Internet DRAFT - draft-ietf-p2psip-diagnostics
draft-ietf-p2psip-diagnostics
P2PSIP Working Group H. Song
Internet-Draft X. Jiang
Intended status: Standards Track R. Even
Expires: September 25, 2016 Huawei
D. Bryan
ethernot.org
Y. Sun
ICT
March 24, 2016
P2P Overlay Diagnostics
draft-ietf-p2psip-diagnostics-22
Abstract
This document describes mechanisms for P2P overlay diagnostics. It
defines extensions to the RELOAD base protocol to collect diagnostic
information, and details the protocol specifications for these
extensions. Useful diagnostic information for connection and node
status monitoring is also defined. The document also describes the
usage scenarios and provides examples of how these methods are used
to perform diagnostics.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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This Internet-Draft will expire on September 25, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Diagnostic Scenarios . . . . . . . . . . . . . . . . . . . . 4
4. Data Collection Mechanisms . . . . . . . . . . . . . . . . . 5
4.1. Overview of Operations . . . . . . . . . . . . . . . . . 5
4.2. "Ping-like" Behavior: Extending Ping . . . . . . . . . . 7
4.2.1. RELOAD Request Extension: Ping . . . . . . . . . . . 7
4.3. "Traceroute-like" Behavior: The Path_Track Method . . . . 8
4.3.1. New RELOAD Request: PathTrack . . . . . . . . . . . . 9
4.4. Error Code Extensions . . . . . . . . . . . . . . . . . . 11
5. Diagnostic Data Structures . . . . . . . . . . . . . . . . . 11
5.1. DiagnosticsRequest Data Structure . . . . . . . . . . . . 12
5.2. DiagnosticsResponse Data Structure . . . . . . . . . . . 13
5.3. dMFlags and Diagnostic Kind ID Types . . . . . . . . . . 15
6. Message Processing . . . . . . . . . . . . . . . . . . . . . 18
6.1. Message Creation and Transmission . . . . . . . . . . . . 18
6.2. Message Processing: Intermediate Peers . . . . . . . . . 19
6.3. Message Response Creation . . . . . . . . . . . . . . . . 20
6.4. Interpreting Results . . . . . . . . . . . . . . . . . . 21
7. Authorization through Overlay Configuration . . . . . . . . . 21
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
9.1. Diagnostics Flag . . . . . . . . . . . . . . . . . . . . 22
9.2. Diagnostic Kind ID . . . . . . . . . . . . . . . . . . . 23
9.3. Message Codes . . . . . . . . . . . . . . . . . . . . . . 24
9.4. Error Code . . . . . . . . . . . . . . . . . . . . . . . 25
9.5. Message Extension . . . . . . . . . . . . . . . . . . . . 25
9.6. XML Name Space Registration . . . . . . . . . . . . . . . 25
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.1. Normative References . . . . . . . . . . . . . . . . . . 26
11.2. Informative References . . . . . . . . . . . . . . . . . 27
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 27
A.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 28
A.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 28
A.3. Example 3 . . . . . . . . . . . . . . . . . . . . . . . . 28
Appendix B. Problems with Generating Multiple Responses on Path 28
Appendix C. Changes to the Draft . . . . . . . . . . . . . . . . 28
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C.1. Changes since -00 version . . . . . . . . . . . . . . . . 29
C.2. Changes since -01 version . . . . . . . . . . . . . . . . 29
C.3. Changes since -02 version . . . . . . . . . . . . . . . . 29
C.4. Changes since -03 version . . . . . . . . . . . . . . . . 29
C.5. Changes since -04 version . . . . . . . . . . . . . . . . 29
C.6. Changes since -05 version . . . . . . . . . . . . . . . . 29
C.7. Changes in version -10 . . . . . . . . . . . . . . . . . 29
C.8. Changes in version -15 . . . . . . . . . . . . . . . . . 30
C.9. Changes in version -20 . . . . . . . . . . . . . . . . . 30
C.10. Changes in version -22 . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
1. Introduction
In the last few years, overlay networks have rapidly evolved and
emerged as a promising platform for deployment of new applications
and services in the Internet. One of the reasons overlay networks
are seen as an excellent platform for large scale distributed systems
is their resilience in the presence of failures. This resilience has
three aspects: data replication, routing recovery, and static
resilience. Routing recovery algorithms are used to repopulate the
routing table with live nodes when failures are detected. Static
resilience measures the extent to which an overlay can route around
failures even before the recovery algorithm repairs the routing
table. Both routing recovery and static resilience rely on accurate
and timely detection of failures.
There are a number of situations in which some nodes in a Peer-to-
Peer (P2P) overlay may malfunction or behave badly. For example,
these nodes may be disabled, congested, or may be misrouting
messages. The impact of these malfunctions on the overlay network
may be a degradation of quality of service provided collectively by
the peers in the overlay network or an interruption of the overlay
services. It is desirable to identify malfunctioning or badly
behaving peers through diagnostic tools, and exclude or reject them
from the P2P system. Node failures may also be caused by failures of
underlying layers. For example, recovery from an incorrect overlay
topology may be slow when the speed at which IP routing recovers
after link failures is very slow. Moreover, if a backbone link fails
and the failover is slow, the network may be partitioned, leading to
partitions of overlay topologies and inconsistent routing results
between different partitioned components.
Some keep-alive algorithms based on periodic probe and acknowledge
mechanisms enable accurate and timely detection of failures of one
node's neighbors [Overlay-Failure-Detection], but these algorithms by
themselves can only detect the disabled neighbors using the periodic
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method. This may not be sufficient for the service provider
operating the overlay network.
A P2P overlay diagnostic framework supporting periodic and on-demand
methods for detecting node failures and network failures is
desirable. This document describes a general P2P overlay diagnostic
extension to the base protocol RELOAD [RFC6940] and is intended as a
complement to keep-alive algorithms in the P2P overlay itself.
Readers are advised to consult [I-D.ietf-p2psip-concepts] for further
background on the problem domain.
2. Terminology
This document uses the concepts defined in RELOAD [RFC6940].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Diagnostic Scenarios
P2P systems are self-organizing and ideally setup and configuration
of individual P2P nodes requires no network management in the
traditional sense. However, users of an overlay, as well as P2P
service providers may contemplate usage scenarios where some
monitoring and diagnostics are required. We present a simple
connectivity test and some useful diagnostic information that may be
used in such diagnostics.
