Hi All, I have been selected to do a routing directorate aQA review of this draft. https://datatracker.ietf.org/doc/draft-ietf-rtgwg-ni-model/ The QA review is described (https://trac.ietf.org/trac/rtg/wiki/RtgDirDocQa) as: "The WG Draft Quality Assurance process exists to provide cross-WG and expert review early in the IETF process after a WG has adopted a WG draft or while the WG is deciding to adopt a draft. Since a WG adopts a draft as a good starting point for the work, providing early excellent review of such drafts allows for good technical discussion and the ability to enhance the WG draft to solve identified issues. The earlier in the process that substantial issues (technical or editorial) are resolved, the more quickly and smoothly a WG draft is likely to proceed." For more information about the Routing Directorate, please see ​http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir Document: draft-ietf-rtgwg-ni-model-02.txt Reviewer: John Scudder Review Date: April 28, 2017 Summary: I found the document easy to follow, clear and almost painless to read, thank you. Note that my level of Yang expertise is pretty low, so you should be looking elsewhere for a critique of anything other than the grossest Yang-specific aspects of the document. (I found the schema-mount example in section 3.2 particularly opaque.) Comments and Questions: 1. There's a significant amount of duplication of explanatory and background text between this document and draft-ietf-rtgwg-lne-model-01. In reading it, I tried to consider whether it would be OK to cut out some of the text explaining what an LNE is, but on the whole I think it's better left in -- the document would have been more difficult to read without having that context in-line. However, it does lead to the question, is there some good reason the two documents are separate, instead of a single document? The duplication between them suggests there's at least some motivation to refactor them into one. (I realize there may be many reasons to keep them separate, including "seriously, John? The cost/benefit just isn't there", but I had to ask.) 2. The abstract is almost a copy of the abstract for draft-ietf-rtgwg-lne-model-01. Comments in #1 above notwithstanding, I do think brevity is the soul of wit when it comes to an abstract, so I suggest removing the LNE definition here, and just define the stuff *this* doc is about. (Similar suggestion applies to the companion doc's abstract.) 3. It seems to me the "TBD" for network-instance-policy represents a significant open issue and deserves to be included in your open issues list (section 1.1). Other TBDs sprinkled throughout don't seem to rise to this level, but of course do represent open issues. 4. Speaking of network instance policy, although since it's left TBD there's not much to be said, the examples you give (RTs, RDs, VNIs, VPLS neighbors) mostly don't seem like what I think of as "policy". I suppose it's one of the most overloaded terms in our industry, so maybe someone else does think of it that way, but this choice of terminology was a speed bump for my understanding of the doc. 5. The example given in section 3.2 doesn't seem to follow the same pattern as the one given in section 3. I'm too much of a Yang neophyte to know if there might be some Yang feature in play that makes this make sense, but on the face of it the example in section 3 seems to tell me I'm supposed to bind a network-instance-name to a specific instance of an interface (so, if:interfaces/if:interface), whereas what I see in 3.2 is a network-instance-name at the if:interfaces level -- which doesn't make a lot of intuitive sense, either. Minor Issues and Nits: 6. I've edited various minor suggestions into a copy of draft-ietf-rtgwg-ni-model-02.txt and attached it, you can look at them using your diff tool of choice. 7. This sentence isn't quite right: Network instance policies are used to control how NI information is represented at the device level, VRF routing policies, and VRF/VSI identifiers. Without knowing your intent I'm not able to offer you a rewrite. Possibly it would be enough to reorder the items in your list, to put the big compound one at the end, as in "Network instance policies are used to control VRF routing policies, VRF/VSI identifiers, and how NI information is represented at the device level"? 