Network Working Group George Swallow Internet Draft Cisco Systems, Inc. Category: Standards Track
Expiration Date: January 2009Vanson Lim Cisco Systems, Inc. July 14,November 3, 2008 Proxy LSP Ping draft-ietf-mpls-remote-lsp-ping-02.txtdraft-ietf-mpls-remote-lsp-ping-03.txt 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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This document defines a means of remotely initiating Multiprocal Label Switched Protocol Pings on Label Switched Paths. A proxy ping request is sent to any Label Switching Routers along a Label Switched Path. The primary motivations for this facility are first to limit the number of messages and related processing when using LSP Ping in large Point-to-Multipoint LSPs, and second to enable leaf to root tracing. Contents 1 Introduction .............................................. 3 1.1 Conventions ............................................... 34 2 Proxy Ping Overview ....................................... 4 3 Proxy MPLS Echo Request / Reply Pprocedures ............... 5 3.1 Procedures for the initiator .............................. 5 3.2 Procedures for the proxy LSR .............................. 6 3.2.1 Sending an MPLS proxy ping reply .......................... 7 3.2.2 Sending the MPLS echo requests ............................ 78 4 Proxy Ping Request / Reply Messages ....................... 9 4.1 Proxy Ping Request / Reply Message formats ................ 9 4.2 Proxy Ping Request Message contents ....................... 1011 4.3 Proxy Ping Reply Message Contents ......................... 11 5 Object formats ............................................ 1112 5.1 Proxy Echo Parameters Object .............................. 1112 5.1.1 Next Hop sub-Object ....................................... 1314 5.2 Reply-to Address Object ................................... 1415 5.3 Previous Hop Address Object ............................... 15 6 Security Considerations ................................... 16 7 IANA Considerations ....................................... 16 7.1 Message and Object Type Assignments ....................... 16 7.2 Return Code Assignments ...................................17 8 References ................................................ 1718 8.1 Normative References ...................................... 1718 8.2 Informative References .................................... 1718 9 Authors' Addresses ........................................ 18 1. Introduction It is anticipated that very large Point-to-Multipoint (P2MP) Label Switched Paths (LSPs) will exist. Further it is anticipated that many of the applications for P2MP tunnels will require OAM that is both rigorous and scalable. Suppose one wishes to trace a P2MP LSP to localize a fault which is affecting one egress or a set of egresses. Suppose one follows the normal procedure for tracing - namely repeatedly pinging from the root, incrementing the TTL by one after each three or so pings. Such a procedure has the potential for producing a large amount of pro- cessing at the P2MP-LSP midpoints and egresses. It also could pro- duce an unwieldy number of replies back to the root. One alternative would be to begin sending pings from points at or near the affected egress(es) and working backwards toward the root. The TTL could be held constant as say two, limiting the the number of responses to the number of next-next-hops of the point where thea ping wasis initiated. This document defines protocol extensions to MPLS ping [RFC4379] to allow a third party to remotely cause an MPLS echo request message to be sent down a Label Switched Path (LSP) or part of an LSP. The pro- cedure described in the paragraphs above proceduredoes require that the rootini- tiator know the previous-hop node to the one which was pinged on the prior iteration. This infor- mationinformation is readily available in [P2MP-TE]. This also document provides a means for obtaining this information for [mLDP] as well as defining a means for remotely causing an MPLS echo request message to be sent down a Label Switched Path (LSP) or part of an LSP.[mLDP]. While the motivaton for this document came from multicast scaling concerns, its applicability may be wider. However other uses of this facility are beyond the scope of this document. In particular, the procedures defined in this document only allow testing of a FEC stack consisting of a single FEC. It also does not allow the initiator to specify the label assigned to that FEC, nor does it allow the initia- tor to cause any additional labels to be added to the label stack of the actual MPLS echo request message. Further the discus- siondiscussion is cauched in terms of multipoint LSPs. 1.1. Conventions 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 RFC 2119 [KeyWords]. The term "Must Be Zero" (MBZ) is used in object descriptions for reserved fields. These fields MUST be set to zero when sent and ignored on receipt. Based on context the terms leaf and egress are used interchangeably. Egress is used where consistency with [RFC4379] was deemed appropri- ate. Receiver is used in the context of receiving protocol messages. [Note (to be removed after assignments occur): <tba> = to be assigned