The common usage scenarios for P2P diagnostics can be broadly
categorized in three classes:
a. Automatic diagnostics built into the P2P overlay routing
protocol. Nodes perform periodic checks of known neighbors and
remove those nodes from the routing tables that fail to respond
to connectivity checks [Handling_Churn_in_a_DHT]. Unresponsive
nodes may only be temporarily disabled, for example due to a
local cryptographic processing overload, disk processing overload
or link overload. It is therefore useful to repeat the
connectivity checks to see nodes have recovered and can be again
placed in the routing tables. This process is known as 'failed
node recovery' and can be optimized as described in the paper
"Handling Churn in a DHT" [Handling_Churn_in_a_DHT].
b. Diagnostics used by a particular node to follow up on an
individual user complaint or failure. For example, a technical
support staff member may use a desktop sharing application (with
the permission of the user) to remotely determine the health of,
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and possible problems with, the malfunctioning node. Part of the
remote diagnostics may consist of simple connectivity tests with
other nodes in the P2P overlay and retrieval of statistics from
nodes in the overlay. The simple connectivity tests are not
dependent on the type of P2P overlay. Note that other tests may
be required as well, including checking the health and
performance of the user's computer or mobile device and checking
the bandwidth of the link connecting the user to the Internet.
c. P2P system-wide diagnostics used to check the overall health of
the P2P overlay network. These include checking the consumption
of network bandwidth, checking for the presence of problem links
and checking for abusive or malicious nodes. This is not a
trivial problem and has been studied in detail for content and
streaming P2P overlays [Diagnostic_Framework], and has not been
addressed in earlier documents
[Diagnostics_and_NAT_traversal_in_P2PP]. While this is a
difficult problem, a great deal of information that can help in
diagnosing these problems can be obtained by obtaining basic
diagnostic information for peers and the network. This document
provides a framework for obtaining this information.
4. Data Collection Mechanisms
4.1. Overview of Operations
The diagnostic mechanisms described in this document are primarily
intended to detect and locate failures or monitor performance in P2P
overlay networks. It provides mechanisms to detect and locate
malfunctioning or badly behaving nodes including disabled nodes,
congested nodes and misrouting peers. It provides a mechanism to
detect direct connectivity or connectivity to a specified node, a
mechanism to detect the availability of specified resource records
and a mechanism to discover P2P overlay topology and the underlay
topology failures.
The RELOAD diagnostics extensions define two mechanisms to collect
data. The first is an extension to the RELOAD Ping mechanism,
allowing diagnostic data to be queried from a node, as well as to
diagnose the path to that node. The second is a new method,
PathTrack, for collecting diagnostic information iteratively.
Payloads for these mechanisms allowing diagnostic data to be
collected and represented are presented, and additional error codes
are introduced. Essentially, this document reuses RELOAD
[RFC6940]specification and extends them to introduce the new
diagnostics methods. The extensions strictly follow how RELOAD
specifies message routing, transport, NAT traversal, and other RELOAD
protocol features.
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This document primarily describes how to detect and locate failures
including disabled nodes, congested nodes, misrouting behaviors and
underlying network faults in P2P overlay networks through a simple
and efficient mechanism. This mechanism is modeled after the ping/
traceroute paradigm: ping [RFC0792] is used for connectivity checks,
and traceroute is used for hop-by-hop fault localization as well as
path tracing. This document specifies a "ping-like" mode (by
extending the RELOAD Ping method to gather diagnostics) and a
"traceroute-like" mode (by defining the new PathTrack method) for
diagnosing P2P overlay networks.
One way these tools can be used is to detect the connectivity to the
specified node or the availability of the specified resource-record
through the extended Ping operation. Once the overlay network
receives some alarms about overlay service degradation or
interruption, a Ping is sent. If the Ping fails, one can then send a
PathTrack to determine where the fault lies.
The diagnostic information can only be provided to authorized nodes.
Some diagnostic information can be provided to all the participants
in the P2P overlay, and some other diagnostic information can only be
provided to the nodes authorized by the local or overlay policy. The
authorization depends on the type of the diagnostic information and
the administrative considerations, and is application specific.
This document considers the general administrative scenario based on
diagnostic Kind, where a whole overlay can authorize a certain kind
of diagnostic information to a small list of particular nodes (e.g.
administrative nodes). That means, if a node gets the authorization
to access a diagnostic Kind, it can access that information from all
nodes in the overlay network. It leaves the scenario where a
particular node authorizes its diagnostic information to a particular
list of nodes out of scope. This could be achieved by extension of
this document if there is requirement in the near future. The
default policy or access rule for a type of diagnostic information is
"deny" unless specified in the diagnostics extension document. As
the RELOAD protocol already requires that each message carries the
message signature of the sender, the receiver of the diagnostics
requests can use the signature to identify the sender. It can then
use the overlay configuration file with this signature to determine
which types of diagnostic information that node is authorized for.
In the remainder of this section we define mechanisms for collecting
data, as well as the specific protocol extensions (message
extensions, new methods, and error codes) required to collect this
information. In Section 5 we discuss the format of the data
collected, and in Section 6 we discuss detailed message processing.
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It is important to note that the mechanisms described in this
document do not guarantee that the information collected is in fact
related to the previous failures. However, using the information
from previous traversed nodes, the user (or management system) may be
able to infer the problem. Symmetric routing can be achieved by
using the Via List [RFC6940] (or an alternate DHT routing algorithm),
but the response path is not guaranteed to be the same.
4.2. "Ping-like" Behavior: Extending Ping
To provide "ping-like" behavior, the RELOAD Ping method is extended
to collect diagnostic data along the path. The request message is
forwarded by the intermediate peers along the path and then
terminated by the responsible peer. After optional local
diagnostics, the responsible peer returns a response message. If an
error is found when routing, an Error response is sent to the
initiator node by the intermediate peer.
The message flow of a Ping message (with diagnostic extensions) is as
follows:
Peer A Peer B Peer C Peer D
| | | |
|(1). PingReq | | |
|------------------->|(2). PingReq | |
| |------------------->|(3). PingReq |
| | |------------------->|
| | | |
| | |<-------------------|
| |<-------------------|(4). PingAns |
|<-------------------|(5). PingAns | |
|(6). PingAns | | |
| | | |
Figure 1: Ping Diagnostic Message Flow
4.2.1. RELOAD Request Extension: Ping
To extend the ping request for use in diagnostics, a new extension of
RELOAD is defined. The structure for a MessageExtension in RELOAD is
defined as:
struct {
MessageExtensionType type;
Boolean critical;
opaque extension_contents<0..2^32-1>;
} MessageExtension;
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For the Ping request extension, we define a new MessageExtensionType,
extension 0x0002 named Diagnostic_Ping, as specified in Table 4. The
extension contents consists of a DiagnosticsRequest structure,
defined later in this document in Section 5.1. This extension MAY be
used for new requests of the Ping method and MUST NOT be included in
requests using any other method.
This extension is not critical. If a peer does not support the
extension, they will simply ignore the diagnostic portion of the
message, and will treat the message as if it was a normal ping.
Senders MUST accept a response that lacks diagnostic information and
SHOULD NOT resend the message expecting a reply. Receivers who
receive a method other than Ping including this extension MUST ignore
the extension.
