Title
On the utility of unregulated IP DiffServ Code Point (DSCP) usage by end systems
Abstract
DiffServ was designed to implement service provider quality of service (QoS) policies, where routers change and react upon the DiffServ Code Point (DSCP) in the IP header. However, nowadays, applications are beginning to directly set the DSCP themselves, in the hope that this will yield a more appropriate service for their respective video, audio and data streams. WebRTC is a prime example of such an application. We present measurements, for both IPv4 and IPv6, of what happens to DSCP values along Internet paths after an end system has set them without any prior agreement between a customer and a service provider. We find that the DSCP is often changed or zeroed along the path, but detrimental effects from using the DSCP are extremely rare; moreover, DSCP values sometimes remain intact (potentially having an effect on traffic) for several AS hops. This positive result motivates an analysis of the potential latency impact from such DSCP usage, for which we present the first measurement results. We find that routers at approximately 3% of more than 100,000 links differentiate between the WebRTC DSCP values (EF, AF42 and CS1) and consistently reduce delay in comparison with probes carrying a zero value (CS0) under congestion. In contrast, routers at around 2% of these links increase the delay by a comparable amount under congestion, uniformly for EF, AF42 and CS1.
Year
DOI
Venue
2019
10.1016/j.peva.2019.102036
Performance Evaluation
Keywords
DocType
Volume
DiffServ,DiffServ Code Point,QoS,WebRTC,Latency
Journal
135
ISSN
Citations 
PageRank 
0166-5316
0
0.34
References 
Authors
0
6
Name
Order
Citations
PageRank
Runa Barik1113.47
Michael Welzl2518.40
Ahmed Elmokashfi327623.88
Thomas Dreibholz434130.73
Safiqul Islam593.42
Stein Gjessing6118299.28