Danny Goderis, Alcatel Yves T'joens, Alcatel Christian Jacquenet, France Telecom R&D George Memenios, NTUA George Pavlou, UniS Richard Egan, Racal Research Ltd David Griffin, UCL Panos Georgatsos, AlgoSystems Leonidas Georgiadis, Univ. Thessaloniki Pim Van Heuven, IMEC INTERNET DRAFT November, 2000 Expires March 2001 Service Level Specification Semantics and Parameters. Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This document identifies the basic information to be included in Service Level Specifications (SLS, [RFC 2475], [DS-TERMS]) when considering the deployment of value-added IP service offerings over the Internet. Such IP service offerings can be provided together with a given quality of service (QoS), which is expected to be defined in such SLS, from a technical perspective. Since these IP services are TEQUILA consortium Expires March 2001 [Page 1] Internet Draft draft-tequila-sls-00.txt October, 2000 likely to be provided over the whole Internet, their corresponding QoS will be based upon a set of technical parameters that both customers and services providers will have to agree upon. From this perspective, this draft aims at listing (and promoting a standard formalism for) a set of basic parameters which will actually compose the elementary contents of an SLS. Such a specification effort tries to address the following concerns: - Provide a standard set of information to be negotiated between a customer and a service provider or amongst services providers within the context of processing an SLS; - Provide the corresponding semantics of such information, so that it might be appropriately modeled and processed by the above-mentioned parties (in an automated fashion). Table of Contents 1. Introduction 1.1 Motivation 1.2 Objective 2. Basic assumptions and terminology 3. SLS content & template 3.1. Scope 3.2. Flow Description 3.3. Traffic Envelop and Traffic Conformance 3.4. Excess Treatment 3.5. Performance Guarantees 3.6. Service Schedule 3.7. Reliability 4. Service Level Specification examples 4.1. Virtual Leased Line 4.2. Bandwidth Pipe for data-services 4.3. Real-time micro-flows 4.4. Minimum rate guarantee with allowed excess 4.5. Qualitative Olympic Services 4.6. The funnel services 4.7. Best Effort Traffic 5. SLS negotiation requirements 6. Security considerations 7. Acknowledgements 0. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", TEQUILA consortium Expires March 2001 [Page 2] Internet Draft draft-tequila-sls-00.txt October, 2000 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 ([RFC-2119]). 1. Introduction 1.0 Changes w.r.t. the previous version This is the second version of an Internet Draft of the issue of Service Level Specifications (SLS). The first version 1) - (1,any) - one-to-any communication - (N,1) - many-to-one communication (N>1) - (any,1) - any-to-one communication The above taxonomy excludes the many-to-many communication (M,N). Either ingress OR egress MUST be specified to exactly ONE interface identifier (with a non-exclusive OR). Many-to-many communication (M,N) can be decomposed into M times one-to-many communication (1,N). This taxonomy SHOULD avoid all ambiguity about the IP flow (defined as a set of IP datagrams sharing at least one common characteristic, like e.g. the same [source address; destination address] pair), and its corresponding description. (see section 3.2 and 3.3). If the ingress is a single interface identifier, then the traffic envelop and flow description concerns the incoming IP packet stream at the unique ingress point. If (only) the egress is a single interface, TEQUILA consortium Expires March 2001 [Page 6] Internet Draft draft-tequila-sls-00.txt October, 2000 i.e. (N|any,1), then the traffic envelop and flow description concerns the outgoing (aggregate) traffic on the egress link. More details about the latter can be found in the example 4.5. In the remaining part of this document SLSs with an associated scope (topology) of (1,1) ; (1,N) ; (N,1) will be called respectively Pipe, Hose and Funnel SLSs. Disclaimer: An ingress (or egress) interface identifier should uniquely determine the boundary link as defined in [RFC-2475] on which packets arrive/depart at the border of a DS domain. This link identifier MAY be an IP address, but it may also be any other mutually agreed upon identifier which uniquely identifies a boundary link. Fore example a layer-two identifier in case of e.g. ethernet, or for unnumbered links like in e.g. PPP(Point-to-Point Protocol, [RFC-1661])-based access configurations. The interface identifier(s) may also implicitly be derived from the source or destination address information in the Flow Description field (see next section 3.2) combined with e.g. BGP4 (Border Gateway Protocol, version 4, [RFC- 1771]) routing information. 