| DetNet | B. Varga, Ed. |
| Internet-Draft | J. Farkas |
| Intended status: Standards Track | Ericsson |
| Expires: November 7, 2019 | L. Berger |
| D. Fedyk | |
| LabN Consulting, L.L.C. | |
| A. Malis | |
| S. Bryant | |
| Huawei Technologies | |
| J. Korhonen | |
| May 6, 2019 |
DetNet Data Plane: IP
draft-ietf-detnet-ip-00
This document specifies the Deterministic Networking data plane when operating in an IP packet switched network.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
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/.
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Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
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Deterministic Networking (DetNet) is a service that can be offered by a network to DetNet flows. DetNet provides these flows extremely low packet loss rates and assured maximum end-to-end delivery latency. General background and concepts of DetNet can be found in the DetNet Architecture [I-D.ietf-detnet-architecture].
This document specifies the DetNet data plane operation for IP hosts and routers that provide DetNet service to IP encapsulated data. No DetNet specific encapsulation is defined to support IP flows, instead the existing IP and higher layer protocol header information is used to support flow identification and DetNet service delivery. Common data plane procedures and control information for all DetNet data planes can be found in the [I-D.ietf-detnet-framework].
The DetNet Architecture models the DetNet related data plane functions decomposed into two sub-layers: functions into two sub-layers: a service sub-layer and a forwarding sub-layer. The service sub-layer is used to provide DetNet service protection and reordering. The forwarding sub-layer is used to provides congestion protection (low loss, assured latency, and limited reordering). Since no DetNet specific headers are added to support DetNet IP flows, only the forwarding sub-layer functions are supported using the DetNet IP defined by this document. Service protection can be provided on a per sub-net basis using technologies such as MPLS [I-D.ietf-detnet-dp-sol-mpls] and Ethernet as specified in the IEEE 802.1 TSN task group(referred to in this document simply as IEEE802.1 TSN).
This document provides an overview of the DetNet IP data plane in Section 3, considerations that apply to providing DetNet services via the DetNet IP data plane in Section 4. Section 5 provides the procedures for hosts and routers that support IP-based DetNet services.
This document uses the terminology and concepts established in the DetNet architecture [I-D.ietf-detnet-architecture], and the reader is assumed to be familiar with that document and its terminology.
The following abbreviations used in this document:
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 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This document describes how IP is used by DetNet nodes, i.e., hosts and routers, identify DetNet flows and provide a DetNet service using an IP data plane. From a data plane perspective, an end-to-end IP model is followed. As mentioned above, existing IP and higher layer protocol header information is used to support flow identification and DetNet service delivery. Common data plane procedures and control information for all DetNet data planes can be found in the [I-D.ietf-detnet-framework].
The DetNet IP data plane uses "6-tuple" based flow identification, where 6-tuple refers to information carried in IP and higher layer protocol headers. The 6-tuple referred to in this document is the same as that defined in [RFC3290]. Specifically 6-tuple is (destination address, source address, IP protocol, source port, destination port, and differentiated services (DiffServ) code point (DSCP). General background on the use of IP headers, and 5-tuples, to identify flows and support Quality of Service (QoS) can be found in [RFC3670]. [RFC7657] also provides useful background on the delivery of DiffServ and "tuple" based flow identification. Referring to a 6-tuple allows DetNet nodes to forward packets with the 6-tuple as is or remap the DSCP where required by the DetNet service.
DetNet flow aggregation may be enabled via the use of wildcards, masks, prefixes and ranges. IP tunnels may also be used to support flow aggregation. In these cases, it is expected that DetNet aware intermediate nodes will provide DetNet service assurance on the aggregate through resource allocation and congestion control mechanisms.