4.3. "Traceroute-like" Behavior: The Path_Track Method
We define a simple PathTrack method for retrieving diagnostic
information iteratively.
The operation of this request is shown below in Figure 2. The
initiator node A asks its neighbor B which is the next hop peer to
the destination ID, and B returns a message with the next hop peer C
information, along with optional diagnostic information for B to the
initiator node. Then the initiator node A asks the next hop peer C
(direct response routing [RFC7263] or via symmetric routing) to
return next hop peer D information and diagnostic information of C.
Unless a failure prevents the message from being forwarded, this step
can be iteratively repeated until the request reaches responsible
peer D for the destination ID, and retrieves diagnostic information
of peer D.
The message flow of a PathTrack message (with diagnostic extensions)
is as follows:
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Peer-A Peer-B Peer-C Peer-D
| | | |
|(1).PathTrackReq | | |
|------------------->| | |
|(2).PathTrackAns | | |
|<-------------------| | |
| |(3).PathTrackReq | |
|--------------------|------------------->| |
| |(4).PathTrackAns | |
|<-------------------|--------------------| |
| | |(5).PathTrackReq |
|--------------------|--------------------|------------------->|
| | |(6).PathTrackAns |
|<-------------------|--------------------|--------------------|
| | | |
Figure 2: PathTrack Diagnostic Message Flow
There have been proposals that RouteQuery and a series of Fetch
requests can be used to replace the PathTrack mechanism, but in the
presence of high rates of churn, such an operation would not,
strictly speaking, provide identical results, as the path may change
between RouteQuery and Fetch operations. While obviously the path
could change between steps of PathTrack as well, with a single
message rather than two messages for query and fetch, less
inconsistency is likely, and thus the use of a single message is
preferred.
Given that in a typical diagnostic scenario the peer sending the
PathTrack request desires to obtain information about the current
path to the destination, in the event that succesive calls to
PathTrack return different paths, the results should be discarded and
the request resent, ensuring that the second request traverses the
appropriate path.
4.3.1. New RELOAD Request: PathTrack
This document defines a new RELOAD method, PathTrack, to retrieve the
diagnostic information from the intermediate peers along the routing
path. At each step of the PathTrack request, the responsible peer
responds to the initiator node with requested status information.
Status information can include a peer's congestion state, processing
power, available bandwidth, the number of entries in its neighbor
table, uptime, identity, network address information, and next hop
peer information.
A PathTrack request specifies which diagnostic information is
requested using a DiagnosticsRequest data structure, defined and
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discussed in detail later in this document in Section 5.1. Base
information is requested by setting the appropriate flags in the data
structure in the request. If all flags are clear (no bits are set),
then the PathTrack request is only used for requesting the next hop
information. In this case the iterative mode of PathTrack is
degraded to a RouteQuery method which is only used for checking the
liveness of the peers along the routing path. The PathTrack request
can be routed using direct response routing or other routing methods
chosen by the initiator node.
A response to a successful PathTrackReq is a PathTrackAns message.
The PathTrackAns contains general diagnostic information in the
payload, returned using a DiagnosticResponse data structure. This
data structure is defined and discussed in detail later in this
document in Section 5.2. The information returned is determined
based on the information requested in the flags in the corresponding
request.
4.3.1.1. PathTrack Request
The structure of the PathTrack request is as follows:
struct{
Destination destination;
DiagnosticsRequest request;
}PathTrackReq;
The fields of the PathTrackReq are as follows:
destination : The destination which the initiator node is
interested in. This may be any valid destination object,
including a NodeID, opaque ids, or ResourceID. One example should
be noted that, for debugging purpose, the initiator will use the
destination ID as it was used when failure happened.
request : A DiagnosticsRequest, as discussed in Section 5.1.
4.3.1.2. PathTrack Response
The structure of the PathTrack response is as follows:
struct{
Destination next_hop;
DiagnosticsResponse response;
}PathTrackAns;
The fields of the PathTrackAns are as follows:
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next_hop : The information of the next hop node from the
responding intermediate peer to the destination. If the
responding peer is the responsible peer for the destination ID,
then the next_hop node ID equals the responding node ID, and after
receiving a PathTrackAns where the next_hop node ID equals the
responding node ID the initiator MUST stop the iterative process.
response : A DiagnosticsResponse, as discussed in Section 5.2.
4.4. Error Code Extensions
This document extends the Error response method defined in the RELOAD
specification to support error cases resulting from diagnostic
queries. When an error is encountered in RELOAD, the Message Code
0xFFFF is returned. The ErrorResponse structure includes an error
code. We define new error codes to report possible error conditions
detected while performing diagnostics:
Code Value Error Code Name
TBD1 Underlay Destination Unreachable
TBD2 Underlay Time exceeded
TBD3 Message Expired
TBD4 Upstream Misrouting
TBD5 Loop detected
TBD6 TTL hops exceeded
The final error codes will be assigned by IANA as specified in RELOAD
protocol [RFC6940]. The error code is returned by the upstreaming
node before the failure node. And the upstreaming node uses the
normal ping to detect the failure type and return it to the initiator
node, which will help the user (initiator node) to understand where
the failure happened and what kind of error happened, as the failure
may happen at the same location and for the same reason when sending
the normal message and the diagnostics message.
As defined in RELOAD, additional information may be stored (in an
implementation-specific way) in the optional error_info byte string.
While the specifics are obviously left to the implementation, as an
example, in the case of TBD1, the error_field could be used to
provide additional information as to why the underlay destination is
unreachable (net unreachable, host unreachable, fragmentation needed,
etc.)
5. Diagnostic Data Structures
Both the extended Ping method and PathTrack method use the following
common diagnostics data structures to collect data. Two common
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structures are defined: DiagnosticsRequest for requesting data, and
DiagnosticsResponse for returning the information.
5.1. DiagnosticsRequest Data Structure
The DiagnosticsRequest data structure is used to request diagnostic
information and has the following form:
enum{ (2^16-1) } DiagnosticKindId;
struct{
DiagnosticKindId kind;
opaque diagnostic_extension_contents<0..2^32-1>;
}DiagnosticExtension;
struct{
uint64 expiration;
uint64 timestamp_initiated;
uint64 dMFlags;
uint32 ext_length;
DiagnosticExtension diagnostic_extensions_list<0..2^32-1>;
}DiagnosticsRequest;
The fields in the DiagnosticsRequest are as follows:
expiration : The time when the request will expire represented as
the number of milliseconds elapsed since midnight Jan 1, 1970 UTC
not counting leap seconds. This will have the same values for
seconds as standard UNIX time or POSIX time. More information can
be found at UnixTime [UnixTime]. This value MUST have a value of
between 1 and 600 seconds in the future. This value is used to
prevent replay attacks.
timestamp_initiated : The time when the diagnostics request was
initiated represented as the number of milliseconds elapsed since
midnight Jan 1, 1970 UTC not counting leap seconds. This will
have the same values for seconds as standard UNIX time or POSIX
time.
dMFlags : A mandatory field which is an unsigned 64-bit integer
indicating which base diagnostic information the request initiator
node is interested in. The initiator sets different bits to
retrieve different kinds of diagnostic information. If dMFlags is
set to zero, then no base diagnostic information is conveyed in
the PathTrack response. If dMFlag is set to all '1's, then all
base diagnostic information values are requested. A request may
set any number of the flags to request the corresponding
diagnostic information.
