Abstract
IP networks are the federative transport networks for a large set of emerging services. These services demand hard guarantees in term of the service availability, experienced Quality of Service (QoS) and robustness. Moreover, to be able to reach customers on a large scale, most of these services should be deployed with an Inter-domain scope. In order to meet QoS requirements of these services in an interdomain context, several issues should be solved. This chapter focuses on two issues: provider-to-provider agreements and enhancements to inter-domain routing protocol to convey QoS-related information. A concept called Meta-QoS-Class is introduced together with an enriched version of Border Gateway Protocol. This chapter provides a framework suitable for the promotion of QoS-enabled services with an inter-domain scope: the Parallel Internet. This concept is a viable way for the management of IP resources so as to deliver end-to-end QoS-enabled services.
Top1 Introduction
Background and Focus
Quality of Service (QoS) is one of the topics that succeeded to federate various Internet actors. Indeed, experts from both academia and industry have contributed to promote QoS-centric solutions within standardisation bodies, such as IntServ (Integrated Services) or DiffServ (Differentiated Services) Initiatives within the IETF (Internet Engineering Task Force)(IETF is the main IP standardisation body. This is the place where IP-related issues, protocols and architectures are designed.). Most of that effort has been put into solving intra-domain (i.e. within the IP infrastructure owned and managed by the same IP Network Provider) specific issues. Moreover, some of the QoS proposals have been adopted by Network Providers and even have been activated in their operational networks. Before it is conceivable to have an operational deployment of end-to-end QoS services (i.e. across domains owned by plethora of IP Network Providers), a number of issues still appear to need further elaboration as identified in Huston (2000). In fact, there is a strong lack of inter-domain QoS investigation and few “big picture” solutions have been proposed. This chapter’s ambition is to contribute to this area and advocate for the introduction of solutions dealing with inter-domain QoS delivery services.
For readers who are not familiar with QoS notion, we provide the ITU definition of Quality of Service as defined in E.800. Indeed, QoS is defined as “the collective effect of service performance which determines the degree of satisfaction of a user of the service”.
As stated in Deleuze (1996), concepts should always be created in relation to specific problems. This section focuses exclusively on inter-domain QoS service delivery issues since intra-domain ones have benefited from a large amount of effort in both academia and standardisation bodies. This paper proposes novel means and mechanisms to ease extending intra-domain QoS capabilities beyond the boundaries of a single Network Provider. A concept denoted by Meta-QoS-Class and an extended BGP (Border Gateway Protocol) protocol to be able to convey QoS-related information (see Boucadair (2005)) are introduced. A framework is also described to promote the notion of Parallel Internet (refer to Boucadair (2006)). An implementation example based on joint exploitation of QoS-Enhanced BGP and Meta-QoS-Class is provided.
The emergence of Parallel Internet is essentially driven by the needs of end-to-end applications mainly in terms of QoS and resilience requirements. Owing to the adoption of Meta-QoS-Class concept, a coherent and consistent QoS treatment will be experienced by IP flows when crossing several Autonomous Systems managed by distinct Network Providers. QoS-Enhanced BGP ensures a global reachability within a Meta-QoS-Class routing plane, since several routing tables will be maintained, each per Meta-QoS-Class. Parallel Internet is a step forward to implement end-to-end service differentiation and facilitate the emergence of new business models suitable for the services of the future. Adhering to this approach, telecom players will clarify business roles and frontiers will be abolished between Service Providers.
Within this chapter, we introduce a QoS-Inferred Parallel Internet. Availability and robustness issues are out of scope of this paper.
Structure
This paper is structured as follows. Section 2 analyzes provider-to-provider QoS agreements suitable for a global QoS-enabled Internet and introduces the concept of Meta-QoS-Class. This concept drives and federates the way QoS inter-domain relationships are built between Network Providers. Section 3 is dedicated to QoS-Enhanced BGP proposal, an enriched version of BGP. This section describes attributes to convey QoS-related information in inter-domain routing protocol and presents also novel logics to compare and select QoS-Inferred BGP routes. Finally, Section 4 advocates for the introduction of Parallel Internet so as to offer a global infrastructure for delivering end-to-end QoS services.
Key Terms in this Chapter
QoS-Enhanced BGP (q-BGP): An enhanced BGP that takes into account QoS information it carries in its messages as an input to its route selection process.
Domain: A network infrastructure composed of one or several Autonomous Systems managed by a single administrative entity.
Local-QoS-Class (l-QC): A QoS transfer capability across a single domain, characterized by a set of QoS performance parameters denoted by (D, J, L). From DiffServ perspective, an l-QC is an occurrence of a Per Domain Behavior.
L-QC Thread: Chain of neighboring bound l-QCs.
Service Provider (SP): An entity that provides Internet connectivity. We assume that an SP owns and administers an IP network called a domain. Sometimes simply referred to as provider.
QoS-Related Information: Can be expressed in terms of one-way delay, inter-packet delay variation, loss rate, DSCP marking, or a combination of these parameters;
Extended QC: A QoS transfer capability provided using both the local domain and neighbour domains. An extended QC is provided by combining the local QC of local domain with the ones of adjacent domains. The topological scope of an extended QC extends the boundaries of local domain.
L-QC Binding: Two l-QCs from two neighboring domains are bound together once the two providers have agreed to transfer traffic from one l-QC to the other.
SP Chain: The chain of Service Providers whose domains are used to convey packets for a given IP connectivity service.
Inter-Domain QoS Delivery Solution: Is used to denote an inter-domain system that aims at offering inter-domain QoS services.
“QoS Service”-Related Attributes: Denotes dedicated q-BGP attributes for the usage of a given QoS service;
Meta-QoS-Class (MQC): An MQC provides the limits of the QoS parameter values that two l-QCs must respect in order to be bound together. An MQC is used as a label that certifies the support of a set of applications that bear similar network QoS requirements.
IP Connectivity Service: Transfer capability characterized by a (Destination, D, J, L) tuple where Destination is a group of IP addresses and (D, J, L) is the QoS performance to get to Destination.