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Checking references for intended status: Best Current Practice ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Missing reference section? 'RFC4607' on line 505 looks like a reference -- Missing reference section? 'RFC4604' on line 500 looks like a reference -- Missing reference section? 'RFC2784' on line 494 looks like a reference -- Missing reference section? 'IETF-ID-AMT' on line 497 looks like a reference Summary: 3 errors (**), 0 flaws (~~), 5 warnings (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 MBONED Working Group Percy S. Tarapore 2 Internet Draft Robert Sayko 3 Intended status: BCP AT&T 4 Expires: January 15, 2014 Greg Shepherd 5 Toerless Eckert 6 Cisco 7 Ram Krishnan 8 Brocade 9 July 15, 2013 11 Multicasting Applications Across Inter-Domain Peering Points 12 draft-tarapore-mboned-multicast-cdni-03.txt 14 Status of this Memo 16 This Internet-Draft is submitted in full conformance with the 17 provisions of BCP 78 and BCP 79. 19 Internet-Drafts are working documents of the Internet Engineering 20 Task Force (IETF), its areas, and its working groups. Note that 21 other groups may also distribute working documents as Internet- 22 Drafts. 24 Internet-Drafts are draft documents valid for a maximum of six 25 months and may be updated, replaced, or obsoleted by other documents 26 at any time. It is inappropriate to use Internet-Drafts as 27 reference material or to cite them other than as "work in progress." 29 The list of current Internet-Drafts can be accessed at 30 http://www.ietf.org/ietf/1id-abstracts.txt 32 The list of Internet-Draft Shadow Directories can be accessed at 33 http://www.ietf.org/shadow.html 35 This Internet-Draft will expire on January 15, 2014. 37 Copyright Notice 39 Copyright (c) 2013 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with 47 respect to this document. Code Components extracted from this 48 document must include Simplified BSD License text as described in 49 Section 4.e of the Trust Legal Provisions and are provided without 50 warranty as described in the Simplified BSD License. 52 Abstract 54 This document examines the process of transporting applications via 55 multicast across inter-domain peering points. The objective is to 56 describe the setup process for multicast-based delivery across 57 administrative domains and document supporting functionality to 58 enable this process. 60 Table of Contents 62 1. Introduction...................................................2 63 2. Overview of Inter-domain Multicast Application Transport.......3 64 3. Inter-domain Peering Point Requirements for Multicast..........4 65 3.1. Native Multicast..........................................4 66 3.2. Peering Point Enabled with GRE Tunnel.....................6 67 3.3. Peering Point Enabled with an AMT - Both Domains Multicast 68 Enabled........................................................7 69 3.4. Peering Point Enabled with an AMT - AD-2 Not Multicast 70 Enabled........................................................9 71 4. Supporting Functionality......................................11 72 4.1. Network Transport and Security Guidelines................11 73 4.2. Routing Aspects and Related Guidelines...................11 74 4.3. Back Office Functions - Billing and Logging Guidelines...11 75 4.4. Operations - Service Performance and Monitoring Guidelines12 76 4.5. Reliability Models/Service Assurance Guidelines..........12 77 4.6. Provisioning Guidelines..................................12 78 4.7. Client Models............................................12 79 4.8. Addressing Guidelines....................................12 80 5. Security Considerations.......................................12 81 6. IANA Considerations...........................................12 82 7. Conclusions...................................................13 83 8. References....................................................13 84 8.1. Normative References.....................................13 85 8.2. Informative References...................................13 86 9. Acknowledgments...............................................13 88 1. Introduction 90 Several types of applications (e.g., live video streaming, software 91 downloads) are well suited for delivery via multicast means. The use 92 of multicast for delivering such applications offers significant 93 savings for utilization of resources in any given administrative 94 domain. End user demand for such applications is growing. Often, 95 this requires transporting such applications across administrative 96 domains via inter-domain peering points. 98 The objective of this Best Current Practices document is twofold: 99 o Describe the process and establish guidelines for setting up 100 multicast-based delivery of applications across inter-domain 101 peering points, and 102 o Catalog all required information exchange between the 103 administrative domains to support multicast-based delivery. 105 While there are several multicast protocols available for use, this 106 BCP will focus the discussion to those that are applicable and 107 recommended for the peering requirements of today's service model, 108 including: 110 o Protocol Independent Multicast - Source Specific Multicast 111 (PIM-SSM) [RFC4607] 112 o Internet Group Management Protocol (IGMP) v3 [RFC4604] 113 o Multicast Listener Discovery (MLD) [RFC4604] 115 This document therefore serves the purpose of a "Gap Analysis" 116 exercise for this process. The rectification of any gaps identified 117 - whether they involve protocol extension development or otherwise - 118 is beyond the scope of this document and is for further study. 