Internet DRAFT - draft-bagnulo-lmap-http
draft-bagnulo-lmap-http
Network Working Group M. Bagnulo
Internet-Draft UC3M
Intended status: Standards Track T. Burbridge
Expires: March 14, 2015 BT
S. Crawford
SamKnows
J. Schoenwaelder
V. Bajpai
Jacobs University Bremen
September 10, 2014
Large MeAsurement Platform Protocol
draft-bagnulo-lmap-http-03
Abstract
This documents specifies the LMAP protocol based on HTTP for the
Control and Report in Large Scale Measurement Platforms.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Naming Considerations . . . . . . . . . . . . . . . . . . . . 4
4. Information model . . . . . . . . . . . . . . . . . . . . . . 6
5. Transport protocol . . . . . . . . . . . . . . . . . . . . . 7
5.1. Pre-configured information . . . . . . . . . . . . . . . 7
5.2. Control Protocol . . . . . . . . . . . . . . . . . . . . 7
5.2.1. Retrieving Instructions . . . . . . . . . . . . . . . 8
5.2.2. Handling communication failures . . . . . . . . . . . 10
5.2.3. Pushing Information from the Controller to the MA . . 10
5.3. Report protocol . . . . . . . . . . . . . . . . . . . . . 11
5.3.1. Handling communication failures . . . . . . . . . . . 12
6. LMAP Data Model . . . . . . . . . . . . . . . . . . . . . . . 13
6.1. Timing Information . . . . . . . . . . . . . . . . . . . 13
6.2. Channels . . . . . . . . . . . . . . . . . . . . . . . . 15
6.3. Configuration . . . . . . . . . . . . . . . . . . . . . . 15
6.4. Instruction . . . . . . . . . . . . . . . . . . . . . . . 16
6.5. Measurement Supression . . . . . . . . . . . . . . . . . 16
6.6. Measurement Task Configurations . . . . . . . . . . . . . 16
6.7. Measurement Schedules . . . . . . . . . . . . . . . . . . 17
6.8. Logging . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.9. Capability and Status . . . . . . . . . . . . . . . . . . 18
6.10. Reporting . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Security considerations . . . . . . . . . . . . . . . . . . . 22
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
10.1. Normative References . . . . . . . . . . . . . . . . . . 24
10.2. Informative References . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
A Large MeAsurement Platform (LMAP) is an infrastructure deployed in
the Internet that enables performing measurements from a very large
number of vantage points.
The main components of a LMAP are the following:
o The Measurement Agents (MAs): these are the processes that perform
the measurements. The measurements can be both active or passive
measurements.
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o The Controller: this is the element that controls the MAs. In
particular it provides configuration information and it instructs
the MA to perform a set of measurements.
o The Collector: this is the repository where the MAs send the
results of the measurements that they have performed.
These and other terms used in this document are defined in
[I-D.ietf-lmap-framework]. We only include the definition of the
main elements in this document so it is self-contained and can be
read without the need to consult other documents. The reader is
referred to the terminology draft for further details.
In order for a LMAP to work, the following protocols are required:
o Measurement protocols: These are the protocols used between the MA
and the Measurement Peer in active measurements. These are the
actual packets being used for the measurement operations.
o Control Protocol. This is the protocol between the Controller and
the MAs. This protocol is used to convey measurement
Instruction(s) from the Controller to the MA as well as logging,
failure and capabilities information from the MA to the
Controller.
o Report Protocol. This is the protocol between the MAs and the
Collector. This protocol conveys information about the results of
the measurements performed by the MA to the Collector.
Both the Control protocol and the Report protocol have essentially
two parts:a transport and a data model. The data model represents
the information about measurement instructions and logging/failure/
capabilities (in the Control protocol) and the information about
measurement results (in the Report protocol) that is being exchanged
between the parties. The transport is the underlying protocol used
to exchange that information. This document specifies the use of
HTTP 1.1 [RFC7230] [RFC7231] [RFC7232] [RFC7233] [RFC7234] [RFC7235]
as a transport for the Control and the Report protocol. This
document also defines the data model for the Control and Report
protocols. The data model described in this document follows the
information model described in [I-D.ietf-lmap-information-model].
The Measurement protocols are out of the scope for this document.
At this stage, the goal of this document is to explore different
options that can be envisioned to use the HTTP protocol to exchange
LMAP information and to foster discussion about which one to use (if
any). Because of that, the document contains several discussion
paragraphs that explore different alternative approaches to perform
the same function.