DetNet IP Relay Relay DetNet IP
End System Node Node End System
+----------+ +----------+
| Appl. |<------------ End to End Service ----------->| Appl. |
+----------+ ............ ........... +----------+
| Service |<-: Service :-- DetNet flow --: Service :->| Service |
+----------+ +----------+ +----------+ +----------+
|Forwarding| |Forwarding| |Forwarding| |Forwarding|
+--------.-+ +-.------.-+ +-.---.----+ +-------.--+
: Link : \ ,-----. / \ ,-----. /
+......+ +----[ Sub ]----+ +-[ Sub ]-+
[Network] [Network]
`-----' `-----'
|<--------------------- DetNet IP --------------------->|
Figure 1: A Simple DetNet (DN) Enabled IP Network
Figure 1 illustrates a DetNet enabled IP network. The DetNet enabled end systems originate IP encapsulated traffic that is identified as DetNet flows, relay nodes understand the forwarding requirements of the DetNet flow and ensure that node, interface and sub-network resources are allocated to ensure DetNet service requirements. The dotted line around the Service component of the Relay Nodes indicates that the transit routers are DetNet service aware but do not perform any DetNet service sub-layer function, e.g., PREOF. IEEE 802.1 TSN is an example sub-network type which can provide support for DetNet flows and service.
Note: The sub-network can represent a TSN, MPLS or IP network segment.
IP Edge Edge IP
End System Node Node End System
+----------+ +.........+ +.........+ +----------+
| Appl. |<--:Svc Proxy:-- E2E Service---:Svc Proxy:-->| Appl. |
+----------+ +.........+ +.........+ +----------+
| IP |<--:IP : :Svc:---- IP flow ----:Svc: :IP :-->| IP |
+----------+ +---+ +---+ +---+ +---+ +----------+
|Forwarding| |Fwd| |Fwd| |Fwd| |Fwd| |Forwarding|
+--------.-+ +-.-+ +-.-+ +-.-+ +-.-+ +---.------+
: Link : \ ,-----. / / ,-----. \
+.......+ +----[ Sub ]----+ +--[ Sub ]--+
[Network] [Network]
`-----' `-----'
|<--- IP --->| |<------ DetNet IP ------>| |<--- IP --->|
Figure 2: Non-DetNet aware IP end systems with DetNet IP Domain
Figure 2 illustrates a variant of Figure 1 where the end systems are not DetNet aware. In this case, edge nodes sit at the boundary of the DetNet domain and provide DetNet service proxies for the end applications by initiating and terminating DetNet service for the application's IP flows. The existing header information or an approach such as described in Section 4.6 can be used to support DetNet flow identification.
Non-DetNet and DetNet IP packets are identical on the wire. From data plane perspective, the only difference is that there is flow-associated DetNet information on each DetNet node that defines the flow related characteristics and required forwarding behavior. As shown above, edge nodes provide a Service Proxy function that "associates" one or more IP flows with the appropriate DetNet flow-specific information and ensures that the receives the proper traffic treatment within the domain.
Note: The operation of IEEE802.1 TSN end systems over DetNet enabled IP networks is not described in this document. TSN over MPLS is discribed in [I-D.ietf-detnet-tsn-over-mpls].
This section provides informative considerations related to providing DetNet service to flows which are identified based on their header information.
Data-flows requiring DetNet service are generated and terminated on end systems. This document deals only with IP end systems. The protocols used by an IP end system are specific to an application and end systems peer with end systems using the same application encapsulation format. This said, DetNet's use of 6-tuple IP flow identification means that DetNet must be aware of not only the format of the IP header, but also of the next protocol carried within an IP packet.
When IP end systems are DetNet aware, no application-level or service-level proxy functions are needed inside the DetNet domain. For DetNet unaware IP end systems service-level proxy functions are needed inside the DetNet domain.
End systems need to ensure that DetNet service requirements are met when processing packets associated with a DetNet flow. When forwarding packets, this means that packets are appropriately shaped on transmission and received appropriate traffic treatment on the connected sub-network, see Section 4.5 and Section 4.2.1 for more details. When receiving packets, this means that there are appropriate local node resources, e.g., buffers, to receive and process a DetNet flow packets.
As a general rule, DetNet IP domains need to be able to forward any DetNet flow identified by the IP 6-tuple. Doing otherwise would limit end system encapsulation format. From a practical standpoint this means that all nodes along the end-to-end path of DetNet flows need to agree on what fields are used for flow identification, and the transport protocols (e.g., TCP/UDP/IPsec) which can be used to identify 6-tuple protocol ports.
