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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-02) exists of draft-xia-sdnrg-service-description-language-00 -- Obsolete informational reference (is this intentional?): RFC 2629 (Obsoleted by RFC 7749) Summary: 0 errors (**), 0 flaws (~~), 9 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SDNRG Y. Xia, Ed. 3 Internet-Draft S. Jiang, Ed. 4 Intended status: Standards Track T. Zhou, Ed. 5 Expires: January 5, 2015 S. Hares 6 Huawei Technologies Co., Ltd 7 July 4, 2014 9 NEMO (NEtwork MOdeling) Language 10 draft-xia-sdnrg-nemo-language-00 12 Abstract 14 The North-Bound Interface (NBI), located between the network control 15 plane and the applications, is essential to enable the application 16 innovations and nourish the eco-system of SDN. 18 While most of the NBIs are provided in the form of API, this document 19 proposes the NEtwork MOdeling (NEMO) language which is anther NBI 20 fashion. Concept, model and syntax are introduced in the document. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on January 5, 2015. 39 Copyright Notice 41 Copyright (c) 2014 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 3. Related work . . . . . . . . . . . . . . . . . . . . . . . . 4 59 4. The NEMO Language overview . . . . . . . . . . . . . . . . . 5 60 4.1. Network Model of the NEMO Language . . . . . . . . . . . 5 61 4.2. Primitives . . . . . . . . . . . . . . . . . . . . . . . 7 62 5. The NEMO Language Examples . . . . . . . . . . . . . . . . . 9 63 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 64 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 65 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 66 9. Informative References . . . . . . . . . . . . . . . . . . . 10 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 69 1. Introduction 71 While SDN (Software Defined Network) is becoming one of the most 72 important directions of network evolution, the essence of SDN is to 73 make the network more flexible and easy to use. The North-Bound 74 Interface (NBI), located between the control plane and the 75 applications, is essential to enable the application innovations and 76 nourish the eco-system of SDN by abstracting the network 77 capabilities/information and opening the abstract/logic network to 78 applications. 80 The NBI is usually provided in the form of API (Application 81 Programming Interface). Different vendors provide self-defined API 82 sets. Each API set, such as OnePK from Cisco and OPS from Huawei, 83 often contains hundreds of specific APIs. Diverse APIs without 84 consistent style are hard to remember and use, and nearly impossible 85 to be standardized. 87 Most of those APIs are designed by network domain experts, who are 88 used to thinking from the network system perspective. The interface 89 designer does not know how the users will use the device and exposes 90 information details as much as possible. It enables better control 91 of devices, but leaves huge burden of selecting useful information to 92 users without well training. Since the NBI is used by network users, 93 a more appropriate design is to think from the user perspective and 94 abstract the network from the top down. 95 [I-D.sdnrg-service-description-language] describe the requirements 96 for a service description language and the design considerations. 98 A top-down NBI design contains following features: 100 o Express user intent 102 To simplify the operation, applications or users can use the NBI 103 directly to describe their requirements for the network without 104 taking care of the implementation. All the parameters without 105 user concern will be concealed by the NBI. 107 o Platform independent 109 With the NBI, the application or user can describe network demand 110 in a generic way, so that any platform or system can get the 111 identical knowledge and consequently execute to the same result. 112 Any low-level and device/vendor specific configurations and 113 dependencies should be avoided. 115 o Intuitive domain specific language (DSL) for network 117 The expression of the DSL should be human-friendly and be easily 118 understood by network operators. DSL should be directly used by 119 the system. 121 o Privilege control 123 Every application or user is authorized within a specific network 124 domain, which can be physical or virtual. While different network 125 domains are isolated without impact, the application or user may 126 have access to all the resource and capabilities within its 127 domain. The user perception of the network does not have to be 128 the same as the network operators. The proposed NEtwork MOdeling 129 (NEMO) language works on the user's view so the users can create 130 topologies based on the resources the network-operators allow them 131 to have. 133 o Declarative style 135 As described above, NEMO language is designed to help defining 136 service requirement to network, detailed configurations and 137 instructions performed by network devices are opaque to network 138 operators. So NEMO language should be declarative rather than 139 imperative. 