8. This sentence no verb: For layer 3, this consistent with the routing-instance definition in ietf-routing Again, without knowing your intent I can't offer a rewrite. Maybe the verb "to be" is what you want? Network Working Group L. Berger Internet-Draft LabN Consulting, L.L.C. Intended status: Standards Track C. Hopps Expires: September 14, 2017 Deutsche Telekom A. Lindem Cisco Systems D. Bogdanovic March 13, 2017 YANG Network Instances draft-ietf-rtgwg-ni-model-02 Abstract This document defines a network instance module. This module along with the logical network element module can be used to manage the logical and virtual resource representations that may be present on a network device. Examples of common industry terms for logical resource representations are Logical Systems or Logical Routers. Examples of common industry terms for virtual resource representations are Virtual Routing and Forwarding (VRF) instances and Virtual Switch Instances (VSIs). Status of This Memo 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 http://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 September 14, 2017. 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 Berger, et al. Expires September 14, 2017 [Page 1] Internet-Draft YANG NIs March 2017 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Status of Work and Open Issues . . . . . . . . . . . . . 3 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Network Instances . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Network Instance Policy . . . . . . . . . . . . . . . . . 6 3.2. Network Instance Management . . . . . . . . . . . . . . . 7 3.3. Network Instance Instantiation . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Network Instance Model . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1. Normative References . . . . . . . . . . . . . . . . . . 14 7.2. Informative References . . . . . . . . . . . . . . . . . 15 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 16 Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction This document defines the second of two new modules that are defined to support the configuration and operation of network devices that allow for the partitioning of resources from both, or either, management and networking perspectives. Both make use of the YANG functionality enabled by YANG Schema Mount [I-D.ietf-netmod-schema-mount]. Two forms of resource partitioning are supported: The first form, which is defined in [I-D.ietf-rtgwg-lne-model], provides a logical partitioning of a network device where each partition is separately managed as essentially an independent network element which is 'hosted' by the base network device. These hosted network elements are referred to as logical network elements, or LNEs, and are supported by the logical-network-element module defined in [I-D.ietf-rtgwg-lne-model]. The module is used to identify LNEs and associate resources from the network-device with each LNE. LNEs themselves are represented in YANG as independent network devices; each accessed independently. Optionally, and when supported by the Berger, et al. Expires September 14, 2017 [Page 2] Internet-Draft YANG NIs March 2017 implementation, they may also be accessed from the host system. Examples of vendor terminology for an LNE include logical system or logical router, and virtual switch, chassis, or fabric. The second form, which is defined in this document, provides support for what is commonly referred to as Virtual Routing and Forwarding (VRF) instances as well as Virtual Switch Instances (VSI), see [RFC4026]. In this form of resource partitioning multiple control plane and forwarding/bridging instances are provided by and managed via a single (physical or logical) network device. This form of resource partitioning is referred to as Network Instances and is supported by the network-instance module defined below. Configuration and operation of each network-instance is always via the network device and the network-instance module. This document was motivated by, and derived from, [I-D.ietf-rtgwg-device-model]. 