Network Function Virtualization is a growing concept in the research field because of its ability to decouple network functions, like network address translation (NAT), domain name service (DNS), firewall, intrusion detection (IDS) etc., from proprietary hardware equipment. They can now run in software making the network more flexible and agile. This also reduces hardware and maintenance costs of the network. Nowadays many applications use multicasting as it saves a huge amount of communication bandwidth. But many packets need intermediary processing before reaching their destinations. For this processing, Virtual Network functions (VNFs) are implemented in the network where processing of packets takes place. Because of this the path through which the packets traverse changes, and delay increases. This project considers different number and placements of VNFs in four real-world topologies namely NSFNET, Cost239, Arpanet and Random12, and observes the delay for every case. As the VNFs are duplicated on different nodes in the network, the cost of deployment and maintenance of VNFs is increased, but the delay decreases up to a certain number of VNFs. After this, the delay becomes constant. This project presents this trade-off between cost and delay.