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2. Overview
This section provides an overview of the architecture envisioned for
a LMAP using HTTP as transport protocol. As we described in the
previous section, a LMAP is formed by a large number of MAs, one or
more Controllers and one or more Collectors. We assume that before
the MAs are deployed, it is possible to pre-configure some
information in them. Typically this includes information about the
MA itself (like its identifier), security information (like some
certificates) and information about the Controller(s) available in
the measurement platform. Once that the MA is deployed it will
retrieve additional configuration information from the pre configured
Controller. After obtaining the configuration information, the MA is
ready to receive Instructions from the Controller and initiate
measurement tasks. The MA will perform the following operations:
o It will obtain Instructions from one of the configured
Controllers. These Instructions include information about the set
of measurement tasks to be performed, a schedule for the execution
of the measurements as well as a set of report channels. This
information is downloaded by the MA from the Controller. The MA
will periodically check whether there are new Instructions
available from the Controller. This document specifies how the MA
uses the HTTP protocol to retrieve information from the
Controller.
o The MA will execute measurement tasks either by passively
listening to traffic or by actively sending and receiving
measurement packets. How this is done is out of the scope of this
document.
o After one or more measurements have been performed, the MA reports
the results to the Collector. The timing of these uploads is
specified in the measurement Instruction i.e. each measurement
specified in a measurement Instruction contains a report
information, defining when the MA should report the results back
to the Collector. This document specifies how the MA uses the
HTTP protocol to upload the measurement results to the Collector.
o In addition, the MA will periodically report back to the
Controller information about its capabilities (like the number of
interfaces it has, the corresponding IP addresses, the set of
measurement methods it supports, etc) and also logging information
(whether some of the requested measurement tasks failed and
related information).
3. Naming Considerations
In this section we define how the different elements of the LMAP
architecture are identified and named.
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The Controller and the Collectors can be assumed to have both an IP
address and a Fully Qualified Domain Name (FQDN). It is natural to
use these as identifiers for these elements. In this document we
will use FQDNs, but IP addresses can be used as well.
The MAs on the other hand, are likely to be executed in devices
located in the end user premises and are likely to be located behind
a NAT box. It is reasonable to assume they have neither a public IP
address nor a FQDN. We propose then that the MAs are identified
using an Universally Unique IDentifier URN as defined in RFC 4122
[RFC4122]. In particular each MA has a version 4 UUID, which is
randomly or pseudo randomly generated.
DISCUSSION:
MA ID Configuration: Some open issues related to this are: a)
whether the MA ID is configured before of after the MA is
deployed, b) if configured after deployment whether the MA ID is
generated locally and posted or fetched from the Controller and c)
whether this is within the scope of this (or other) specification
if any. These issues seem also to be related to the nature of the
MA platform (wether the MA is a software downloaded into a general
purpose device or it is a special purpose hardware box). Consider
the case that the MA is located in a special purpose hardware box,
then having the MA ID pre configure before deployment requires a
per device customization that is expensive. It would be more
costly efficient to reuse an existent (hopefully) unique
identifier available in the hardware (such as a MAC address) to
serve as a one-time pre configured identifier to be used to fetch
(or post a self generated) the MA ID from the Controller once the
MA is deployed. The requirement for such one-time identifier is
that they must be unique (which is not always true for the MACs).
About the local generation of the MA ID (as opposed to fetch it
from the Controller), the generation process performed in the MA
MUST be idempotent, i.e. if the MA was factory-reset then the
server would still see it with the same MA ID when it came back
up. This is probably easier to achieve if it is generated in the
Controller and then fetched by the MA. Finally, it is not clear
at this stage if this needs to be specified in this document or in
the information model document or left open to the implementers.
Group identifiers. In some cases, like the case of measurements
in mobile devices, it may be important because of privacy
considerations for the MA not to have a unique identifier. It is
possible then to assign "Group identifiers" to a set of devices
that share relevant characteristics from the measurement
perspective (e.g. devices from the same operator, with the same
type of contract or other relevant feature). In this case, the
MAs within the same group would retrieve common measurement
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Instructions from the controller by presenting the same Group ID
and would report results including the Group ID in the report.
This would imply that it would not be possible for the platform to
correlate specific measurement data with any given MA. The
downside of this is that some MAs may be over-represented while
other under-represented in the measurement data and it would not
be possible to detect this case (for instance a given MA may have
reported 20 results while another one only one). In order to deal
with this issue, the MA behaviour must be programmed accordingly
(e.g. the MA should not perform more than one measurement every
given period of time).In addition, it should be noted that privacy
is only achieved in a holistic way. This means that really
anonymity of the MA is incompatible with strong authentication.
In particular, if a measurement platform's goal is to keep MAs
anonymous, it cannot require any form of strong authentication
(other than weak group authentication e.g. a password shared by a
group), which has security implications. In particular, the
threat for report forgery (i.e. enabling an attacker to submit
forged reports as discussed in the security considerations)
increases.