1.1. Status of Work and Open Issues The top open issues are: 1. This document will need to match the evolution and standardization of [I-D.openconfig-netmod-opstate] or [I-D.ietf-netmod-opstate-reqs] by the Netmod WG. 2. Overview In this document, we consider network devices that support protocols and functions defined within the IETF Routing Area, e.g, routers, firewalls and hosts. Such devices may be physical or virtual, e.g., a classic router with custom hardware or one residing within a server-based virtual machine implementing a virtual network function (VNF). Each device may sub-divide their resources into logical network elements (LNEs) each of which provides a managed logical device. Examples of vendor terminology for an LNE include logical system or logical router, and virtual switch, chassis, or fabric. Each LNE may also support virtual routing and forwarding (VRF) and virtual switching instance (VSI) functions, which are referred to below as a network instances (NIs). This breakdown is represented in Figure 1. Berger, et al. Expires September 14, 2017 [Page 3] Internet-Draft YANG NIs March 2017 ,''''''''''''''''''''''''''''''''''''''''''''''`. | Network Device (Physical or Virtual) | | ..................... ..................... | | : Logical Network : : Logical Network : | | : Element : : Element : | | :+-----+-----+-----+: :+-----+-----+-----+: | | :| Net | Net | Net |: :| Net | Net | Net |: | | :|Inst.|Inst.|Inst.|: :|Inst.|Inst.|Inst.|: | | :+-----+-----+-----+: :+-----+-----+-----+: | | : | | | | | | : : | | | | | | : | | :..|.|...|.|...|.|..: :..|.|...|.|...|.|..: | | | | | | | | | | | | | | | `'''|'|'''|'|'''|'|'''''''''|'|'''|'|'''|'|''''' | | | | | | | | | | | | Interfaces Interfaces Figure 1: Module Element Relationships A model for LNEs is described in [I-D.ietf-rtgwg-lne-model] and the model for network instances is covered in Section 3. For more information on how these models may be used within an overall device model structure, see [I-D.ietf-rtgwg-device-model]. The interface management model [RFC7223] is an existing model that is impacted by the definition of LNEs and network instances. This document and [I-D.ietf-rtgwg-lne-model] define augmentations to the interface module to support LNEs and NIs. Similar elements, although perhaps only for LNEs, may also need to be included as part of the definition of the hardware and QoS modules. Interfaces are a crucial part of any network device's configuration and operational state. They generally include a combination of raw physical interfaces, link-layer interfaces, addressing configuration, and logical interfaces that may not be tied to any physical interface. Several system services, and layer 2 and layer 3 protocols may also associate configuration or operational state data with different types of interfaces (these relationships are not shown for simplicity). The interface management model is defined by [RFC7223]. The logical-network-element and network-instance modules augment the existing interface management model in two ways: The first, by the logical-network-element module, adds an identifier which is used on physical interface types to identify an associated LNE. The second, by the network-instance module, adds a name which is used on interface or sub-interface types to identify an associated network instance. Similarly, this name is also added for IPv4 and IPv6 types, as defined in [RFC7277]. Berger, et al. Expires September 14, 2017 [Page 4] Internet-Draft YANG NIs March 2017 The interface related augmentations are as follows: module: ietf-logical-network-element augment /if:interfaces/if:interface: +--rw bind-lne-name? string module: ietf-network-instance augment /if:interfaces/if:interface: +--rw bind-network-instance-name? string augment /if:interfaces/if:interface/ip:ipv4: +--rw bind-network-instance-name? string augment /if:interfaces/if:interface/ip:ipv6: +--rw bind-network-instance-name? string The following is an example of envisioned combined usage. The interfaces container includes a number of commonly used components as examples: +--rw if:interfaces | +--rw interface* [name] | +--rw name string | +--rw lne:bind-lne-name? string | +--rw ethernet | | +--rw ni:bind-network-instance-name? string | | +--rw aggregates | | +--rw rstp | | +--rw lldp | | +--rw ptp | +--rw vlans | +--rw tunnels | +--rw ipv4 | | +--rw ni:bind-network-instance-name? string | | +--rw arp | | +--rw icmp | | +--rw vrrp | | +--rw dhcp-client | +--rw ipv6 | +--rw ni:bind-network-instance-name? string | +--rw vrrp | +--rw icmpv6 | +--rw nd | +--rw dhcpv6-client The [RFC7223] defined interface model is structured to include all interfaces in a flat list, without regard to logical or virtual instances (e.g., VRFs) supported on the device. The bind-lne-name and bind-network-instance-name leaves provide the association between an interface and its associated LNE and NI (e.g., VRF or VSI). Berger, et al. Expires September 14, 2017 [Page 5] Internet-Draft YANG NIs March 2017 3. Network Instances The network