Multicast On-Path Telemetry Using In Situ Operations, Administration, and Maintenance (IOAM)Futurewei Technologies2330 Central ExpresswaySanta ClaraCAUnited States of Americahsong@futurewei.comFuturewei Technologies2330 Central ExpresswaySanta ClaraCAUnited States of Americammcbride@futurewei.comEricssonUnited States of Americagregimirsky@gmail.comVerizon Inc.United States of Americagyan.s.mishra@verizon.comNational Institute of Information and Communications TechnologyJapanasaeda@nict.go.jpHuawei TechnologiesBeijingChinazhoutianran@huawei.com
OPS
mbonedMulticastTelemetryThis document specifies two solutions to meet the requirements of
on-path telemetry for multicast traffic using IOAM. While
IOAM is advantageous for multicast traffic telemetry, some unique
challenges are present. This document provides the solutions based on
the IOAM trace option and direct export option to support the
telemetry data correlation and the multicast tree reconstruction without
incurring data redundancy.
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RFC 7841.
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Table of Contents
. Introduction
. Requirements Language
. Requirements for Multicast Traffic Telemetry
. Issues of Existing Techniques
. Modifications and Extensions Based on Existing Solutions
. Per-Hop Postcard Using IOAM DEX
. Per-Section Postcard for IOAM Trace
. Application Considerations for Multicast Protocols
. Mtrace Version 2
. Application in PIM
. Application of MVPN PMSI Tunnel Attribute
. Security Considerations
. IANA Considerations
. References
. Normative References
. Informative References
Acknowledgments
Authors' Addresses
IntroductionIP multicast has had many useful applications for several decades.
provides a thorough historical perspective about the design and
deployment of many of the multicast routing protocols in use with various applications. We will mention of few of these throughout this
document and in the Application Considerations section (). IP multicast has been used by residential broadband customers across operator networks,
private MPLS customers, and internal customers within corporate intranets. IP multicast has provided real-time interactive online meetings or
podcasts, IPTV, and financial markets' real-time data, all of which rely on UDP's unreliable transport. End-to-end QoS, therefore,
should be a critical component of multicast deployments in order to provide a good end-user experience within a specific operational domain.
In multicast real-time media streaming, if a single packet is lost within a keyframe and
cannot be recovered using forward error correction, many receivers will be unable to decode subsequent frames
within the Group of Pictures (GoP), which results in video freezes or black pictures until another keyframe is delivered. Unexpectedly long
delays in delivery of packets can cause timeouts with similar results. Multicast packet loss and delays can therefore affect application
performance and the user experience within a domain.It is essential to monitor the performance of multicast traffic. New on-path telemetry techniques, such as
IOAM ,
IOAM Direct Export (DEX) ,
IOAM Postcard-Based Telemetry - Marking (PBT-M) , and
Hybrid Two-Step (HTS) ,
complement existing active OAM performance monitoring methods like ICMP ping . However, multicast traffic's unique characteristics
present challenges in applying these techniques efficiently.The IP multicast packet data for a particular (S,G) state remains identical across different branches to multiple receivers .
When IOAM trace data is added to multicast packets, each replicated packet retains telemetry data for its entire forwarding path.
This results in redundant data collection for common path segments, unnecessarily consuming extra network bandwidth.
For large multicast trees, this redundancy is substantial. Using solutions like IOAM DEX could be more efficient by eliminating data redundancy,
but IOAM DEX lacks a branch identifier, complicating telemetry data correlation and multicast tree reconstruction.This document provides two solutions to the IOAM data-redundancy problem based on the IOAM standards. The requirements for multicast traffic telemetry
are discussed along with the issues of the existing on-path telemetry techniques. We propose modifications and extensions
to make these techniques adapt to multicast in order for the original multicast tree to be correctly reconstructed while
eliminating redundant data. This document does not cover the operational considerations such as how to enable the telemetry on a subset of the traffic to avoid overloading
the network or the data collector.Requirements Language
The key words "MUST", "MUST NOT",
"REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT",
"RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be
interpreted as described in BCP 14 when, and only when, they appear in all capitals, as
shown here.
Requirements for Multicast Traffic Telemetry Multicast traffic is forwarded through a multicast tree. With PIM and Point-to-Multipoint (P2MP), the forwarding
tree is established and maintained by the multicast routing protocol. The requirements for multicast traffic telemetry that are addressed by the solutions in this document are:
Reconstruct and visualize the multicast tree through data-plane monitoring.
Gather the multicast packet delay and jitter performance on each path.
Find the multicast packet-drop location and reason.