There are additional naming considerations related to:
o The measurements. In order to enable a Controller to properly
convey a measurement schedule, it must be possible for the
Controller to specify a measurement to be performed while
providing the needed input parameters. While this is critical, it
is out of the scope of this document. There is a proposed
registry for metrics/measurements in
[I-D.bagnulo-ippm-new-registry-independent])
o The resources being exchanged, namely, the configuration
information, the measurement Instructions and the reports. These
are being discussed in the upcoming sections.
4. Information model
The information model for LMAP is described
[I-D.ietf-lmap-information-model]. It contains basically two models
one for the control information (i.e. the Instructions from the
Controller to the MA) and a model for the Report information. We
briefly describe their overall structure here.
The control information (or Instruction) has the following five
elements:
o The Set of Measurement Task Configurations: This element defines
the measurements/test that the MA will perform without defining
the schedule when they will be performed.
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o The Set of Report Channels: This element defines the set of
collectors as well as the reporting schedules for the reports.
o The Set of Measurement Schedules for Repeated Tasks: defines the
schedules for the repeated measurements, by referencing the
measurement tasks defined in the second element.
o Suppression information
Summary of Report information model here.
Summary of Capability and Status information model here.
Summary of Logging information model here.
5. Transport protocol
5.1. Pre-configured information
As we mentioned earlier, the MAs contain pre-configured information
before being deployed. The pre-configured information is the
following:
o The UUID for the MA. This should be pre-configured so that the
Controller is aware of the MA and can feed configuration
information and measurement Instructions to it.
o Information about one or more Controllers. The MA MUST have
enough information to create the URL for the Instruction
resources. This includes the the FQDN of each of the Controller
or the IP addresses of the Controller, as well as the well-known
path prefix and its identifier.
o The certificate for the Certification authority that is used in
the platform to generate the certificates for the Controller and
the Collector. See the Security considerations section below.
o The security related information for the MA (it can be a
certificate for the MA and the corresponding private key, or
simply a key/password depending on the security method used, see
the security considerations section below).
5.2. Control Protocol
The Control protocol is used by the MA to retrieve Instruction
information from the Controller. In this section we describe how to
use HTTP to transport Instructions. The Instruction information is
structured as defined in the LMAP Information model
[I-D.ietf-lmap-information-model] as described in the previous
section. The MA uses the Control protocol to retrieve all the
resources described above, namely, the Agent information, the Set of
Measurement Task Configurations, the Set of Report Channels, the Set
of Measurement Schedules for Repeated Tasks and the Set of
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Measurement Schedules for Isolated Tasks. The main difference from
the HTTP perspective is that the MA MUST have the URL for the Agent
Information resource pre-configured as described in the previous
section, while the URLs for all the other resources are contained in
the Agent Information resource itself.
5.2.1. Retrieving Instructions
In order to retrieve the Instruction resources from the Controller
the MA can use either the GET or the POST method using the
corresponding URL.
5.2.1.1. Using the GET method
One way of using the GET method to retrieve configuration information
is to explicitly name the configuration information resources and
then apply the GET method. The MA retrieves its Instruction when it
is first connected to the network and periodically after that. The
frequency for the periodical retrieval is contained in the Agent
Information (???).
The URL for the Agent Information resource is formed as the FQDN of
the Controller, a well-known path prefix and the MA UUID. The well-
known path prefix is /.well-known/lmap/ma-info. The URL for the
remaining resources that compose the Instruction are contained in the
Agent Information.
Agent Information retrieval: In order to retrieve the Agent
information the MA uses the HTTP GET method follows:
GET /.well-known/lmap/ma-info/ < ma-iid> HTTP/1.1
Host: FQDN or IP of the Controller
Accept: application/json (as per [RFC7159])
The Agent Information should contain the Configuration Retrieval
Schedule (i.e. how often the MA should retrieve configuration
information) and also the Measurement Instruction Retrieval Schedule
(i.e. how often the MA should retrieve the Measurement Instruction
from the Controller). COMMENT: this is missing from the Data Model
The retrieval of the remaining resources of the Instruction using the
GET method is analogous, only that the URL is extracted from the
Agent Information file rather than constructed with pre-configured
information.
The format for the response should be described here
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Periodical Instruction retrieval: After having downloaded the initial
Instruction information, the MA will periodically look for updated
Instruction information. The frequency with which the MA polls for
the new Instructions from the Controller is contained in the last
Agent Information downloaded. In order to retrieve the Agent
Information, the MA uses the GET method as follows:
GET /.well-known/lmap/ma-info/ma-iid/ HTTP/1.1
Host: FQDN or IP of the Controller
Accept: application/json (as per [RFC7159])
If-None-Match: the eTag of the last retrieved Agent Information
(an alternative option here is to use If-Modified-Since, not sure
which one is best)
For the other Instruction resources, the GET method is applied in the
same way just that the URL used are the ones retrieved in the last
Agent Information.