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Note this memo specifies the initial set of flags, the flags can
be extended. The dMflags indicate general diagnostic information
The mapping between the bits in the dMFlags and the diagnostic
information kind presented is as described in Section 9.1.
ext_length : the length of the extended diagnostic request
information in bytes. If the value is greater than or equal to 1,
then some extended diagnostic information is being requested, on
the assumption this information will be included in the response
if the recipient understands the extended request and is willing
to provide it. The specific diagnostic information requested is
defined in the diagnostic_extensions_list below. A value of zero
indicates no extended diagnostic information is being requested.
The value of ext_length MUST NOT be negative. Note that it is not
the length of the entire DiagnosticsRequest data structure, but of
the data making up the diagnostic_extensions_list.
diagnostic_extensions_list : consists of one or more
DiagnosticExtension structures (see below) documenting additional
diagnostic information being requested. Each DiagnosticExtension
consists of the following fields:
kind : a numerical code indicating the type of extension
diagnostic information (see Section 9.2). Note that kinds
0xF000 - 0xFFFE are reserved for overlay specific diagnostics
and may be used without IANA registration for local diagnostic
information. Kinds from 0x0000 to 0x003F MUST NOT be indicated
in the diagnostic_extensions_list in the message request, as
they may be represented using the dMFlags in a much simpler
(and more space efficient) way.
diagnostic_extension_contents : the opaque data containing the
request for this particular extension. This data is extension
dependent.
5.2. DiagnosticsResponse Data Structure
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enum { (2^16-1) } DiagnosticKindId;
struct{
DiagnosticKindId kind;
opaque diagnostic_info_contents<0..2^16-1>;
}DiagnosticInfo;
struct{
uint64 expiration;
uint64 timestamp_initiated;
uint64 timestamp_received;
uint8 hop_counter;
uint32 ext_length;
DiagnosticInfo diagnostic_info_list<0..2^32-1>;
}DiagnosticsResponse;
The fields in the DiagnosticsResponse are as follows:
expiration : The time when the response will expire represented as
the number of milliseconds elapsed since midnight Jan 1, 1970 UTC
not counting leap seconds. This will have the same values for
seconds as standard UNIX time or POSIX time. This value MUST have
a value of between 1 and 600 seconds in the future.
timestamp_initiated: This value is copied from the diagnostics
request message. The benefit of containing such a value in the
response message is that the initiator node does not have to
maintain the state.
timestamp_received : The time when the diagnostic request was
received represented as the number of milliseconds elapsed since
midnight Jan 1, 1970 UTC not counting leap seconds. This will
have the same values for seconds as standard UNIX time or POSIX
time.
hop_counter : This field only appears in diagnostic responses. It
MUST be exactly copied from the TTL field of the forwarding header
in the received request. This information is sent back to the
request initiator, allowing it to compute the number of hops that
the message traversed in the overlay.
ext_length : the length of the returned DiagnosticInfo information
in bytes. If the value is greater than or equal to 1, then some
extended diagnostic information (as specified in the
DiagnosticsRequest) was available and is being returned. In that
case, this value indicates the length of the returned information.
A value of zero indicates no extended diagnostic information is
included, either because none was requested or the request could
not be accommodated. The value of ext_length MUST NOT be
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negative. Note that it is not the length of the entire
DiagnosticsRequest data structure, but of the data making up the
diagnostic_info_list.
diagnostic_info_list : consists of one or more DiagnosticInfo
structures containing the requested diagnostic_info_contents. The
fields in the DiagnosticInfo structure are as follows:
kind : A numeric code indicating the type of information being
returned. For base data requested using the dMFlags, this code
corresponds to the dMFlag set, and is described in Section 5.1.
For diagnostic extensions, this code will be identical to the
value of the DiagnosticKindId set in the "kind" field of the
DiagnosticExtension of the request. See Section 9.2.
diagnostic_info_contents : Data containing the value for the
diagnostic information being reported. Various kinds of
diagnostic information can be retrieved, Please refer to
Section 5.3 for details of the diagnostic Kind ID for the base
diagnostic information that may be reported.
5.3. dMFlags and Diagnostic Kind ID Types
The dMFlags field described above is a 64 bit field that allows
initiator nodes to identify up to 62 items of base information to
request in a request message (the first and last flags being
reserved). The dMFlags also reserves all "0"s that means nothing is
requested, and all "1"s that means everything is requested. But at
the same time, the first and last bits cannot be used for other
purposes, and they MUST be set to 0 when other particular diagnostic
information kinds are requested. When the requested base information
is returned in the response, the value of the diagnostic Kind ID will
correspond to the numeric field marked in the dMFlags in the request.
The values for the dMFlags are defined in Section 9.1 and the
diagnostic Kind IDs are defined in Section 9.2. The information
contained for each value is described in this section. Access to
each kind of diagnostic information MUST NOT be allowed unless
compliant to the rules defined in Section 7.
STATUS_INFO (8 bits):A single value element containing an unsigned
byte representing whether or not the node is in congestion status.
An example usage of STATUS_INFO is for congestion-aware routing.
In this scenario, each peer has to update its congestion status
periodically. An intermediate peer in the distributed hash table
(DHT) network will choose its next hop according to both the DHT
routing algorithm and the status information. This is done to
avoid increasing load on congested peers. The rightmost 4 bits
are used and other bits MUST be cleared to "0"s for future use.
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There are 16 levels of congestion status, with "0x00" represent
zero load and "0x0F" represent congested. This document does not
provide a specific method for congestion, leaving this decision to
each overlay implementation. One possible option for an overlay
implementation would be to take node's CPU/memory/bandwidth usage
percentage in the past 600 seconds and normalize the highest value
to the range from 0x00 to 0x0F. And an overlay implementation can
also decide to not use all that 16 values from 0x00 to 0x0F. A
future draft may define an objective measure or specific algorithm
for this.
ROUTING_TABLE_SIZE (32 bits): A single value element containing an
unsigned 32-bit integer representing the number of peers in the
peer's routing table. The administrator of the overlay may be
interested in statistics of this value for reasons such as routing
efficiency.
PROCESS_POWER (64 bits): A single value element containing an
unsigned 64-bit integer specifying the processing power of the
node in unit of MIPS. Fractional values are rounded up.