From a connection type perspective two scenarios are identified:
L3 (IP) end systems may use any of these connection types. A DetNet domain allows communication between any end-systems using the same encapsulation format, independent of their connection type and DetNet capability. DN attached end systems have no knowledge about the DetNet domain and its encapsulation format. See Figure 3 for L3 end system connection examples.
____+----+
+----+ _____ / | ES3|
| ES1|____ / \__/ +----+___
+----+ \ / \
+ |
____ \ _/
+----+ __/ \ +__ DetNet IP domain /
| ES2|____/ L2/L3 |___/ \ __ __/
+----+ \_______/ \_______/ \___/
Figure 3: Connection types of L3 end systems
Within a DetNet domain, the DetNet enabled IP Routers interconnect links and sub-networks to support end-to-end delivery of DetNet flows. From a DetNet architecture perspective, these routers are DetNet relays, as they must be DetNet service aware. Such routers identify DetNet flows based on the IP 6-tuple, and ensure that the DetNet service required traffic treatment is provided both on the node and on any attached sub-network.
This solution provides DetNet functions end to end, but does so on a per link and sub-network basis. Congestion protection and latency control and the resource allocation (queuing, policing, shaping) are supported using the underlying link / sub net specific mechanisms. However, service protections (packet replication and packet elimination functions) are not provided at the DetNet layer end to end. Instead service protection can be provided on a per underlying L2 link and sub-network basis.
+------+ +------+
| X | | X |
+======+ +------+
End-system | IP | | IP |
-----+------+-------+======+--- --+======+--
DetNet |L2/SbN| |L2/SbN|
+------+ +------+
Figure 4: Encapsulation of DetNet Routing in simplified IP service L3 end-systems
The DetNet Service Flow is mapped to the link / sub-network specific resources using an underlying system specific means. This implies each DetNet aware node on path looks into the forwarded DetNet Service Flow packet and utilize e.g., a 5- (or 6-) tuple to find out the required mapping within a node.
As noted earlier, the Service Protection is done within each link / sub-network independently using the domain specific mechanisms (due the lack of a unified end to end sequencing information that would be available for intermediate nodes). Therefore, service protection (if enabled) cannot be provided end-to-end, only within sub-networks. This is shown for a three sub-network scenario in Figure 5, where each sub-network can provide service protection between its borders.
______
____ / \__
____ / \__/ \___ ______
+----+ __/ +====+ +==+ \ +----+
|src |__/ SubN1 ) | | \ SubN3 \____| dst|
+----+ \_______/ \ Sub-Network2 | \______/ +----+
\_ _/
\ __ __/
\_______/ \___/
+---+ +---------E--------+ +-----+
+----+ | | | | | | | +----+
|src |----R E--------R +---+ E------R E------+ dst|
+----+ | | | | | | | +----+
+---+ +-----R------------+ +-----+
Figure 5: Replication and elimination in sub-networks for DetNet IP networks
If end to end service protection is desired, it can be implemented, for example, by the DetNet end systems using Layer-4 (L4) transport protocols or application protocols. However, these protocols are out of scope of this document.
[Editor's note: This section is TBD. OAM may be dropped from this document and left for future study.]
Class of Service (CoS) for DetNet flows carried in IPv6 is provided using the standard differentiated services code point (DSCP) field [RFC2474] and related mechanisms. The 2-bit explicit congestion notification (ECN) [RFC3168] field MAY also be used.
One additional consideration for DetNet nodes which support CoS services is that they MUST ensure that the CoS service classes do not impact the congestion protection and latency control mechanisms used to provide DetNet QoS. This requirement is similar to requirement for MPLS LSRs to that CoS LSPs do not impact the resources allocated to TE LSPs via [RFC3473].
Quality of Service (QoS) for DetNet service flows carried in IP MUST be provided locally by the DetNet-aware hosts and routers supporting DetNet flows. Such support leverages the underlying network layer such as 802.1 TSN. The traffic control mechanisms used to deliver QoS for IP encapsulated DetNet flows are expected to be defined in a future document. From an encapsulation perspective, the combination of the 6-tuple i.e., the typical 5-tuple enhanced with the DSCP code, uniquely identifies a DetNet service flow.
