--- 1/draft-ietf-mboned-mtrace-v2-21.txt 2017-12-20 05:13:24.087770014 -0800 +++ 2/draft-ietf-mboned-mtrace-v2-22.txt 2017-12-20 05:13:24.163771806 -0800 @@ -1,20 +1,20 @@ MBONED Working Group H. Asaeda Internet-Draft NICT Intended status: Standards Track K. Meyer -Expires: May 6, 2018 Cisco +Expires: June 23, 2018 W. Lee, Ed. - November 2, 2017 + December 20, 2017 Mtrace Version 2: Traceroute Facility for IP Multicast - draft-ietf-mboned-mtrace-v2-21 + draft-ietf-mboned-mtrace-v2-22 Abstract This document describes the IP multicast traceroute facility, named Mtrace version 2 (Mtrace2). Unlike unicast traceroute, Mtrace2 requires special implementations on the part of routers. This specification describes the required functionality in multicast routers, as well as how an Mtrace2 client invokes a query and receives a reply. @@ -26,21 +26,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. 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." - This Internet-Draft will expire on May 6, 2018. + This Internet-Draft will expire on June 23, 2018. Copyright Notice Copyright (c) 2017 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -67,31 +67,31 @@ 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 6 3. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Mtrace2 TLV format . . . . . . . . . . . . . . . . . . . 8 3.2. Defined TLVs . . . . . . . . . . . . . . . . . . . . . . 8 3.2.1. Mtrace2 Query . . . . . . . . . . . . . . . . . . . . 9 3.2.2. Mtrace2 Request . . . . . . . . . . . . . . . . . . . 11 3.2.3. Mtrace2 Reply . . . . . . . . . . . . . . . . . . . . 11 3.2.4. IPv4 Mtrace2 Standard Response Block . . . . . . . . 12 - 3.2.5. IPv6 Mtrace2 Standard Response Block . . . . . . . . 15 + 3.2.5. IPv6 Mtrace2 Standard Response Block . . . . . . . . 16 3.2.6. Mtrace2 Augmented Response Block . . . . . . . . . . 18 3.2.7. Mtrace2 Extended Query Block . . . . . . . . . . . . 19 4. Router Behavior . . . . . . . . . . . . . . . . . . . . . . . 20 4.1. Receiving Mtrace2 Query . . . . . . . . . . . . . . . . . 20 4.1.1. Query Packet Verification . . . . . . . . . . . . . . 20 4.1.2. Query Normal Processing . . . . . . . . . . . . . . . 21 4.2. Receiving Mtrace2 Request . . . . . . . . . . . . . . . . 21 4.2.1. Request Packet Verification . . . . . . . . . . . . . 21 4.2.2. Request Normal Processing . . . . . . . . . . . . . . 22 - 4.3. Forwarding Mtrace2 Request . . . . . . . . . . . . . . . 23 + 4.3. Forwarding Mtrace2 Request . . . . . . . . . . . . . . . 24 4.3.1. Destination Address . . . . . . . . . . . . . . . . . 24 4.3.2. Source Address . . . . . . . . . . . . . . . . . . . 24 4.3.3. Appending Standard Response Block . . . . . . . . . . 24 4.4. Sending Mtrace2 Reply . . . . . . . . . . . . . . . . . . 25 4.4.1. Destination Address . . . . . . . . . . . . . . . . . 25 4.4.2. Source Address . . . . . . . . . . . . . . . . . . . 25 4.4.3. Appending Standard Response Block . . . . . . . . . . 25 4.5. Proxying Mtrace2 Query . . . . . . . . . . . . . . . . . 25 4.6. Hiding Information . . . . . . . . . . . . . . . . . . . 26 @@ -148,43 +148,46 @@ On the other hand, walking up the tree from a receiver to a source is easy, as most existing multicast routing protocols know the upstream router for each source. Tracing from a receiver to a source can involve only the routers on the direct path. This document specifies the multicast traceroute facility named Mtrace version 2 or Mtrace2 which allows the tracing of an IP multicast routing path. Mtrace2 is usually initiated from an Mtrace2 client by sending an Mtrace2 Query to a Last Hop Router (LHR) or to a Rendezvous Point (RP). The RP is a special router where sources and - receivers meet in PIM-SM [5]. From the LHR/RP receiving the query, - the tracing is directed towards a specified source if a source - address is specified and source specific state exists on the - receiving router. If no source address is specified or if no source - specific state exists on a receiving LHR, the tracing is directed - toward the RP for the specified group address. Moreover, Mtrace2 - provides additional information such as the packet rates and losses, - as well as other diagnostic information. Mtrace2 is primarily - intended for the following purposes: + receivers meet in Protocol Independent Multicast - Sparse Mode (PIM- + SM) [5]. From the LHR/RP receiving the query, the