Network Working Group Hewen. Zheng Internet-Draft Xingfeng. Jiang Intended status: Standards Track Huawei Technologies Expires: June 13, 2008 December 11, 2007 Diagnose P2PSIP Overlay Network Failures draft-zheng-p2psip-diagnose-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 13, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document describes a simple and efficient mechanism that can be used to detect and localize failures in P2PSIP overlay network. This document mainly consists of two parts: information carried in a P2PSIP Peer "Echo request" message and "Echo response" message for the purpose of fault detection and localization, and mechanisms for processing those messages. Zheng & Jiang Expires June 13, 2008 [Page 1] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Overview of Functions . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Packets Formats . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Message Header . . . . . . . . . . . . . . . . . . . . . . 5 5.2. Message Attributes . . . . . . . . . . . . . . . . . . . . 6 5.2.1. Response Attribute . . . . . . . . . . . . . . . . . . 6 5.2.2. Echo Attribute . . . . . . . . . . . . . . . . . . . . 7 5.2.3. Respond Peer Info Attribute . . . . . . . . . . . . . 10 6. Message . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Echo request . . . . . . . . . . . . . . . . . . . . . . . 12 6.2. Echo response . . . . . . . . . . . . . . . . . . . . . . 12 6.2.1. Echo response from the terminator peer . . . . . . . . 13 6.2.2. Echo response from the intermediate peer . . . . . . . 14 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. P2PSIP Ping . . . . . . . . . . . . . . . . . . . . . . . 16 9.2. P2PSIP Traceroute . . . . . . . . . . . . . . . . . . . . 17 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Intellectual Property and Copyright Statements . . . . . . . . . . 21 Zheng & Jiang Expires June 13, 2008 [Page 2] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 1. Introduction Service is provisioned by more than one peers collectively in the P2PSIP overlay network, this mode avoids "a single point of failure" introduced by the traditional Client/Server mode. "Collectivity" means that the failure occurred in one peer can not impact service provided by the overlay network, i.e., most peers can continuously and normally be served by the overlay network, but some peer or peers are impacted. The quality of service provided by the overlay network will degrade or even be interrupted due to the failure. Considering the complexity of service provisioning in the overlay network, a diagnostics system is more desirable for the overlay network than the usual network adopting Client/Server mode. This document describes a simple and efficient mechanism that can be used to detect and localize failures in P2PSIP overlay network, i.e., this document describes a P2PSIP diagnostics protocol. This document mainly consists of two parts: information carried in a P2PSIP Peer "Echo request" message and "Echo response" message for the purpose of fault detection and localization, and mechanisms for processing those messages. An important consideration in this design is that P2PSIP Peer Echo requests follow the same data path that normal P2PSIP peer protocol packets would traverse. 2. Overview of Functions As one diagnostics protocol, P2PSIP diagnostics protocol is mainly used to detect and localize failures in P2PSIP overlay network. It provides mechanisms to detect and localize malfunctioning or badly behaving peers including disabled peers, congested peer and misrouting peers. It provides a mechanism to detect connectivity to the specified peer, a mechanism to detect availabilities of specified resource record and a mechanism to discover P2PSIP overlay topology and responding underlay topology. P2PSIP diagnostics protocol reuses P2PSIP peer protocol [I-D.jiang- p2psip-sep]; essentially it reuses P2PSIP peer protocol specification and then introduces one new type of message (i.e., Echo message). P2PSIP diagnostics protocol strictly follows the P2PSIP peer protocol specification on the messages routing, transporting and NAT traverse etc. 3. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this Zheng & Jiang Expires June 13, 2008 [Page 3] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 document are to be interpreted as described in [RFC2119]. The other concepts used in this document are compatible with P2PSIP Work Group Draft "Concepts and Terminology for Peer to Peer SIP" [I-D.ietf-p2psip-concepts]. 