UPSTREAM_BANDWIDTH (64 bits): A single value element containing an
unsigned 64-bit integer specifying the upstream network bandwidth
(provisioned or maximum, not available) of the node in unit of
Kbps. Fractional values are rounded up. For multihomed hosts,
this should be the link used to send the response.
DOWNSTREAM_BANDWIDTH (64 bits): A single value element containing
an unsigned 64-bit integer specifying the downstream network
bandwidth (provisioned or maximum, not available) of the node in
unit of Kbps. Fractional values are rounded up. For multihomed
hosts, this should be the link the request was received from.
SOFTWARE_VERSION: A single value element containing a US-ASCII
string that identifies the manufacture, model, operating system
information and the version of the software. Given that there are
very large number of peers in some networks, and no peer is likely
to know all other peer's software, this information may be very
useful to help determine if the cause of certain groups of
misbehaving peers is related to specific software versions. While
the format is peer-defined, a suggested format is as follows:
"ApplicationProductToken (Platform; OS-or-CPU) VendorProductToken
(VendorComment)". For example: "MyReloadApp/1.0 (Unix; Linux
x86_64) libreload-java/0.7.0 (Stonyfish Inc.)". The string is a
C-style string, and MUST be terminated by "\0"."\0" MUST NOT be
included in the string itself to prevent confusion with the
delimiter.
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MACHINE_UPTIME (64 bits): A single value element containing an
unsigned 64-bit integer specifying the time the node's underlying
system has been up in seconds.
APP_UPTIME (64 bits): A single value element containing an
unsigned 64-bit integer specifying the time the P2P application
has been up in seconds.
MEMORY_FOOTPRINT (64 bits): A single value element containing an
unsigned 64-bit integer representing the memory footprint of the
peer program in kilobytes (1024 bytes). Fractional values are
rounded up.
DATASIZE_STORED (64 bits): An unsigned 64-bit integer representing
the number of bytes of data being stored by this node.
INSTANCES_STORED: An array element containing the number of
instances of each kind stored. The array is indexed by Kind-ID.
Each entry is an unsigned 64-bit integer.
MESSAGES_SENT_RCVD: An array element containing the number of
messages sent and received. The array is indexed by method code.
Each entry in the array is a pair of unsigned 64-bit integers
(packed end to end) representing sent and received.
EWMA_BYTES_SENT (32 bits): A single value element containing an
unsigned 32-bit integer representing an exponential weighted
average of bytes sent per second by this peer. sent = alpha x
sent_present + (1 - alpha) x sent_last where sent_present
represents the bytes sent per second since the last calculation
and sent_last represents the last calculation of bytes sent per
second. A suitable value for alpha is 0.8 (the implementation can
decide other suitable value for this). This value is calculated
every five seconds (the implementation can also decide other
length of the time period). The value for the very first time
period should simply be the average of bytes sent in that time
period.
EWMA_BYTES_RCVD (32 bits): A single value element containing an
unsigned 32-bit integer representing an exponential weighted
average of bytes received per second by this peer. rcvd = alpha x
rcvd_present + (1 - alpha) x rcvd_last where rcvd_present
represents the bytes received per second since the last
calculation and rcvd_last represents the last calculation of bytes
received per second. A suitable value for alpha is 0.8 (the
implementation can decide other suitable value for this). This
value is calculated every five seconds (the implementation can
also decide other length of the time period). The value for the
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very first time period should simply be the average of bytes
received in that time period.
UNDERLAY_HOP (8 bits): Indicates the IP layer hops from the
intermediate peer which receives the diagnostics message to the
next hop peer for this message. (Note: RELOAD does not require
the intermediate peers to look into the message body. So here we
use PathTrack to gather underlay hops for diagnostics purpose).
BATTERY_STATUS (8 bits): The left-most bit is used to indicate
whether this peer is using a battery or not. If this bit is clear
(set to '0'), then the peer is using a battery for power. The
other 7 bits are to be determined by specific applications.
6. Message Processing
6.1. Message Creation and Transmission
When constructing either a Ping message with diagnostic extensions or
a PathTrack message, the sender first creates and populates a
DiagnosticsRequest data structure. The timestamp_initiated field is
set to the current time, and the expiration field is constructed
based on this time. The sender includes the dMFlags field in the
structure, setting any number (including all) of the flags to request
particular diagnostic information. The sender MAY leave all the bits
unset, requesting no particular diagnostic information.
The sender MAY also include diagnostic extensions in the
DiagnosticsRequest data structure to request additional information.
If the sender includes any extensions, it MUST calculate the length
of these extensions and set the ext_length field to this value. If
no extensions are included, the sender MUST set ext_length to zero.
The format of the DiagnosticRequest data structure and its fields
MUST follow the restrictions defined in Section 5.1.
When constructing a Ping message with diagnostic extensions, the
sender MUST create an MessageExtension structure as defined in RELOAD
[RFC6940], setting the value of type to 0x0002, and the value of
critical to FALSE. The value of extension_contents MUST be a
DiagnosticsRequest structure as defined above. The message MAY be
directed to a particular NodeId or ResourceID, but MUST NOT be sent
to the broadcast NodeID.
When constructing a PathTrack message, the sender MUST set the
message_code for the RELOAD MessageContents structure to
path_track_req TBD7. The request field of the PathTrackReq MUST be
set to the DiagnosticsRequest data structure defined above. The
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destination field MUST be set to the desired destination, which MAY
be either a NodeId or ResourceID but SHOULD NOT be the broadcast
NodeID.
6.2. Message Processing: Intermediate Peers
When a request arrives at a peer, if the peer's responsible ID space
does not cover the destination ID of the request, then the peer MUST
continue processing this request according to the overlay specified
routing mode from RELOAD protocol.
In P2P overlay, error responses to a message can be generated by
either an intermediate peer or the responsible peer. When a request
is received at a peer, the peer may find connectivity failures or
malfunctioning peers through the pre-defined rules of the overlay
network, e.g. by analyzing via list or underlay error messages. In
this case, the intermediate peer returns an error response to the
initiator node, reporting any malfunction node information available
in the error message payload. All error responses generated MUST
contain the appropriate error code.
Each intermediate peer receiving a Ping message with extensions (and
which understands the extension) or receiving a PathTrack request/
response MUST check the expiration value (Unix time format) to
determine if the message is expired. If the message expired, the
intermediate peer MUST generate a response with Error Code TBD3
"Message Expired", return the response to the initiator node, and
discard the message.
The intermediate peer MUST return an error response with the Error
Code TBD1 "Underlay Destination Unreachable" when it receives an ICMP
message with "Destination Unreachable" information after forwarding
the received request to the destination peer.
The intermediate peer MUST return an error response with the Error
Code TBD2 "Underlay Time Exceeded" when it receives an ICMP message
with "Time Exceeded" information after forwarding the received
request.
