Lightweight Protection Against Inflated Subscription in Multicast Congestion Control

Group membership regulation is a useful mechanism for multicast congestion control: RLM, RLC, FLID-DL, and WEBRC form a promising line of multi-group protocols where receivers provide no feedback to the sender but control congestion via group subscription. Unfortunately, the group subscription mechanism also offers receivers an opportunity to elicit self-beneficial bandwidth allocations. In particular, a misbehaving receiver can ignore guidelines for group subscription and choose an unfairly high subscription level in a multi-group multicast session; this poses a serious threat to fairness of bandwidth allocation. In this paper, we present a lightweight solution for the problem of inflated subscription. Our design guards access to multicast groups with dynamic keys and consists of two independent components: DELTA (Distribution of ELigibility To Access) – a novel method for in-band distribution of group keys to receivers that are eligible to access the groups according to the congestion control protocol, and SIGMA (Secure Internet Group Management Architecture) – a generic architecture for key-based group access at edge routers. DELTA and SIGMA are the first to solve the problem of inflated subscription in multi-group protocols for multicast congestion control.