The format for the response should be described here
Alternatively, instead of explicitly naming the Instruction resources
for each MA, it is possible to perform a query using the GET method
as well. In this case, the MA could perform a GET for the following
URI http://controller.example.org/?ma=maid & q=ma-info (similar
queries can be constructed for the other Instruction resources). (I
am not sure how to express in this case the condition that the MA
wishes to retrieve the configuration if it is newer than the last one
it downloaded.)
5.2.1.2. Using the POST method
An alternative to retrieve Instruction resources is to use the POST
method to perform a query (similar to the query using GET). In this
case there is no explicit naming of the Instruction information of
each MA, but a general Instruction resource and the POST method is
used to convey a query for the Instruction information of a
particular MA. For the case of the Agent Information resource, this
would look like as follows:
POST /.well-known/lmap/ma-info/ma-iid/ HTTP/1.1
Host: controller.example.com
Content-Type: application/lmap-maid+json
Accept: application/lmap-config+json
{
"ma-id" : "550e8400-e29b-11d4-a716-446655440000",
}
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The reply for this query would contain the actual configuration
information as follows:
HTTP/1.1 200 OK
Content-Length: xxx
Content-Type: application/lmap-config+json
{
// whatever config goes here
}
In this case, the URLs contained in the Agent information can be
generic and not MA specific, since the MA will use the POST method
including its own identifier when retrieving the Instruction
resources.
The argument for this approach is that this is much more extensible
since the POST can carry complex information and there is no need to
"press" arguments into the strict hierarchy of URIs.
We need to describe how to use this to retrieve newer information in
the periodic case.
5.2.2. Handling communication failures
The cases that the MA is unable to retrieve the Instructions are
handled as follows:
o The MA will use a timeout for the communication of TIMEOUT
seconds. The value of TIMEOUT MUST be configurable via the
aforementioned Configuration Information retrieval protocol. The
default value for the TIMEOUT is 3 seconds. If after the timeout,
the communication with the Controller has not been established,
the MA will retry doing an exponential backoff and doing a round
robin between the different Controllers it has available.
o If a HTTP error message (5xx) is received from the Controller as a
response to the GET request, the MA will retry doing an
exponential back-off and doing a round robin between the different
Controllers it has available. The 5xx error codes indicate that
this Controller is currently incapable of performing the requested
operation.
5.2.3. Pushing Information from the Controller to the MA
The previous sections described how the MA periodically polls the
Controller to retrieve Instruction information. The frequency of the
downloads is configurable. The question is whether this is enough or
a mechanism for pushing Instruction information is needed. Such
method would enable to contact the MA in any moment and take actions
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like triggering a measurement right away or for instance to stop an
ongoing measurement (e.g. because it is disturbing the network).
The need for such a mechanism is likely to depend on the use case of
the platform. Probably the ISP use case is more likely to require
this feature than the regulator/benchmarking use case. It is
probably useful then to provide this as an optional feature.
The main challenge in order to provide this feature is that the MAs
are likely to be placed behind NATs, so it is not possible for the
Controller to initiate a communication with the MA unless there is a
binding in the NAT to forward the packets to the MA. There are
several options that can be considered to enable this communication:
o The MA can use one of the NAT control protocols, such as PCP or
UPNP. If this approach is used, the MA will create a binding in
the NAT opening a hole. After that, the MA should inform the
Controller about which is the IP address and port available for
communication. It would be possible to re-use existing protocols
to forward this information. The problem with this is that the
NAT may not support these protocols or they may not be activated.
In any case, a solution should try to use them in the case they
are available.
o If it is not possible to use a NAT control protocol, then the MA
can open a hole in the NAT by establishing a connection to the
Controller and keeping it open. This allows the Controller to
push information to the MA through that connection. One concern
with this approach is that the MA is playing the role of the
client and the Controller is playing the role of the server (the
MA is initiating the TCP connection), but it would be the
Controller who would use the PUT method towards the MA reversing
the roles. An alternative approach is that the MA has a long
running GET pending which is answered by the server if the
measurement Instruction changes (or the server times out, in which
case the MA restarts the long running GET. More discussion is
needed about whether one of these options is acceptable or not.
In addition, this would imply that the Controller should maintain
as many open sessions as MAs it is managing, which imposes
additional burden in the Controller. There are security
considerations as well, but these are covered in the Security
Considerations section below.