The peer MUST return an Error response with Error Code TBD4 "Upstream
Misrouting" when it finds its upstream peer disobeys the routing
rules defined in the overlay. The immediate upstream peer
information MUST also be conveyed to the initiator node.
The peer MUST return an Error response with Error Code TBD5 "Loop
detected" when it finds a loop through the analysis of via list.
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The peer MUST return an Error response with Error Code TBD6 "TTL hops
exceeded" when it finds that the TTL field value is no more than 0
when forwarding.
6.3. Message Response Creation
When a diagnostic request message arrives at a peer, it is
responsible for the destination ID specified in the forwarding
header, and assuming it understands the extension (in the case of
Ping) or the new request type PathTrack, it MUST follow the
specifications defined in RELOAD to form the response header, and
perform the following operations:
When constructing a PathTrack response, the sender MUST set the
message_code for the RELOAD MessageContents structure to
path_track_ans TBD8.
The receiver MUST check the expiration value (Unix time format) in
the DiagnosticsRequest to determine if the message is expired. If
the message is expired, the peer MUST generate a response with the
Error Code TBD3 "Message Expired", return the response to the
initiator node, and discard the message.
If the message is not expired, the receiver MUST construct a
DiagnosticsResponse structure, as follows: The TTL value from the
forwarding header is copied to the hop_counter field of the
DiagnosticsResponse structure. Note that the default value for TTL
at the beginning represents 100-hops unless overlay configuration has
overridden the value. The receiver generates an Unix time format
timestamp for the current time of day and places it in the
timestamp_received field, and constructs a new expiration time and
places it in the expiration field of the DiagnosticsResponse.
The destination peer MUST check if the initiator node has the
authority to request specific types of diagnostic information, and if
appropriate, append the diagnostic information requested in the
dMFlags and diagnostic_extensions (if any) using the
diagnostic_info_list field to the DiagnosticsResponse structure. If
any information returned, the receiver MUST calculate the length of
the response and set ext_length appropriately. If no diagnostic
information is returned, ext_length MUST be set to zero.
The format of the DiagnosticResponse data structure and its fields
MUST follow the restrictions defined in Section 5.2.
In the event of an error, an error response containing the error code
followed by the description (if they exist) MUST be created and sent
to the sender. If the initiator node asks for diagnostic information
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that they are not authorized to query, the receiving peer MUST return
an Error response with the Error Code 2 "Error_Forbidden".
6.4. Interpreting Results
The initiator node, as well as the responding peer, may compute the
overlay One-Way-Delay time through the value in timestamp_received
and the timestamp_initiated field. However, for a single hop
measurement, the traditional measurement methods (IP layer ping) MUST
be used instead of the overlay layer diagnostics methods.
The P2P overlay network using the diagnostics methods specified in
this document MUST enforce time synchronization with a central time
server. Network Time Protocol [RFC5905] can usually maintain time to
within tens of milliseconds over the public Internet, and can achieve
better than one millisecond accuracy in local area networks under
ideal conditions. However, this document does not specify the choice
for time resolution and synchronization, leaving it to the
implementation.
The initiator node receiving the Ping response may check the
hop_counter field and compute the overlay hops to the destination
peer for the statistics of connectivity quality from the perspective
of overlay hops.
7. Authorization through Overlay Configuration
Different level of access control can be made for different users/
nodes. For example, diagnostic information A can be accessed by node
1 and 2, but diagnostic information B can only be accessed by node 2.
The overlay configuration file MUST contain the following XML
elements for authorizing a node to access the relative diagnostic
Kinds.
diagnostic-kind: This has the attribute "kind" with the hexadecimal
number indicating the diagnostic Kind ID, this attribute has the same
value with Section 9.2, and at least one sub element "access-node".
access-node: This element contains one hexadecimal number indicating
a NodeID, and the node with this NodeID is allowed to access the
diagnostic "kind" under the same diagnostic-kind element.
8. Security Considerations
The authorization for diagnostic information must be designed with
care to prevent it becoming a method to retrieve information for bot
attacks. It should also be noted that attackers can use diagnostics
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to analyze overlay information to attack certain key peers. For
example, diagnostic information might be used to fingerprint a peer
where the peer will loose its anonymity characteristics, but
anonymity might be very important for some P2P overlay networks, and
defenses against such fingerprinting are probably very hard. As
such, networks where anonymity is of very high importance may find
implementation of diagnostics problematic or even undesirable,
despite the many advantages it offers. As this document is a RELOAD
extension, it follows RELOAD message header and routing
specifications, the common security considerations described in the
base document [RFC6940] are also applicable to this document.
Overlays may define their own requirements on who can collect/share
diagnostic information.
9. IANA Considerations
9.1. Diagnostics Flag
IANA is asked to create a "RELOAD Diagnostics Flag" Registry under
protocol RELOAD. Entries in this registry are 1-bit flags contained
in a 64-bits long integer dMFlags denoting diagnostic information to
be retrieved as described in Section 4.3.1. New entries SHALL be
defined via [RFC5226] Standards Action. The initial contents of this
registry are:
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+-------------------------+----------------------------+----------+
| diagnostic information |diagnostic flag in dMFlags | RFC |
|-------------------------+----------------------------+----------|
|Reserved All 0s value | 0x 0000 0000 0000 0000 |RFC-[TBDX]|
|Reserved First Bit | 0x 0000 0000 0000 0001 |RFC-[TBDX]|
|STATUS_INFO | 0x 0000 0000 0000 0002 |RFC-[TBDX]|
|ROUTING_TABLE_SIZE | 0x 0000 0000 0000 0004 |RFC-[TBDX]|
|PROCESS_POWER | 0x 0000 0000 0000 0008 |RFC-[TBDX]|
|UPSTREAM_BANDWIDTH | 0x 0000 0000 0000 0010 |RFC-[TBDX]|
|DOWNSTREAM_ BANDWIDTH | 0x 0000 0000 0000 0020 |RFC-[TBDX]|
|SOFTWARE_VERSION | 0x 0000 0000 0000 0040 |RFC-[TBDX]|
|MACHINE_UPTIME | 0x 0000 0000 0000 0080 |RFC-[TBDX]|
|APP_UPTIME | 0x 0000 0000 0000 0100 |RFC-[TBDX]|
|MEMORY_FOOTPRINT | 0x 0000 0000 0000 0200 |RFC-[TBDX]|
|DATASIZE_STORED | 0x 0000 0000 0000 0400 |RFC-[TBDX]|
|INSTANCES_STORED | 0x 0000 0000 0000 0800 |RFC-[TBDX]|
|MESSAGES_SENT_RCVD | 0x 0000 0000 0000 1000 |RFC-[TBDX]|
|EWMA_BYTES_SENT | 0x 0000 0000 0000 2000 |RFC-[TBDX]|
|EWMA_BYTES_RCVD | 0x 0000 0000 0000 4000 |RFC-[TBDX]|
|UNDERLAY_HOP | 0x 0000 0000 0000 8000 |RFC-[TBDX]|
|BATTERY_STATUS | 0x 0000 0000 0001 0000 |RFC-[TBDX]|
|Reserved Last Bit | 0x 8000 0000 0000 0000 |RFC-[TBDX]|
|Reserved All 1s value | 0x FFFF FFFF FFFF FFFF |RFC-[TBDX]|
+-------------------------+----------------------------+----------+
[To RFC editor: Please replace all RFC-[TBDX] in this document with
the RFC number of this document.]