3.2. Flow Description The flow description of an SLS associated to a given service offering indicates for which IP packets the QoS guarantees for that specific service offering is to be enforced. A flow description identifies a stream of IP datagrams sharing at least one common characteristic. An SLS contains one (and only one) flow description, which MAY formally be specified by providing one or more of the following attributes: flow description = (Differentiated Services information, source information, destination information, application information) - Differentiated Services information = DSCP value | set of DSCP values | any The Differentiated Services Code Point (DSCP) IP header field is defined in [RFC-2474]. - Source information = source address | set of source addresses | source prefix | set of source prefixes | any - Destination information = destination address | set of destination addresses | destination prefix | set of destination TEQUILA consortium Expires March 2001 [Page 7] Internet Draft draft-tequila-sls-00.txt October, 2000 prefixes | any - Application information = protocol number | protocol number and source port, destination port | any Note: "any" is again logically equivalent with unspecified. Thus, the flow description may be expressed by information attributes related to the source/destination nodes, the application or the DS field in the IP header. The flow description provides the necessary information for classifying the packets at a DS boundary node. This datagram classification can either be Behaviour Aggregate (BA) or Multi-Field (MF)classification based. In case of MF-classification all attributes MAY be specified, including the DSCP field. MF classification may depict as well micro-flows as aggregate macro-flows, based on e.g. source network prefix [DS-MODEL]. Also the "set-of" semantics allows for the specification of aggregate flows. If a flow description is e.g. specified by a set of two IP source addresses, then any packet with either of the two concerned source addresses belongs to the IP packet stream identified by this flow description. In case of BA-classification [RFC-2475], the DSCP attribute MUST be specified and the other attributes MUST NOT be specified. If a set of DSCP-values is specified, then any packet having a DSCP belonging to this set is part of the Flow (description) packet stream (analogous to the example above with the IP source addresses). As an example consider an Ordered Aggregate (OA) IP packet stream of a particular Assured Forwarding Class AFx (AF1,AF2,AF3,AF4 - see [RFC 2597]). This stream could be specified within one flow description using three DSCP-values, indicating the three drop precedences levels, respectively colored in green, yellow and red. It should however be noticed that the DSCP-value(s) specified in the SLS has (have) as such nothing to do with the DSCP-marking of packets inside the DiffServ network. The latter, i.e. the "interior" DSCP is used for differentiating packets according to Per Hop Behaviours (PHBs). The former, i.e. the "ingress" DSCP value (specified in the SLS), is just another way of identifying a packet stream, eventually in combination with other IP header fields. At the ingress DiffServ node (incoming) packets are classified based on the "ingress" DSCP value (amongst others), after which they may be re-marked by the "interior" DSCP-value. Finally note also that the IP routing scheme MAY put restrictions on combining scope and flow description within an SLS. TEQUILA consortium Expires March 2001 [Page 8] Internet Draft draft-tequila-sls-00.txt October, 2000 In general, if (only) the flow description is specified by source and destination IP address (IP-src, IP-dest), and the scope is unspecified, then there is no a-priori assumption about the actual ingress/egress points that this traffic will use. Indeed, it is the responsibility of the service provider to define the most appropriate route for this traffic, by enforcing the corresponding traffic engineering and routing policy. Thus, the (ingress, egress) information (which is in this case not in the SLS) is then derived from the flow description and the routing policy of the service provider. On the other hand, if the flow description AND scope are specified in the SLS, respectively by the pairs (IP-src, IP-dest) and (IP-ingr, IP-egr) then it is clear that the IP packets MUST follow the route (IP-src,...,IP-ingr,...,IP-egr,...,IP-dest). Thus the restriction is that the scope (IP-ingr, IP-egr) is part of the route from IP-src to IP-dest. Further routing considerations are outside the scope of this document. Finally remark that the exclusion of the many-to-many communication scope model puts similar constraints on the source/destination fields of the Flow Description. 