141 To implement such an NBI design, we can learn from the successful 142 case of SQL (Structured Query Language), which simplified the 143 complicated data operation to a unified and intuitive way in the form 144 of language. Applications do not care about the way of data storage 145 and data operation, but to describe the demand for the data storage 146 and operation and then get the result. As a data domain DSL, SQL is 147 simple and intuitive, and can be embedded in applications. So what 148 we need for the network NBI is a set of "network domain SQL". 150 2. Terminology 152 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 153 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 154 "OPTIONAL" in this document are to be interpreted as described in 155 [RFC2119] when they appear in ALL CAPS. When these words are not in 156 ALL CAPS (such as "should" or "Should"), they have their usual 157 English meanings, and are not to be interpreted as [RFC2119] key 158 words. 160 Network service also "service" for short, is the service logic that 161 contains network operation requirements; 163 Network APP also "APP" for short, is the application to implement 164 the network service; 166 Network user also "user" for short, is the network administrator or 167 operator. 169 3. Related work 171 YANG is a data modeling language used to model configuration and 172 state data manipulated by the Network Configuration Protocol 173 (NETCONF), NETCONF remote procedure calls, and NETCONF notifications 174 [RFC6020]. Although it is extensible for more data modeling in 175 addition to NETCONF, YANG is not capable of describing high level 176 network requirements, such as SLA (Service Level Agreement). YANG is 177 designed for north-bound interfaces of the device, which is also the 178 south-bound of the controller. It is not proper to model the north- 179 bound interface of the controller, aka the NBI. Moreover, the YANG 180 is not capable of describing the service processing logic, which 181 typically includes transition of conditions and states. 183 UML (Unified Modeling Language) is a powerful modeling language, 184 which is domain agnostic. It is hard to describe the network demand, 185 and cannot be embedded in network applications. UML is appropriate 186 to describe the model behind the NBI language not the NBI itself. 188 With the emergence of the SDN concept, it is a consensus to simplify 189 the network operation, which leads to many cutting-edge explorations 190 in the academic area. 192 Nick McKeown from Stanford University proposed the SFNet [TSFNet], 193 which translated the high level network demand to the underlying 194 controller interfaces. By concealing the low level network details, 195 the controller simplified the operation of resource, flow, and 196 information for applications. The SFNet is used for the SDN 197 architecture design, and does not go into the NBI design. 199 Jennifer from Princeton University designed the Frenetic [Frenetic] 200 based on the OpenFlow protocol. It is an advanced language for flow 201 programming, and systematically defines the operating model and mode 202 for the flow. However, the network requirement from the service is 203 not only the flow operations, but also includes operations of 204 resource, service conditions, and service logic. 206 In the book [PBNM], John Strassner defined the policy concept and 207 proposed the formal description for network operations by using the 208 policy. The method for querying network information is absent in the 209 book. Virtual tenant network and operations to the tenant network 210 are not considered. 212 All these investigations direct to the future SDN that use simple and 213 intuitive interfaces to describe the network demands without complex 214 programming. 216 4. The NEMO Language overview 218 NEMO language is a domain specific language (DSL) based on 219 abstraction of network models and conclusion of operation patterns. 220 It provides NBI fashion in the form of language. With limited number 221 of key words and expressions, NEMO language defines the entity and 222 capability models for users with different view of network 223 abstraction, and enables network users/applications to describe their 224 demands for network resources, services and logical operations in an 225 intuitive expression. And finally the NEMO language description can 226 be explained and executed by a language engine. 