9.2. Diagnostic Kind ID
IANA is asked to create a "RELOAD Diagnostic Kind ID" Registry under
protocol RELOAD. Entries in this registry are 16-bit integers
denoting diagnostics extension data kinds carried in the diagnostic
request and response message, as described in Section 5.2. Code
points from 0x0001 to 0x003E are asked to be assigned together with
flags within "RELOAD Diagnostics Flag" registry via RFC 5226
[RFC5226] standards action. Code points in the range 0x003F to
0xEFFF SHALL be registered via RFC 5226 standards action.
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+---------------------------+---------------+---------------+
| Diagnostic Kind | Code | Specification |
+---------------------------+---------------+---------------+
| reserved | 0x0000 | RFC-[TBDX] |
| STATUS_INFO | 0x0001 | RFC-[TBDX] |
| ROUTING_TABLE_SIZE | 0x0002 | RFC-[TBDX] |
| PROCESS_POWER | 0x0003 | RFC-[TBDX] |
| UPSTREAM_BANDWIDTH | 0x0004 | RFC-[TBDX] |
| DOWNSTREAM_BANDWIDTH | 0x0005 | RFC-[TBDX] |
| SOFTWARE_VERSION | 0x0006 | RFC-[TBDX] |
| MACHINE_UPTIME | 0x0007 | RFC-[TBDX] |
| APP_UPTIME | 0x0008 | RFC-[TBDX] |
| MEMORY_FOOTPRINT | 0x0009 | RFC-[TBDX] |
| DATASIZE_STORED | 0x000A | RFC-[TBDX] |
| INSTANCES_STORED | 0x000B | RFC-[TBDX] |
| MESSAGES_SENT_RCVD | 0x000C | RFC-[TBDX] |
| EWMA_BYTES_SENT | 0x000D | RFC-[TBDX] |
| EWMA_BYTES_RCVD | 0x000E | RFC-[TBDX] |
| UNDERLAY_HOP | 0x000F | RFC-[TBDX] |
| BATTERY_STATUS | 0x0010 | RFC-[TBDX] |
| reserved for future flags | 0x0011-3E | RFC-[TBDX] |
| local use (reserved) | 0xF000-0xFFFE | RFC-[TBDX] |
| reserved | 0xFFFF | RFC-[TBDX] |
+---------------------------+---------------+---------------+
Table 1: Diagnostic Kind
9.3. Message Codes
This document introduces two new types of messages and their
responses, requiring the following additions to the "RELOAD Message
Code" Registry defined in RELOAD [RFC6940]. These additions are:
+-------------------+------------+----------+
| Message Code Name | Code Value | RFC |
+-------------------+------------+----------+
| path_track_req | [TBD7] | RFC-AAAA |
| path_track_ans | [TBD8] | RFC-AAAA |
+-------------------+------------+----------+
Table 2: Extensions to RELOAD Message Codes
[To RFC editor: Values starting at TBD1 were used to prevent
collisions with RELOAD base values and other extensions. Please
replace with the next highest available values. The final message
codes will be assigned by IANA. And all RFC-AAAA should be replaced
with the RFC number of RELOAD when publication.]
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9.4. Error Code
This document introduces the following new error codes, extending the
"RELOAD Message Code" registry as described below:
+----------------------------------------+------------+----------+
| Message Code Name | Code Value | RFC |
+----------------------------------------+------------+----------+
| Error_Underlay_Destination_Unreachable | [TBD1] | RFC-AAAA |
| Error_Underlay_Time_Exceeded | [TBD2] | RFC-AAAA |
| Error_Message_Expired | [TBD3] | RFC-AAAA |
| Error_Upstream_Misrouting | [TBD4] | RFC-AAAA |
| Error_Loop_Detected | [TBD5] | RFC-AAAA |
| Error_TTL_Hops_Exceeded | [TBD6] | RFC-AAAA |
+----------------------------------------+------------+----------+
Table 3: Extensions to RELOAD Error Codes
[To RFC editor: Values starting at TBD1 were used to prevent
collisions with RELOAD base values and other extensions. Please
replace with the next highest available values. The final message
codes will be assigned by IANA. And all RFC-AAAA should be replaced
with the RFC number of RELOAD when publication.]
9.5. Message Extension
This document introduces the following new RELOAD extension code:
+-----------------+------------+----------+
| Extension Name | Code Value | RFC |
+-----------------+------------+----------+
| Diagnostic_Ping | 0x0002 | RFC-AAAA |
+-----------------+------------+----------+
Table 4: New RELOAD Extension Code
[To RFC editor: The value 0x0002 was used to prevent collisions with
other extensions. Please replace with the next highest available
value. The final codes will be assigned by IANA. And all RFC-AAAA
should be replaced with the RFC number of RELOAD when publication.]
9.6. XML Name Space Registration
This document registers a URI for the config-diagnostics XML
namespaces in the IETF XML registry defined in [RFC3688]. All the
elements defined in this document belong to this namespace.
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URI: urn:ietf:params:xml:ns:p2p:config-diagnostics
Registrant Contact: The IESG.
XML: N/A, the requested URIs are XML namespaces
And the overlay configuration file MUST contain the following xml
language declaring P2P diagnostics as a mandatory extension to
RELOAD.
<mandatory-extension>
urn:ietf:params:xml:ns:p2p:config-diagnostics
</mandatory-extension>
10. Acknowledgments
We would like to thank Zheng Hewen for the contribution of the
initial version of this document. We would also like to thank Bruce
Lowekamp, Salman Baset, Henning Schulzrinne, Jiang Haifeng and Marc
Petit-Huguenin for the email discussion and their valued comments,
and special thanks to Henry Sinnreich for contributing to the usage
scenarios text. We would like to thank the authors of the RELOAD
protocol for transferring text about diagnostics to this document.
11. References
11.1. Normative References
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<http://www.rfc-editor.org/info/rfc792>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<http://www.rfc-editor.org/info/rfc3688>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<http://www.rfc-editor.org/info/rfc5905>.
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[RFC6940] Jennings, C., Lowekamp, B., Ed., Rescorla, E., Baset, S.,
and H. Schulzrinne, "REsource LOcation And Discovery
(RELOAD) Base Protocol", RFC 6940, DOI 10.17487/RFC6940,
January 2014, <http://www.rfc-editor.org/info/rfc6940>.