tracing is + directed towards a specified source if a source address is specified + and source specific state exists on the receiving router. If no + source address is specified or if no source specific state exists on + a receiving LHR, the tracing is directed toward the RP for the + specified group address. Moreover, Mtrace2 provides additional + information such as the packet rates and losses, as well as other + diagnostic information. Mtrace2 is primarily intended for the + following purposes: o To trace the path that a packet would take from a source to a receiver. o To isolate packet loss problems (e.g., congestion). - o To isolate configuration problems (e.g., TTL threshold). + o To isolate configuration problems (e.g., Time to live (TTL) + threshold). - Figure 1 shows a typical case on how Mtrace2 is used. FHR represents - the first-hop router, LHR represents the last-hop router, and the - arrow lines represent the Mtrace2 messages that are sent from one - node to another. The numbers before the Mtrace2 messages represent - the sequence of the messages that would happen. Source, Receiver and - Mtrace2 client are typically hosts. + Figure 1 shows a typical case on how Mtrace2 is used. First-hop + router (FHR) represents the first-hop router, LHR represents the + last-hop router (LHR), and the arrow lines represent the Mtrace2 + messages that are sent from one node to another. The numbers before + the Mtrace2 messages represent the sequence of the messages that + would happen. Source, Receiver and Mtrace2 client are typically + hosts. 2. Request 2. Request +----+ +----+ | | | | v | v | +--------+ +-----+ +-----+ +----------+ | Source |----| FHR |----- The Internet -----| LHR |----| Receiver | +--------+ +-----+ | +-----+ +----------+ \ | ^ \ | / @@ -232,28 +235,30 @@ repeat the process until it receives an Mtrace2 Reply message. The details are Mtrace2 client specific and outside the scope of this document. Note that when a router's control plane and forwarding plane are out of sync, the Mtrace2 Requests might be forwarded based on the control states instead. In this case, the traced path might not represent the real path the data packets would follow. Mtrace2 supports both IPv4 and IPv6. Unlike the previous version of - Mtrace, which implements its query and response as IGMP messages [8], - all Mtrace2 messages are UDP-based. Although the packet formats of - IPv4 and IPv6 Mtrace2 are different because of the address families, - the syntax between them is similar. + Mtrace, which implements its query and response as Internet Group + Management Protocol (IGMP) messages [8], all Mtrace2 messages are + UDP-based. Although the packet formats of IPv4 and IPv6 Mtrace2 are + different because of the address families, the syntax between them is + similar. This document describes the base specification of Mtrace2 that can - serve as a basis for future proposals such as Mtrace2 for AMT [9] and - Mtrace2 for MVPN [10]. They are therefore out of the scope of this + serve as a basis for future proposals such as Mtrace2 for Automatic + Multicast Tunneling (AMT) [9] and Mtrace2 for Multicast in MPLS/BGP + IP VPNs (MVPN) [10]. They are therefore out of the scope of this document. 2. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [1], and indicate requirement levels for compliant Mtrace2 implementations. @@ -301,45 +306,44 @@ communicate with their adjacent routers that are running the same routing protocol. For instance, the IPv4 'ALL-PIM-ROUTERS' group is '224.0.0.13', and the IPv6 'ALL-PIM-ROUTERS' group is 'ff02::d' [5]. 3. Packet Formats This section describes the details of the packet formats for Mtrace2 messages. - All Mtrace2 messages are encoded in TLV format (see Section 3.1). - The first TLV of a message is a message header TLV specifying the - type of message and additional context information required for - processing of the message and for parsing of subsequent TLVs in the - message. Subsequent TLVs in a message, referred to as Blocks, are - appended after the header TLV to provide additional information - associated with the message. If an implementation receives an - unknown TLV type for the first TLV in a message, it SHOULD ignore and - silently discard the TLV and any subsequent TLVs in the packet - containing the TLV. If an implementation receives an unknown TLV - type for a subsequent