4. Motivation In the last few years, overlay networks have rapidly evolved and emerged as a promising platform to deploy 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 relies on accurate and timely detection of failures. As descriptions in the "Security requirements in P2PSIP" [I-D.matuszewski-p2psip-security- requirement] and "Security Mechanisms for Peer to Peer SIP"[I-D.jennins-p2psip-security- mechanisms], there are some malfunctioning or badly behaving peers in the P2PSIP overlay, those peers may be disabled peers, congested peer or peers behaving with misrouting, and the impact of those peers in the overlay network is degradation of quality of service provided collectively by the peers in the overlay network or interruption of those services. It is desirable to identify malfunctioning or badly behaving peers through some diagnostics tools, and exclude or reject them from the P2PSIP system. Besides those faults, node failures may caused by underlying failures, for example, when the IP layer routing failover speed after link failures is very slow, then the recovery from the incorrect overlay topology may also be slow. Moreover, if a backbone link fails and the failover is slow, the network may be partitioned, which may lead to partitions of overlay topologies and inconsistent routing results between different partitioned components. Some keep-alive algorithms basing on periodically probe and acknowledge enable accurate and timely detection of failures of one peer's neighbors [Overlay-Failure-Detection], but those algorithms only can detect the disabled neighbors using the periodical method, it is evidently not enough for overlay network. One general P2PSIP overlay diagnostics protocol supporting periodical Zheng & Jiang Expires June 13, 2008 [Page 4] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 method and on-demand method for node failures and network failures is desirable, especially for P2PSIP overlay network operator. This document describe one general P2PSIP overlay diagnostics protocol basing on P2PSIP peer protocol, at some degree, it is a good complementation for some keep-alive algorithms in the P2PSIP peer protocol implementation. In this document, we mainly describe how to detect and localize those failures including disabled peers, congested peers, misrouting behaviors and underlying network faults in P2PSIP overlay network through a simple and efficient mechanism. This mechanism is modeled after the ping/traceroute paradigm: ping (ICMP echo request [RFC792]) 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" mode and a "traceroute" mode for diagnose P2PSIP overlay network. The basic idea is to transmit a P2PSIP peer protocol request message (Echo request message) along the same path which all other P2PSIP peer protocol request messages would traverse. In "Ping" mode, an Echo request message are forwarded by the intermediate peers along the path and then terminated by the last peer, and after local diagnosis, the last peer returns an Echo response message. In "Traceroute" mode, an Echo request message is received and disposed by each peer along the path, and after completing diagnosis procedure using predetermined method, each peer along the path returns an Echo response message with local diagnostics information including the result and causes if existing. One way these tools can be used is to detect the connectivity to the specified peer or the availability of the specified resource-record through P2PSIP Ping operation once the overlay network receives some alarms about overlay service degradation or interruption, if the ping fails, one can then initiate a P2PSIP Traceroute to determine where the fault lies. 5. Packets Formats This document reuses P2PSIP peer protocol to carry diagnostics information. Considering special usage due to diagnostics, this document extends P2PSIP peer protocol by introducing one new type of message and some attributes. 5.1. Message Header The mechanism defined in this document follows P2PSIP peer protocol specification, the introduced message whatever request form or Zheng & Jiang Expires June 13, 2008 [Page 5] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 response form adopts the same message format with existing P2PSIP peer protocol messages, those message uses the common header. Different types of messages convey different contents according to the protocol design, and then those different contents are described by different TLV (Type-Length-Value) style objects combinations. Those objects are called as "Attributes". Please refer to P2PSIP peer protocol [I-D.jiang-p2psip-sep] for the detailed format of Message Header. This document introduces one new type of message as below: Message Type Name 11 Echo 5.2. Message Attributes As P2PSIP peer protocol, A P2PSIP diagnostics protocol message contains zero, one or multiple Attributes which describe the specified contents. All attributes follow P2PSIP peer protocol specification and adopt TLV style. Please refer to P2PSIP peer protocol [I-D.jiang- p2psip-sep] for the detailed format of Message Attributes. This document introduces two new types of attributes as below: Attribute Type Name 15 Echo 16 Respond Peer Info In addition to the newly introduced Echo attribute, this document extends the Response attribute defined in P2PSIP peer protocol specification. 