Enable Multicast Issue

[KarimM]

Hi,

I have the following managed switch: Cisco Catalyst IE-3300-8T2S Rugged Switch

Currently I have an issue with PTP synchronization, and after some troubleshooting with the manufacture of the master PTP device, I have discovered that I need "Multicast" to be enabled on the switch.

The way I discovered that the issue is in the cisco switch, is I put an unmanaged switch and all of my devices started syncing.

Now I am trying to enable Multicast but I cannot even find the parameter that all the guides mentions: "ip multicast-routing"

I am not that knowledgeable in cisco switches, but I kept digging around in parameters, when I try to enter:

#global-address-family ipv4 multicast

I get the following message

 Cannot enter Address-family ipv4 multicast mode because topology (default ipv4 multicast base) multi-topology mode is not enabled.

 Can someone guide me on how to configure this switch to enable multicast?

[Jon Marshall]

Never configured these before but start here - 

https://www.cisco.com/c/en/us/td/docs/switches/lan/cisco_ie3X00/software/17_3/b_multicast_17-3_iot_switch_cg/m-173-mc-basic-multicast-routing-cg.html

note no mention of enabling ip multicast-routing you just add PIM configuration to relevant interfaces. 

Jon

[KarimM]

I have tried to follow this before, but I am cannot even find "pim" or "mfib" under ip. I don't know if there is something blocking me from the multicasting options in general or what exactly.

[Jon Marshall]

So just to check, you are definitely trying to configure PIM on an interface and that interface is a L3 interface ? 

Jon

[KarimM]

I am going to be completely honest with you, all I want is for the PTP to work, and all I got to go with is that the switches need to enable multicast on all of its open ports.

The only configuration I did on the switch were the following:

1- Hostname

2- vlan1 ip address

3- domain name

4- enable ssh

5- enable spanning tree 

6- shutdown unused ports

That is it. I think it is a very basic configuration to do compared what normally what other will do with a switch like this.

[Jon Marshall]

So that chapter is for multicast routing and for that (routing) you need L3 interfaces. 

If I understand that is not really what you want, you just want any device connected to the switch to receive multicast packets from a source also connected to the switch ? 

If so you with no multicast configured some switches just treat multicast packets as broadcasts but it sounds like that is not happening on your switch. 

It may be IGMP snooping is running and you just need a querier but at the moment I am not finding any documentation on that. 

Jon

[KarimM]

The switch has industrial devices connected to it communicating with a SCADA (monitoring software) using modbus protocol.

[Jon Marshall]

Looking at the docs it appears your switch does support IGMP and an IGMP snooping querier function, just need to work out how to configure them. 

Try this guide and see if the commands are there - 

https://www.cisco.com/c/en/us/td/docs/switches/lan/cisco_ie3000/software/release/12-2_52_se/configuration/guide/ie3000scg/swigmp.html

Jon