TLV within a message, it SHOULD ignore and - silently discard the TLV. If the length of a TLV exceeds the + All Mtrace2 messages are encoded in the Type/Length/Value (TLV) + format (see Section 3.1). The first TLV of a message is a message + header TLV specifying the type of message and additional context + information required for processing of the message and for parsing of + subsequent TLVs in the message. Subsequent TLVs in a message, + referred to as Blocks, are appended after the header TLV to provide + additional information associated with the message. If an + implementation receives an unknown TLV type for the first TLV in a + message (i.e., the header TLV), it SHOULD ignore and silently discard + the entire packet. If an implementation receives an unknown TLV type + for a subsequent TLV within a message, it SHOULD ignore and silently + discard the entire packet. If the length of a TLV exceeds the available space in the containing packet, the implementation MUST ignore and silently discard the TLV and any remaining portion of the - containing packet. Any data in the packet after the specified TLV - length is considered to be outside the boundary of the TLV and MUST - be ignored during processing of the TLV. + containing packet. All Mtrace2 messages are UDP packets. For IPv4, Mtrace2 Query and Request messages MUST NOT be fragmented. For IPv6, the packet size for the Mtrace2 messages MUST NOT exceed 1280 bytes, which is the - smallest MTU for an IPv6 interface [2]. The source port is uniquely - selected by the local host operating system. The destination port is - the IANA reserved Mtrace2 port number (see Section 8). All Mtrace2 - messages MUST have a valid UDP checksum. + smallest Maximum Transmission Unit (MTU) for an IPv6 interface [2]. + The source port is uniquely selected by the local host operating + system. The destination port is the IANA reserved Mtrace2 port + number (see Section 8). All Mtrace2 messages MUST have a valid UDP + checksum. Additionally, Mtrace2 supports both IPv4 and IPv6, but not mixed. For example, if an Mtrace2 Query or Request message arrives in as an IPv4 packet, all addresses specified in the Mtrace2 messages MUST be IPv4 as well. Same rule applies to IPv6 Mtrace2 messages. 3.1. Mtrace2 TLV 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 @@ -435,21 +439,21 @@ This field specifies an IPv4 or IPv6 address, which can be either: m-1: a multicast group address to be traced; or, m-2: all 1's in case of IPv4 or the unspecified address (::) in case of IPv6 if no group-specific information is desired. Source Address: 32 bits or 128 bits This field specifies an IPv4 or IPv6 address, which can be either: - s-1: an unicast address of the source to be traced; or, + s-1: a unicast address of the source to be traced; or, s-2: all 1's in case of IPv4 or the unspecified address (::) in case of IPv6 if no source-specific information is desired. For example, the client is tracing a (*,g) group state. Note that it is invalid to have a source-group combination of (s-2, m-2). If a router receives such combination in an Mtrace2 Query, it MUST silently discard the Query. Mtrace2 Client Address: 32 bits or 128 bits @@ -529,28 +533,29 @@ | Rtg Protocol | Multicast Rtg Protocol | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Fwd TTL | MBZ |S| Src Mask |Forwarding Code| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MBZ: 8 bits This field MUST be zeroed on transmission and ignored on reception. Query Arrival Time: 32 bits - The Query Arrival Time is a 32-bit NTP timestamp specifying the - arrival time of the Mtrace2 Query or Request packet at this - router. The 32-bit form of an NTP timestamp consists of the - middle 32 bits of the full 64-bit form; that is, the low 16 bits - of the integer part and the high 16 bits of the fractional part. + The Query Arrival Time is a 32-bit Network Time Protocol (NTP) + timestamp specifying the arrival time of the Mtrace2 Query or + Request packet at this router. The 32-bit form of an NTP + timestamp consists of the middle 32 bits of the full 64-bit form; + that is, the low 16 bits of the integer part and the high 16 bits + of the fractional part. - The following formula converts from a UNIX timeval to a 32-bit NTP - timestamp: + The following formula converts from a timespec (fractional part in + nanoseconds) to a 32-bit NTP