MPLS Forwarding Compliance and Performance Requirements
draft-ietf-mpls-forwarding-07

   This document reviews forwarding behavior specified elsewhere and
   points out compliance and performance requirements.  As such it
   introduces no new security requirements or concerns.

   Discussion of hardware support and other equipment hardening against
   DoS attack can be found in Section 2.6.1.  Section 3.6 provides a
   list of question regarding DoS to be asked of suppliers.  Section 4.6
   suggests types of testing that can provide some assurance of the
   effectiveness of supplier DoS hardening claims.

   Knowledge of potential performance shortcomings may serve to help new
   implementations avoid pitfalls.  It is unlikely that such knowledge
   could be the basis of new denial of service as these pitfalls are
   already widely known in the service provider community and among
   leading equipment suppliers.  In practice extreme data and packet
   rate are needed to affect existing equipment and to affect networks
   that may be still vulnerable due to failure to implement adequate
   protection.  The extreme data and packet rates make this type of
   denial of service unlikely and make undetectable denial of service of
   this type impossible.

   The set of normative references each contain security considerations.
   A brief summarization of MPLS security considerations applicable to
   forwarding follows:

   1.   MPLS encapsulation does not support an authentication extension.
        This is reflected in the security section of [RFC3032].
        Documents which clarify MPLS header fields such as TTL
        [RFC3443], the explicit null label [RFC4182], renaming EXP to TC
        [RFC5462], ECN for MPLS [RFC5129], and MPLS Ethernet
        encapsulation [RFC5332] make no changes to security
        considerations in [RFC3032].

   2.   Some cited RFCs are related to Diffserv forwarding.  [RFC3270]
        refers to MPLS and Diffserv security.  [RFC2474] mentions theft
        of service and denial of service due to mismarking.  [RFC2474]
        mentions IPsec interaction, but with MPLS, not being carried by
        IP, this type of interaction in [RFC2474] is not relevant.

   3.   [RFC3209] is cited here due only to make-before-break forwarding
        requirements.  This is related to resource sharing and the theft
        of service and denial of service concerns in [RFC2474] apply.

   4.   [RFC4090] defines FRR which provides protection but does not add
        security concerns.  RFC4201 defines link bundling but raises no
        additional security concerns.

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   5.   Various OAM control channels are defined in [RFC4385] (PW CW),
        [RFC5085] (VCCV), [RFC5586] (G-Ach and GAL).  These documents
        describe potential abuse of these OAM control channels.

   6.   [RFC4950] defines ICMP extensions when MPLS TTL expires and
        payload is IP.  This provides MPLS header information which is
        of no use to an IP attacker, but sending this information can be
        suppressed through configuration.

   7.   GTSM [RFC5082] provides a means to improve protection against
        high traffic volume spoofing as a form of DoS attack.

   8.   BFD [RFC5880] [RFC5884] [RFC5885] provides a form of OAM used in
        MPLS and MPLS-TP.  The security considerations related to the
        OAM control channel are relevant.  The BFD payload supports
        authentication unlike the MPLS encapsulation or MPLS or PW
        control channel encapsulation is carried in.  Where an IP return
        OAM path is used IPsec is suggested as a means of securing the
        return path.

   9.   Other forms of OAM are supported by [RFC6374] [RFC6375] (Loss
        and Delay Measurement), [RFC6428] (Connectivity Check/
        Verification based on BFD), and [RFC6427] (Fault Management).
        The security considerations related to the OAM control channel
        are relevant.  IP return paths, where used, can be secured with
        IPsec.

   10.  Linear protection is defined by [RFC6378] and updated by
        [I-D.ietf-mpls-psc-updates].  Security concerns related to MPLS
        encapsulation and OAM control channels apply.  Security concerns
        reiterate [RFC5920] as applied to protection switching.

   11.  The PW Flow Label [RFC6391] and MPLS Entropy Label [RFC6790]
        affect multipath load balancing.  Security concerns reiterate
        [RFC5920].  Security impacts would be limited to load
        distribution.

   MPLS security including data plane security is discussed in greater
   detail in [RFC5920] (MPLS/GMPLS Security Framework).  The MPLS-TP
   security framework [RFC6941] build upon this, focusing largely on the
   MPLS-TP OAM additions and OAM channels with some attention given to
   using network management in place of control plane setup.  In both
   security framework documents MPLS is assumed to run within a "trusted
   zone", defined as being where a single service provider (SP) has
   total operational control over that part of the network.

   If control plane security and management plane security are
   sufficiently robust, compromise of a single network element may

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   result in chaos in the data plane anywhere in the network through
   denial of service attacks, but not a Byzantine security failure in
   which other network elements are fully compromised.