3.3 Traffic Envelop and Traffic Conformance The traffic envelop describes the traffic (conformance) characteristics of the IP packet stream identified by the flow description. The traffic envelop is a set of Traffic Conformance Parameters, describing how the packet stream should look like to get the guarantees indicated by the performance parameters (defined in section 3.5) The Traffic Conformance Parameters are the basic input for the Traffic Conformance Algorithm. Traffic Conformance Testing as the combination of the Traffic Conformance Parameters and the Traffic Conformance Algorithm. This will usually be done at a DS-boundary node. The algorithm and the conformance test can be binary-based or multi- level based. Binary Traffic Conformance Testing is a set of actions which uniquely identifies the "in-profile" and "out-of profile" (or excess) packets of an IP stream (identified by Flow-Id). In this case the Traffic Conformance Parameters describe the reference values the traffic (identified by the flow description) will have to comply with, thus TEQUILA consortium Expires March 2001 [Page 9] Internet Draft draft-tequila-sls-00.txt October, 2000 yielding the notions of "in" and "out" of profile traffics. The Traffic Conformance Algorithm is the mechanism enabling unambiguously to identify all "in" or "out" of profile packets based on these Conformance parameters. In case of multi-level (n) Traffic Conformance Testing a packet will be tagged (by the algorithm) as belonging to a particular level (1...n). Packets tagged as level n are called "excess" packets. The SLS MUST indicate the concerned level (n) of the conformance testing algorithm: - Multi-level conformance testing n (integer) The following gives a (non-exhaustive) list of potential conformance parameters. - Peak rate p (bits per second) - Token bucket rate r (bits per second) - bucket depth b (bytes) - Maximum Transport Unit (MTU) M (bytes) - Minimum packet size (bytes) Binary-based Traffic Conformance Testing examples: - Conformance parameters = token bucket parameters (b,r); conformance algorithm = token bucket algorithm. - Conformance parameters = token bucket parameters and peak rate (b,r,p) with p larger than r; conformance algorithm = the combined token bucket (b,r) and (b,p). This is the conformance test for Integrated Services Controlled Load and Guaranteed Service IP flows in the IntSer QoS architecture [RFC-2211, RFC-2212]. The scheme permits bursty traffic to be sent, limited to a burst of b bytes, with a (long-term) average rate of r and a peak rate of no more than p. - Conformance parameters = MTU; conformance algorithm = all packets allowed with size smaller than MTU; packets larger than MTU are fragmented or dropped. Three-level based Traffic Conformance Testing example - The Two-rate Three-colour marker [REF] is based on two token TEQUILA consortium Expires March 2001 [Page 10] Internet Draft draft-tequila-sls-00.txt October, 2000 buckets with rates r1 and r2 (larger than r1), containing respectively green and yellow tokens. The simplest operational mode is the "colour-blank" mode. A packet is tagged "green" if there are green and yellow tokens available, yellow if only yellow tokens are available and otherwise it is tagged red. 3.4. Excess Treatment This section describes how the service provider will process excess traffic, i.e. out-of-profile traffic (in case of binary conformance testing) or n-level traffic (in case of n-level conformance testing). The process takes place after Traffic Conformance Testing, described previously. Excess traffic may be dropped, shaped and/or remarked. The SLS MUST specify the appropriate action by the following attribute. - Excess Treatment If Excess Treatment is not indicated, then excess traffic is dropped. Depending on the appropriate action, more parameters MAY be required The following is an indication in