timestamp: query_arrival_time = ((tv.tv_sec + 32384) << 16) + ((tv.tv_nsec << 7) / 1953125) The constant 32384 is the number of seconds from Jan 1, 1900 to Jan 1, 1970 truncated to 16 bits. ((tv.tv_nsec << 7) / 1953125) is a reduction of ((tv.tv_nsec / 1000000000) << 16). Note that Mtrace2 does not require all the routers on the path to have synchronized clocks in order to measure one-way latency. @@ -578,52 +583,53 @@ this router expects packets from this source. This may be a multicast group (e.g., ALL-[protocol]-ROUTERS group) if the upstream router is not known because of the workings of the multicast routing protocol. However, it should be 0 if the incoming interface address is unknown or unnumbered. Input packet count on incoming interface: 64 bits This field contains the number of multicast packets received for all groups and sources on the incoming interface, or all 1's if no count can be reported. This counter may have the same value as - ifHCInMulticastPkts from the IF-MIB [12] for this interface. + ifHCInMulticastPkts from the Interfaces Group MIB (IF-MIB) [12] + for this interface. Output packet count on outgoing interface: 64 bit This field contains the number of multicast packets that have been transmitted or queued for transmission for all groups and sources on the outgoing interface, or all 1's if no count can be reported. This counter may have the same value as ifHCOutMulticastPkts from the IF-MIB [12] for this interface. Total number of packets for this source-group pair: 64 bits This field counts the number of packets from the specified source forwarded by the router to the specified group, or all 1's if no count can be reported. If the S bit is set (see below), the count is for the source network, as specified by the Src Mask field (see below). If the S bit is set and the Src Mask field is 127, indicating no source-specific state, the count is for all sources sending to this group. This counter should have the same value as - ipMcastRoutePkts from the IPMROUTE-STD-MIB [13] for this + ipMcastRoutePkts from the IP Multicast MIB [13] for this forwarding entry. Rtg Protocol: 16 bits This field describes the unicast routing protocol running between this router and the upstream router, and it is used to determine the RPF interface for the specified source or RP. This value - should have the same value as ipMcastRouteRtProtocol from the - IPMROUTE-STD-MIB [13] for this entry. If the router is not able - to obtain this value, all 0's must be specified. + should have the same value as ipMcastRouteRtProtocol from the IP + Multicast MIB [13] for this entry. If the router is not able to + obtain this value, all 0's must be specified. Multicast Rtg Protocol: 16 bits This field describes the multicast routing protocol in use between the router and the upstream router. This value should have the - same value as ipMcastRouteProtocol from the IPMROUTE-STD-MIB [13] + same value as ipMcastRouteProtocol from the IP Multicast MIB [13] for this entry. If the router cannot obtain this value, all 0's must be specified. Fwd TTL: 8 bits This field contains the configured multicast TTL threshold, if any, of the outgoing interface. S: 1 bit If this bit is set, it indicates that the packet count for the source-group pair is for the source network, as determined by @@ -739,25 +745,24 @@ for this interface. Outgoing Interface ID: 32 bits This field specifies the interface ID to which packets from the source or RP are expected to transmit, or 0 if unknown. This ID should be the value taken from InterfaceIndex of the IF-MIB [12] for this interface Local Address: 128 bits This field specifies a global IPv6 address that uniquely - identifies the router. An unique local unicast address [11] - SHOULD NOT be used unless the router is only assigned link-local - and unique local addresses. If the router is only assigned link- - local addresses, its link-local address can be specified in this - field. + identifies the router. A unique local unicast address [11] SHOULD + NOT be used unless the router is only assigned link-local and + unique local addresses. If the router is only assigned link-local + addresses, its link-local address can be specified in this field. Remote Address: 128 bits This field specifies the address of the upstream router, which, in most cases, is a link-local unicast address for the upstream