5.3. Report protocol
The MA after performing the measurements reports the results to a
collector. There can be more than one collector within a LMAP
framework. Each collector is identified by its FQDN or IP address
which is retrieved as part of the Agent information from a pre-
configured controller as previously discussed. The number of
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Collectors that the MA uploads the results to as well as the schedule
when it does so is defined in the measurement Instruction previously
downloaded from the Controller. The MA themselves are identified by
a UUID.
There are two options that can be considered for the MA to upload
reports to the Collector either to use the PUT method or to use the
POST method.
If the PUT method option is used, then the MA need to perform the PUT
method using an explicit name for the report resource it is
transferring to the Collector. The name of the resource is contained
in the Agent Information previously retrieved by the MA
The other option is for the MA to use the POST method to upload the
measurement reports to one or more Collectors. In this case,, the
POST message body can contain the identifier of the MA and additional
information describing the report in addition to the report itself.
One argument to consider is that PUT is idempotent. This means that
if the network is bad at some point and the MA is not sure whether
its request made it through, it can send it a second (or nth) time,
and it is guaranteed that the request will have exactly the same
effect as sending it for the first time. POST does not by itself
guarantee this. This can be achieved by verifying the report data
itself, and contrast it with data already stored int he Collector
database.
5.3.1. Handling communication failures
The MA will use a timeout for the communication with the Collector of
TIMEOUT seconds. The value of TIMEOUT MUST be configurable via the
aforementioned Configuration Information retrieval protocol. The
default value for the TIMEOUT is 3 seconds.
If the MA is uploading the report to several Collectors and it
manages to establish the communication before TIMEOUT seconds with at
least one of them, but not with one or more of the other Collectors,
then the MA gives up after TIMEOUT seconds and it MAY issue an alarm.
The definition of how to do that operation is out of the scope of
this document.
If the MA is uploading the report to only one Collector, and it does
not manages to establish a communication before TIMEOUT seconds, then
it retry doing an exponential backoff and doing a round robin between
the different Collectors it has available.
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Similarly, if an HTTP error message (5xx) is received from the
Collector as a response to the PUT request, the MA will retry doing
an exponential backoff and doing a round robin between the different
Collectors it has available. The 5xx error codes indicate that this
Collector is currently incapable of performing the requested
operation.
In order to support this, the information model must express the
difference between a report sent to multiple collectors and multiple
collectors used for fallback.
6. LMAP Data Model
This section will contain the data model in json.
6.1. Timing Information
An example immediate timing object with no defined randomness is
shown below:
{
"timings": [
{
"id": 1,
"ma_periodic_end": 1410017611,
"ma_periodic_interval": 3600000,
"ma_periodic_start": 1410017613,
"ma_randomness_spred": 0,
"ma_timing_name": "hourly"
},
{
"id": 3,
"ma_periodic_end": 1410017611,
"ma_periodic_interval": 86400,
"ma_periodic_start": 1410017613,
"ma_randomness_spred": 0,
"ma_timing_name": "daily"
},
{
"id": 2,
"ma_periodic_end": 1410017611,
"ma_periodic_interval": 3600000,
"ma_periodic_start": 1410017613,
"ma_randomness_spred": 0,
"ma_timing_name": "hourly"
},
{
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"id": 4,
"ma_calendar_days_of_month": "",
"ma_calendar_days_of_week": "tuesday, thursday, sunday",
"ma_calendar_end": 1410017613,
"ma_calendar_hours": "18",
"ma_calendar_minutes": "04",
"ma_calendar_months": "",
"ma_calendar_seconds": "42",
"ma_calendar_start": 1410017612,
"ma_calendar_timezone_offset": 2,
"ma_randomness_spred": 0,
"ma_timing_name": "tuesday-thursday-sunday"
},
{
"id": 5,
"ma_calendar_days_of_month": "",
"ma_calendar_days_of_week": "",
"ma_calendar_end": 1410017619,
"ma_calendar_hours": "0, 6 12 18",
"ma_calendar_minutes": "0",
"ma_calendar_months": "",
"ma_calendar_seconds": "0",
"ma_calendar_start": 1410017612,
"ma_calendar_timezone_offset": 2,
"ma_randomness_spred": 21600000,
"ma_timing_name": "once-every-six-hours"
},
{
"id": 6,
"ma_one_off_time": 1410017613,
"ma_randomness_spred": 0,
"ma_timing_name": "immediate"
},
{
"id": 7,
"ma_one_off_time": 1410017613,
"ma_randomness_spred": 0,
"ma_timing_name": "immediate"
},
{
"id": 8,
"ma_randomness_spred": 12345,
"ma_timing_name": "startup"
}
]
}
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6.2. Channels
An example channel object using the aforementioned timing object is
shown below:
{
"channels": [
{
"id": 1,
"ma_channel_credentials": "MIIFEzCCAvsCAQEwDQYJ...",
"ma_channel_interface_name": "eth0",
"ma_channel_name": "default-collector-channel",
"ma_channel_target": "collector.example.org"
},
{
"id": 2,
"ma_channel_credentials": "MIIFEzCCAvsCAQEwDQYJ...",
"ma_channel_interface_name": "eth0",
"ma_channel_name": "default-controller-channe",
"ma_channel_target": "controller.example.org"
}
]
}
6.3. Configuration
An example config object using the aforementioned channel objects is
shown below:
{
"config": [
{
"id": 1,
"ma_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_channel_name": "default-controller-channel",
"ma_control_channel_fail_tresh": "10",
"ma_credentials": "MIIFEzCCAvsCAQEwDQYJ...",
"ma_device_id": "01:23:45:67:89:ab",
"ma_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_ma_id_flag": "1"
}
]
}
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6.4. Instruction
The instruction object is essentially a wrapper around suppression,
schedule, task, channel objects.