   MPLS security, or lack of, can affect whether traffic can be
   misrouted and lost, or intercepted, or intercepted and reinserted (a
   man-in-the-middle attack) or spoofed.  End user applications,
   including control plane and management plane protocols used by the
   SP, are expected to make use of appropriate end-to-end authentication
   and where appropriate end-to-end encryption.

8.  References

8.1.  Normative References

   [I-D.ietf-mpls-psc-updates]
              Osborne, E., "Updates to PSC", draft-ietf-mpls-psc-
              updates-01 (work in progress), January 2014.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, January 2001.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.

   [RFC3270]  Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
              P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
              Protocol Label Switching (MPLS) Support of Differentiated
              Services", RFC 3270, May 2002.

   [RFC3443]  Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing
              in Multi-Protocol Label Switching (MPLS) Networks", RFC
              3443, January 2003.

   [RFC4090]  Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
              Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May
              2005.

   [RFC4182]  Rosen, E., "Removing a Restriction on the use of MPLS
              Explicit NULL", RFC 4182, September 2005.

   [RFC4201]  Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
              in MPLS Traffic Engineering (TE)", RFC 4201, October 2005.

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   [RFC4385]  Bryant, S., Swallow, G., Martini, L., and D. McPherson,
              "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
              Use over an MPLS PSN", RFC 4385, February 2006.

   [RFC4950]  Bonica, R., Gan, D., Tappan, D., and C. Pignataro, "ICMP
              Extensions for Multiprotocol Label Switching", RFC 4950,
              August 2007.

   [RFC5082]  Gill, V., Heasley, J., Meyer, D., Savola, P., and C.
              Pignataro, "The Generalized TTL Security Mechanism
              (GTSM)", RFC 5082, October 2007.

   [RFC5085]  Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
              Connectivity Verification (VCCV): A Control Channel for
              Pseudowires", RFC 5085, December 2007.

   [RFC5129]  Davie, B., Briscoe, B., and J. Tay, "Explicit Congestion
              Marking in MPLS", RFC 5129, January 2008.

   [RFC5332]  Eckert, T., Rosen, E., Aggarwal, R., and Y. Rekhter, "MPLS
              Multicast Encapsulations", RFC 5332, August 2008.

   [RFC5586]  Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
              Associated Channel", RFC 5586, June 2009.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, June 2010.

   [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
              "Bidirectional Forwarding Detection (BFD) for MPLS Label
              Switched Paths (LSPs)", RFC 5884, June 2010.

   [RFC5885]  Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
              Detection (BFD) for the Pseudowire Virtual Circuit
              Connectivity Verification (VCCV)", RFC 5885, June 2010.

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374, September 2011.

   [RFC6375]  Frost, D. and S. Bryant, "A Packet Loss and Delay
              Measurement Profile for MPLS-Based Transport Networks",
              RFC 6375, September 2011.

   [RFC6378]  Weingarten, Y., Bryant, S., Osborne, E., Sprecher, N., and
              A. Fulignoli, "MPLS Transport Profile (MPLS-TP) Linear
              Protection", RFC 6378, October 2011.

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   [RFC6391]  Bryant, S., Filsfils, C., Drafz, U., Kompella, V., Regan,
              J., and S. Amante, "Flow-Aware Transport of Pseudowires
              over an MPLS Packet Switched Network", RFC 6391, November
              2011.

   [RFC6427]  Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S.,
              and D. Ward, "MPLS Fault Management Operations,
              Administration, and Maintenance (OAM)", RFC 6427, November
              2011.

   [RFC6428]  Allan, D., Swallow Ed. , G., and J. Drake Ed. , "Proactive
              Connectivity Verification, Continuity Check, and Remote
              Defect Indication for the MPLS Transport Profile", RFC
              6428, November 2011.

   [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
              L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
              RFC 6790, November 2012.

8.2.  Informative References

   [ACK-compression]
              , , , "Observations and Dynamics of a Congestion Control
              Algorithm: The Effects of Two-Way Traffic", Proc. ACM
              SIGCOMM, ACM Computer Communications Review (CCR) Vol 21,
              No 4, 1991, pp.133-147., 1991.

   [I-D.ietf-mpls-in-udp]
              Building, K., Sheth, N., Yong, L., Pignataro, C., and F.
              Yongbing, "Encapsulating MPLS in UDP", draft-ietf-mpls-in-
              udp-05 (work in progress), January 2014.

   [I-D.ietf-mpls-special-purpose-labels]
              Kompella, K., Andersson, L., and A. Farrel, "Allocating
              and Retiring Special Purpose MPLS Labels", draft-ietf-
              mpls-special-purpose-labels-03 (work in progress), July
              2013.

   [I-D.ietf-tictoc-1588overmpls]
              Davari, S., Oren, A., Bhatia, M., Roberts, P., and L.
              Montini, "Transporting Timing messages over MPLS
              Networks", draft-ietf-tictoc-1588overmpls-05 (work in
              progress), June 2013.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791, September
              1981.

