Multiparty interactive network applications such as teleconferencing, network gaming, and online trading are gaining popularity. In addition to end-to-end latency bounds, these applications require that the delay difference among multiple clients of the service is minimized for a good interactive experience. We propose a Latency EQualization (LEQ) service, which equalizes the perceived latency for all clients participating in an interactive network application. To effectively implement the proposed LEQ service, network support is essential. The LEQ architecture uses a few routers in the network as hubs to redirect packets of interactive applications along paths with similar end-to-end delay. We first formulate the hub selection problem, prove its NP-hardness, and provide a greedy algorithm to solve it. Through extensive simulations, we show that our LEQ architecture significantly reduces delay difference under different optimization criteria that allow or do not allow compromising the per-user end-to-end delay. Our LEQ service is incrementally deployable in today’s networks, requiring just software modifications to edge routers.
Improving online interactive application experiences considered application-based solutions either at the client or server side to achieve equalized delay. Client side solutions are hard to implement because they require that all clients exchange latency information to all other clients. They are also vulnerable to cheating. Server-side techniques rely on the server to estimate network delay, which is not sufficiently accurate in some scenarios. This delay estimation places computational and memory overhead on the application servers, which limits the number of clients the server can support . Previous studies have investigated different interactive applications, and they show the need for network support to reduce delay difference since the prime source of the delay difference is from the network. The importance of reducing latency imbalances is further emphasized when scaling to wide geographical areas as witnessed by a press release from AT&T .
The design and implement network-based Latency EQualization (LEQ), which is a service that Internet service providers (ISPs) can provide for various interactive network applications. Compared to application-based latency equalization solutions, ISPs have more detailed knowledge of current network traffic and congestion, and greater access to network resources and routing control. Therefore, ISPs can better support latency equalization routing for a large number of players with varying delays to the application servers. This support can significantly improve game experience, leading to longer play time and thus larger revenue streams. Our network-based LEQ service provides equalized-latency paths between the clients and servers by redirecting interactive application traffic from different clients along paths that minimize their delay difference. We achieve equalized-latency paths by using a few routers in the network as hubs, and interactive application packets from different clients are redirected through these hubs to the servers. Hubs can also be used to steer packets away from congested links.
Our LEQ architecture provides a flexible routing framework that enables the network provider to implement different delay and delay difference optimization policies in order to meet
the requirements of different types of interactive applications.
To achieve LEQ routing, we formulate the hub selection problem, which decides which routers in the network can be used as hubs and the assignment of hubs to different client edge routers to minimize delay difference. We prove that this hub selection problem is NP-hard and inapproximable. Our LEQ routing significantly reduces delay difference in different network settings
- Client Node
- Hub Selection process
- Server Node
- Latency EQualization (LEQ)
- LEQ Hub Routing
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