Packets that are marked with a DetNet Class of Service value, but that have not been the subject of a completed reservation, can disrupt the QoS offered to properly reserved DetNet flows by using resources allocated to the reserved flows. Therefore, the network nodes of a DetNet network must:
The ability to aggregate individual flows, and their associated resource control, into a larger aggregate is an important technique for improving scaling of messaging in the data, management and control planes. This document identifies the traffic identification related aspects of aggregation of DetNet flows. The resource control and management aspects of aggregation (including the queuing/shaping/policing implications) will be covered in other documents. The data plane implications of aggregation are independent for PW/MPLS and IP encapsulated DetNet flows.
DetNet flows forwarded via IP have more limited aggregation options, due to the available traffic flow identification fields of the IP solution. One available approach is to manage the resources associated with a DSCP identified traffic class and to map (remark) individually controlled DetNet flows onto that traffic class. This approach also requires that nodes support aggregation ensure that traffic from aggregated LSPs are placed (shaped/policed/enqueued) in a fashion that ensures the required DetNet service is preserved.
In both the MPLS and IP cases, additional details of the traffic control capabilities needed at a DetNet-aware node may be covered in the new service descriptions mentioned above or in separate future documents. Management and control plane mechanisms will also need to ensure that the service required on the aggregate flow (H-LSP or DSCP) are provided, which may include the discarding or remarking mentioned in the previous sections.
Section 3 introduces the use of the IP "6-tuple" for flow identification, and Section 4.5 goes on to discuss how identified flows use specific QoS mechanisms for flow-specific traffic treatment, including path control and resource allocation. Section 5.1 contains detailed DetNet IP flow identification procedures. Flow identification plays an important role for the DetNet controller plane.
Section 4.6 and Section 4.9 discuss the use of flow aggregation in DetNet. Flow aggregation can be accomplished using any of the 6-tuple fields defined in Section 5.1, using a DSCP identified traffic class or other field. It will be the responsibility of the DetNet controller plane to be able to properly provision the use of these aggregation mechanisms.
While the DetNet IP data plane must support bidirectional DetNet flows, there are no special bidirectional features with respect to the data plane other than the need for the two directions of a co-routed bidirectional flow to take the same path. That is to say that bidirectional DetNet flows are solely represented at the management and control plane levels, without specific support or knowledge within the DetNet data plane. Fate sharing and associated or co-routed bidirectional flows can be managed at the control level.
Control and management mechanisms need to support bidirectional flows, but the specification of such mechanisms are out of scope of this document. An example control plane solution for MPLS can be found in [RFC7551].
The use of prefixes, wildcards, bitmasks, and port ranges allows a DetNet node to aggregate DetNet flows. This aggregation can take place within a single node, when that node maintains state about both the aggregated and component flows. It can also take place between nodes, where one node maintains state about only flow aggregates while the other node maintains state on all or a portion of the component flows. In either case, the management or control function that provisions the aggregate flows must ensure that adequate resources are allocated and configured to provide combined service requirements of the component flows. As DetNet is concerned about latency and jitter, more than just bandwidth needs to be considered.
This section provides DetNet IP data plane procedures. These procedures have been divided into the following areas: flow identification, forwarding and traffic treatment. Flow identification includes those procedures related to matching IP and higher layer protocol header information to DetNet flow (state) information and service requirements. Flow identification is also sometimes called Traffic classification, for example see [RFC5777]. Forwarding includes those procedures related to next hop selection and delivery. Traffic treatment includes those procedures related to providing an identified flow with the required DetNet service.
DetNet IP data plane establishment and operational procedures also have requirements on the control and management systems for DetNet flows and these are covered in this section. Specifically this section identifies a number of information elements that require support via the management and control interfaces supported by a DetNet node. The specific mechanism used for such support is out of the scope of this document. A summary of the requirements for management and control related information is included. Conformance language is not used in the summary since applies to future mechanisms such as those that may be provided in YANG models [YANG-REF-TBD].
IP and higher layer protocol header information is used to identify DetNet flows. All DetNet implementations that support this document MUST identify individual DetNet flows based on the set of information identified in this section. Note, that additional flow identification requirements, e.g., to support other higher layer protocols, may be defined in future.