by IANA] 2. Proxy Ping Overview This document defines a protocol interaction between a first node and a node which is part of an LSP to allow the first node to remotely initiate a an LSP ping for the LSP. Two new LSP Ping messages are defined for remote pinging, the MPLS proxy ping request and the MPLS proxy ping reply. A remote ping operation on a P2MP LSP involves at least three LSRs; in some scenarios none of these are the ingress (root) or an egress (leaf) of the LSP. We refer to these nodes with the following terms: Initiator - the node which initiates the ping operation by sending an MPLS proxy ping request message Proxy LSR - the node which is the destination of the MPLS proxy request message and potential initiator of the MPLS echo request Receiver(s) - the receivers of the MPLS echo request messages The initiator formats an MPLS proxy ping request message and sends it to the proxy LSR, a node it believes to be on the path of the LSP. This message specifies the MPLS echo request to be sent inband of the LSP. It may also request the proxy LSR to acknowledge the receipt of the proxy ping request message and/or respond with the address of the previous hop, i.e. the LSR upstream of it on this LSP. The proxy LSR validates that it has a label mapping for the specified FEC and that it is authorized to send the specified MPLS echo request on behalf of the initiator. Depending on the Reply Mode carried in the header of the proxy ping request message and the above results an MPLS remote echo reply message might be sent back to the initiator. This message may also communicate the address of the previous hop. If the proxy LSR has a label mapping for the FEC and and all autho- rization checkchecks have passed, the proxy LSR formats an MPLS echo request. If the source address of the IP packet is not the initia- tor, it includes a Reply-to Address object containing the initiator's address. It then sends it inband of the LSP. The receivers process the MPLS echo request as normal, sending their MPLS echo replies back to the initiator. 3. Proxy MPLS Echo Request / Reply Pprocedures 3.1. Procedures for the initiator The initiator creates an MPLS proxy ping request message. The message MUST contain a Target FEC Stack that describes the FEC being tested. [Note for the current version of the ID, the FEC stack is limited to a single FEC as we have not yet fully considered the operational and security impacts of permitting more FECs]The message MUST contain a Proxy Echo Parameters object. TheIn that object, the address type is set to either IPv4 or IPv6. The DestinationDestina- tion IP Address is set to the value to be used in the MPLS echo request packet. If the Address Type is IPv4, an address from the range 127/8. If the Address Type is IPv6, an address from the range 0:0:0:0:0:FFFF:127/104. By default the source address will be set to an address of the proxy LSR.0:0:0:0:0:FFFF:7F00:0/104. The Reply mode and Global Flags of the Proxy Echo Parameters object are set to the values to be used in the MPLS echo request message header. The Source UDP Port is set to the value to be used in the MPLS echo request packet. The TTL is set to the value to be used in the outgoing MPLS label stack. See section 22.214.171.124 for further details. Flags MAY be set to requestIf the previous hop address and/or a down- streamdownstream mapping object from the proxy LSR.LSR is needed the corresponding flag in the Flags field of the Proxy Echo Parameters object is set. A list of Next Hop IP Addresses MAY be included to limit the next hops towards which the MPLS echo request message will be sent. These are encoded as Next Hop sub-objects and included in the Proxy Echo Parameters object. Any of following objects MAY be included; these objects will be copied into the MPLS echo request messages: Pad Vendor Enterprise Number Reply TOS Byte P2MP Egress Identifier [McstPing] Echo Jitter TLV [McstPing] Vendor Private TLVs Downstream Mapping objects MAY be included. These objects will be matched to the next hop address for inclusion in those particular MPLS echo request messages. The message is then encapsulated in a UDP packet. The source UDP port is chosen by the sender; the destination UDP port is set to 3503. The IP header is set as follows: the source IP address is a routable address of the sender; the destination IP address is a routable address of the midpoint. The packet is then sent with the IP TTL is set to 255. 