6.5. Measurement Supression
An example supression object used by the aforementioned instruction
object is shown below:
{
"supression": [
{
"id": 1,
"ma_supression_enabled": 0,
"ma_supression_end": 0,
"ma_supression_schedule_names": "icmp-latency-immediate",
"ma_supression_start": 1410037509,
"ma_supression_stop_ongoing_task": 0,
"ma_supression_task_names": "iperf-server"
}
]
}
6.6. Measurement Task Configurations
An example task object used by the aforementioned instruction object
is shown below:
{
"tasks": [
{
"id": 1,
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "udp-latency-test",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
},
{
"id": 5,
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "reporting-daily",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
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},
{
"id": 2,
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "icmp-latency-test",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
},
{
"id": 3,
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "iperf-server",
"ma_task_options": "{\\\"name\\\":\\\"role\\\",
\\\"value\\\":\\\"server\\\"}",
"ma_task_registry_entry": "server",
"ma_task_supress_default": "false"
},
{
"id": 4,
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "lmap-reporting-task",
"ma_task_options": "",
"ma_task_registry_entry": "lmap-reportd",
"ma_task_supress_default": "true"
}
]
}
6.7. Measurement Schedules
An example schedule object used by the aforementioned instruction
object is shown below:
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{
"schedules": [
{
"id": 1,
"ma_sched_channel_interface_select": "0",
"ma_sched_channel_names": "default-collector-channel",
"ma_sched_task_downstream_config_names": "reporting-daily",
"ma_sched_task_output_selection": "1",
"ma_schedule_name": "reporting-immediate",
"ma_schedule_task_name": "icmp-latency-test",
"ma_timing_name": "immediate"
}
]
}
6.8. Logging
An example log object is shown below:
{
"logging": [
{
"id": 1,
"ma_log_agent_id": "0e49b32b01fa11e4bcaf10ddb1bd23b5",
"ma_log_code": "200",
"ma_log_description": "OK",
"ma_log_event_time": 1404313752
}
]
}
6.9. Capability and Status
An example status object is shown below:
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{
"status": [
{
"id": 1,
"ma_agent_id": "c54c284a01ee11e48dd310ddb1bd23b5",
"ma_condition_code": "8081",
"ma_condition_text": "Cond_Text",
"ma_device_id": "urn:dev:mac:0024befffe804ff1",
"ma_firmware": "4560",
"ma_hardware": "TL-MR3020",
"ma_interface_dns_server": "8.8.8.8",
"ma_interface_gateway": "192.168.1.1",
"ma_interface_ip_address": "192.168.1.10",
"ma_interface_name": "eth0",
"ma_interface_speed": "100Mbps",
"ma_interface_type": "100baseTX",
"ma_last_config": "140423245",
"ma_last_instruction": "140431312",
"ma_last_measurement": "1404315031",
"ma_last_report": "1404315053",
"ma_link_layer_addr": "01:23:45:67:89:ab",
"ma_task_name": "Report",
"ma_task_registry": "urn:ietf:lmap:report:http_report",
"ma_task_role": "Role",
"ma_version": "Busybox"
}
]
}
6.10. Reporting
An example report object is shown below:
{
"reporting": [
{
"id": 1,
"ma_report_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_report_date": 1404315031,
"ma_report_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_result_conflict_task": "0",
"ma_report_result_cross_traffic": 20,
"ma_report_result_end_time": 1404315031,
"ma_report_result_start_time": 1404315031,
"ma_report_result_values": "result_values",
"ma_report_task_column_labels": "\"start-time\",
\"conflicting-tasks\", \"cross-traffic\", \"mean\",
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\"min\", \"max\"",
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "udp-latency-test",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
},
{
"id": 2,
"ma_report_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_report_date": 1404315031,
"ma_report_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_result_conflict_task": "0",
"ma_report_result_cross_traffic": 20,
"ma_report_result_end_time": 1404315031,
"ma_report_result_start_time": 1404315031,
"ma_report_result_values": "result_values",
"ma_report_task_column_labels": "\"start-time\",
\"conflicting-tasks\", \"cross-traffic\",
\"mean\", \"min\", \"max\"",
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "icmp-latency-test",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
},
{
"id": 3,
"ma_report_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_report_date": 1404315031,
"ma_report_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_result_conflict_task": "0",
"ma_report_result_cross_traffic": 20,
"ma_report_result_end_time": 1404315031,
"ma_report_result_start_time": 1404315031,
"ma_report_result_values": "result_values",
"ma_report_task_column_labels": "\"start-time\",
