Quoting from the Vyatta official announcement:
Vyatta, the leader in Linux-based networking, today announced that its open-source networking software has received VMware Virtual Appliance Certification, thereby providing customers with a solution that has been optimized for a production-ready VMware environment. The company also announced it has joined the VMware Technology Alliance Partner (TAP) Program. As a member of TAP, Vyatta will offer its solutions via the TAP program website. With the Vyatta virtual appliance for VMware environments, organizations can now include Vyatta’s router, firewall and VPN functions as part of their virtualized infrastructure…
Vyatta offers an open-source software platform which can be installed on any x86 computer and which provides most routing capabilities currently available only through well-known vendors like Cisco, Nortel, etc.
Cisco is expected to release a virtual version of its networking devices inside VMware ESX Server, as virtualization.info revealed in July. Despite the companies didn’t make an official announcement during VMworld 2007, the informations has been confirmed by several parts.
So emerging competitor Vyatta has all interests in partnering with VMware and have same opportunity Cisco has.