Multicast session flooding vlan



  • We have a FOG server which resides on our server VLAN (vlan 2). We image clients across VLANs (for example, vlan 4). Recently, during multicast sessions, our network guys claimed it caused an outage due to a flood of traffic on the VLAN the server resides on. I do not have a whole lot of details from them yet, but they claimed it was flooding the interfaces of all devices on that VLAN, much like a broadcast.

    I will attach a capture of the multicast.log file showing the udp-sender parameters that were run on Monday.

    in the mean time, has anyone had any issues like this?

    We use FOG at several of our sites and as the local IT team enjoy using it very much. They are threatening to make us use WDS if we can’t find a root cause on this.



  • Any attemp to multicast on network switches that do not have IGMP Snooping will cause network flooding of broadcast packages. IGMP (Internet Group Management Protocol) settings should be found on your switches.



  • I would say have the networking guys check out which pim mode is set. Cisco, the best IMO is sparse mode because it is a pull type multicast rather then push to everything on the vlan and have it prunned off. I have sparse mode set on mine, and havent had any problems



  • I would say have the networking guys check out which pim mode is set. Cisco, the best IMO is sparse mode because it is a pull type multicast rather then push to everything on the vlan and have it prunned off. I have sparse mode set on mine, and havent had any problems



  • If you are using cisco switches see [url]http://www.fogproject.org/wiki/index.php?title=Cisco_Multi_Cast[/url] for sample config



  • what switches are you using?



  • the multicast works fine across VLAN’s. However it seems like it ‘broadcasts’ to the VLAN that the server is located on at the same time.


  • Moderator

    sounds like the network guys, do not have the correct config on the switches, I can multicast accross vlans just fine


Log in to reply
 

428
Online

38951
Users

10701
Topics

101540
Posts

Looks like your connection to FOG Project was lost, please wait while we try to reconnect.