228 4.1. Network Model of the NEMO Language 230 Behind the NEMO language, there is a set of meta-models abstracting 231 the network demands from the top down according to the service 232 requirement. Those demands can be divided into two types: the demand 233 for network resources and the demands for network behaviors. 235 The network resource is composed of three kinds of entities: node, 236 link and flow. Each entity contains property and statistic 237 information. With a globally unique identifier, the network entity 238 is the basic object for operation. 240 o Node model: describes the entity with the capability of packet 241 processing. According to the functionality, there are three types 242 of node 244 * The forwarding node (FN) only deals with L2/3 forwarding. It 245 forwards packets according to the forwarding table and modifies 246 packet heads. 248 * The processing node (PN) provides L4-7 network services, and 249 will modify the body of packets. 251 * The logical node (LN) describes a set of network elements and 252 their links, such as subnet, autonomous system, and internet. 253 It conceals the internal topology and exposes properties as one 254 entity. It also enables iteration, i.e., a network entity may 255 include other network entities. 257 o Link model: describes the connectivity between node entities. 258 According to the forwarding capability, links are usually divided 259 into layer 2 and layer 3 types 261 o Flow model: describes a sequence of packets with certain common 262 characters, such as source/destination IP address, port, and 263 protocol. From the northbound perspective, flow is the special 264 traffic with user concern, which may be per device or across many 265 devices. So the flow characters also include ingress/egress node, 266 and so on. 268 Network behavior includes the information and control operations. 270 The information operation provides two methods to get the network 271 information for users. 273 o Query: a synchronous mode to get the information, i.e., one can 274 get the response when a request is sent out. 276 o Notification: an asynchronous mode to get the information, i.e., 277 with one request, one or multiple responses will be sent to the 278 subscriber automatically whenever trigger conditions meet. 280 The NEMO language uses policy to describe the control operation. 282 o Policy: control the behavior of specific entities by APP, such as 283 flow policy, node policy. All the policies follow the same 284 pattern "with , to execute ", and can be 285 applied to any entity 287 4.2. Primitives 289 The primitives of NEMO language are derived from the network model, 290 and fall into four categories. 292 a. Resource access primitives 294 Node/UnNode entity_id Type {FN|PN|LN} 295 Owner node_id 296 Properties key1 ,value1 298 Node/UnNode: create/delete a node 299 Entity id: system allocated URI for the node entity 300 Type: Node type of FN (forwarding node), PN (processing node) 301 or LN (logical node) 302 Owner: since the node can be nested, this primitive figures 303 out which node the new one belongs to 304 Properties: other properties to describe the node in the form of 305 (key, value). 307 Link/UnLink entity_id Endnodes (node1_id,node2_id) 308 SLA key,value 309 Properties key1 ,value1 311 Link/UnLink: create/delete a link. 312 Entity id: system allocated URI for the link entity 313 Endnodes: two end-node IDs of the link 314 SLA: SLA description for the link 315 Properties: other properties to describe the link in the form of 316 (key, value). 318 Flow/UnFlow entity_id Match/UnMatch key1, value1| 319 Range(value, value) | 320 Mask(value, value) 321 Properties key1 ,value1 323 Flow/UnFlow: create/delete a flow. 324 Match/UnMatch: create/delete match items for the flow 325 Range: describe the range of the value 326 Mask: use mask to describe a range of the value 327 Properties: other properties to describe the flow in the form of 328 (key, value). 330 b. Behavior primitives 331 Query key Value {value} 332 From entity_id 334 Query: generate a synchronously query 335 key: the parameter name to be queried 336 Value: the return value for the query 337 From: the entity to be queried (define entity_id). 339 Policy/UnPolicy policy_id Appliesto entity_id 340 Condition {expression} 341 Action {"forwardto"|"drop"|"gothrough"| 342 "bypass"|"guaranteeSLA"|"Set"| 343 "Packetout"|Node|UnNode|Link|Unlink} 345 Policy/UnPolicy: create/delete a policy 346 Appliesto: apply the policy to an entity 347 Condition: condition to execute the policy 348 Action: actions to be executed when conditions are met 350 Notification/UnNotification entity_id On key 351 Every period 352 RegisterListener 353 callbackfunc 355 Notification/UnNotification: create/delete a notification for an 356 entity 357 On: the notification will monitor the state change of a 358 parameter identified by the "key" 359 Every: time period at which to report the state 360 RegisterListener: the callback function that is used to process the 361 notification. 