3.2. Procedures for the proxy LSR A proxy LSR that receives an MPLS proxy ping request message, parses the packet to ensure that it is a well-formed packet. It checks that the TLVs that are not marked "Ignore" are understood. If not, it sets the Return Code set to "Malformed echo request received" or "TLV not understood" (as appropriate), and the Subcode set to zero. If the Reply Mode of the message header is not 1, an MPLS proxy ping reply message SHOULD be sent as described below. In the latter case, the misunderstood TLVs (only) are included in an Errored TLVs object. The header fields Sender's Handle and Sequence Number are not exam- ined, but are saved to be included in the MPLS proxy ping reply and MPLS echo request messages. The proxy LSR validates that it has a label mapping for the specified FEC, it then determines if it is an egress, transit or bud node and sets the Return Code as appropriate. The proxy LSR then determines if it is authorized to send the speci- fied MPLS echo request on behalf of the initiator. An LSR MUST be capable of filtering addresses to validate initiators. Other filters on FECs or MPLS echo request contents MAY be applied. If a filter has been invoked (i.e. configured) and an address does not pass the filter, then an MPLS echo request message MUST NOT be sent, and the event SHOULD be logged. An MPLS proxy ping reply message mayMAY be sent with a Return Code of <tba>, "Remote Ping not authorized". The destination address specified in the Proxy Echo Parameters object is checked to ensure that it conforms to the address allowed IPv4 or IPv6 address range. If not, it sets the Return Code set to "Mal- formed echo request received" and the Subcode set to zero. If the Reply Mode of the message header is not 1, an MPLS proxy ping reply message SHOULD be sent as described below. If the "Request for Previous Hop" flag is set, a Previous Hop Address Object is formatted for inclusion in the MPLS proxy ping reply. If the previous HOP is unknown or ambiguous the Address Type is set to "No Address Supplied". If there is a list ofare Next Hop addressessub-objexts in the Proxy Echo Parameters object, each address is examined to determine if it is a next hop for this FEC. If any are not, those addressessub-objects are deletedfrom the list. The updatedProxy Echo Parameters object. The updated object is included in the MPLS proxy ping reply. If the "Request for Downstream Mapping" flag is set the LSR formats a Downstream Mapping object for each interface thatover which the MPLS echo request will be sent out.sent. If the Reply Mode of the message header is not1 or 5,is 5 and no errors or modificatons have occurred no MPLS proxy ping reply is sent. Other- wise an MPLS remote echoproxy ping reply message SHOULD be sent as described below. 3.2.1. Sending an MPLS proxy ping reply The Reply mode, Sender's Handle and Sequence Number fields are copied from the proxy ping request message. VariousThe objects are included asspecified above.above are included. The message is encapsulated in a UDP packet. The source IP address is a routable address of the proxy LSR; the source port is the well-known UDP port for LSP ping. The destination IP address and UDP port are copied from the source IP address and UDP port of the echo request. The IP TTL is set to 255. 3.2.2. Sending the MPLS echo requests A base MPLS echo request is formed as decribed in the next section. The section below that describes how the base MPLS echo request is sent on each interface. 126.96.36.199. Forming the base MPLS echo request A Next_Hop_List is created as follows. If Next Hop addressessub-objects were included in the received Proxy Parameters object, the Next_Hop_List is copiedcreated from the Proxy Echo Parameters objectaddress in those sub-ojects as adjusted above. Otherwise,Oth- erwise, the list is set to all the next hops to which the FEC would be forwarded. The proxy LSR then formats an MPLS echo request message. The Global Flags and Reply Mode are copied from the Proxy Echo Parameters object. The Return Code and Return Subcode are set to zero. The Sender's Handle and Sequence Number are copied from the remote echo request message. The TimeStamp Sent is set to the time-of-day (in seconds and microseconds) that the echo request is sent. The TimeStamp Received is set to zero. A Reply-to Address object containing the initiator's address is included. The following objects are copied from the MPLS proxy ping request message. Note that of these, only the Target FEC Stack is REQUIRED to appear in the MPLS proxy ping request message. Target FEC Stack Pad Vendor Enterprise Number Reply TOS Byte P2MP Egress Identifier [McstPing] Echo Jitter TLV [McstPing] Vendor Private TLVs The message is then encapsulated in a UDP packet. The source UDP port is copied from the Proxy Echo Parameters object. destination ports areThe destina- tion port copied from the proxy ping request message. The source IP address is set to a routable address of the proxy LSR. Per usual the TTL of the IP packet is set to 1. If the Explicit DSCP flag is set, the Requested DSCP byte is exam- ined. If the setting is permitted then the DSCP byte of the IP header of the MPLS Echo Request message is set to that value. Other- wise the DSCP byte is set to a default value. In this case the MPLS Proxy Echo Parameters with the Explicit DSCP flag cleared MUST be included in any MPLS proxy ping reply message. The return code MUST be set to <tba>, "Proxy ping parameters modified". The DSCP field of the MPLS Proxy Echo Parameters SHOULD be set to the actual value used. 188.8.131.52. Per interface sending procedures The proxy LSR now iterates through the Next_Hop_List modifying the base MPLS echo request to form the MPLS echo request packet which is then sent on that particular interface. For each next hop address, the outgoing label stack is determained. The TTL for the label corresponding to the topmostFEC specified in the FEC stack is set such that the TTL on the wire will be one less than the TTL specified in the Proxy Echo Parameters. If any additional labels are pushed onto the stack, their TTLs are set to 255. If the MPLS proxy ping request message contained Downstream Mapping objects, they are examined. If the Downstream IP Address matches the next hop address that Downstream Mapping object is included in the MPLS echo request. The packet is then transmitted on this interface. 