instance container is used to represent virtual routing and forwarding instances (VRFs) and virtual switching instances (VSIs), [RFC4026]. VRFs and VSIs are commonly used to isolate routing and switching domains, for example to create virtual private networks, each with their own active protocols and routing/switching policies. The model represents both core/provider and virtual instances. Network instances reuse and build on [RFC8022] and are shown below: module: ietf-network-instance +--rw network-instances +--rw network-instance* [name] +--rw name string +--rw type? identityref +--rw enabled? boolean +--rw description? string +--rw network-instance-policy | ... +--rw root? yang-schema-mount | ... augment /if:interfaces/if:interface: +--rw bind-network-instance-name? string augment /if:interfaces/if:interface/ip:ipv4: +--rw bind-network-instance-name? string augment /if:interfaces/if:interface/ip:ipv6: +--rw bind-network-instance-name? string A network instance is identified by a `name` string. This string is used both as an index within the network-instance module and to associate resources with a network instance as shown above in the interface augmentation. Type is used to indicate the type of NI, such as L3-VRF, VPLS, L2-VSI, etc. Network instance policy and root are discussed in greater detail below. 3.1. Network Instance Policy Network instance policies are used to control how NI information is represented at the device level, VRF routing policies, and VRF/VSI identifiers. Examples include BGP route targets (RTs) and route distinguishers (RDs), virtual network identifiers (VN-IDs), VPLS neighbors, etc. The structure is expected to be: Berger, et al. Expires September 14, 2017 [Page 6] Internet-Draft YANG NIs March 2017 module: ietf-network-instance +--rw network-instances +--rw network-instance* [name] +--rw network-instance-policy (TBD) 3.2. Network Instance Management Modules that may be used to represent network instance specific information will be available under `root`. As with LNEs, actual module availability is expected to be implementation dependent. The use-schema mechanism defined as part of the Schema Mount module [I-D.ietf-netmod-schema-mount] is expected to be the primary method used to identify supported modules. Resource related control and assignment is expected to be managed at the network-device level, not the network instance level, based on the `bind-network-instance-name` augmentation mentioned above. Mounted modules will access such information, as well as any other information contained within a module at the device root, by using the parent-reference mechanism defined in [I-D.ietf-netmod-schema-mount]. As an example, consider the case where a network instance with a `name` of "green" is defined on a network device. In this case the following logical structure might be made available: +--rw yanglib:modules-state [RFC7895] +--rw if:interfaces [RFC7223] | +--rw bind-network-instance-name="green" string +--rw network-instances +--rw network-instance* [name] +--rw name="green" string +--rw type? identityref +--rw enabled=true boolean +--rw description="The Green VRF" string +--rw network-instance-policy | ... (RT=1000:1, RD=1.2.3.4) +--rw root? yang-schema-mount with a corresponding logical structure in the schema-mount module: Berger, et al. Expires September 14, 2017 [Page 7] Internet-Draft YANG NIs March 2017 module: ietf-yang-schema-mount +--ro schema-mounts : +--ro mount-point* [module name] | +--ro module="ietf-network-instance" | +--ro name="root" | +--ro config=true | +--ro (schema-ref)? | +--:(use-schema) | +--ro use-schema* [name] | +--ro name="ni-vrf" : : : +--ro schema* [name] +--ro name="ni-vrf" string +--ro module* [name revision] | +--ro name="mm:network-services" : : | +--ro name="nn:oam-protocols" : : | +--ro name="oo:routing" : : | +--ro name="pp:mpls" : : +--ro mount-point* [network-instance] : All modules that represent control-plane and data-plane information may be present at the `root`, and be accessible via paths modified per [I-D.ietf-netmod-schema-mount]. The list of available modules is expected to be implementation dependent, as is the method used by an implementation to support NIs. 3.3. Network Instance Instantiation Network instances may be controlled by clients using existing list operations. When list entries are created, a new instance is instantiated. The models mounted under a NI root are expected to be dependent on the server implementation. When a list entry is deleted, an existing network instance is destroyed. For more information see [RFC7950] Section 7.8.6. 