Overlay Networking Essay

1968 Words4 Pages

I. INTRODUCTION
The overlay networking technologies have become very important part of the internet today as more and more sites are connecting to each other in all over the world. The overlay networking technologies give freedom to implement any routing protocol and network design on top of the internet. There are many proven overlay technologies are there, however they also have some shortcomings, which lead us think about more scalable and secure overlay technology. Some of the disadvantages of the overlay technologies that are currently being used are complicated configuration and networking topology, difficult in expansion and maintenance, GRE (Generic Routing Encapsulation) tunnel’s inability to traverse NAT, IPsec’s inability to support dynamic routing [1].
Dynamic Multipoint Virtual Private Network (DMVPN) is in general combination of GRE tunnels, IP Security Protocol (IPsec), NHRP (Next Hop Resolution Protocol) along with some advance features to help getting more scalable and robust solutions to the current problems. DMVPN can be used when hub and spoke topology needed, for example in the case of main site and branch sites (Spokes) topology. DMVPN reduces configuration required on the hub and also reduces bandwidth utilization to the great amount, as traffic from spokes can directly go to other spokes by forming dynamic spoke to spoke tunnels and does not have to travel every time through the hub.
This paper is organized as follows. The second part will talk about the building components of DMVPN. The third and fourth part will talk about redundancy provision in DMVPN in the case of fail over and optimum utilization of bandwidth using load balancer respectively. The fifth part will discuss about dynamic routing protoc...

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...rely over unsecure internet. As dynamic spoke to spoke tunnels can be created, traffic does not have to travel every time through the hub, which reduces bandwidth utilization and the amount that CPU has to process. DMVPN can provide highly scalable and hierarchical topology support using phase 3. It is very useful when new branch site comes up, as there is no need to add the configuration on hub routers. Due to high throughput at hub router, DMVPN is ideal for VoIP, because VoIP requires low latency and higher throughput. However, DMVPN is exclusive to the Cisco and cannot be implemented on the non-Cisco routers, further, QOS policies cannot be configured for spoke to spoke tunnels. In spite of having few shortcomings, usefulness of DMVPN suppress its disadvantages, and it is the most cutting-edge tool that should be used to connect remote sites of an organization.

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