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   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474, December
              1998.

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, December 1998.

   [RFC2597]  Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
              "Assured Forwarding PHB Group", RFC 2597, June 1999.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3168]  Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
              of Explicit Congestion Notification (ECN) to IP", RFC
              3168, September 2001.

   [RFC3429]  Ohta, H., "Assignment of the 'OAM Alert Label' for
              Multiprotocol Label Switching Architecture (MPLS)
              Operation and Maintenance (OAM) Functions", RFC 3429,
              November 2002.

   [RFC3471]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Functional Description", RFC 3471,
              January 2003.

   [RFC3550]  Schulzrinne, H., Casner, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", STD 64, RFC 3550, July 2003.

   [RFC3828]  Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and
              G. Fairhurst, "The Lightweight User Datagram Protocol
              (UDP-Lite)", RFC 3828, July 2004.

   [RFC3985]  Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-
              Edge (PWE3) Architecture", RFC 3985, March 2005.

   [RFC4023]  Worster, T., Rekhter, Y., and E. Rosen, "Encapsulating
              MPLS in IP or Generic Routing Encapsulation (GRE)", RFC
              4023, March 2005.

   [RFC4110]  Callon, R. and M. Suzuki, "A Framework for Layer 3
              Provider-Provisioned Virtual Private Networks (PPVPNs)",
              RFC 4110, July 2005.

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   [RFC4124]  Le Faucheur, F., "Protocol Extensions for Support of
              Diffserv-aware MPLS Traffic Engineering", RFC 4124, June
              2005.

   [RFC4206]  Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
              Hierarchy with Generalized Multi-Protocol Label Switching
              (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.

   [RFC4221]  Nadeau, T., Srinivasan, C., and A. Farrel, "Multiprotocol
              Label Switching (MPLS) Management Overview", RFC 4221,
              November 2005.

   [RFC4340]  Kohler, E., Handley, M., and S. Floyd, "Datagram
              Congestion Control Protocol (DCCP)", RFC 4340, March 2006.

   [RFC4377]  Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S.
              Matsushima, "Operations and Management (OAM) Requirements
              for Multi-Protocol Label Switched (MPLS) Networks", RFC
              4377, February 2006.

   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", RFC 4379,
              February 2006.

   [RFC4664]  Andersson, L. and E. Rosen, "Framework for Layer 2 Virtual
              Private Networks (L2VPNs)", RFC 4664, September 2006.

   [RFC4817]  Townsley, M., Pignataro, C., Wainner, S., Seely, T., and
              J. Young, "Encapsulation of MPLS over Layer 2 Tunneling
              Protocol Version 3", RFC 4817, March 2007.

   [RFC4875]  Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
              "Extensions to Resource Reservation Protocol - Traffic
              Engineering (RSVP-TE) for Point-to-Multipoint TE Label
              Switched Paths (LSPs)", RFC 4875, May 2007.

   [RFC4928]  Swallow, G., Bryant, S., and L. Andersson, "Avoiding Equal
              Cost Multipath Treatment in MPLS Networks", BCP 128, RFC
              4928, June 2007.

   [RFC4960]  Stewart, R., "Stream Control Transmission Protocol", RFC
              4960, September 2007.

   [RFC5036]  Andersson, L., Minei, I., and B. Thomas, "LDP
              Specification", RFC 5036, October 2007.

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   [RFC5317]  Bryant, S. and L. Andersson, "Joint Working Team (JWT)
              Report on MPLS Architectural Considerations for a
              Transport Profile", RFC 5317, February 2009.

   [RFC5462]  Andersson, L. and R. Asati, "Multiprotocol Label Switching
              (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
              Class" Field", RFC 5462, February 2009.

   [RFC5640]  Filsfils, C., Mohapatra, P., and C. Pignataro, "Load-
              Balancing for Mesh Softwires", RFC 5640, August 2009.

   [RFC5695]  Akhter, A., Asati, R., and C. Pignataro, "MPLS Forwarding
              Benchmarking Methodology for IP Flows", RFC 5695, November
              2009.

   [RFC5860]  Vigoureux, M., Ward, D., and M. Betts, "Requirements for
              Operations, Administration, and Maintenance (OAM) in MPLS
              Transport Networks", RFC 5860, May 2010.

   [RFC5905]  Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
              Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, June 2010.

   [RFC5920]  Fang, L., "Security Framework for MPLS and GMPLS
              Networks", RFC 5920, July 2010.

   [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
              D., and S. Mansfield, "Guidelines for the Use of the "OAM"
              Acronym in the IETF", BCP 161, RFC 6291, June 2011.

