As your organization grows and need to open offices in disparate geographic Locations, the question of how to access IT resources such as your SAP/Dynamics ERP systems and other centralized applications will arise. Currently business may choose to use one of three technologies to meet your connectivity objectives.
1:Businesses may choose to use IPsec based VPNs. These VPNs connect your locations using commodity internet services which will greatly reduce your Wan charges since you will not be required to pay for a dedicated WAN service. IPsec VPNs provide security via symmetric encryption algorithms which are used to protect data traversing the internet.
The primary advantage of IPsec VPNs are cost and security but the down side relates to the internet services over which it is constructed. Typical non dedicated internet services provide asymmetrical bandwidth which usually means that download speeds are much greater than its upload speeds. The nature of these connections means that data access will only be optimal in one direction.Also since these IPsec VPNs utilize the public internet they will be unable to provide quality of service to traffic between sites,lack of QOS means that Voice and Video Traffic might suffer from high delays and latency which will result in skipping and choppines of voice and video sessions between sites.
2: Multi Protocol Label Services or MPLS is a layer three WAN service that provides enterprises with symmetric bandwidth,Security and Quality of services. MPLS is a very scalable Wide area solution based on BGP routing and Label switching of customer traffic.
MPLS services relieves enterprises of the routing and qos configuration necessary when dealing with layer 2 services such as ATM and Frame relay. The only major disadvantages of MPLS is latency when compared to Metro Ethernet and Cost.
3: Metro Ethernet uses Optical networks to transmit customer traffic encapsulated as Ethernet frames. Ethernet scalability is limited by Spanning Tree and a hard limit of on the number of VLANS that can be supported by an Ethernet network. Metro Ethernet scales up to 10 Gigabits per second and provides low latency forwarding of customer traffic.
The main drawbacks of Metro Ethernet is the need for the customer to configure their own routing policies and the potential for network outages due to STP loops should the customer decides to use layer two switches instead of routers to terminate the Metro-E circuits at each location.