363 c. Connection management primitives 365 Connect conn_id Address ip_address 366 Port port_num 367 Disconnect conn_id 369 Connect: set up a connection to the controller 370 Address: IP address of the controller to connect to 371 Port: port of the controller to connect to 372 Disconnect: disconnect to the controller. 374 d. Transaction primitives 375 Transaction 376 Commit 378 Transaction: indicate the beginning of a transaction 379 Commit: commit to execute the transaction 381 5. The NEMO Language Examples 383 A tenant needs two connections to carry different service flows 384 between two datacenters. 386 one connection of the tenant is 40G bandwidth with less than 400ms 387 delay, another connection is 100M bandwidth with less than 50ms 388 delay. 390 { 391 Link Link1_id 392 Endnodes (DC1_node_id, DC2_node_id) 393 Property "NAME","DC1_DC2_link_one","Bandwith",40G,"Delay",400ms 394 Link Link2_id 395 Endnodes (DC1_node_id, DC2_node_id) 396 Property "NAME","DC1_DC2_link_two","Bandwith",100M,"Delay",50ms 397 } 399 The tenant has two types of traffic, CDN sync traffic uses high 400 bandwidth connection and online game traffic uses low latency 401 connection. 403 { 404 Flow flow1_id 405 Match "srcip","10.0.1.1/24","dstip","20.0.1.1/24","Port","55555" 406 Property "NAME","CDN sync flow","Bidirection","true" 407 Flow flow2_id 408 Match "srcip","10.0.1.1/24","dstip","20.0.1.1/24","Port","56663" 409 Property "NAME","online Game","Bidirection","true" 410 Policy policy1_id 411 Appliesto flow1_id 412 Action "forwardto",link1_id 413 Policy policy2_id 414 Appliesto flow2_id 415 Action "gothrough",link2_id 416 } 418 The tenant wants the online game traffic to go through WOC in 419 nighttime before it is carried by low latency connection. 421 { 422 Policy policy3_id 423 Appliesto flow2_id 424 Condition {Time>18:00 or Time< 2:00} 425 Action "gothrough",{woc_node_id ,link2_id} 426 } 428 6. Security Considerations 430 Because the network customers are allowed to customize their own 431 services, they may bring potentially big impacts to a running IP 432 network. A strong user authentication mechanism is needed for the 433 northbound interface of the SDN controller. User authorization 434 should be carefully managed by the network administrator to avoid any 435 dangerous operations and prevent any abuse of network resources. 437 7. IANA Considerations 439 This memo includes no request to IANA. 441 8. Acknowledgements 443 The authors would like to thanks the valuable comments made by Wei 444 Cao, Xiaofei Xu, Fuyou Miao and Wenyang Lei. 446 This document was produced using the xml2rfc tool [RFC2629]. 448 9. Informative References 450 [Frenetic] 451 Foster, N., Harrison, R., Freedman, M., Monsanto, C., 452 Rexford, J., Story, A., and D. Walker, "Frenetic: A 453 Network Programming Languages, ICFP' 11", . 455 [I-D.sdnrg-service-description-language] 456 Xia, Y., Jiang, S., and S. Hares, "Requirements for a 457 Service Description Language and Design Considerations, 458 draft-xia-sdnrg-service-description-language-00, Work in 459 progress", July 2014. 461 [PBNM] Strassner, J., "Policy-Based Network Management: Solutions 462 for the Next Generation, Morgan Kaufmann Publishers Inc. 463 San Francisco, CA, USA.", 2003. 465 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 466 Requirement Levels", BCP 14, RFC 2119, March 1997. 468 [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, 469 June 1999. 471 [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the 472 Network Configuration Protocol (NETCONF)", RFC 6020, 473 October 2010. 475 [TSFNet] Yap, K., Huang, T., Dodson, B., Lam, M., and N. McKeown, 476 "Towards Software-Friendly Networks, APSys 2010, pp:49-54, 477 2010, New Delhi, India.", . 479 Authors' Addresses 481 Yinben Xia (editor) 482 Huawei Technologies Co., Ltd 483 Q14, Huawei Campus, No.156 Beiqing Road 484 Hai-Dian District, Beijing, 100095 485 P.R. China 487 Email: xiayinben@huawei.com 489 Sheng Jiang (editor) 490 Huawei Technologies Co., Ltd 491 Q14, Huawei Campus, No.156 Beiqing Road 492 Hai-Dian District, Beijing, 100095 493 P.R. China 495 Email: jiangsheng@huawei.com 497 Tianran Zhou (editor) 498 Huawei Technologies Co., Ltd 499 Q14, Huawei Campus, No.156 Beiqing Road 500 Hai-Dian District, Beijing, 100095 501 P.R. China 503 Email: zhoutianran@huawei.com 505 Susan Hares 506 Huawei Technologies Co., Ltd 507 7453 Hickory Hill 508 Saline, CA 48176 509 USA 511 Email: shares@ndzh.com