The configuration and control information used to identify an individual DetNet flow MUST be ordered by an implementation. Implementations MUST support a fixed order when identifying flows, and MUST identify a DetNet flow by the first set of matching flow information.
Implementations of this document MUST support DetNet flow identification when the implementation is acting as a DetNet end systems, a relay node or as an edge node.
Implementations of this document MUST support DetNet flow identification based on IP header information. The IPv4 header is defined in [RFC0791] and the IPv6 is defined in [RFC8200].
Implementations of this document MUST support DetNet flow identification based on the Source Address field of an IP packet. Implementations SHOULD support longest prefix matching for this field, see [RFC1812] and [RFC7608]. Note that a prefix length of zero (0) effectively means that the field is ignored.
Implementations of this document MUST support DetNet flow identification based on the Destination Address field of an IP packet. Implementations SHOULD support longest prefix matching for this field, see [RFC1812] and [RFC7608]. Note that a prefix length of zero (0) effectively means that the field is ignored.
Note: any IP address value is allowed, including an IP multicast destination address.
Implementations of this document MUST support DetNet flow identification based on the IPv4 Protocol field when processing IPv4 packets, and the IPv6 Next Header Field when processing IPv6 packets. An implementation MUST support flow identification based based the next protocol values defined in Section 5.1.2. Other, non-zero values, MUST be used for flow identification. Implementations SHOULD allow for these fields to be ignored for a specific DetNet flow.
These fields are used to support Differentiated Services [RFC2474] and Explicit Congestion Notification [RFC3168]. Implementations of this document MUST support DetNet flow identification based on the IPv4 Type of Service field when processing IPv4 packets, and the IPv6 Traffic Class Field when processing IPv6 packets. Implementations MUST support bitmask based matching, where bits set to one (1) in the bitmask indicate which subset of the bits in the field are to be used in determining a match. Note that all bits set to zero (0) value as a bitmask effectively means that these fields are ignored.
Implementations of this document SHOULD support identification of DetNet flows based on the IPv6 Flow Label field. Implementations that support matching based on this field MUST allow for this field to be ignored for a specific DetNet flow. When this field is used to identify a specific DetNet flow, implementations MAY exclude the IPv6 Next Header field and next header information as part of DetNet flow identification.
Implementations of this document MUST support DetNet flow identification based on header information identified in this section. Support for TCP, UDP and IPsec flows is defined. Future documents are expected to define support for other protocols.
DetNet flow identification for TCP [RFC0793] and UDP [RFC0768] is achieved based on the Source and Destination Port fields carried in each protocol's header. These fields share a common format and common DetNet flow identification procedures.
Implementations of this document MUST support DetNet flow identification based on the Source Port field of a TCP or UDP packet. Implementations MUST support flow identification based on a particular value carried in the field, i.e., an exact value. Implementations SHOULD support range-based port matching. Implementation MUST also allow for the field to be ignored for a specific DetNet flow.
Implementations of this document MUST support DetNet flow identification based on the Destination Port field of a TCP or UDP packet. Implementations MUST support flow identification based on a particular value carried in the field, i.e., an exact value. Implementations SHOULD support range-based port matching. Implementation MUST also allow for the field to be ignored for a specific DetNet flow.
IPsec Authentication Header (AH) [RFC4302] and Encapsulating Security Payload (ESP) [RFC4303] share a common format for the Security Parameters Index (SPI) field. Implementations MUST support flow identification based on a particular value carried in the field, i.e., an exact value. Implementation SHOULD also allow for the field to be ignored for a specific DetNet flow.
General requirements for IP nodes are defined in [RFC1122], [RFC1812] and [RFC6434], and are not modified by this document. The typical next-hop selection process is impacted by DetNet. Specifically, implementations of this document SHALL use management and control information to select the one or more outgoing interfaces and next hops to be used for a packet belonging to a DetNet flow.
The use of multiple paths or links, e.g., ECMP, to support a single DetNet flow is NOT RECOMMENDED. ECMP MAY be used for non-DetNet flows within a DetNet domain.
The above implies that management and control functions will be defined to support this requirement, e.g., see [YANG-REF-TBD].