4. Proxy Ping Request / Reply Messages TwoThis document defines two new LSP Ping messages are defined for remote pinging,messages, the MPLS proxy ping request messageand the MPLS proxy ping reply. 4.1. Proxy Ping Request / Reply Message formats Except where noted, the definitions of all fields in the messages are identical to those found in [LSP-PING].[RFC4379]. The messages have the fol- lowingfollow- ing format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version Number | MUST Be Zero | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Type | Reply mode | Return Code | Return Subcode| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender's Handle | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLVs ... | . . . . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Version Number The Version Number is currently 1. (Note: the Version Number is to be incremented whenever a change is made that affects the ability of an implementation to correctly parse or process an MPLS echo request/reply. These changes include any syntactic or semantic changes made to any of the fixed fields, or to any TLV or sub-TLV assignment or format that is defined at a certain version number. The Version Number may not need to be changed if an optional TLV or sub-TLV is added.) Message Type Type Message ---- ------- 5 MPLS proxy ping request 6 MPLS proxy ping reply Reply mode The reply modes are the same as [LSP-PING][RFC4379] with the addtion of value 5. For completeness, the full list of reply modes follows: Value Meaning ----- ------- 1 Do not reply 2 Reply via an IPv4/IPv6 UDP packet 3 Reply via an IPv4/IPv6 UDP packet with Router Alert 4 Reply via application level control channel 5 Reply via an IPv4/IPv6 UDP packet only if the proxy request is not fulfilled or is modified 4.2. Proxy Ping Request Message contents The MPLS proxy ping request message MAY contain the following objects: Type Object ---- ----------- 1 Target FEC Stack 2 Downstream Mapping 3 Pad 5 Vendor Enterprise Number 10 Reply TOS Byte tba Proxy Echo Parameters tba P2MP Egress Identifier [McstPing] tba Echo Jitter TLV [McstPing] Vendor Private TLVs 4.3. Proxy Ping Reply Message Contents The MPLS proxy ping reply message MAY contain the following objects: Type Object ---- ----------- 1 Target FEC Stack 2 Downstream Mapping 5 Vendor Enterprise Number 9 Errored TLVs tba Proxy Echo Parameters tba Previous Hop Address Vendor Private objects 5. Object formats 5.1. Proxy Echo Parameters Object The Proxy Echo Parameters object is a TLV that MUST be included in an MPLS Proxy Echo Request message. The length of the TLV is 12 + K + S, where K is the length of the Destination IP Address field and S is the total length of the sub-objects. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address Type | Flags | Reply mode | TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Rqst'd DSCP | Must be Zero | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source UDP Port | Global Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : Destination IP Address : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : : : Sub-Objects : : : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Type The type and length of the address found in the in the Destination IP Address and Next Hop IP Addresses fields. The type codes appear in the table below: Address Family Type Length IPv4 1 4 IPv6 3 16 Flags Request for Previous Hop 0x01 When set this requests that the proxy LSR supply the previous hop address in the MPLS proxy ping reply message Request for Downstream Mapping 0x02 When set this requests that the proxy LSR supply a Downstream Mapping object in the MPLS proxy ping reply message Explicit DSCP Request 0x04 When set this requests that the proxy LSR supply a use the supplied DSCP byte in the echo request message Reply mode The reply mode to be sent in the MPLS Echo Request message; the values are as specified in [RFC4379] TTL The TTL to be used in the label stack entry corresponding to the topmost FEC in the in the MPLS Echo Request packet Requested DSCP This field is valid only if the Explicit DSCP flag is set. If not set, the field MUST be zero on transmission and ignored on receipt. When the flag is set this field contains the DSCP value to be used in the MPLS echo request packet IP header. Source UDP Port The source UDP port to be sent in the MPLS Echo Request packet Global Flags The Global Flags to be sent in the MPLS Echo Request messge Destination IP Address If the Address Type is IPv4, an address from the range 127/8; If the Address Type is IPv6, an address from the range 0:0:0:0:0:FFFF:127/1040:0:0:0:0:FFFF:7F00:0/104 Sub-Objects A TLV encoded list of sub-objects. Currently one is defined. Sub-Type Length Value Field -------- ------ ----------- 1 8+ Next Hop 5.1.1. Next Hop sub-Object This sub-object is used to describe a particular next hop towards which the Echo Request packet should be sent. If the topmost FEC in the FEC-stack is a multipoint LSP, this sub-object may appear multi- ple times. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Addr Type | MUST be Zero | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Hop IP Address (4 or 16 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Hop Interface (0, 4 or 16 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Type Type Type of Next Hop Addr Length IF Length 1 IPv4 Numbered 4 4 2 IPv4 Unnumbered 4 4 3 IPv6 Numbered 16 16 4 IPv6 Unnumbered 16 4 5 IPv4 Protocol Adj 4 0 6 IPv6 Protocol Adj 16 0 Note: Types 1-4 correspond to the types in the DS Mapping object. They are expected to populated with information obtained through a previously returned DS Mapping object. Types 5 and 6 are intended to be populated from the local address information obtained from a previously returned Previous Hop Address Object. Next Hop IP Address A next hop address that the echo request message is to be sent towards Next Hop Interface Identifier of the interface through which the echo request message is to be sent 5.2. Reply-to Address Object +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address Type | MUST be Zero | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : Reply-to Address : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Type A type code as specified in the table below: Type Type of Address 1 IPv4 3 IPv6 5.3. Previous Hop Address Object +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |PHOP Addr Type |Local Addr Type| MUST be Zero | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : Previous Hop Address : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | : Local Address : | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PHOP Addr Type; Local Addr Type These two fields determine the type and length of the respective addresses. The codes are specified in the table below: Type Type of Address Length 0 No Address Supplied 0 1 IPv4 4 3 IPv6 16 Previous Hop Address The address of the immediate upstream neighbor for the topmost FEC in the FEC stack. If protocol adjacency exists by which the label for this FEC was exchanged, this address MUST be the address used in that protocol exchange. Local Address The local address used in the protocol adjacency exists by which the label for this FEC was exchanged. 6. Security Considerations [ToThe mechanisms described in this document are intended to be used within a Service Provider network and to be initiated only under the authority of that administration. If such a network also carries internet traffic, or permits IP access from other administrations, MPLS proxy ping message SHOULD be dis- carded at those points. This can be accomplished by filtering on source address or by filtering all MPLS ping messages on UDP port. Any node which acts as a proxy node SHOULD validate requests against a set of valid source addresses. An implementation MUST provide such filtering capabilities. MPLS proxy ping request messages are IP addressed directly to the Proxy node. If a node which receives an MPLS proxy ping message via TTL expiration, it MUST NOT be acted upon. MPLS proxy ping requests are limited to making their request via the specification of a FEC. This ensures that only valid MPLS echo request messages can be written]created. No label spoofing attacks are possible. 7. IANA Considerations [Not complete] 7.1. Message and Object Type AssignmentsThis document makes the following codepointassigments (pending IANA action): Registry Codepoint PurposeLSP Ping Message Types Type Value Field ---- ----------- tba MPLS proxy ping request message tba MPLS proxy ping reply LSP Ping ObjectObjects and Sub-Objects Type Sub-Type Value Field ---- -------- ----------- tba Proxy Echo Parameters 1 Next Hop tba Reply-to Address tba Previous Hop Address 7.2.Return Code AssignmentsCodes Value Meaning ----- ------- tba ProxyRemote ping requestnot authorized tba Proxy ping parameters modified Reply Modes [pending IANA assignment] Value Meaning ----- ------- 5 Reply via an IPv4/IPv6 UDP packet only if the proxy request is not fulfilled or is modified 8. References 8.1. Normative References [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [KeyWords] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [McstPing] Farrel, A. et al, "Detecting Data Plane Failures in Point-to-Multipoint MPLS Traffic Engineering - Extensions to LSP Ping", draft-ietf-mpls-p2mp-lsp-ping-06.txt, Junedraft-ietf-mpls-p2mp-lsp-ping-07.txt, September 2008. 8.2. Informative References [P2MP-TE] Aggarwal, R., et al., "Extensions to RSVP-TE for Point-to-Multipoint TE LSPs", RFC 4875, May 2007. [mLDP] Minei, I., et. al., "Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths" draft-ietf-mpls-ldp-p2mp-05.txt, May 2008. 9. Authors' Addresses George Swallow Cisco Systems, Inc. 1414 Massachusetts Ave Boxborough, MA 01719 Email: firstname.lastname@example.org Vanson Lim Cisco Systems, Inc. 1414 Massachusetts Ave Boxborough, MA 01719 Email: email@example.com Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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