In order to meet all of these requirements, we need the ability to directly monitor the multicast traffic and derive data from the multicast packets.
The conventional OAM mechanisms, such as multicast ping , trace , and
RTCP , are not sufficient to meet all of these requirements. The telemetry methods in this document meet
these requirements by providing granular hop-by-hop network monitoring along with the reduction of data redundancy.Issues of Existing Techniques On-path telemetry techniques that directly retrieve data from multicast traffic's live network experience are ideal for
addressing the aforementioned requirements. The representative techniques include
IOAM Trace option ,
IOAM DEX option , and
PBT-M . However,
unlike unicast, multicast poses some unique challenges to applying these techniques. Multicast packets are replicated at each branch fork node in the corresponding multicast tree. Therefore, there are
multiple copies of the original multicast packet in the network. When the IOAM trace option is utilized for on-path data collection, partial trace data is replicated into the packet
copy for each branch of the multicast tree. Consequently, at the leaves of the multicast tree, each copy of the multicast packet
contains a complete trace. This results in data redundancy, as most of the data (except from the final leaf branch) appears in multiple copies,
where only one is sufficient. This redundancy introduces unnecessary header overhead, wastes network bandwidth, and complicates data processing.
The larger the multicast tree or the longer the multicast path, the more severe the redundancy problem becomes. The postcard-based solutions (e.g., IOAM DEX) can eliminate data redundancy because each
node on the multicast tree sends a postcard with only local data. However, these methods cannot accurately track and correlate the tree branches due to the absence of branching
information. For instance, in the multicast tree shown in , Node B has two branches, one to Node C and the
other to node D; further, Node C leads to Node E, and Node D leads to Node F (not shown). When applying postcard-based methods, it is impossible to determine whether Node E
is the next hop of Node C or Node D from the received postcards alone, unless one correlates the exporting nodes with knowledge about the tree collected by other
means (e.g., mtrace). Such correlation is undesirable because it introduces extra work and complexity. The fundamental reason for this problem is that there is not an identifier (either implicit or explicit) to correlate the
data on each branch. Modifications and Extensions Based on Existing SolutionsWe provide two solutions to address the above issues. One is based on IOAM DEX and requires an extension to the DEX Option-Type header.
The second solution combines the IOAM trace option and postcards for redundancy removal.Per-Hop Postcard Using IOAM DEXOne way to mitigate the postcard-based telemetry's tree-tracking weakness is to augment it with a branch identifier field. This works for
the IOAM DEX option because the DEX Option-Type header can be used to hold
the branch identifier. To make the branch identifier
globally unique, the Branching Node ID plus an index is used. For example, as shown in , Node B has two branches: one to Node C and the other to
Node D. Node B may use [B, 0] as the branch identifier for the branch to C, and [B, 1] for the branch to D. The identifier is carried with the multicast packet until the
next branch fork node. Each node MUST export the branch identifier in the received IOAM DEX header in the postcards it sends.
The branch identifier, along with the other fields such as Flow ID and Sequence Number, is sufficient for the data collector to
reconstruct the topology of the multicast tree. shows an example of this solution. "P" stands for the postcard packet. The square brackets contains the branch identifier. The
curly braces contain the telemetry data about a specific node. Per-Hop Postcard
P:[A,0]{A} P:[A,0]{B} P:[B,1]{D} P:[B,0]{C} P:[B,0]{E}
^ ^ ^ ^ ^
: : : : :
: : : : :
: : : +-:-+ +-:-+
: : : | | | |
: : +---:----->| C |------>| E |-...
+-:-+ +-:-+ | : | | | |
| | | |----+ : +---+ +---+
| A |------->| B | :
| | | |--+ +-:-+
+---+ +---+ | | |
+-->| D |--...
| |
+---+
Each branch fork node needs to generate a unique branch identifier (i.e., Multicast Branch ID) for each branch in its multicast tree instance and include
it in the IOAM DEX Option-Type header. The Multicast Branch ID remains unchanged until the next branch fork node. The Multicast Branch ID contains two parts:
the Branching Node ID and an Interface Index. Conforming to the node ID specification in IOAM , the Branching Node ID is a 3-octet unsigned integer.