router. Although a link-local address does not have enough information to identify a node, it is possible to detect the upstream router with the assistance of Incoming Interface ID and the current router address (i.e., Local Address). @@ -773,21 +778,21 @@ Output packet count on outgoing interface: 64 bits Same definition as in IPv4. Total number of packets for this source-group pair: 64 bits Same definition as in IPv4, except if the S bit is set (see below), the count is for the source network, as specified by the Src Prefix Len field. If the S bit is set and the Src Prefix Len field is 255, indicating no source-specific state, the count is for all sources sending to this group. This counter should have - the same value as ipMcastRoutePkts from the IPMROUTE-STD-MIB [13] + the same value as ipMcastRoutePkts from the IP Multicast MIB [13] for this forwarding entry. Rtg Protocol: 16 bits Same definition as in IPv4. Multicast Rtg Protocol: 16 bits Same definition as in IPv4. MBZ 2: 15 bits This field MUST be zeroed on transmission and ignored on @@ -964,22 +969,23 @@ With the exception of the LHR, whose Request was just converted from a Query, each Request received by a router should have at least one Standard Response Block filled in. 4.2.1. Request Packet Verification If the Mtrace2 Request does not come from an adjacent router, or if the Request is not addressed to this router, or if the Request is addressed to a multicast group which is not a link-scoped group (i.e., 224.0.0.0/24 for IPv4, FFx2::/16 [3] for IPv6), it MUST be - silently ignored. GTSM [14] SHOULD be used by the router to - determine whether the router is adjacent or not. + silently ignored. The Generalized TTL Security Mechanism (GTSM) [14] + SHOULD be used by the router to determine whether the router is + adjacent or not. If the sum of the number of the Standard Response Blocks in the received Mtrace2 Request and the value of the Augmented Response Type of 0x01, if any, is equal or more than the # Hops in the Mtrace2 Request, it MUST be silently ignored. 4.2.2. Request Normal Processing When a router receives an Mtrace2 Request message, it performs the following steps. Note that it is possible to have multiple @@ -1274,27 +1280,28 @@ because a failure requires waiting for the [Mtrace Reply Timeout] period. 5.7. Non-Supported Router When a non-supported router receives an Mtrace2 Query or Request message whose destination address is a multicast address, the router will silently discard the message. When the router receives an Mtrace2 Query which is destined to - itself, the router would return an ICMP port unreachable to the - Mtrace2 client. On the other hand, when the router receives an - Mtrace2 Request which is destined to itself, the router would return - an ICMP port unreachable to its adjacent router from which the - Request receives. Therefore, the Mtrace2 client needs to terminate - the trace when the [Mtrace Reply Timeout] timeout has occurred, and - may then issue another Query with a lower number of # Hops. + itself, the router would return an Internet Control Message Protocol + (ICMP) port unreachable to the Mtrace2 client. On the other hand, + when the router receives an Mtrace2 Request which is destined to + itself, the router would return an ICMP port unreachable to its + adjacent router from which the Request receives. Therefore, the + Mtrace2 client needs to terminate the trace when the [Mtrace Reply + Timeout] timeout has occurred, and may then issue another Query with + a lower number of # Hops. 5.8. Mtrace2 Termination When performing an expanding hop-by-hop trace, it is necessary to determine when to stop expanding. 5.8.1. Arriving at Source A trace can be determined to have arrived at the source if the Incoming Interface of the last router in the trace is non-zero, but @@ -1324,30 +1331,31 @@ will send back an Mtrace2 Reply to the Mtrace2 client, and continue with a new Request (see Section 4.3.3). In this case, the Mtrace2 client may receive multiple Mtrace2 Replies from different routers along the path. When this happens, the client MUST treat them as a single Mtrace2 Reply message. If a trace times out, it is very likely that a router in the middle of the path does not support Mtrace2. That router's address will be in the Upstream Router field of the last Standard Response Block in the last received Reply. A