5.2.1. Response Attribute This document extends the Response attribute defined in the P2PSIP peer protocol specification to describe the result of diagnostics as Figure 1. Zheng & Jiang Expires June 13, 2008 [Page 6] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |M| Reserved |Attribute Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Response code | Response sub-code | +-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ Figure 1 Response Attribute Format M-flag: the value is 1; Reserved (7 bits): those bits are reserved and ignored; Attribute Type (8 bits): the value is 7 (0x07); Length (16 bits): the length in bytes of this attribute; Response Code (16 bits): response code determined by the initiator, this field is necessary for any response attribute; Response Sub-Code (16 bits): response sub-code determined by the initiator, this field is optional for one response attribute. This document introduces new response codes as below: Response Code Meaning 414 Underlay Destination Unreachable 415 Underlay Time exceeded 416 Upstream Misrouting 417 Loop detected 419 TTL hops exceeded This document introduces response sub-codes for response code 414 as below: Response Sub-Code Meaning 0 net unreachable 1 host unreachable 2 protocol unreachable 3 port unreachable 4 fragmentation needed 5 source route failed 5.2.2. Echo Attribute This document introduces Echo attribute to describe diagnosing control information, including but not limited to: the forward mode of the Echo request message, the reply mode of the Echo response message, the reply rule to generate the Echo response message, the Zheng & Jiang Expires June 13, 2008 [Page 7] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 timestamp of initiating the Echo request message, the timestamp of receiving the Echo request message, the lifetime of the Echo request message in the overlay and the expiration time of the Echo request message. The Echo attribute format is shown as Figure 2: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |M|U|P|Reserved |Attribute Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Forward mode | Reply mode | Reply rule | Underlay TTL | +-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ | TimeStamp Initiated (seconds) | +-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ | TimeStamp Initiated (microseconds) | +-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ | TimeStamp Received (seconds) | +-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ | TimeStamp Received (microseconds) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Expiration time (seconds) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Expiration time (microseconds) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Echo Attribute Format M-flag: the value is 1; U-flag: indicate whether the receiver of Echo request message needs to carry information of its immediate upstream peer in the following Echo response message. If set (U=1), the Echo response message must carry information of its immediate upstream peer such as Peer-ID; P-flag: indicate whether the intermediate peer continues to forward the Echo request message when it detects misrouting behavior of its immediate upstream peer for this Echo request message. If set (P=1), the intermediate peer continues to forward the Echo request message upon detecting misrouting behavior of its immediate upstream peer; otherwise the intermediate peer stops forwarding. Certainly the intermediate peer should stop forwarding any received Echo request message once detecting looping even when P-flag is set; Reserved (5 bits): those bits are reserved and ignored; Attribute Type (8 bits): the value is 15 (0x0F); Zheng & Jiang Expires June 13, 2008 [Page 8] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Length (16 bits): the length in bytes of this attribute; Forward mode (8 bits): indicate the Echo request message overlay routing mode specified by the initiator. It does not impact the overlay routing behavior of any Echo response message; Reply mode (8 bits): indicate the Echo response message returning mode specified by the initiator. It does not impact the routing behavior of any Echo request message; Reply rule (8 bits): indicate the Echo request message process policy specified by the initiator; Underlay TTL (8 bits): indicate the underlay TTL which the Echo request message forwarded by the intermediate peer adopts, it is specified by the initiator; Timestamp Initiated (64 bits): the time-of-day (in seconds and microseconds, according to the sender's clock) in NTP format [RFC2030] when the P2PSIP Overlay Echo request is sent。