The Interface Index is a two-octet unsigned integer. As shown in , the Multicast Branch ID consumes 8 octets in total. The three unused octets MUST be set to 0;
otherwise, the header is considered malformed and the packet MUST be dropped. Multicast Branch ID 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Branching Node ID | unused |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Index | unused |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
shows that the Multicast Branch ID is carried as an optional field after the Flow ID and Sequence Number optional fields
in the IOAM DEX option header. Two bits "N" and "I" (i.e., the third and fourth bits in the Extension-Flags field) are reserved to indicate the presence of
the optional Multicast Branch ID field. "N" stands for the Branching Node ID, and "I" stands for the Interface Index. If "N" and "I" are both set to 1, the optional Multicast
Branch ID field is present. Two Extension-Flag bits are used because specifies that each extension flag only indicates the presence of a 4-octet optional data field,
while we need more than 4 octets to encode the Multicast Branch ID.
The two flag bits MUST be both set or cleared; otherwise, the header is considered malformed and the packet MUST be dropped. Carrying the Multicast Branch ID in the IOAM DEX Option-Type Header
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Namespace-ID | Flags |F|S|N|I|E-Flags|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IOAM-Trace-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow ID (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Branch ID (as shown in Figure 2) |
| (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Once a node gets the branch ID information from the upstream node, it MUST carry this information in its
telemetry data export postcards so the original multicast tree can be correctly reconstructed based on the postcards. Per-Section Postcard for IOAM TraceThe second solution is a combination of the IOAM trace option and the postcard-based telemetry .
To avoid data redundancy, at each branch fork node, the trace data accumulated up to this node is exported
by a postcard before the packet is replicated. In this solution, each branch also needs to maintain some identifier to help correlate the postcards
for each tree section. The natural way to accomplish this is to simply carry the branch fork node's data (including its ID) in the trace of each branch.
This is also necessary because each replicated multicast packet can have different telemetry data pertaining to this particular copy (e.g., node
delay, egress timestamp, and egress interface). As a consequence, the local data exported by each branch fork node can only contain the common
data shared by all the replicated packets (e.g., ingress interface and ingress timestamp). shows an example in a segment of a multicast tree. Node B and D are two branch fork nodes, and they will export
a postcard covering the trace data for the previous section. The end node of each path will also need to export the data of the last section as a
postcard.Per-Section Postcard
P:{A,B'} P:{B1,C,D'}
^ ^
: :
: :
: : {D1}
: : +--...
: +---+ +---+ |
: {B1} | |{B1,C}| |--+ {D2}
: +-->| C |----->| D |-----...
+---+ +---+ | | | | |--+
| | {A} | |--+ +---+ +---+ |
| A |---->| B | +--...
| | | |--+ +---+ {D3}
+---+ +---+ | | |{B2,E}
+-->| E |--...
{B2} | |
+---+
There is no need to modify the IOAM trace option header format as specified in . We just need to configure the branch fork nodes, as well as the leaf nodes, to
export the postcards that contain the trace data collected so far and refresh the IOAM header and data in the packet (e.g., clear the node data list to all zeros and reset the RemainingLen field to the initial value).Application Considerations for Multicast ProtocolsMtrace Version 2Mtrace version 2 (Mtrace2) is a protocol that allows the tracing of an IP multicast routing path. Mtrace2 provides
additional information such as the packet rates and losses, as well as other diagnostic information. Unlike unicast traceroute, Mtrace2 traces the path
that the tree-building messages follow from the receiver to the source. An Mtrace2 client sends an Mtrace2 Query to a Last-Hop Router (LHR), and the LHR
forwards the packet as an Mtrace2 Request towards the source or a Rendezvous Point (RP) after appending a response block. Each router along the
path proceeds with the same operations. When the First-Hop Router (FHR) receives the Request packet, it appends its own response block, turns the
Request packet into a Reply, and unicasts the Reply back to the Mtrace2 client. New on-path telemetry techniques will enhance Mtrace2, and other existing OAM solutions, with more granular and real-time network status data through
direct measurements. There are various multicast protocols that are used to forward the multicast data. Each will require its own unique on-path telemetry solution.
Mtrace2 doesn't integrate with IOAM directly, but network management systems may use Mtrace2 to learn about routers of interest. Application in PIMPIM - Sparse Mode (PIM-SM) is the most widely used multicast routing protocol deployed today. PIM - Source-Specific Multicast (PIM-SSM), however, is the preferred method due to
its simplicity and removal of network source discovery complexity. With PIM, control plane state is established in the network in order to forward multicast
UDP data packets. PIM utilizes network-based source discovery. PIM-SSM, however, utilizes application-based source discovery. IP multicast packets fall within the range
of 224.0.0.0 through 239.255.255.255 for IPv4 and ff00::/8 for IPv6. The telemetry solution will need to work within these IP address ranges and provide telemetry data for this UDP traffic. A proposed solution for encapsulating the telemetry instruction header and metadata in IPv6 packets is described in
. Application of MVPN PMSI Tunnel AttributeIOAM, and the recommendations of this document, are equally applicable to multicast MPLS forwarded packets as described in .