\"conflicting-tasks\", \"cross-traffic\",
\"mean\", \"min\", \"max\"",
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "iperf-server",
"ma_task_options": "{\\\"name\\\":\\\"role\\\",
\\\"value\\\":\\\"server\\\"}",
"ma_task_registry_entry": "server",
"ma_task_supress_default": "false"
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},
{
"id": 4,
"ma_report_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_report_date": 1404315031,
"ma_report_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_result_conflict_task": "0",
"ma_report_result_cross_traffic": 20,
"ma_report_result_end_time": 1404315031,
"ma_report_result_start_time": 1404315031,
"ma_report_result_values": "result_values",
"ma_report_task_column_labels": "\"start-time\",
\"conflicting-tasks\", \"cross-traffic\",
\"mean\", \"min\", \"max\"",
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "lmap-reporting-task",
"ma_task_options": "",
"ma_task_registry_entry": "lmap-reportd",
"ma_task_supress_default": "true"
},
{
"id": 5,
"ma_report_agent_id": "550e8400-e29b-41d4-a716-446655440000",
"ma_report_date": 1404315031,
"ma_report_group_id": "550e8400-e29b-41d4-a716-446655440123",
"ma_report_result_conflict_task": "0",
"ma_report_result_cross_traffic": 20,
"ma_report_result_end_time": 1404315031,
"ma_report_result_start_time": 1404315031,
"ma_report_result_values": "result_values",
"ma_report_task_column_labels": "\"start-time\",
\"conflicting-tasks\", \"cross-traffic\",
\"mean\", \"min\", \"max\"",
"ma_role": "",
"ma_task_cycle_id": "1",
"ma_task_name": "reporting-daily",
"ma_task_options": "",
"ma_task_registry_entry": "urn:...",
"ma_task_supress_default": "true"
}
]
}
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7. Security considerations
Large Measurement Platforms may result in a security hazard if they
are not properly secured. This is so because they encompass a large
number of MAs that can be managed and coordinated easily to generate
traffic and they can potentially be used for generating DDoS attacks
or other forms of security threats.
From the perspective of the protocols described in this documents, we
can identify the following threats:
o Hijacking: Probably the worst threat is that an attacker takes
over the control of one or more MAs. In this case the attacker
would be able to instruct the MAs to generate traffic or to
eavesdrop traffic in their location. It is then critical that the
MA is able to strongly authenticate the Controller. An
alternative way to achieve this attack is to alter the
communication between the Controller and the MAs. In order to
prevent this form of attack, integrity protection of the
communication between the Controller and the MAs is required.
o Polluting: Another type of attack is that an attacker is able to
pollute the Collectors database by providing false results. In
this case, the attacker would attempt to impersonate one or more
MAs and upload fake results in the Collector. In order to prevent
this, the authentication of the MAs with the Collector is needed.
An alternative way to achieve this is for an attacker to alter the
communication between the MA and the Collector. In order to
prevent this form of attack, integrity protection of the
communication between the MA and the Collector is needed.
o Disclosure: Another threat is that an attacker may gather
information about the MAs and their configuration and the
Measurement schedules. In order to do that, it would connect to
the Controller and download the information about one or more MAs.
This can be prevented by using MA authentication with the
Controller. An alternative mean to achieve this would be for the
attacker to eavesdrop the communication between the MA and the
Controller. In order to prevent this, confidentiality in the
communication between the MA and the Controller is required.
Similarly, an attacker may wish to obtain measurement result
information by eavesdropping the communication between the MA and
the Collector. In order to prevent this, confidentiality in the
communication between the MA and the Collector is needed.
In order to address all the identified threats, the HTTPS protocol
must be used for LMAP (i.e. using HTTP over TLS). HTTPS provides
confidentiality, integrity protection and authentication, satisfying
all the aforementioned needs. Ideally, mutual authentication should
be used. In any case, server side authentication MUST be used. In
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order to achieve that, both the Controller and the Collector MUST
have certificates. The certificate of the CA used to issue the
certificates for the Controller and the Collector MUST be pre
configured in the MAs, so they can properly authenticate them. As
mentioned earlier, ideally, mutual authentication should be used.