It can be carried in the Echo response message from the receiver; certainly it first appears in the Echo request message; Timestamp Received (64 bits): it is in an Echo response message and the time-of-day (according to the receiver's clock) in NTP format [RFC2030] that the corresponding the P2PSIP Overlay Echo request was received; Expiration time (64 bits): the expiration time of Echo request message, it is the time-of-day in NTP format [RFC2030]. If the time receiving this Echo request message is equal or later than the expiration time indicated by this field of the Echo request message, this message should be discarded silently. In the Traceroute mode described in the following sections, the immediate node updates this field in the forwarding message with the new value which is the sum of Timestamp Received and Life time. This document defines those forward modes as below: Zheng & Jiang Expires June 13, 2008 [Page 9] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Forward mode Meaning 0 Choice by the receiver 1 Recursive 2 Iterative 3 Preferable recursive 4 Preferable iterative This document defines those reply modes as below: Reply mode Meaning 0 Determined by the receiver 1 Reply via IP directly 2 Reply via Overlay This document defines those reply rules as below: Reply rule Meaning 1 Do not reply except last peer 2 Immediately reply 5.2.3. Respond Peer Info Attribute This document introduces Respond Peer attribute to describe Peer information such as Peer-ID. Respond Peer Info attribute is also a composite attribute. Like the Source Peer Info attribute and Destination Peer Info attribute, it may be also comprised of Peer-ID attribute, Peer Service Capability attribute and several Peer Address Info attributes, the Peer-ID attribute and at least one Peer Address Info attribute are necessary among them. The Respond Peer Info attribute format is shown as Figure 3. Zheng & Jiang Expires June 13, 2008 [Page 10] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |M|U|D|Reserved |Attribute Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peer-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peer service capability | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peer Address Info - 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ............ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peer Address Info - N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Respond Peer Info attribute format M-flag: the value is 1; U-flag: indicate whether this attribute describe the immediate upstream peer of the initiator generating this attribute. If set (U=1), the attribute is used to describe the immediate upstream peer on the path; D-flag: indicate whether this attribute describe the immediate downstream peer of the initiator generating this attribute (e.g. next-hop peer in the overlay forwarding path). If set (D=1), the attribute is used to describe the immediate downstream peer on the path. If U=0 and D=0, the attribute is used to describe the peer itself (i.e. the attribute generator); Reserved (5 bits): those bits are reserved and ignored; Attribute Type (8 bits): the value is 16 (0x10); Length (16 bits): the length in bytes of this attribute. 6. Message All P2PSIP peer protocol messages use the common message header after which zero, one or more TLV-style attributes follow. Each type of message contains the request form and its response form. This document introduces one new type of message to detect and localize failures in P2PSIP overlay network. It is called "Echo" message, including "Echo request" form and "Echo response" form. Zheng & Jiang Expires June 13, 2008 [Page 11] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 6.1. Echo request An Echo request message is used to detect possible failures in the specified path of P2PSIP overlay network, including disabled peers, congested peers, misrouting behavior and underlying network faults. An Echo request message is also used to discover the topology of the specified path and check the reachability to the specified peer or the availability of the specified resource-record. An Echo request message is normal P2PSIP peer protocol message; it can be initiated by any formal peer supporting P2PSIP peer protocol specification in the P2PSIP overlay network. An Echo request message must contain a message header and an Echo attribute. Echo request = Message Header Echo Attribute 6.2. Echo response An Echo response message is used to convey local diagnostics information including result, causes and possible other assistant information. One implementation to estimate whether one peer is disabled is that the initiator of an Echo request message uses local timer to determine whether the expected Echo response message is expired, i.e., the peer thinks that the