[RFC7263] Zong, N., Jiang, X., Even, R., and Y. Zhang, "An Extension
to the REsource LOcation And Discovery (RELOAD) Protocol
to Support Direct Response Routing", RFC 7263,
DOI 10.17487/RFC7263, June 2014,
<http://www.rfc-editor.org/info/rfc7263>.
11.2. Informative References
[UnixTime]
"UnixTime", <Wikipedia, "Unix Time",
<http:/wikipedia.org/wiki/Unix_time>.>.
[I-D.ietf-p2psip-concepts]
Bryan, D., Matthews, P., Shim, E., Willis, D., and S.
Dawkins, "Concepts and Terminology for Peer to Peer SIP",
draft-ietf-p2psip-concepts-08 (work in progress), February
2016.
[Overlay-Failure-Detection]
Zhuang, S., "On failure detection algorithms in overlay
networks", Proc. IEEE Infocomm, Mar 2005.
[Handling_Churn_in_a_DHT]
Rhea, S., "Handling Churn in a DHT", USENIX Annual
Conference, June 2004.
[Diagnostic_Framework]
Jin, X., "A Diagnostic Framework for Peer-to-Peer
Streaming", 2005.
[Diagnostics_and_NAT_traversal_in_P2PP]
Gupta, G., "Diagnostics and NAT Traversal in P2PP - Design
and Implementation", Columbia University Report , June
2008.
Appendix A. Examples
Below, we sketch how these metrics can be used.
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A.1. Example 1
A peer may set EWMA_BYTES_SENT and EWMA_BYTES_RCVD flags in the
PathTrackReq to its direct neighbors. A peer can use EWMA_BYTES_SENT
and EWMA_BYTES_RCVD of another peer to infer whether it is acting as
a media relay. It may then choose not to forward any requests for
media relay to this peer. Similarly, among the various candidates
for filling up routing table, a peer may prefer a peer with a large
UPTIME value, small RTT, and small LAST_CONTACT value.
A.2. Example 2
A peer may set the STATUS_INFO Flag in the PathTrackReq to a remote
destination peer. The overlay has its own threshold definition for
congestion. The peer can obtain knowledge of all the status
information of the intermediate peers along the path. Then it can
choose other paths to that node for the subsequent requests.
A.3. Example 3
A peer may use Ping to evaluate the average overlay hops to other
peers by sending PingReq to a set of random resource or node IDs in
the overlay. A peer may adjust its timeout value according to the
change of average overlay hops.
Appendix B. Problems with Generating Multiple Responses on Path
An earlier version of this document considered an approach where a
response was generated by each intermediate peer as the message
traversed the overlay. This approach was discarded. One reason this
approach was discarded was that it could provide a DoS mechanism,
whereby an attacker could send an arbitrary message claiming to be
from a spoofed "sender" the real sender wished to attack. As a
result of sending this one message, many messages would be generated
and sent back to the spoofed "sender" - one from each intermediate
peer on the message path. While authentication mechanisms could
reduce some risk of this attack, it still resulted in a fundamental
break from the request-response nature of the RELOAD protocol, as
multiple responses are generated to a single request. Although one
request with responses from all the peers in the route will be more
efficient, it was determined to be too great a security risk and
deviation from the RELOAD architecture.
Appendix C. Changes to the Draft
To RFC editor: This section is to track the changes. Please remove
this section before publication.
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C.1. Changes since -00 version
1. Changed title from "Diagnose P2PSIP Overlay Network" to "P2PSIP
Overlay Diagnostics".
2. Changed the table of contents. Add a section about message
processing and a section of examples.
3. Merge diagnostics text from the p2psip base draft -01.
4. Removed ECHO method for security reasons.
C.2. Changes since -01 version
Added BATTERY_STATUS as diagnostic information.
Removed UnderlayTTL test from the Ping method, instead adding an
UNDERLAY_HOP diagnostic information for PathTrack method.
Give some examples for diagnostic information, and give some
editor's notes for further work.
C.3. Changes since -02 version
Provided further explanation as to why the base draft Ping in the
current form cannot be used to replace Ping, and why some combination
of methods cannot replace PathTrack.
C.4. Changes since -03 version
Modified structure used to share information collected. Both
mechanisms now use a common data structure to convey information.
C.5. Changes since -04 version
Updated the authors' addresses and modified the last sentence in .
(Section 4.3.1.2)
C.6. Changes since -05 version
Resolve Marc's comments from the mailing list. And define the
details of STATUS_INO.
C.7. Changes in version -10
Resolve the authorization issue and other comments (e.g. define
diagnostics as a mandatory extension) from WGLC. And check for the
languages.
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C.8. Changes in version -15
Changed several diagnostic Kind return values to be 64 bit vs. 32 bit
to provide headroom. Split bandwidth into upstream and downstream.
Renamed length in diagnostic request object to ext_length, added
ext_length to response object, and clarified that ext_length is
length of diagnostic info/extensions being returned, not the length
of the object.
Aligned many flags/values with RELOAD by using hex vs decimal values.
Significant reorganization and edit for readability.
C.9. Changes in version -20
Addressed the IESG comments:
(1) this document does not update RFC 6940, but is an extension
(2) remove "p2psip" from the document, according to Ben and
Benoit's comments
(3) update Roni's email address
(4) re-check the document to make sure that access control policy
is the same
(5) change Trust policy from "pre-5378" to "200902"
(6) adress the EWMA_BYTES_RCVD and EWMA_BYTES_SENT equation
problem rasied by Alisa
(7) replace "IANA SHALL" with "IANA is asked to" according to
Spencer and Barry's concern
(8) replace "SHOULD's with "MUST"s in Section 6.2, change "MAY" to
"may" in Section 6.4 according to Ben's comments
(9) add a paragraph in Section 4.3 to explain this document does
not gurantee the same path fro Path_Track, but only provides
information for analysis, according to the list discussion with
Alvaro
(10) change "directly or via symmetric routing" in Section 4.3 to
"direct response routing or via symmetric routing", and give a
reference to direct response routing RFC, according to the list
discussion with Alvaro
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(11) change Section 5.3 and 9.1 about the reserved dMFlags bits
issue according to Jari and Alexey's comment
(12) replace "diagnostic kind type" with "diagnostic Kind"
(12) correct other minor editorial issues
C.10. Changes in version -22
(1) fix the bugs in IANA section
Authors' Addresses
Haibin Song
Huawei
Email: haibin.song@huawei.com
Jiang Xingfeng
Huawei
Email: jiangxingfeng@huawei.com
Roni Even
Huawei
14 David Hamelech
Tel Aviv 64953
Israel
Email: ron.even.tlv@gmail.com
David A. Bryan
ethernot.org
Cedar Park, Texas
United States of America
Email: dbryan@ethernot.org
Yi Sun
ICT
Email: sunyi@ict.ac.cn
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