HOTSPOT
You have an Exchange Server organization that contains four servers. The servers are configured as
shown in the following table.
SiteA contains an IP gateway that uses a dial plan named Dialplan1. SiteB contains a Lync Server
2013 server that uses a dial plan named Dialplan2.
You plan to migrate all Unified Messaging (UM) functionalities to Exchange Server 2013.
You need to identify which tasks must be performed to complete the migration.
Which tasks should you identify? (To answer, select the tasks that are required and not required in
the answer area.)
Answer: 
shouldn’t “EX3 to Dialplan2” be required as well for coexistence?
correction mean to say shouldn’t “EX3 to Dialplan1” be required as well for coexistence?
like questions $56 http://www.aiotestking.com/microsoft/which-three-exchange-servers-should-you-associate-to-the-um-dial-plans-4/
I would think you would associate the 2 2013 servers with dial plan 1, and the 1 2010 UM server with dial plan 2?
Thinking about this again and doing more research…
With regards to dial plan 1, this uses an IP gateway (meaning it is not using a SIP URI dial plan) – Client Access and Mailbox servers can’t be associated with Telephone Extension or E.164 dial plans.
Dial plan 2, this uses a SIP URI dial plan as it has a lync server – you must manually add all Client Access and Mailbox servers to all SIP URI dial plans that you’ve created for Lync Server
So… My thinking is you only need to add EX2 and EX3 to dial plan 2. And as you can’t add servers to Telephone Extension or E.164 dial plans, you don’t need to do any of the ones that include dial plan 1.
agree
So Do I,
I agree
SIP clients, such as IP/VoIP gateways and IP/PBXs, can use TCP port 5060 or port 5061 (for Secure SIP) to connect to SIP servers.
Site1 contains IP Gateway, so EX3 (CAS 2013) shoud be assigned to Dialplan1.