specified peer is disabled if it does not receive the Echo response message before the local timer expires started when issuing an Echo request message to the specified peer in the P2PSIP overlay network. This local timer can be updated in the specified interval by the Echo response message from the intermediate peers in the "Traceroute" mode; the interval is set by the initiator of the Echo request message and indicated by the Life time field of the Echo attribute. Any intermediate peer which forwards an Echo request message must not modify the message body except updating Expiration time field of the Echo attribute. An Echo response message must contain a message header, a Response attribute, an Echo attribute and one or more Respond Peer Info attributes. It may contain a Resource Info attribute and a Status attribute. If the peer is one immediate peer, the Echo response message must contain three Respond Peer Info attributes to describe self, immediate upstream peer and next-hop peer individually. If the Zheng & Jiang Expires June 13, 2008 [Page 12] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 peer is the last peer terminating the Echo request message, the Echo message must contain two Respond Peer Info attributes to describe self and immediate upstream peer. In the following section, the last peer terminating the Echo request message is called as the "terminator peer", in comparison with "intermediate peer" and "initiator peer" or "initiator". Echo response = Message Header Response Attribute Echo Attribute Respond Peer Info Attribute [Resource Info Attribute] [Status Attribute] 6.2.1. Echo response from the terminator peer When an Echo request message arrived at a peer, if the peer's responsible ID space covers the destination ID of the Echo request message or the peer finds that the destination ID is unreachable in the P2PSIP overlay (e.g., detecting loop), then the peer constructs and returns an Echo response message using the specified Reply mode indicated by the Echo request message when the Reply rule field of the received Echo attribute is not Zero, or the peer does not give any response when the Reply rule field is Zero. The Echo response message must carry a Response attribute, a Respond Peer Info attribute describing the receiver of the Echo request message, an Echo attribute containing Time Received field and Time Initiated field copied from the received Echo request message. The returning Echo response message further must carry a Resource attribute when the responsible resource-record exists in the peer. If the Echo response message does not carry any Resource attribute, it means that the resource-record whose Resource-ID is equal to the destination ID of the Echo request message does not exist in the peer. If the peer finds that it is bush or congested, the returning Echo response message must carry a Status attribute. If the peer finds that its immediate upstream peer behaves with misrouting, the returning Echo response message must carry a Response attribute with the response code 416 "Upstream Misrouting" and a Respond Peer Info attribute describing information of its immediate upstream peer. Zheng & Jiang Expires June 13, 2008 [Page 13] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 6.2.2. Echo response from the intermediate peer When an Echo request message arrived at a peer, if the peer's responsible ID space does not cover the destination ID of the Echo request message, then the peer continues to forward this Echo Request message according to the specified Forward mode field in the received Echo request message. The peer should return an Echo response message carrying a Response attribute with the response code 414 "Underlay Destination Unreachable" when it receives an ICMP message with "Destination Unreachable" information after forwarding the received Echo request message. The peer should return an Echo response message carrying a Response attribute with the response code 415 "Underlay Time Exceeded" when it receives an ICMP message with "Time Exceeded" information after forwarding the received Echo request message. When an Echo request message arrived at a peer, if the peer's responsible ID space does not cover the destination ID of the Echo request message and the value of received Reply rule field is 2, then the peer must construct and return an Echo response besides continuing to forward the Echo request message. The Echo response message must carry a Response attribute, a Respond Peer Info attribute describing the receiver of the Echo request message, a Respond Peer Info attribute describing the immediate downstream peer (i.e. next hop to forward the Echo request message in the P2PSIP overlay network), an Echo attribute containing Time Received field and Time Initiated field copied from the received Echo request