Symantec Ghost Multicast kills my network.

[mike.bradley]

I have a flat network with a bunch of 2950's connected to a 3550. When I utilize Ghost in either broadcast or multicast mode to image workstations my network grinds to a halt. I'm aware that all interfaces are being flooded with the traffic. Not sure how to control it to only go to the intended targets stations.

[dcooper_191]

Hello,

I'm not sure if this will help but I've had my own problems with this very issue.

Depending on what IOS versions are on your 2950's they may not have IGMP Snooping enabled. I had problems until I updated to a newer IOS (because it enabled IGMP Snooping by default)

Anyway, check this out. http://www.cisco.com/warp/public/473/22.html#intro

The only thing I did on some of our other sitches (2950's) was turn on IGMP Snooping and that's it, it had a great effect on our setups for the good. However I'm very new to the whole cisco world and I've not configured IGMP Snooping beyond simply turning it on.

I hope this at least gives you some direction to look in.

Take care.

[milan.kulik]

Hi,

I've fixed this problem in my network.

See http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Archive&topic=Network%20Infrastructure&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.ee93165/7#selected_message

Regards,

Milan

[mike.bradley]

Thanks - I'm working on the changes suggested.

[mike.bradley]

Any chance you can repost the above link? It no longer works for me. I need to print it off again.

Thanks

Mike

[mike.bradley]

Never mind I guess I just had to be patient. Sorry to bother you again.

[milan.kulik]

Yes,

it's here from the archive:

Hi,

my solution is following:

1) set a mutlicast storm control on the port the Ghost server (multicast source) is connected to the network. I'm using 2000 rising and 1500

falling thresholds. This decreases the absolute number of multicasts flooded to the network. So even if all other features fail your network will not be flooded by multicasts.

I'm not sure if Catalyst 6509 supports this feature. If not, move the Ghost server to Cat3524 which does.

The commands on Cat3524 are

interface FastEthernet.....

description Ghost

port storm-control broadcast action filter

port storm-control broadcast threshold rising 2500 falling 1500

port storm-control multicast action filter

port storm-control multicast threshold rising 3000 falling 2000

Tune the treshold values regarding your Ghost traffic (I'm using the above ones).

2) enable IGMP snooping on switches which are IGMP-snooping enable (Cat6500, 2950) and set CGMP enable on switches which are not

(Cat4000). On Cat3500 and 2900 CGMP is enabled by default.

3) configure

ip pim sparse-mode

ip cgmp

on your router LAN port.

You need a router to "translate" from IGMP to CGMP.

If the Ghost server and the client PC are in different VLANs you need to configure multicast routing on your router which is more complicated.

My solution is not describing it, I'm just fixing multicats flooding in one VLAN.

Don't use CGMP fast-leave if you're using HSRP in your network (address conflict).

The way this scenario works:

At the moment wokstation joins a multicast group it sends a IGMP join message. IGMP-enable switches detects it and they send multicast

traffic to appropriate ports only then. IGMP-not-enabled switches receive this info through CGMP - a router "translating" from IGMP to CGMP

is necessary.

There are some minor problems remaining (if the workstation joins several multicast groups rapidly it takes some time to detect it and

aproximately 30 sec multicast storm apears, e.g.) but generally this scenario works.

The above description is very rough, for detailed info see:

http://www.cisco.com/warp/public/473/38.html

http://www.cisco.com/warp/public/473/22.html

http://service4.symantec.com/SUPPORT/ghost.nsf/docid/1999033015222425

A good news in the end: There is a new Ghost version available which should be much more flexible and user friendly regarding unicats/multicasts options. It should enable using unicasts to send image to one PC and leave multicast as on option for image distribution to a PC group.

Hope to help,

Milan