case of binary conformance testing. Multi-level conformance testing (like the definition of a hierarchical drop preference model) MAY also be enforced, but this concern has been left for further study. - If excess traffic is dropped, then all packets marked as "out- of-profile" by the Traffic Conformance Algorithm are dropped. No extra parameters are needed. - If excess traffic is shaped, then all packets marked as "out- of-profile" by the Traffic Conformance Algorithm are delayed until they are "in-profile". The shaping rate is the policing/token bucket rate r. The extra parameter is the buffer size of the shaper. - If excess traffic is marked or remarked, then all packets marked as "out-of-profile" by the Traffic Conformance Algorithm are (re-) marked with a particular DSCP-value (yellow or red). The extra parameter is the DSCP. 3.5. Performance Guarantees The performance parameters describe the service guarantees the network offers to the customer for the packet stream described by the flow description and over the geographical/topological extent given TEQUILA consortium Expires March 2001 [Page 11] Internet Draft draft-tequila-sls-00.txt October, 2000 by the scope. There are four performance parameters: - delay, time interval, optional quantile - jitter, time interval, optional quantile - packet loss, time interval - throughput, time interval Delay, jitter and packet loss guarantees are for the in-profile traffic in case of binary conformance testing. For multi-level (n) conformance testing, delay, jitter and loss guarantees MAY be specified for each conformance level-i, except the last one (n). For example if n = 3, one can have a delay guarantee for the "conformance level-1" packets and a different delay guarantee for the "conformance level-2" packets. No guarantees are given for excess ("conformance level-n") traffic. The throughput is an overall guarantee for the IP packet stream, independent of a particular level (see below). The following definitions always consider the (measurable) performance parameters related to the packet stream specified by the flow description. For simplicity the definitions below are given for binary conformance testing (n=2), but generalisation is straightforward. The delay and jitter indicate respectively the maximum packet transfer delay and packet transfer delay variation from ingress to egress, measured over (any) time period with a length equal to the (indicated) time interval. Delay and jitter may either be specified as worst case (deterministic) bounds or as quantiles. Indeed, the worst case delay/jitter bounds will be very rare events and customers may find measurements of e.g. 99.5th percentile a more relevant empirical gauge of delay/jitter. Suppose e.g. that the SLS specifies the triple (delay = 10ms, time interval = 5 minutes, quantile = 10E-3). Then the probability that the transfer delay of a packet (between ingress-egress) is larger than 10ms, is less than 10E-3; and this for any measurement period of 5 minutes. TEQUILA consortium Expires March 2001 [Page 12] Internet Draft draft-tequila-sls-00.txt October, 2000 The above syntax for delay/jitter can be generalised by specifying in the SLS an array of e.g. N (delay/jitter, quantile)-couples. The more couples, the better the delay probability tail distribution can be approximated. Such a specification together with the eventual need of such a generalisation is for further study. The packet loss probability is ratio of the lost (in-profile) packets between ingress and egress and the offered (in-profile) packets at ingress. lost packets between (and including) ingress and egress packet loss = ------------------------------------------------------- offered (injected) packets at ingress The ratio is measured over (any) time period with a length equal to the (indicated) time interval. The throughput is the rate measured at egress counting all packets identified by the flow description. Notice that all packets, independently of their conformance level (in/out-of-profile) contribute. Indeed, if the customer (only) wants a throughput guarantee, then he/she does not care whether in- or out-profile packets are dropped, but is only interested in the overall throughput of its packet stream. Note on the relation with the Traffic Conformance Parameters (section 3.3) in case of a binary-based conformance testing algorithm: - The Traffic Conformance Algorithm (and parameters) MUST be specified when guaranteeing delay/jitter or packet