message. The returning Echo response message must carry a Resource attribute when the responsible resource-record exists in the peer. If the Echo response message does not carry any Resource attribute, it means that the resource-record whose Resource-ID is equal with the destination ID of the Echo request message does not exist in the peer. If the peer finds that it is bush or congested, the returning Echo response message must carry a Status attribute. If the peer finds that its immediate upstream peer behaves with misrouting, the returning Echo response message must carry a Response attribute with the response code 416 "Upstream Misrouting" and Respond Peer Info attribute describing information of its immediate upstream peer. Zheng & Jiang Expires June 13, 2008 [Page 14] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 7. Security Considerations One feasible P2PSIP Traceroute implementation basing on the value of "Reply Rule" field 2 "Immediately reply" (Section 9.2) may cause DoS attack to the initiator, though this implementation is more efficient than traditional Traceroute operation of Internet using pacing ICMP message. An advice is to use the efficient Traceroute operation in administrated P2PSIP overlay and use the pacing-style Traceroute operation in the untrustworthy P2PSIP overlay network, certainly, the probability of this type of DoS attack is very low because the overlay is distributed and the it is very hard for the attacker to know the accurate Peer-IDs and attack most of all peers simultaneously. 8. IANA Considerations Message Type: this document introduces a new type of message as below: Message Type Name 11 Echo Attribute Type: this document introduces two new types of attributes as below: Attribute Type Name 15 Echo 16 Respond Peer Info Response Code: this document introduces some new response definitions as below: Result Code Name 414 Underlay Destination Unreachable 415 Underlay Time exceeded 416 Upstream Misrouting 417 Loop detected 419 TTL hops exceeded Response Sub-Code: this document defines response sub-codes for the response code 414 "Underlay Destination Unreachable" as below: Zheng & Jiang Expires June 13, 2008 [Page 15] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Response Sub-Code Meaning 0 net unreachable 1 host unreachable 2 protocol unreachable 3 port unreachable 4 fragmentation needed 5 source route failed 9. Examples 9.1. P2PSIP Ping Any peer supporting P2PSIP diagnostics protocol can use P2PSIP Ping operation to check the reachablity to the specified peer in the overlay or the availability of the specified resource-record. In the normal P2PSIP Ping operation, a peer constructs and issues an Echo request message to the specified destination ID. The destination ID of the Echo request message is the specified Peer-ID or Resource-ID, the source ID of the Echo request message is the Peer-ID of the initiator. The "Reply Rule" value must be 1 "Do not reply except last peer", and the initiator determines the "Forward mode", "Reply mode" and "Underlay TTL" of the Echo request message by itself. Any intermediate peer does only simply forward this message to its next hop in the overlay and not disposes this Echo request message until the message arrives at the terminator peer who may be the destination peer or one peer who finds that the destination ID is unreachable, eventually the terminator peer returns an Echo response message. Here is an example of a P2PSIP Ping operation; it is shown as Figure 4: Zheng & Jiang Expires June 13, 2008 [Page 16] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Peer-1 Peer-2 Peer-3 Peer-4 | | | | | (1).Echo Request | | | |------------------->| | | | | (2).Echo Request | | | |------------------->| | | | | (3).Echo Request | | | |------------------->| | | | | | | | (4).Echo Response | |<-------------------|--------------------|--------------------| | | | | Figure 4 P2PSIP Ping example The overlay network operator may use P2PSIP Ping operation to measure the message transmission delay and jitter between two specified peers. 9.2. P2PSIP Traceroute Any peer supporting P2PSIP diagnostics protocol can use P2PSIP traceroute operation to detect and localize malfunctioning or badly behaving peers including disabled peers, congested peers and misrouting peers, or detect and localize network failure, or to discover the topology of the specified path in the overlay network. In one possible P2PSIP Traceroute operation, a peer constructs and issues an Echo request message to the specified destination ID. The destination ID in the Echo request message is the specified Peer-ID or Resource-ID, the source ID in the Echo request message is the Peer-ID of the initiator. The value of "Reply Rule" field must be 2 "Immediately reply", and the initiator determines the "Forward mode", "Reply mode" and "Underlay TTL" of the Echo request message by itself. Any intermediate peer does dispose this Echo request message, i.e., forwards this message to its next hop in the overlay and then returns an Echo response message. The terminator peer for the Echo request message is the destination peer or one peer who finds that the destination ID is unreachable; eventually the terminator peer returns an Echo response message. Here is an example of a P2PSIP Traceroute operation; it is shown as Figure 5: Zheng & Jiang Expires June 13, 2008 [Page 17] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Peer-1 Peer-2 Peer-3 Peer-4 | | | | | (1).Echo Request | | | |------------------->| | | | | (2).Echo Request | | | |------------------->| | | (3).Echo Response | | | |<-------------------| | | | | | (4).Echo Request | | | |------------------->| | | (5).Echo Response | | |<-------------------|--------------------| | | | | (6).Echo Response | |<-------------------|--------------------|--------------------| | | | | Figure 5 P2PSIP Traceroute example 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC792] Postel, J., "Internet Control Message Protocol", STD5, RFC 792, September 1981. [RFC2030] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", RFC 2030, October 1996. [RFC4981] J. Risson, "Survey of Research towards Robust Peer-to-Peer Networks: Search Methods", RFC 4981, September 2007. [I-D.ietf-p2psip-concepts] Bryan, D., "Concepts and Terminology for Peer to Peer SIP", draft-ietf-p2psip-concepts-00 (work in progress), June 2007. [I-D.matuszewski-p2psip-security-requirement] M. Matuszewski, "Security requirements in P2PSIP", draft-matuszewski-p2psip-security-requirements-01 (work in progress), July 2007 [I-D.jennins-p2psip-security-mechanisms] C. Jennings, "Security Zheng & Jiang Expires June 13, 2008 [Page 18] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Mechanisms for Peer to Peer SIP", draft-jennings-p2psip-security-00 (work in progress), February 2007 [I-D.jiang-p2psip-sep] X. Jiang, "Service Extensible P2P Peer Protocol", draft-jiang-p2psip-sep-00 (work in progress), November 2007. [I-D.bryan-p2psip-requirement] D. Bryan, "P2PSIP Protocol Framework and Requirements", draft-bryan-p2psip-requirements-00 (work in progress), July 2007 [Overlay-Failure-Detection] S. Zhuang, "On failure detection algorithms in overlay networks", Proc. IEEE Infocomm, Mar 13-17 2005. [P2PSIP-Concepts-Terminology] Dean Willis, "P2PSIP Concepts and Terminology", http://www3.ietf.org/proceedings/07jul/slides/p2psip- 13.pdf, July 2007 10.2. Informative References [I-D.ietf-behave-rfc3489bis] Rosenberg, J., Huitema, C., Mahy, R., and D. Wing, "Simple Traversal Underneath Network Address Translators (NAT) (STUN)", draft-ietf-behave- rfc3489bis-08 (work in progress), July 2007. [I-D.ietf-behave-turn] Rosenberg, J., Mahy, R., and C. Huitema, "Obtaining Relay Addresses from Simple Traversal Underneath NAT (STUN)", draft-ietf-behave-turn-04 (work in progress), July 2007. [I-D.ietf-mmusic-ice] Rosenberg, J., "Interactive Connectivity Establishment (ICE): A Methodology for Network Address Translator (NAT) Traversal for Offer/Answer Protocols", draft-ietf-mmusic-ice-17 (work in progress), July 2007 [I-D.bryan-p2psip-dsip] Bryan, D., "dSIP: A P2P Approach to SIP Registration and Resource Location", draft-bryan-p2psip-dsip-00 (work in progress), February 2007. [I-D.bryan-p2psip-reload] Bryan, D., "REsource LOcation And Discovery (RELOAD)", draft-bryan-p2psip-reload-00 (work in progress), June 2007. [I-D.baset-p2psip-p2pp] S. Baset, "Peer-to-Peer Protocol (P2PP)", draft-baset-p2psip-p2pp-00 (work in progress), July 2007. [I-D.Jennings-p2psip-asp] C. Jennings, "Address Settlement by Peer to Peer", draft-jennings-p2psip-asp-00 (work in progress), July 2007. Zheng & Jiang Expires June 13, 2008 [Page 19] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 [I-D.marocco-p2psip-xpp-pcan] Marocco, E. and E. Ivov, "XPP Extensions for Implementing a Passive P2PSIP Overlay Network based on the CAN Distributed Hash Table", draft-marocco-p2psip-xpp-pcan-00 (work in progress), June 2007. [I-D.matthews-p2psip-hip-hop] Cooper, E., "A Distributed Transport Function in P2PSIP using HIP for Multi-Hop Overlay Routing", draft-matthews-p2psip-hip-hop-00 (work in progress), June 2007. Authors' Addresses Zheng Hewen Huawei Technologies Baixia Road No. 91 Nanjing, Jiangsu Province 210001 PRC Phone: +86-25-84565467 Fax: +86-25-84565848 Email: hwzheng@huawei.com Jiang Xingfeng Huawei Technologies Baixia Road No.91 Nanjing, Jiangsu Province 210001 PRC Phone: +86-25-84565468 Fax: +86-25-84565848 Email: jiang.x.f@huawei.com Zheng & Jiang Expires June 13, 2008 [Page 20] Internet-Draft Diagnose P2PSIP Overlay Network Failures December 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Zheng & Jiang Expires June 13, 2008 [Page 21]