea2e32aa3fc0a98b9dc1f29123a6b14..93d81548b23986d167e4fb67f349660477b3d5c1
--- 1/doc/developer/topotests.rst
--- 2/doc/developer/topotests.rst
+++ b/doc/developer/topotests.rst
@@@ -21,9 -21,9 +21,10 @@@ Installing Mininet Infrastructur
     apt-get install mininet
     apt-get install python-pip
     apt-get install iproute
 +   apt-get install iperf
     pip install ipaddr
     pip install "pytest<5"
+    pip install "scapy>=2.4.2"
     pip install exabgp==3.4.17 (Newer 4.0 version of exabgp is not yet
     supported)
     useradd -d /var/run/exabgp/ -s /bin/false exabgp