loss, i.e. if one of these performance parameters is quantified in the SLS. Conformance testing is required because the delay/jitter and loss guarantees are only for the stream of in-profile packets. - When only guaranteeing a throughput, or if non of the other performance parameters is quantified, the traffic conformance algorithm MAY be specified. It is not required to specify the Conformance Algorithm, because the (eventual) troughput guarantee does not require the strict distinction between in/out-of-profile traffic. However, the network operator will probably protect his network by implementing a Traffic Conditioner at Ingress and specifying the token policing rate (r) (almost) equal to the throughput guarantee R, r~R. He may or may not tag/mark excess traffic, according to his own - internal - policy rules. See also example 4.2. TEQUILA consortium Expires March 2001 [Page 13] Internet Draft draft-tequila-sls-00.txt October, 2000 Note on the relation between throughput R, packet loss p and excess treatment in case of a binary-based conformance testing algorithm: - First consider the case where excess traffic is dropped (or shaped to in-profile) based on the token bucket (b,r) traffic conformance algorithm. As only in-profile packets are allowed at ingress, the following equality holds: throughput R = (1-p) * token rate r Thus the throughput guarantee can be derived from the loss probability and token rate and is therefore not an independent parameter. - If excess traffic is allowed (and marked accordingly), then "throughput" is an independent parameter because it also takes into account the out-of-profile packets (measured at egress). One has obviously the inequality: throughput R >= (1-p) * token rate r Quantitative performance guarantees A performance parameter is said to be quantified if its value is specified to a numeric (quantitative) value. The service guarantee described by the SLS is said to be quantitative IF at least one of the 4 performance parameters is quantified. Qualitative performance guarantees If non of the SLS performance parameters are quantified, then the performance parameters "delay" and "packet loss" MAY be "qualified". Possible qualitative values (for delay and/or loss): high, medium, low. Relative delay guarantees: - gold service : value = low - silver service : value = medium - bronze service : value = high or not indicated Relative loss guarantees TEQUILA consortium Expires March 2001 [Page 14] Internet Draft draft-tequila-sls-00.txt October, 2000 - green service : value = low - yellow service : value = medium - red service : value = high or not indicated The quantification of relative difference between is a provider policy (e.g. high = 2 x medium ; medium = 2 x low). The above taxonomy yields the following combinations of qualitative services. ------------------------------------------------------- |\ delay | | | | | \------| low | medium |high | | loss | | | | |------------------------------------------------------| | low | gold green | silver green | bronze green | | medium | gold yellow | silver yellow | bronze yellow | | high | gold red | silver red | bronze red | |------------------------------------------------------| Combinations table The service guarantee described by the SLS is said to be qualitative if it is NOT quantitative and either delay or loss (non-exclusive) are qualified to "medium" or "low", i.e. excluding bronze/red from the above. The service guarantee described by the SLS is said to be best-effort if it is NOT quantified nor qualified. 3.6. Service schedule The service schedule indicates the start time and end time of the service, i.e. when is the service available. This might be expressed as collection of the following parameters: - Time of the day range - Day of the week range - Month of the year range Some examples are: - Time of the day range 08h00-18h00 TEQUILA consortium Expires March 2001 [Page 15] Internet Draft draft-tequila-sls-00.txt October, 2000 - Day of the week range A single day A group of sequential days - Month of the year range A single month A group of sequential months - Year range A single year A group of sequential years Remark: service schedule "from now on" [now, infinity] can be captured by putting the above to their full range. 3.7. Reliability Reliability indicates the maximum allowed mean downtime per year (MDT) and the maximum allowed time to repair (TTR) in case of service breakdown (e.g. in case of cable cut). The Mean Down Time might be expressed in minutes per year and the Maximum Time To Repair might be expressed in seconds. 