Multicast

Hi

I have an issue using Symantec Ghostcast server, when we need to restore an image to a client using multicast we have to wait until no one is using the network so as not to disrupt them. We have 2 networks in our school, Curriculum and Admin and are seperated using VLAN's on the switches. When we multicast on the Curr network all the shares on the Admin network are not available, logging into the Curr newtork whilst multicasting also causes issues like not pulling the profile.

Has anyone heard of this before, is there a way to multicast at the same time the Network is being uses

Any help would be great

Lee H

Find more posts tagged with

Save $250 on 2025 certification boot camps from Infosec!

Book now with code EOY2025

Button

Comments

Danman32

Ip/Ethernet multicasts shouldn't by themselves affect anything else. Could be a simple bandwidth problem, though a multicast should ease bandwidth, since one packet is received by multiple hosts rather than one source host sending multiple packets of the same data, each destined for one host.

sprkymrk

I have trouble similar to that with Ghost Casting. It has a lot to do with the VLAN in the switches. For some reason it's problematic. I often use a directed broadcast in those cases which works fine, but again you will flood the network so it needs to be done after hours. Otherwise, if I am only restoring a single host image I use unicast.

EdTheLad

Danman32 wrote:

Ip/Ethernet multicasts shouldn't by themselves affect anything else. Could be a simple bandwidth problem, though a multicast should ease bandwidth, since one packet is received by multiple hosts rather than one source host sending multiple packets of the same data, each destined for one host.

Multicast can flood the network are eat all the resource, this is why its a good idea to use vlans.

EdTheLad

Lee H wrote:

We have 2 networks in our school, Curriculum and Admin and are seperated using VLAN's on the switches. When we multicast on the Curr network all the shares on the Admin network are not available, logging into the Curr newtork whilst multicasting also causes issues like not pulling the profile.

Multicasts on one vlan shouldnt affect the other vlan,maybe you have a stray
cable connecting the two vlans.

Lee H

this software procliams to use little bandwidth thus not affecting the network, so how is it that i am flooding the network, users are not able to log in whilst i am multicasting

sprkymrk

Lee H wrote:

this software procliams to use little bandwidth thus not affecting the network, so how is it that i am flooding the network, users are not able to log in whilst i am multicasting

I think if you look through the Implementation Guide or Administrators Guide that comes with the Ghost software, it warns you that it actually can use a lot of bandwidth. It's a little deceiving the way they do it, because the simple help files do seem to indicate that it won't use a lot of bandwidth, but if you read closely it seems to be saying "compared to" other ways, say like Unincasting to 50 workstations.

Your post made me curious enough to go read that stuff in the manuals again. Notice that they also have bandwidth throttling available, where you can limit the bandwidth used for pushing images or AI jobs. Try using that and see if it helps.