Large-Scale Measurement of Broadband Performance
|Document||Proposed charter||Large-Scale Measurement of Broadband Performance WG (lmap) Snapshot|
|Title||Large-Scale Measurement of Broadband Performance|
|IESG||Responsible AD||Benoît Claise|
|Charter edit AD||(None)|
|Send notices to||(None)|
Measuring portions of the Internet on a large scale is vital for accurate
characterizations of performance over time and geography, for network diagnostic
investigations by providers and their users, and for collecting information to support public policy development. The ultimate goal is to have the same measurements for a
large number of points on the Internet, conducted according to the same
characterization plan, and to have the results collected and stored in the same form.
Many measurement systems that exist today use proprietary, custom-designed
mechanisms to coordinate their Measurement Agents (MAs) deployed across
networks, to communicate between MAs and measurement Controllers, and to transfer results to measurement Collectors. Standardizing these mechanisms (Control protocol, Report protocol, and corresponding data models) will make it possible to incorporate interoperable measurement communications into home and enterprise edge routers, personal computers, mobile devices and other networking devices, whether wired or wireless. Standards will help these management capabilities become more pervasive and facilitate measurement results that are directly comparable.
The Large-Scale Measurement of Broadband Performance (LMAP) working group is
chartered to determine the form of data models and select/extend one or more
protocols for the communications between the Measurement Agents' (MAs) function
and their Controller function and Collector function. These three functions comprise the LMAP measurement system.
The standardized LMAP mechanisms will allow a Controller to instruct MAs what
performance metrics to measure, when to measure them, how/when to report the measurement results to a Collector, and then for the MA to report the results to the
Collector. The primary products of the working group are the data models that define
the measurement instructions and reports, and protocols for securely delivering these
data models to/from the MAs. Data models should be extensible for new and additional measurements.
A key assumption constraining the initial work is that the measurement system is under the control of a single organization (for example, an Internet Service Provider or a regulator). However, the components of an LMAP measurement system can be deployed in administrative domains that are not owned by the measuring organization.
Thus, the system of functions deployed by a single organization constitutes a single LMAP domain which may span ownership or other administrative boundaries.
The LMAP architecture will allow for measurements that utilize either IPv4 or IPv6, or possibly both. Devices containing MAs may have several interfaces using different link technologies. Multiple address families and interfaces must be considered in the Control and Report protocols.
It is assumed that different organization's LMAP measurement domains can overlap, and that active measurement packets appear along with normal user traffic when crossing another organization's network. In the initial chartering phase, there is no requirement to specify a mechanism for coordination between the LMAP measurements in overlapping domains (for instance a home network with MAs on the home hub, set top box and laptop). In principle, there are no restrictions on the type of device in which the MA function resides.
Both active and passive measurements are in scope, although there may be differences in their applicability to specific use cases, or in the security measures needed according to the threats specific to each measurement category. At a high level, LMAP systems are agnostic to the measurements and results, and extensible to incorporate evolution in the measurement area, but the details such as the data models must be standardized to match the measurements.
Inter-organization communication of results is not addressed in the LMAP system and is deferred to bi-lateral agreements.
Many measurement aspects are already within the charter of IPPM. These include standardized definitions of performance metrics, MA-to-MA measurement protocols, and a registry of frequently-used metrics and parameter settings so they can be identified in an efficient and consistent fashion. Neither the definition of the new metrics and methods of measurement, nor the post-processing and analysis of results falls within the remit of LMAP.
The case where an end user can independently perform network diagnostic measurements (beyond their private network) is not directly in scope, recognizing that users have many opportunities to do this today. However, end users can obtain an MA to run measurement tasks if desired and report their results to whomever they want, most likely the supplier of the MA. This provides for user-initiated on-demand measurement, which is an important component of the ISP use case.
Another area that is out of scope is the management protocol to bootstrap the MAs in measurement devices, although a bootstrapping process may be described and conducted in many ways, such as configuration during manufacture or with a local USB interface. Discovering the service parameters on the MAs or sharing the service parameters between MAs are out of the scope of the LMAP charter. However, if the service parameters are available to the MAs, they could be combined with the measurement results in the Report Protocol.
Service parameters, such as product category, can be useful to decide which measurements to run and how to interpret the results. These parameters are already gathered and stored by existing operations systems. Deciding the set of measurements to run is a business decision and is out of scope.
Exhaustive protection against all possibilities of gaming the measurements - where gaming is defined as intentionally (and perhaps maliciously) inserting inaccuracy into the overall system or measurement process - is beyond the scope of work. Some protections are lawyer problems, not engineering problems. However, the working group may include protections that do not add significant complexity, as determined by working group consensus.
The LMAP working group will coordinate with other standards bodies working in this area (e.g., BBF, IEEE 802.16, ETSI) regarding the information model, and other IETF working groups in the areas of data models, protocols, multiple interface management, and measurement of performance metrics.
LMAP will consider re-use of existing protocols and data model languages in its efforts to produce the following work items:
- The LMAP Framework - provides common terminology and justifies the simplifying constraints
- The LMAP Use Cases - provides the motivating use cases as a basis for the work
- Information Model, the abstract definition of the information carried from the Controller to the MA and the information carried from the MA to the Collector. It includes
* the metric(s) that can be measured and values for its parameters such as the Peer MA participating in the measurement and the desired environmental conditions (for example, only conduct the measurement when there is no user traffic observed)
* the schedule: when the measurement should be run and how the results should be reported (when and to which Collector)
* the report: the metric(s) measured and when, the actual result, and supporting metadata such as location. Result reports may be organized in batches or may be reported immediately, such as for an on-demand measurement.
- The Control protocol and the associated data model: The definition of how instructions are delivered from a Controller to a MA; this includes a Data Model consistent with the Information Model plus a transport protocol. This is a simple instruction - response protocol, and LMAP will specify how it operates over an existing protocol (to be selected, perhaps REST-style HTTP(s) or NETCONF).
- The Report protocol and the associated data model: The definition of how the Report is delivered from a MA to a Collector; this includes a Data Model consistent with the Information Model plus a transport protocol (to be selected, perhaps REST-style HTTP(s) or IPFIX).
The WG will decide later whether protocols and data models (for Control, respectively
Report) will be defined in one or separated documents.