Category: Multicast

Enable Source-Specific Multicast in Iperf

I was preparing lab environment to test configuration of Source-Specific Multicast on Juniper SRX Equipment and needed a tool to generate and measure Source-Specific Multicast streams.

I was aware that Iperf is a good enough tool to generate and measure multicast and unicast traffic but support for SSM was missing from current version. Fortunately there are always some developers which are interested in networking so one of them developed a special Iperf version 2.0.5 with SSM support.

The idea here is to show how to make this version of Iperf work on your Cent OS or similar Linux machine.

Here are few steps that should work from your Cent OS 6.8 Linux Server and hopefully from other similar distributions to:

Source-Specific Multicast Configuration

In SSM, Source-Specific Multicast, things are done differently from standard multicast forwarding. SSM is specifying a group of hosts that are receiving same multicast stream using group IP address and additionally using stream unicast source IP.

In this article it is shown how to configure Source Specific Multicast on Cisco and Juniper equipment.

In standard multicast, forwarding is done using group IP address which is an IP from multicast dedicated range 224.0.0.0/4 (224.0.0.0 – 239.255.255.255) or FF00::/8 in IPv6. Each multicast group IP address is a single address which specifies all hosts receiving a specific stream, streamed towards that group IP address from multicast source. In standard multicast everybody can start to stream with some IP multicast group IP, becoming in that way, the multicast source.

Juniper vMX Lab Setup on VMware

This is a description on how to deploy a Juniper LAB of 8 vMX routers and making a simple topology in VMware vSphere environment. vMX is Juniper’s virtual production router so this could be the same procedure for deploying vMX device in production except different number of routers and their interconnection with vSwitch setup.

Juniper vMX router

Two VMs interconnected with VLAN801 – making one Juniper vMX router

As you might have seen from my previous post, I’m trying to get into Juniper configuration lately. One of the things that I needed is to set up a simple lab running Juniper vMX machines with multicast forwarding enabled.

It was a simple lab experiment with few commands on each device. As it turns out, being a Cisco fellow, each of those commands presented a complicated googling routine until the thing finally started to work.

Most time I spent configuring Virtual Machines and boot them properly, after that Juniper Configuration Guides were enough to make fist lab scenarios.

Googling went somewhat like this:

  • How to set up Juniper vMX on Vmware ESXi 6.0 and interconnect 8 instances of vMX?
  • How to configure Vmware network and vSwitches to make this work?
  • How to configure VCE and VPE vMX Control and Forwarding plane VM communication?
  • How to configure interfaces and map them to VMware vSwitch interfaces?
  • How to configure Juniper eth interfaces, OSPF, Multicast with PIM Sparse mode?
  • Why this does not work from the first try? Do I need vMX Evaluation licence to do that?
  • What for …. does ‘tunnel-services statement on one or more online FPC and PIC’ mean?

…so when it actually finally worked, I decided to share it so you can have one post that would describe it from start all the way to VLC Multicast streaming.

Juniper vMX Multicast Configuration

I’m fairly new to Juniper CLI. For one of my first tries, I decided to make my life difficult by starting with multicast configuration on virtual vMX routers running as VMs on VMware ESXi.

It took a lot of investigation about some part of this configuration specially the tunnel interface which you will see below. I decided to put it here all in one place with the explanation of every step because Juniper documentation tends to assume that you know more than me. If that is not the case, this short description is for you.

Here’s how the topology looks like. I have 8 routers making this topology with the plan to source multicast streams from right to left, from PC 10.10.99.11 towards PC 10.10.98.11

Juniper vMX topology

Configuration