4. Security Considerations TBD Berger, et al. Expires September 14, 2017 [Page 8] Internet-Draft YANG NIs March 2017 5. IANA Considerations This document registers a URI in the IETF XML registry [RFC3688]. Following the format in RFC 3688, the following registration is requested to be made. URI: urn:ietf:params:xml:ns:yang:ietf-network-instance Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. This document registers a YANG module in the YANG Module Names registry [RFC6020]. name: ietf-network-instance namespace: urn:ietf:params:xml:ns:yang:ietf-network-instance prefix: ni reference: RFC XXXX 6. Network Instance Model The structure of the model defined in this document is described by the YANG module below. file "ietf-network-instance@2017-03-13.yang" module ietf-network-instance { yang-version 1.1; // namespace namespace "urn:ietf:params:xml:ns:yang:ietf-network-instance"; prefix ni; // import some basic types import ietf-interfaces { prefix if; } import ietf-ip { prefix ip; } import ietf-yang-schema-mount { prefix yangmnt; } Berger, et al. Expires September 14, 2017 [Page 9] Internet-Draft YANG NIs March 2017 // meta organization "IETF Routing Area Working Group (rtgwg)"; contact "Routing Area Working Group - "; description "This module is used to support multiple network instances within a single physical or virtual device. Network instances are commonly known as VRFs (virtual routing and forwarding) and VSIs (virtual switching instances)."; revision "2017-03-13" { description "Initial revision."; reference "RFC TBD"; } // extension statements feature bind-network-instance-name { description "Network Instance to which an interface instance is bound"; } // identity statements identity network-instance-type { description "Base identity from which identities describing network instance types are derived"; } identity ipv4-interface-protocol-type { description "Base identity for derivation of IPv4 interface protocols"; } identity ipv6-interface-protocol-type { description "Base identity for derivation of IPv6 interface protocols"; } // typedef statements // grouping statements Berger, et al. Expires September 14, 2017 [Page 10] Internet-Draft YANG NIs March 2017 grouping interface-ip-common { description "interface-specific configuration for IP interfaces, IPv4 and IPv6"; } grouping ipv4-interface-protocols { container ipv4-interface-protocols { list ipv4-interface-protocol { key "type"; leaf type { type identityref { base ipv4-interface-protocol-type; } mandatory true; description "ARP, ICMP, VRRP, DHCP Client, etc."; } description "List of IPv4 protocols configured on an interface"; } description "Container for list of IPv4 protocols configured on an interface"; } description "Grouping for IPv4 protocols configured on an interface"; } grouping ipv6-interface-protocols { description "Grouping for IPv6 protocols configured on an interface."; container ipv6-interface-protocols { description "Container for list of IPv6 protocols configured on an interface."; list ipv6-interface-protocol { key "type"; description "List of IPv6 protocols configured on an interface"; leaf type { type identityref { base ipv6-interface-protocol-type; } Berger, et al. Expires September 14, 2017 [Page 11] Internet-Draft YANG NIs March 2017 mandatory true; description "ND, ICMPv6, VRRP, DHCPv6 Client, etc."; } } } } grouping network-instance-policy { description "Network instance policies such as route distinguisher, route targets, VPLS ID and neighbor, Ethernet ID, etc. "; reference "RFC 4364 - BGP/MPLS Virtual Private Networks (VPNs) RFC 6074 - Provisioning, Auto-Discovery, and Signaling in Layer 2 Virtual Private Networks (L2VPNs) RFC 7432 - BGP MPLS-Based Ethernet VPN"; container network-instance-policy { description "Network Instance Policy -- details TBD, perhaps based on BESS model"; } } // top level device definition statements container network-instances { description "Network instances each of which have an independent IP/IPv6 addressing space and protocol instantiations. For layer 3, this consistent with the routing-instance definition in ietf-routing"; reference "RFC 8022 - A YANG Data Model for Routing Management"; list network-instance { key name; description "List of network-instances"; leaf name { type string; description "device scoped identifier for the network instance"; } leaf type { type identityref { base