3.8 Others Other parameters such as route, reporting guarantees, security, scheduled maintenance, etc... remain for further study. 4. Service Level Specification examples. Within this section a number of example instantiations of SLSs are presented to illustrate the potential use of the SLS template defined above. 4.1. Virtual Leased Line The following specifies the SLS for a (uni-directional) VLL with quantified throughput guarantee of e.g 1 Mbps, a delay guarantee of 20 ms for a 10E-3 quantile and zero packet loss. - Scope: one-to-one communication (Ingress, Egress) specified - Flow description: (source,destination) IP-addresses, DSCP=EF. TEQUILA consortium Expires March 2001 [Page 16] Internet Draft draft-tequila-sls-00.txt October, 2000 - Traffic Conditioning: token bucket (b,r), r = 1 Mbps - Excess Treatment = dropping. Thus only in-profile packets are allowed. - Delay guarantee = (d = 20 ms, t = 5 minutes, q = 10E-3) - Loss guarantee p = 0 (imlying a throughput guarantee R = r) - Service Schedule: may be indicated - Reliability: may be indicated Notice that in this example, the throughput guarantee is a derived parameter from the packet loss p=0, the conditioning token bucket parameter r=1 Mbps and the excess treatment=dropping. 4.2 Bandwidth Pipe for data-services The following SLS specifies a bandwidth pipe with a strict throughput guarantee, but with only a loose requirements for packet loss, i.e. "low". Thus, the SLS only mentiones the scope (pipe), the flow description and a throughput guarantee. Remark that there are now traffic conformance parameters (and consequently no excess treatment indication). - Scope: one-to-one communication (Ingress, Egress) specified - Flow description: (source,destination) IP-addresses - Throughput guarantee R = 1 Mbps - Service Schedule: may be indicated - Reliability: may be indicated Although there is no (explicit) traffic conditioning agreement between the customer and the network operator (i.e. not mentioned in the SLS), the operator is likely to protect his network by implementing a traffic conditioner token bucket (b,r). If the operator can guarantee a zero packet loss for the bandwidth pipe, then the token rate equals the throughput guarantee. However, the SLS can also be met by the operator without such a stringent loss requirement, say p = 10E-5. In this case the token rate is derived from the throughput guarantee and the loss probability: token rate r = R / (1-p) TEQUILA consortium Expires March 2001 [Page 17] Internet Draft draft-tequila-sls-00.txt October, 2000 The in-profile packet stream (according to the conditioner (b,r)) has a throughput guarantee of R = r * (1-p) = 1 Mbps. Further, it is up to the operator's policy whether or not excess traffic (again according to the operator's conditioner (b,r), which is not mentioned in the SLS agreement) is allowed or not in his network. 4.3. Real-time micro-flows - Scope: one-to-one communication (Ingress, Egress) specified - Flow description: (source IP-address, destination IP-address, source port number, destination port number, protocol) - Traffic Conditioning: token bucket (b,r), peak rate p= r = 64 Kbps - Excess Treatment = dropping. - Performance Parameters: delay = 10 msec, packet loss = 10E-6, guaranteed throughput R ~ r. 4.4 Minimum rate guarantee with allowed excess The following could be for bulk FTP traffic that requires a minimum throughput, but would take everything it can get (TCP). Also adaptive applications, like video streaming, that however require a minimum throughput for the service. - Scope: one-to-one (Pipe) - Flow description: e.g. DSCP-value indicating a possible AF-PHB. - Traffic Conformance Parameters: (b,r) MUST be indicated - Excess Treatment: Remarking MUST be indicated (excess is given a higher drop precedence) - Performance guarantees: guaranteed throughput R = r. 4.5. Qualitative Olympic services The following SLS is meant for the Olympic Service. It could be used for differentiating applications such as web-browsing and e-mail traffic. SLS 1 (on-line web-browsing) - Scope: one-to-one (pipe) or one-to- TEQUILA consortium Expires March 2001 [Page 18] Internet Draft draft-tequila-sls-00.txt October, 2000 many (hose) - Flow description: MAY be indicated - Traffic Conformance Parameters: token parameters (b,r) The token bucket rate r indicates an (average) maximum Committed Information Rate (CIR) for which "better-than-best-effort" treatment will be applied. - Excess Treatment: remarking. - Performance Parameter: Delay and Packet loss are indicated as "low": gold/green class SLS2 : (background e-mail traffic) This is identical to SLS1 but targeting the silver/green class. 