client may be able to determine (via - mrinfo or SNMP [11][13]) a list of neighbors of the non-responding - router. The neighbors obtained in this way could then be probed (via - the multicast MIB [13]) to determine which one is the upstream (RPF) - neighbor of the non-responding router. This algorithm can identify - the upstream neighbor because, even though there may be multiple - neighbors, the non-responding router should only have sent a "join" - to the one neighbor corresponding to its selected RPF path. Because - of this, only the RPF neighbor should contain the non-responding - router as a multicast next hop in its MIB output list for the - affected multicast route. + mrinfo or the Simple Network Management Protocol (SNMP) [11][13]) a + list of neighbors of the non-responding router. The neighbors + obtained in this way could then be probed (via the multicast MIB + [13]) to determine which one is the upstream neighbor (i.e., Reverse + Path Forwarding (RPF) neighbor) of the non-responding router. This + algorithm can identify the upstream neighbor because, even though + there may be multiple neighbors, the non-responding router should + only have sent a "join" to the one neighbor corresponding to its + selected RPF path. Because of this, only the RPF neighbor should + contain the non-responding router as a multicast next hop in its MIB + output list for the affected multicast route. 6. Protocol-Specific Considerations This section describes the Mtrace2 behavior with the presence of different multicast protocols. 6.1. PIM-SM When an Mtrace2 reaches a PIM-SM RP, and the RP does not forward the trace on, it means that the RP has not performed a source-specific @@ -1385,27 +1393,27 @@ appropriate last hop. When traffic is flowing, PIM Dense Mode routers know whether or not they are the LHR for the link (because they won or lost an Assert battle) and know who the upstream router is (because it won an Assert battle). Therefore, Mtrace2 is always able to follow the proper path when traffic is flowing. 6.4. IGMP/MLD Proxy - When an IGMP/MLD Proxy [7] receives an Mtrace2 Query packet on an - incoming interface, it notes a WRONG_IF in the Forwarding Code of the - last Standard Response Block (see Section 3.2.4), and sends the - Mtrace2 Reply back to the Mtrace2 client. On the other hand, when an - Mtrace2 Query packet reaches an outgoing interface of the IGMP/MLD - proxy, it is forwarded onto its incoming interface towards the - upstream router. + When an IGMP or Multicast Listener Discovery (MLD) Proxy [7] receives + an Mtrace2 Query packet on an incoming interface, it notes a WRONG_IF + in the Forwarding Code of the last Standard Response Block (see + Section 3.2.4), and sends the Mtrace2 Reply back to the Mtrace2 + client. On the other hand, when an Mtrace2 Query packet reaches an + outgoing interface of the IGMP/MLD proxy, it is forwarded onto its + incoming interface towards the upstream router. 7. Problem Diagnosis This section describes different scenarios Mtrace2 can be used to diagnose the multicast problems. 7.1. Forwarding Inconsistencies The Forwarding Error code can tell if a group is unexpectedly pruned or administratively scoped. @@ -1484,22 +1492,22 @@ which the new Forwarding Code is used. 8.2. "Mtrace2 TLV Types" registry Assignment of a TLV Type requires specification of an integer value "Code" in the range 0-255 and a name ("Type"). Initial values for the TLV Types are given in the table at the beginning of Section 3.2. 8.3. UDP Destination Port - The Mtrace2 UDP destination port is assigned when this document is - published as RFC. + IANA has assigned UDP user port 33435 (mtrace) for use by this + protocol as the Mtrace2 UDP destination port. 9. Security Considerations This section addresses some of the security considerations related to Mtrace2. 9.1. Addresses in Mtrace2 Header An Mtrace2 header includes three addresses, source address, multicast address, and Mtrace2 client address. These addresses MUST be @@ -1627,20 +1635,16 @@ Authors' Addresses Hitoshi Asaeda National Institute of Information and Communications Technology 4-2-1 Nukui-Kitamachi Koganei, Tokyo 184-8795 Japan Email: asaeda@nict.go.jp Kerry Meyer - Cisco Systems, Inc. - 510 McCarthy Blvd. - Milpitas, CA 95035 - USA - Email: kerrymey@cisco.com + Email: kerry.meyer@me.com WeeSan Lee (editor) Email: weesan@weesan.com