Implementations if this document MUST ensure that a DetNet flow receives the traffic treatment that is provisioned for it via configuration or the controller plane, e.g., via [YANG-REF-TBD]. General information on DetNet service can be found in [I-D.ietf-detnet-flow-information-model]. Typical mechanisms used to provide different treatment to different flows includes the allocation of system resources (such as queues and buffers) and provisioning or related parameters (such as shaping, and policing). Support can also be provided via an underlying network technology such as MPLS [I-D.ietf-detnet-ip-over-mpls]. and IEEE802.1 TSN [I-D.ietf-ip-over-tsn]. Other than in the TSN case, the specific mechanisms used by a DetNet node to ensure DetNet service delivery requirements are met for supported DetNet flows is outside the scope of this document.
The following summarizes the set of information that is needed to identify an individual DetNet flow:
This information MUST be provisioned per DetNet flow via configuration, e.g., via the controller or management plane.
Information identifying a DetNet flow is ordered and implementations use the first match. This can, for example, be used to provide a DetNet service for a specific UDP flow, with unique Source and Destination Port field values, while providing a different service for all other flows with that same UDP Destination Port value.
The security considerations of DetNet in general are discussed in [I-D.ietf-detnet-architecture] and [I-D.ietf-detnet-security]. Other security considerations will be added in a future version of this draft.
TBD.
RFC7322 limits the number of authors listed on the front page of a draft to a maximum of 5, far fewer than the 20 individuals below who made important contributions to this draft. The editor wishes to thank and acknowledge each of the following authors for contributing text to this draft. See also Section 10.
Loa Andersson Huawei Email: loa@pi.nu Yuanlong Jiang Huawei Email: jiangyuanlong@huawei.com Norman Finn Huawei 3101 Rio Way Spring Valley, CA 91977 USA Email: norman.finn@mail01.huawei.com Janos Farkas Ericsson Magyar Tudosok krt. 11 Budapest 1117 Hungary Email: janos.farkas@ericsson.com Carlos J. Bernardos Universidad Carlos III de Madrid Av. Universidad, 30 Leganes, Madrid 28911 Spain Email: cjbc@it.uc3m.es Tal Mizrahi Marvell 6 Hamada st. Yokneam Israel Email: talmi@marvell.com Lou Berger LabN Consulting, L.L.C. Email: lberger@labn.net Andrew G. Malis Huawei Technologies Email: agmalis@gmail.com Don Fedyk LabN Consulting, L.L.C. Email: dfedyk@labn.net
The author(s) ACK and NACK.
The following people were part of the DetNet Data Plane Solution Design Team:
The DetNet chairs serving during the DetNet Data Plane Solution Design Team:
Thanks for Stewart Bryant for his extensive review of the previous versions of the document.
| [RFC0768] | Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI 10.17487/RFC0768, August 1980. |
| [RFC0791] | Postel, J., "Internet Protocol", STD 5, RFC 791, DOI 10.17487/RFC0791, September 1981. |
| [RFC0793] | Postel, J., "Transmission Control Protocol", STD 7, RFC 793, DOI 10.17487/RFC0793, September 1981. |
| [RFC1812] | Baker, F., "Requirements for IP Version 4 Routers", RFC 1812, DOI 10.17487/RFC1812, June 1995. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [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, DOI 10.17487/RFC2474, December 1998. |
| [RFC3168] | Ramakrishnan, K., Floyd, S. and D. Black, "The Addition of Explicit Congestion Notification (ECN) to IP", RFC 3168, DOI 10.17487/RFC3168, September 2001. |
| [RFC3473] | Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, DOI 10.17487/RFC3473, January 2003. |
| [RFC4302] | Kent, S., "IP Authentication Header", RFC 4302, DOI 10.17487/RFC4302, December 2005. |
| [RFC4303] | Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, DOI 10.17487/RFC4303, December 2005. |
| [RFC7608] | Boucadair, M., Petrescu, A. and F. Baker, "IPv6 Prefix Length Recommendation for Forwarding", BCP 198, RFC 7608, DOI 10.17487/RFC7608, July 2015. |
| [RFC8174] | Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017. |
| [RFC8200] | Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017. |