   [RFC6310]  Aissaoui, M., Busschbach, P., Martini, L., Morrow, M.,
              Nadeau, T., and Y(J). Stein, "Pseudowire (PW) Operations,
              Administration, and Maintenance (OAM) Message Mapping",
              RFC 6310, July 2011.

   [RFC6371]  Busi, I. and D. Allan, "Operations, Administration, and
              Maintenance Framework for MPLS-Based Transport Networks",
              RFC 6371, September 2011.

   [RFC6388]  Wijnands, IJ., Minei, I., Kompella, K., and B. Thomas,
              "Label Distribution Protocol Extensions for Point-to-
              Multipoint and Multipoint-to-Multipoint Label Switched
              Paths", RFC 6388, November 2011.

   [RFC6424]  Bahadur, N., Kompella, K., and G. Swallow, "Mechanism for
              Performing Label Switched Path Ping (LSP Ping) over MPLS
              Tunnels", RFC 6424, November 2011.

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   [RFC6425]  Saxena, S., Swallow, G., Ali, Z., Farrel, A., Yasukawa,
              S., and T. Nadeau, "Detecting Data-Plane Failures in
              Point-to-Multipoint MPLS - Extensions to LSP Ping", RFC
              6425, November 2011.

   [RFC6426]  Gray, E., Bahadur, N., Boutros, S., and R. Aggarwal, "MPLS
              On-Demand Connectivity Verification and Route Tracing",
              RFC 6426, November 2011.

   [RFC6435]  Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, M.,
              and X. Dai, "MPLS Transport Profile Lock Instruct and
              Loopback Functions", RFC 6435, November 2011.

   [RFC6438]  Carpenter, B. and S. Amante, "Using the IPv6 Flow Label
              for Equal Cost Multipath Routing and Link Aggregation in
              Tunnels", RFC 6438, November 2011.

   [RFC6478]  Martini, L., Swallow, G., Heron, G., and M. Bocci,
              "Pseudowire Status for Static Pseudowires", RFC 6478, May
              2012.

   [RFC6639]  King, D. and M. Venkatesan, "Multiprotocol Label Switching
              Transport Profile (MPLS-TP) MIB-Based Management
              Overview", RFC 6639, June 2012.

   [RFC6669]  Sprecher, N. and L. Fang, "An Overview of the Operations,
              Administration, and Maintenance (OAM) Toolset for MPLS-
              Based Transport Networks", RFC 6669, July 2012.

   [RFC6670]  Sprecher, N. and KY. Hong, "The Reasons for Selecting a
              Single Solution for MPLS Transport Profile (MPLS-TP)
              Operations, Administration, and Maintenance (OAM)", RFC
              6670, July 2012.

   [RFC6720]  Pignataro, C. and R. Asati, "The Generalized TTL Security
              Mechanism (GTSM) for the Label Distribution Protocol
              (LDP)", RFC 6720, August 2012.

   [RFC6829]  Chen, M., Pan, P., Pignataro, C., and R. Asati, "Label
              Switched Path (LSP) Ping for Pseudowire Forwarding
              Equivalence Classes (FECs) Advertised over IPv6", RFC
              6829, January 2013.

   [RFC6941]  Fang, L., Niven-Jenkins, B., Mansfield, S., and R.
              Graveman, "MPLS Transport Profile (MPLS-TP) Security
              Framework", RFC 6941, April 2013.

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   [RFC7023]  Mohan, D., Bitar, N., Sajassi, A., DeLord, S., Niger, P.,
              and R. Qiu, "MPLS and Ethernet Operations, Administration,
              and Maintenance (OAM) Interworking", RFC 7023, October
              2013.

   [RFC7074]  Berger, L. and J. Meuric, "Revised Definition of the GMPLS
              Switching Capability and Type Fields", RFC 7074, November
              2013.

   [RFC7079]  Del Regno, N. and A. Malis, "The Pseudowire (PW) and
              Virtual Circuit Connectivity Verification (VCCV)
              Implementation Survey Results", RFC 7079, November 2013.

Appendix A.  Organization of References Section

   The References section is split into Normative and Informative
   subsections.  References that directly specify forwarding
   encapsulations or behaviors are listed as normative.  References
   which describe signaling only, though normative with respect to
   signaling, are listed as informative.  They are informative with
   respect to MPLS forwarding.

Authors' Addresses

   Curtis Villamizar (editor)
   Outer Cape Cod Network Consulting, LLC

   Email: curtis@occnc.com

   Kireeti Kompella
   Juniper Networks

   Email: kireeti@juniper.net

   Shane Amante
   Apple Inc.
   1 Infinite Loop
   Cupertino, California  95014

   Email: samante@apple.com

   Andrew Malis
   Huawei Technologies

   Email: agmalis@gmail.com

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   Carlos Pignataro
   Cisco Systems
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email: cpignata@cisco.com

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