Endpoint Protection

LiveUpdate Server get the update in a large size. It consumes all the bandwidth in my office. Is there anyway to perform the QoS on the LiveUpdate Server?

I tried the Windows QoS but it does not work.

For liveupdate server QOS is not available.You have to try this in your router level only.Any way have a look mat these KBs .It may help you in other way
LiveUpdate Administrator 2.2: What product selections are needed for specific versions of Symantec Endpoint Protection

LiveUpdate Administrator 2.2 Performance Tuning

Only for distribution you can specify the maximum amount of bandwidth it can use...

What kind of the QoS you concerned?
The download of LU Server from Symantec site, or, the content distribution from LU Server to the SEP client?

Downlaod of LU Server from Symantec. 

The LU Server to SEP client we can managed the bandwidth via IIS. But I am not sure with LU Server

In LU server it is not possible.More over LUA is not using IIS.it uses apache..

Maybe I only can schedule it during midnight and seperate the 32 bit and 64 bits download.

Scheduling midnight is a good idea.
Also assure that you are done performance  tuning and also done the proper selection of updates...