MPLS-Enabled Applications: Emerging Developments and New Technologies

12.7. OPERATIONAL CONSIDERATIONS FOR VPLS

Let us consider some of the operational issues that occur when running VPLS services. Because of the nature of the VPLS service and the way it is more entwined with the customer's network than other VPN services, some of the operational issues discussed below do not have analogies in the L3VPN or L2VPN services. A consideration to bear in mind is that having a VPLS service does not allow the enterprise customer to exceed the best common practices with regard to the scope of a LAN, e.g. in terms of the number of attached hosts. The same scaling issues would occur as with a traditional LAN, where the amount of broadcast traffic becomes excessive if too many hosts are attached.

12.7.1. Number of MAC addresses per customer

A consideration for the service provider is the number of MAC addresses to be stored by each PE, bearing in mind that a PE might be providing a VPLS service to a large number of customers. Although implementations exist in which the number of MAC addresses stored can be large, there is always an upper limit. The service provider may need to protect themselves against an exhaustion of MAC address capacity by limiting the number of MAC addresses that are stored for each VPLS customer. VPLS implementations exist that allow the service provider to limit the number of MAC addresses on a per-VPLS basis or on a per-interface basis. This is by analogy with some L3VPN implementations that allow the service provider to limit the ...