4.6. The Funnel service The service offered by the funnel model is primarily a protection service: the customer wants to set a maximum on the amount of traffic (characterized by a DSCP) entering his network. It could e.g. be used for business customers to restrict the amount of web browsing traffic entering their network. /---------------\ |Network _____|______ B | _____/ | A__________|___.___________|______ C /_____ | _____ | \a(out) | \_____|_______D \---------------/ Figure 4: Funnel model In [Figure 4], customer A requires that specific traffic entering his network from B,C and D does not exceed the rate a_out. - Scope: Funnel (N|all,1). - Flow description: DSCP MUST be indicated. The filter (see below) is applied to all traffic characterized by the DSCP -value. - Traffic Conformance Parameters: (b, r) MUST be indicated. The token bucket parameters indicate the maximum allowed throughput (r = a_out) towards the customer network on the specified egress interface. This maximum or filter is applied to all packets marked with the DSCP- TEQUILA consortium Expires March 2001 [Page 19] Internet Draft draft-tequila-sls-00.txt October, 2000 value indicated above. - Excess treatment: dropping (this is actually the service offered by the network). - Performance Parameter: not specified. 4.7. Best effort traffic - Scope : all models - Flow description : none - Traffic Conformance Parameters: if not indicated, then the full link capacity is allowed - Excess Treatment: not specified - Performance Parameters: none - Service Schedule: may be indicated. - Reliability: may be indicated. 5. SLS negotiation requirements [This section is informational and preliminary. More detailed study is required.] A major goal of the availability of an SLS template is helping in the deployment of dynamical SLS negotiation procedures between customer and providers or between providers. This draft only discussed the SLS template and its basic contents. The SLS negotiation protocol is for further study. The following lists a number of conditions which should be met by a (to be defined) SLS negotiation protocol. The SLS negotiation protocol MUST allow for: - Original service requests, according the components of the specified SLS. - Service acknowledgement (ACK), indicating agreement with the requested service level. - Service rejection (NAK) but indicating the possibility of offering a closely related service (or indication of alternative DSCP to use for a particular service). The reply message may indicate the related TEQUILA consortium Expires March 2001 [Page 20] Internet Draft draft-tequila-sls-00.txt October, 2000 offering by overwriting the proposed SLS attributes (hints). - Service rejection (REJECT) indicating incapability of providing the service. - The ACK/NACK procedures require a reliable transport mode for such a negotiation protocol. - Service modification from both user and provider. The following are further requirements for the overall network architecture which SHOULD be fulfilled. - The protocol should be able to interact with feedback of events related to the service. For example performance degradation MAY result in re-negotiation of the SLS. - The protocol should preferentially make use of / be an extension of existing specifications protocol design work available such as RSVP ([RFC-2205]) or PPP/IPCP ([RFC-1661]). 6. Security considerations The information which will yield the instantiation of an SLS template to address the specific requirements of a customer in terms of the quality associated to the service it has subscribed to may require the activation of security features so that: - Identification and authentication of the requesting entity needs to be performed; - Identification and authentication of the peering entities which will participate in the SLS negotiation process needs to be performed; - Preservation of the confidentiality of the information to be conveyed during the SLS negotiation and instantiation procedures between the peering entities is a MUST. 7. Acknowledgements Part of this work has been funded under the European Commission 5th framework IST program. The authors would like to acknowledge all their colleagues in the TEQUILA