[mdt] Getting multicast working

[sidewinder]

After 2 weeks of thinking multicasting wasnt working with MDT, today I've thought that perhaps it actually is.

 

What made me think it isnt working is that on the clients you get 'Attempting multicast transfer' with the bar stuck at a tiny percentage, until they seemingly give up and start the 'expanding windows files' bit

 

But looking at the multicast bit in WDS, both clients are listed and transfer appears to be taking place. I've attached a screenshot.

 

So in fact, does MDT/WDS transfer the whole image first, then files are expanded at the client end? Eg is my setup in fact working?

The thing that made me think it wasnt working is that it didnt seem to be going very quickly but I suppose I wouldnt see much benefit with 2 computers anyway

 

 

[sidewinder]

Anyone?

 

Also, although it was working across some switches, trying to image some machines in another area (goes through the core and then one Procurve 2610, both with multicasting switched on) and multicasting wont even work in the way I described above - transfer rate never gets above 128Kbps

 

Just dont understand it

[ranj]

We are in the process of rolling Windows 7 to about 160 machines I am interesting in looking at the multicast options in WDS (which we haven't set up at the moment) as I understand we will be able to rollout the same image to multiple machines at the same time and multicasting in WDS will certainly help the process.

 

Our plan was to rollout this evening and come back in the morning and hopefully the imaging will be completed so we can do some post installation tasks and its all done.

 

Does anyone have any tips on how best to set this up and things we should look out for?

 

Thanks

[DMcCoy]

I have found WDS multicast to be broken with the HP Procurve small switches, 1Gb uplink, but only 100Mb to the clients, such as the 2510s. I had throughput issues (200KB/s or so). The all Gb switches perform as expected. On the Gb switches it all works very well with an average of 20MB/s to clients when multicasting,

 

The multicast is not broken on the small Procurves when using Ghost multicast, which means i've not been able to find one specific thing to blame yet, ghost perfoms as expected (12MB/s).

 

As for MDT/WDS:

 

If the client moves to expanding windows files without reaching 100% on then it has dropped back to unicast mode.

 

Unicast = client starts on "expanding windows files"

Multi = client starts with "copying" first then moves to the expanding phase.

 

If you are multicasting you really need switches that support IGMP filtering, and it must be turned ON. This will also need to be turned on at a vlan level if you use mulitiple vlans.