network-instance-type; } description Berger, et al. Expires September 14, 2017 [Page 12] Internet-Draft YANG NIs March 2017 "The network instance type -- details TBD Likely types include core, L3-VRF, VPLS, L2-cross-connect, L2-VSI, etc."; } leaf enabled { type boolean; default "true"; description "Flag indicating whether or not the network instance is enabled."; } leaf description { type string; description "Description of the network instance and its intended purpose"; } uses network-instance-policy; yangmnt:mount-point root { description "Root for models supported per network instance. This will typically not be an inline type mount point."; } } } // augment statements augment "/if:interfaces/if:interface" { description "Add a node for the identification of the logical network instance (which is within the interface's identified logical network element) associated with the IP information configured on an interface"; leaf bind-network-instance-name { type string; description "Network Instance to which an interface is bound"; } } augment "/if:interfaces/if:interface/ip:ipv4" { description Berger, et al. Expires September 14, 2017 [Page 13] Internet-Draft YANG NIs March 2017 "Add a node for the identification of the logical network instance (which is within the interface's identified physical or virtual device) associated with the IP information configured on an interface"; leaf bind-network-instance-name { type string; description "Network Instance to which IPv4 interface is bound"; } } augment "/if:interfaces/if:interface/ip:ipv6" { description "Add a node for the identification of the logical network instance (which is within the interface's identified physical or virtual device) associated with the IP information configured on an interface"; leaf bind-network-instance-name { type string; description "Network Instance to which IPv6 interface is bound"; } } // rpc statements // notification statements } 7. References 7.1. Normative References [I-D.ietf-netmod-schema-mount] Bjorklund, M. and L. Lhotka, "YANG Schema Mount", draft- ietf-netmod-schema-mount-04 (work in progress), March 2017. [I-D.ietf-rtgwg-lne-model] Berger, L., Hopps, C., Lindem, A., and D. Bogdanovic, "YANG Logical Network Elements", draft-ietf-rtgwg-lne- model-01 (work in progress), October 2016. Berger, et al. Expires September 14, 2017 [Page 14] Internet-Draft YANG NIs March 2017 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC7223] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, . [RFC7277] Bjorklund, M., "A YANG Data Model for IP Management", RFC 7277, DOI 10.17487/RFC7277, June 2014, . 7.2. Informative References [I-D.ietf-netmod-opstate-reqs] Watsen, K. and T. Nadeau, "Terminology and Requirements for Enhanced Handling of Operational State", draft-ietf- netmod-opstate-reqs-04 (work in progress), January 2016. [I-D.ietf-rtgwg-device-model] Lindem, A., Berger, L., Bogdanovic, D., and C. Hopps, "Network Device YANG Organizational Models", draft-ietf- rtgwg-device-model-01 (work in progress), October 2016. [I-D.openconfig-netmod-opstate] Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling of Operational State Data in YANG", draft-openconfig- netmod-opstate-01 (work in progress), July 2015. [RFC4026] Andersson, L. and T. Madsen, "Provider Provisioned Virtual Private Network (VPN) Terminology", RFC 4026, DOI 10.17487/RFC4026, March 2005, . [RFC7895] Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module Library", RFC 7895, DOI 10.17487/RFC7895, June 2016, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . Berger, et al. Expires September 14, 2017 [Page 15] Internet-Draft YANG NIs March 2017 [RFC8022] Lhotka, L. and A. Lindem, "A YANG Data Model for Routing Management", RFC 8022, DOI 10.17487/RFC8022, November 2016, . Appendix A. Acknowledgments The Routing Area Yang Architecture design team members included Acee Lindem, Anees Shaikh, Christian Hopps, Dean Bogdanovic, Lou Berger, Qin Wu, Rob Shakir, Stephane Litkowski, and Yan Gang. The RFC text was produced using Marshall Rose's xml2rfc tool. Berger, et al. Expires September 14, 2017 [Page 16] Internet-Draft YANG NIs March 2017 Appendix B. Contributors Contributors' Addresses TBD Authors' Addresses Lou Berger LabN Consulting, L.L.C. Email: lberger@labn.net Christan Hopps Deutsche Telekom Email: chopps@chopps.org Acee Lindem Cisco Systems 301 Midenhall Way Cary, NC 27513 USA Email: acee@cisco.com Dean Bogdanovic Email: ivandean@gmail.com Berger, et al. Expires September 14, 2017 [Page 17]