However, this implies that certificates for the MAs are needed.
Certificate management for a large number of MAs may be expensive and
cumbersome. Moreover, the major threats identified are the ones
related to hijacking of the MAs, which are prevented by
authenticating the Controller. MAs authentication is needed to
prevent Polluting and Disclosure threats, which are less severe. So,
in this case, alternative (cheaper) methods for authenticating MAs
can be considered. The simplest method would be to simply use the MA
UUID as a token to retrieve information. Since the MA UUID is 128
bit long, it is hard to guess. It would be also possible to use a
password and use the HTTP method for authentication. It is not
obvious that managing passwords for a large number of MAs is easier
than managing certificates though.
An additional security consideration is posed by the mechanism to
push information from the Controller to the MAs. If this method is
used, it would be possible its abuse by an attacker to control the
MAs. This threat is prevented by the use of HTTPS. If HTTPS is used
in the established connection between the MA and the Controller, the
only effect that a packet generated by an external attacker to the MA
or the Controller would be to reset the HTTPS connection, requiring
the connection to be re-established.
It is required in this document that both the Controller and that the
Collector are authenticated using digital certificates. The current
specification allows for the MA to have information about the
certificate of the Certification authority used for generating the
Controller and Collector certificates while the actual certificates
are exchanged in band using TLS. Another (more secure) option is to
perform certificate pinning i.e. to configure in the MAs the actual
certificates rather than the certification authority certificate.
Another measure to increase the security would be to limit the
domains that the FQDNs of the Controller and/or the Collector (e.g.
only names in the exmaple.org domain).
Large scale measurements can have privacy implications, especially in
some scenarios like mobile devices performing measurements. In this
memo we have considered using Group IDs to the MA in order to avoid
the possibility for the platform to track each individual MA that is
feeding results.
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8. IANA Considerations
Registration of the well-known URL
9. Acknowledgments
We would like to thank Vlad Victor Ungureanu (Jacobs University
Bremen) for providing us external support.
Marcelo Bagnulo, Trevor Burbridge, Sam Crawford, Juergen
Schoenwaelder and Vaibhav Bajpai work in part on the Leone research
project, which receives funding from the European Union Seventh
Framework Programme [FP7/2007-2013] under grant agreement number
317647.
10. References
10.1. Normative References
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, July
2005.
[RFC7159] Bray, T., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, March 2014.
[RFC7230] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Message Syntax and Routing", RFC 7230, June
2014.
[RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Semantics and Content", RFC 7231, June 2014.
[RFC7232] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Conditional Requests", RFC 7232, June 2014.
[RFC7233] Fielding, R., Lafon, Y., and J. Reschke, "Hypertext
Transfer Protocol (HTTP/1.1): Range Requests", RFC 7233,
June 2014.
[RFC7234] Fielding, R., Nottingham, M., and J. Reschke, "Hypertext
Transfer Protocol (HTTP/1.1): Caching", RFC 7234, June
2014.
[RFC7235] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Authentication", RFC 7235, June 2014.
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[I-D.ietf-lmap-information-model]
Burbridge, T., Eardley, P., Bagnulo, M., and J.
Schoenwaelder, "Information Model for Large-Scale
Measurement Platforms (LMAP)", draft-ietf-lmap-
information-model-02 (work in progress), August 2014.
10.2. Informative References
[I-D.bagnulo-ippm-new-registry-independent]
Bagnulo, M., Burbridge, T., Crawford, S., Eardley, P., and
A. Morton, "A registry for commonly used metrics.
Independent registries", draft-bagnulo-ippm-new-registry-
independent-01 (work in progress), July 2013.
[I-D.ietf-lmap-framework]
Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A framework for large-scale
measurement platforms (LMAP)", draft-ietf-lmap-
framework-08 (work in progress), August 2014.
Authors' Addresses
Marcelo Bagnulo
Universidad Carlos III de Madrid
Av. Universidad 30
Leganes, Madrid 28911
SPAIN
Phone: 34 91 6249500
Email: marcelo@it.uc3m.es
URI: http://www.it.uc3m.es
Trevor Burbridge
British Telecom
Adastral Park, Martlesham Heath
IPswitch
ENGLAND
Email: trevor.burbridge@bt.com
Sam Crawford
SamKnows
Email: sam@samknows.com
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Juergen Schoenwaelder
Jacobs University Bremen
Campus Ring 1
28759 Bremen
Germany
Email: j.schoenwaelder@jacobs-university.de
Vaibhav Bajpai
Jacobs University Bremen
Campus Ring 1
28759 Bremen
Germany
Email: v.bajpai@jacobs-university.de
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