Security has several interpretations. A traditional interpretation is the degree of confidentiality, integrity, and authenticity of information. Some experts believe that cryptographic methods are necessary to meet these requirements. There is another interpretation of security that relates to how well a network ensures that only those parties who are configured to exchange certain information can in fact do so. Both ATM and MPLS rely on this security by configuration paradigm. For example, when properly configured, only the source and destination interfaces in a provider network for an ATM virtual connection can receive cells sent by customer devices sent on these interfaces.

Within a service provider network, it may be possible to tap into an information stream, and even to modify it. Here, MPLS and ATM rely on the physical site security of a provider or enterprise to make such actions difficult, if not impossible. Since configuration and physical site security have the potential for human error and compromise, this is why security experts recommend cryptographic protection for sensitive information.

However, often the bulk of an enterprise’s information does not justify the expense of cryptographic equipment and administration, and therefore the configuration and site security are often deemed sufficient.

When used as an infrastructure for support of other services, MPLS and ATM have an additional level of configuration security. This results from the fact that at edge of such a network there is additional configuration of the adaption of the Service to the ATM or MPLS infrastructure. In essence, there are more things that must be configured to compromise security. This is a fundamental driver for the difference of function of a user to network interface versus a network to network one, where the Network to Network interface has both routing and signaling support, where a user to network can have at most the signaling function. By not opening up the routing function, the network is protected from external sources of instability. In a permanent connection service, excluding signaling add further protection as well.

Finally, there is an aspect of security regarding how resilient a network and its management system(s) are to attacks by those who would strive to disrupt or deny service. This begins with configuration security, and restriction of routing, and in some cases signaling, interfaces to only those network elements that are trusted. Read the rest of this entry »