Multipoint Label Distribution Protocol (mLDP), P2MP RSVP-TE, Ingress Replication (IR), and PIM Multicast Distribution Tree (MDT) SAFI with GRE Transport are all commonly
used within a Multicast VPN (MVPN) environment utilizing MVPN procedures such as multicast in MPLS/BGP IP VPNs
and BGP encoding and procedures for multicast in MPLS/BGP IP VPNs . mLDP LDP
extensions for P2MP and multipoint-to-multipoint (MP2MP) label switched paths (LSPs) provide extensions to LDP to establish point-to-multipoint (P2MP) and
MP2MP LSPs in MPLS networks. The telemetry solution will need to be able to follow these P2MP and MP2MP paths.
The telemetry instruction header and data should be encapsulated into MPLS packets on P2MP and MP2MP paths. Security ConsiderationsThe schemes discussed in this document share the same security considerations for the IOAM trace option and the IOAM DEX
option . In particular, since multicast has a built-in nature for packet amplification, the possible amplification risk for the DEX-based
scheme is greater than the case of unicast. Hence, stricter mechanisms for protections need to be applied. In addition to selecting packets to enable DEX and to limit the exported traffic rate, we can also allow only a subset of the nodes in a multicast tree to process the option and export the data (e.g., only the branching nodes in the
multicast tree are configured to process the option). IANA ConsiderationsIANA has registered two Extension-Flags, as described in , in the "IOAM DEX Extension-Flags" registry.
IOAM DEX Extension-Flags
Bit
Description
Reference
2
Multicast Branching Node ID
This RFC
3
Multicast Branching Interface Index
This RFC
ReferencesNormative ReferencesKey words for use in RFCs to Indicate Requirement LevelsIn many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched PathsThis document describes extensions to the Label Distribution Protocol (LDP) for the setup of point-to-multipoint (P2MP) and multipoint-to-multipoint (MP2MP) Label Switched Paths (LSPs) in MPLS networks. These extensions are also referred to as multipoint LDP. Multipoint LDP constructs the P2MP or MP2MP LSPs without interacting with or relying upon any other multicast tree construction protocol. Protocol elements and procedures for this solution are described for building such LSPs in a receiver-initiated manner. There can be various applications for multipoint LSPs, for example IP multicast or support for multicast in BGP/MPLS Layer 3 Virtual Private Networks (L3VPNs). Specification of how such applications can use an LDP signaled multipoint LSP is outside the scope of this document. [STANDARDS-TRACK]Multicast in MPLS/BGP IP VPNsIn order for IP multicast traffic within a BGP/MPLS IP VPN (Virtual Private Network) to travel from one VPN site to another, special protocols and procedures must be implemented by the VPN Service Provider. These protocols and procedures are specified in this document. [STANDARDS-TRACK]BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNsThis document describes the BGP encodings and procedures for exchanging the information elements required by Multicast in MPLS/BGP IP VPNs, as specified in RFC 6513. [STANDARDS-TRACK]Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)This document specifies Protocol Independent Multicast - Sparse Mode (PIM-SM). PIM-SM is a multicast routing protocol that can use the underlying unicast routing information base or a separate multicast-capable routing information base. It builds unidirectional shared trees rooted at a Rendezvous Point (RP) per group, and it optionally creates shortest-path trees per source.This document obsoletes RFC 4601 by replacing it, addresses the errata filed against it, removes the optional (*,*,RP), PIM Multicast Border Router features and authentication using IPsec that lack sufficient deployment experience (see Appendix A), and moves the PIM specification to Internet Standard.Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsRFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.Data Fields for In Situ Operations, Administration, and Maintenance (IOAM)In situ Operations, Administration, and Maintenance (IOAM) collects operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document discusses the data fields and associated data types for IOAM. IOAM-Data-Fields can be encapsulated into a variety of protocols, such as Network Service Header (NSH), Segment Routing, Generic Network Virtualization Encapsulation (Geneve), or IPv6. IOAM can be used to complement OAM mechanisms based on, e.g., ICMP or other types of probe packets.In Situ Operations, Administration, and Maintenance (IOAM) Direct ExportingIn situ Operations, Administration, and Maintenance (IOAM) is used for recording and collecting operational and telemetry information. Specifically, IOAM allows telemetry data to be pushed into data packets while they traverse the network. This document introduces a new IOAM option type (denoted IOAM-Option-Type) called the "IOAM Direct Export (DEX) Option-Type". This Option-Type is used as a trigger for IOAM data to be directly exported or locally aggregated without being pushed into in-flight data packets. The exporting method and format are outside the scope of this document.Informative ReferencesHybrid Two-Step Performance Measurement MethodEricssonZTE CorporationZTE CorporationFuturewei TechnologiesIndependent The development and advancements in network operation automation have
brought new measurement methodology requirements. mong them is the
ability to collect instant network state as the packet being
processed by the networking elements along its path through the
domain. That task can be solved using on-path telemetry, also called
hybrid measurement. An on-path telemetry method allows the
collection of essential information that reflects the operational
state and network performance experienced by the packet. This
document introduces a method complementary to on-path telemetry that
causes the generation of telemetry information. This method,
referred to as Hybrid Two-Step (HTS), separates the act of measuring
and/or calculating the performance metric from collecting and
transporting network state. The HTS packet traverses the same set of
nodes and links as the trigger packet, thus simplifying the
correlation of informational elements originating on nodes traversed
by the trigger packet.
