Exchange 2010 Upgrade on new 08 Child Domain?

My company is preparing to upgrade to Exchange 2010. Recently we have been meeting with consultants to prepare and think of the best plan for deployment and the smoothest upgrade.

Existing Environment:
Exchange 2003 (1 front-end and 1 back-end server) at one location
Active Directory 2003 - Multisite
Root Domain:
All Servers/Computers/Users (EVERYTHING) is currently on
When users logon to their computer or anything it is always the CORP domain.

Future Environment:
MIigrate everything to Exchange 2010 - 2mailbox servers 2Hub/CAS server in primary location (1mailbox/1HUB/CAS with DAG in DR site)

Our domain was previously migrated from an existing Novell domain.

The consultant recommended that we create a new child domain of called "EXCH" or something similar that would be domain 2008.  He recommended that we install our Exchange 2010 configuration on the new domain and create a trust relationship between the two domains.  Another reason for creating a new domain would be that it is cleaner and does not currently have Exchange 2003 or old potential Novell corruption.

I was initilaly weary of creating a new child domain for Exchange as i am not sure what other repurcussions there would be? The Plan would be to eventually upgrade to 08 and upgrade our root domain to 08 as well.

I'd prefer to keep it all on the same domain for simplicity of management and administration. But - i wouldn't mind if it was installed on a cleaner new AD environment if it will not cause any more complexion or confusion. How would the relationship work between the two domains?

Is this a recommended Best Practice to do? What do you Experts think about this plan and what else could we do?

Thank you, Experts.
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There is not need for another child domain.
IF you domain controllers meet the requirements for 2010. Then put it in the domain that the 2003 is. This will be your easisest migration.
If you make another child domain that is another pair of domain controllers you will need to manage.

I would run the Exchange Pre-Deployment Analyzer

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Your consultant is an idiot; if he creates a new child domain, a transitive trust is automatically created. If they can't get that basic detail right - and anyone who's done a single Microsoft server exam should know it - I'd be wary of anything else he has to say.

When transitioning from Exchange 2003 -> 2010, the big things to look for from my experience is this:
You won't be able to add an Exchange 2007 system once 2010 is installed
There are some application compatibility issues with Exchange 2010 (e.g., Blackberry Enterprise server 4.x won't work

I used the Exchange 2010 deployment wizard and had few issues.
RavenIndAuthor Commented:
I believe his skills are sharp and he has a lot of experience with various Exchange 2010 deployments. His main concern was the 03 issues we might have to uncover when upgrading to Exchange 2010. He was thinking that there would be a lot to cleanup from the Novell configuration.

Would you recommend upgrading to 08 domain prior to Exchagne 2010? Or just doing it on our current AD 2003 environment?
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

you only need 2003 sp2 for the domain controllers
I would run the Exchange BPA on your current enviorment to see if there are any issues before you start.
Neil RussellTechnical Development LeadCommented:
Sack your consultant! His plan is a waste of time, money and effort and as brota said, he is stating inacurate facts with regard to trusts.

Unless you STILL have novell running and are still using novell connectors for exchange in 2003 then there are no issues regarding Novell. If you migrated FROM Novell into Exchange and it runs now, why would he think it wont run in 2010?

There is a Phrase for this type of consultant...

Money Grabbing Idiot!
Neil RussellTechnical Development LeadCommented:
Sorry i only just reread that question...

How does creating a new child domain help? The exchange org belongs to the Forest right? Your exchange 2010 would still be a direct part of the exchange 2003 setup.

ONE Forest ONE Exchange Organization.
RavenIndAuthor Commented:
I thought it was an interesting idea indeed. I have read about some organizations that create domains like to install Exchange and SharePoint but I could not find any MS documentation to back it up, or anything on line that said why. Is there any benefits to having your larger more complex apps on a different child domain than your users?
RavenIndAuthor Commented:
The consultant also said that it would take more hours to install Exchange in our current domain that by creating a separate 08 child domain. He said there would be some hours spent in Adsiedit cleaning some things. It would be quicker, in his opinion, to create a new fresh domain with 08 and have a clean environment.
Ask him what, specifically, in AD needs cleaning up. If there's issues with the domain and ADSIedit is needed, those problems will still be there after adding a new domain, too.

Really, it sounds to me like he's ill-equipped to deal with the domain you have and seeks to increase your complexity for his benefit alone.
I can see a resource forest for Exchange but not a child domain because like everyone has said it is still in the same forest.
How many mailboxes?
If anything I would look into collapsing your domain into the root.
If there is major problems in the AD they could be in the root too. If there are major problems I would consider a new forest and do a cross forest migration.

RavenIndAuthor Commented:
I found some MS documentation on creating an Exchange 2010 resource forest. This might have been more what he was referring to: 

Does this make more sense possibly?
I dont see any reason why you would need it.You have a domain that can handle 2010
With a resource forest you need to create disabled user accounts in the domain.
The migration will be a cross forest migration. You may need 3rd party tools to support free busy during the migration since the interorg replication tool does not support free/busy between 2010 and 2003.
The interorg tool should work for public folder replication.

This method is usually done for merger migrations.
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