Multicast packet loss (IPTV bad quality)

[danijel_knezic]

I have SG300-28 switch which runs as L2 and vlan 2 as Multicast vlan for IPTV stream. But problem I have stream quality is very bad and losing a lot multicast packets.

I have configured IGMP snooping and query by MAC based but multicast packets are not coming in good quality.

I started Wireshark to capture some packets and I can see my IGMP is working fine but I am receiving Multicast fragments of a reassembled packet. See attached capture.

I have feeling my switch is faulty or I have multicast storm on my interfaces.    

[Georg Pauwen]

Hello,

on the SG300 switches, there is a functionality called 'Multicast Forward All', which basically lets you fiilter the ports that yiu want to send multicast traffic on. Not sure if that helps in your case. Are the senders/receivers on the same switch, in the same Vlan ?

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-small-business-300-series-managed-switches/smb1782-configuration-of-multicast-forward-all-for-vlan-ports-on-300.html

[danijel_knezic]

Hi Georg,

I have activated Multicast Fwd All on ports where are my senders/receivers but still facing same issue. Even this is active or not. 

All senders/receivers are on same vlan.

[danijel_knezic]

And switch is giving me error duplicated IGMP query IP 10.200.0.5 which don't make sense because it is only one switch in all network and there is no other query configured any else with same IP.

[Georg Pauwen]

Hello,

odd. Do you have any smartport macros configured on your switch ?

[danijel_knezic]

All ports are in Auto Smartport which is default settings.  Should I change something in this settings. 

[danijel_knezic]

Hi Guys,

Any else useful info about Multicast issues which I could check.

[Georg Pauwen]

Hello,

I think all macros implement some sort of storm/broadcasr/multicast control. Try and get rid of any macros on any port, and check if that makes a difference.

[danijel_knezic]

Hello,

So I have disabled all macros. But as well I noticed one of my multicast IP 239.1.1.50 was flooding traffic on my network with no query asking for it. 

I have disable the IP on my IPTV Encoder Server and stream looks now much better. But now I am curies why this IP is not following IGMP query request and doing it's own business. 

Even now when is disabled I can see query start to pop-up lot messages from this IP. Se attached

[Georg Pauwen]

Hello,

is the 'Bridge Multicast filtering' I suggested earlier on still active ?

[danijel_knezic]

Hello,

Bridge Multicast  filtering is still active.

[Georg Pauwen · Accepted solution]

Hello,

is IGMP snooping still active as well ? I am not sure how both interact, so in case both are active simultaneously, you might disable one of the features, and leave just one activated.

[danijel_knezic]

Hello,

SO either IGMP snooping or filtering but not both in same time. At moment I have booth active.

I will test one by one and comapre

Thx

[paul driver · Accepted solution]

Hello
Suggest you apply some storm control on the access-ports for BUM traffic, this way you can negate any flood at the source and have the port shutdown as/when the defined threshold is reached, you could also enable errdisbale recovery if you want the ports to automatically recover from as shutdown as/when the port threshold drops below the defined level but I wouldn't recommend this at first as you would need to understand what ports are affected and why.

Example:
Note: on a 1GB port would result in 100mb threshold  with a 10%  port level so decrease/increase to accommodate if applicable

int x/x
description access-port
storm-control broadcast level 10.00  (% of the of traffic) 
storm-control multicast level 10.00  

storm-control unicast level 10.00
storm-control action shutdown

errdisable recovery cause storm-control
errdisable recovery interval 120

show storm control xxxx

[danijel_knezic]

Hello Paul,

Thanks for heads up mentioned I have already up and running.  Hope this will sort my problem with multicast.