Work in ProgressFramework for In-situ Flow Information TelemetryFutureweiChina MobileChina TelecomLG U+SK Telecom As network scale increases and network operation becomes more
sophisticated, existing Operation, Administration, and Maintenance
(OAM) methods are no longer sufficient to meet the monitoring and
measurement requirements. Emerging data-plane on-path telemetry
techniques, such as IOAM and AltMrk, which provide high-precision
flow insight and issue notifications in real time can supplement
existing proactive and reactive methods that run in active and
passive modes. They enable quality of experience for users and
applications, and identification of network faults and deficiencies.
This document describes a reference framework, named as In-situ Flow
Information Telemetry, for the on-path telemetry techniques.
The high-level framework outlines the system architecture for
applying the on-path telemetry techniques to collect and correlate
performance measurement information from the network. It identifies
the components that coordinate existing protocol tools and telemetry
mechanisms, and addresses deployment challenges for flow-oriented on-
path telemetry techniques, especially in carrier networks.
The document is a guide for system designers applying the referenced
techniques. It is also intended to motivate further work to enhance
the OAM ecosystem.
Work in ProgressMulticast Lessons Learned from Decades of Deployment Experiencelispers.netJuniperFutureweiDeutsche Telekom This document gives a historical perspective about the design and
deployment of multicast routing protocols. The document describes
the technical challenges discovered from building these protocols.
Even though multicast has enjoyed success of deployment in special
use-cases, this draft discusses what were, and are, the obstacles for
mass deployment across the Internet. Individuals who are working on
new multicast related protocols will benefit by knowing why certain
older protocols are no longer in use today.
Work in ProgressOn-Path Telemetry using Packet Marking to Trigger Dedicated OAM PacketsFuturewei TechnologiesEricssonHuaweiHuaweiSwisscomVerizon Inc.SK TelecomLG U+Work in ProgressInternet Control Message ProtocolReal Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)The Session Description Protocol (SDP) is used to describe the parameters of media streams used in multimedia sessions. When a session requires multiple ports, SDP assumes that these ports have consecutive numbers. However, when the session crosses a network address translation device that also uses port mapping, the ordering of ports can be destroyed by the translation. To handle this, we propose an extension attribute to SDP.Multicast Ping ProtocolThe Multicast Ping Protocol specified in this document allows for checking whether an endpoint can receive multicast -- both Source-Specific Multicast (SSM) and Any-Source Multicast (ASM). It can also be used to obtain additional multicast-related information, such as multicast tree setup time. This protocol is based on an implementation of tools called "ssmping" and "asmping". [STANDARDS-TRACK]Mtrace Version 2: Traceroute Facility for IP MulticastThis 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.IPv6 Options for In Situ Operations, Administration, and Maintenance (IOAM)In situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document outlines how IOAM Data-Fields are encapsulated in IPv6.AcknowledgmentsThe authors would like to thank , , , , , ,
, , , and for their comments and suggestions.Authors' AddressesFuturewei Technologies2330 Central ExpresswaySanta ClaraCAUnited States of Americahsong@futurewei.comFuturewei Technologies2330 Central ExpresswaySanta ClaraCAUnited States of Americammcbride@futurewei.comEricssonUnited States of Americagregimirsky@gmail.comVerizon Inc.United States of Americagyan.s.mishra@verizon.comNational Institute of Information and Communications TechnologyJapanasaeda@nict.go.jpHuawei TechnologiesBeijingChinazhoutianran@huawei.com