project for their input and reflection on this work. TEQUILA consortium Expires March 2001 [Page 21] Internet Draft draft-tequila-sls-00.txt October, 2000 The authors also would like to acknowledge Werner Almesberger, Marcus Brunner, Stefaan De Cnodder, Stefano Salsano, Alberto Kamienski and Abdul Malick for their useful comments and suggestions on the mailing list sls@ist-tequila.org and during private conversation. References [TEQUILA] IST-Tequila project http://www.ist-tequila.org/ [RFC 1661] "The Point-to-Point Protocol (PPP)", W. Simpson, http://www.ietf.org/rfc/rfc1661.txt?number=1661 [RFC-1771] A Border Gateway Protocol 4 (BGP-4). Y. Rekhter, T. Li. March 1995. http://www.ietf.org/rfc/rfc2205.txt?number=1771 [RFC 2205] "Resource ReSerVation Protocol (RSVP)- Version 1 Functional Specification", R. Braden et al. http://www.ietf.org/rfc/rfc2205.txt?number=2205 [RFC-2211] J. Wroclawski, "Specification of the Controlled-Load Network Element Service", RFC 2211, September 1997. [RFC-2212] S. Shenker, C. Partridge, R. Guerin, "Specification of Guaranteed Quality of Service", RFC 2212, September 1997. [RFC 2474] "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", K.Nichols, S. Blake, F. Baker, D. Black, www.ietf.org/rfc/rfc2474.txt [RFC 2475] "An Architecture for Differentiated Services", S. Blake, D. Black, M.Carlson,E.Davies,Z.Wang,W.Weiss, www.ietf.org/rfc/rfc2475.txt [RFC 2597] "Assured Forwarding PHB Group", F. Baker, J. Heinanen, W. Weiss, J. Wroclawski, www.ietf.org/rfc/rfc2597.txt [RFC 2598] "An Expedited Forwarding PHB", V.Jacobson, K.Nichols, K.Poduri, www.ietf.org/rfc/rfc2598.txt [RFC 2698] "A Two Rate Three Color Marker." J. Heinanen, R. Guerin. September 1999. www.ietf.org/rfc/rfc2698.txt [DS-MODEL] "A Conceptual Model for Diffserv Routers", Y. Bernet et al., draft-ietf-diffserv-model-03.txt, Work in Progress, May 2000 [DS-TERMS] "New terminology for diffserv", D. Grossman, draft-ietf- diffserv-new-terms-02.txt, work in progress TEQUILA consortium Expires March 2001 [Page 22] Internet Draft draft-tequila-sls-00.txt October, 2000 [QBONE] "Qbone Architecture (v1.0), Ben Teitelbaum (1999), http://www.internet2.edu/qos/wg/papers/qbArch/ [TWOBIT] "A Two-bit Differentiated Services Architecture for the Internet", ftp://ftp.ee.lbl.gov/parpers/dsarch.pdf, 1997 Full copyright statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Authors Addresses Danny Goderis Alcatel Corporate Research Center Fr. Wellesplein 1, 2018 Antwerpen, Belgium. Tel : +32 3 240 7853 Fax : +32 3 240 9932 E-mail: Danny.Goderis@Alcatel.be TEQUILA consortium Expires March 2001 [Page 23] Internet Draft draft-tequila-sls-00.txt October, 2000 Yves T'Joens Alcatel Corporate Research Center Fr. Wellesplein 1, 2018 Antwerpen, Belgium. Tel : +32 3 240 7890 Fax : +32 3 240 9932 E-mail: Yves.TJoens@Alcatel.be Christian Jacquenet France Telecom Research and Development (FT R&D) Rue des Coutures 42, BP6243, 14066 CAEN CEDEX 04 France Tel : +33 2 31 75 94 28 Fax : +33 2 31 73 56 26 E-mail: christian.jacquenet@francetelecom.fr George Memenios Research Associate, Telecommunications Laboratory NTUA Heroon Polytechniou 9, 157 73 Zografou, Athens, Greece Tel : +30 1 772 1494 Fax : +30 1 772 2534 E-mail: gmemen@telecom.ntua.gr George Pavlou Centre for Communication Systems Research (CCSR) Univ. of Surrey, Guildford, Surrey GU2 7XH, UK Tel : +44 (0)1483 259480 Fax : +44 (0)1483 876011 E-mail: G.Pavlou@eim.surrey.ac.uk Richard Egan Racal Research Ltd Worton Drive, Worton Grange Industrial Estate Reading, Berkshire RG2 OSB, UK Tel : +44 118 986 8601 Fax : +44 118 923 8399 E-mail: richard.egan@rrl.co.uk David Griffin Department of Electronic and Electrical Engineering University College London, Torrington Place, London WC1E 7JE, UK Tel : +44 (0)20 7679 3557 Fax : +44 (0)20 7388 9325 E-mail: D.Griffin@ee.ucl.ac.uk TEQUILA consortium Expires March 2001 [Page 24] Internet Draft draft-tequila-sls-00.txt October, 2000 Panos Georgatsos Algosystems S.A. Sardeon str. 4, 172 34 Athens, Greece Tel : +30 1 93 10 281 Fax : +30 1 93 52 873 E-mail: pgeorgat@algo.com.gr Leonidas Georgiadis Aristotel Univ. of Thessaloniki, Faculty of Engineering School of Electrical and Computer Engineering, Telecommunications Dept. PO Box 435, Thessaloniki, 54006, Greece Tel : +30 31 996385 Fax : +30 31 996312 E-mail: leonid@eng.auth.gr Pim Van Heuven Inter-University Micro-Electronics Centre Tel : +32 9 267 3592 E-mail: pvheuven@intec.rug.ac.be TEQUILA consortium Expires March 2001 [Page 25]