CCNA Voice will extend your CCNA as well;
if you start with CVOICE exam before CCNA Voice (ICOMM) you will feel like you are missing something; ICOMM is like a stepping stone to CCNP Voice.
If you pass either the 640-461 ICOMM exam (CCNA Voice) OR the 642-437 CVOICE by or before CCNA expiration date, you will be recertified for 3 years.
For additional CCNA recertification options, visit the About Recertification page.
Good luck and welcome to the Cisco Learning Network!
Cisco Learning Network Moderator