120 2. Overview of Inter-domain Multicast Application Transport 122 A multicast-based application delivery scenario is as follows: 123 o Two independent administrative domains are interconnected via a 124 peering point. 125 o The peering point is either multicast enabled (end-to-end 126 native multicast across the two domains) or it is connected by 127 one of two possible tunnel types: 128 o A Generic Routing Encapsulation (GRE) Tunnel [RFC2784] 129 allowing multicast tunneling across the peering point, or 130 o An Automatic Multicast Tunnel (AMT) [IETF-ID-AMT]. 131 o The application stream originates at a source in Domain 1. 133 o An End User associated with Domain 2 requests the application. 134 It is assumed that the application is suitable for delivery via 135 multicast means (e.g., live steaming of major events, software 136 downloads to large numbers of end user devices, etc.) 137 o The request is communicated to the application source which 138 provides the relevant multicast delivery information to the EU 139 device via a "manifest file". At a minimum, this file contains 140 the {Source, Group} or (S,G) information relevant to the 141 multicast stream. 142 o The application client in the EU device then joins the 143 multicast stream distributed by the application source in 144 domain 1 utilizing the (S,G) information provided in the 145 manifest file. The manifest file may also contain additional 146 information that the application client can use to locate the 147 source and join the stream. 149 It should be noted that the second administrative domain - domain 2 150 - may be an independent network domain (e.g., Tier 1 network 151 operator domain) or it could also be an Enterprise network operated 152 by a single customer. The peering point architecture and 153 requirements may have some unique aspects associated with the 154 Enterprise case. 156 The Use Cases describing various architectural configurations for 157 the multicast distribution along with associated requirements is 158 described in section 3. Unique aspects related to the Enterprise 159 network possibility will be described in this section. A 160 comprehensive list of pertinent information that needs to be 161 exchanged between the two domains to support various functions 162 enabling the application transport is provided in section 4. 164 3. Inter-domain Peering Point Requirements for Multicast 166 The transport of applications using multicast requires that the 167 inter-domain peering point is enabled to support such a process. 168 There are three possible Use Cases for consideration. 170 3.1. Native Multicast 172 This Use Case involves end-to-end Native Multicast between the two 173 administrative domains and the peering point is also native 174 multicast enabled - Figure 1. 176 ------------------- ------------------- 177 / AD-1 \ / AD-2 \ 178 / (Multicast Enabled) \ / (Multicast Enabled) \ 179 / \ / \ 180 | +----+ | | | 181 | | | +------+ | | +------+ | +----+ 182 | | CS |------>| BR |-|---------|->| BR |-------------|-->| EU | 183 | | | +------+ | I1 | +------+ |I2 +----+ 184 \ +----+ / \ / 185 \ / \ / 186 \ / \ / 187 ------------------- ------------------- 189 AD = Administrative Domain (Independent Autonomous System) 190 CS = Content Multicast Source 191 BR = Border Router 192 I1 = AD-1 and AD-2 Multicast Interconnection (MBGP or BGMP) 193 I2 = AD-2 and EU Multicast Connection 195 Figure 1 - Content Distribution via End to End Native Multicast 197 Advantages of this configuration are: 199 o Most efficient use of bandwidth in both domains 201 o Fewer devices in the path traversed by the multicast stream 202 when compared to unicast transmissions. 204 From the perspective of AD-1, the one disadvantage associated with 205 native multicast into AD-2 instead of individual unicast to every EU 206 in AD-2 is that it does not have the ability to count the number of 207 End Users as well as the transmitted bytes delivered to them. This 208 information is relevant from the perspective of customer billing and 209 operational logs. It is assumed that such data will be collected by 210 the application layer. The application layer mechanisms for 211 generating this information need to be robust enough such that all 212 pertinent requirements for the source provider and the AD operator 213 are satisfactorily met. The specifics of these methods are beyond 214 the scope of this document. 216 Architectural Requirements for this Configuration: 218 R3.1-1: Peering points between domains shall be at least dual homed 219 for reliability with full BGP table visibility. 221 R3.1-2: If the peering point between AD-1 and AD-2 is a controlled 222 network environment, then bandwidth can be allocated accordingly by 223 AD-1 and AD-2 to permit the transit of non rate-adaptive multicast 224 traffic, otherwise the multicast traffic should support rate- 225 adaptation. 227 R3.1-3: Each domain AD-1, AD-2 determines by local policy whether to 228 permit sending and/or receiving of IP multicast traffic from the 229 other domain. If AD-1 is for example a service provider and AD-2 an 230 enterprise, then AD-1 may often only support traffic delivery to, 231 but not traffic reception from AD-2. 233 R3.1-4: Relevant information on the multicast streams delivered to 234 End Users in AD-2 shall be collected at the application layer. The 235 precise nature of the collected information will be driven by 236 requirements set down by the source owner and the domain operators. 238 3.2. Peering Point Enabled with GRE Tunnel 240 The peering point is not native multicast enabled in this Use Case. 241 There is a Generic Routing Encapsulation Tunnel provisioned over the 242 peering point. In this case, the interconnection I1 between AD-1 and 243 AD-2 in Figure 1 is multicast enabled via a Generic Routing 244 Encapsulation Tunnel (GRE) [RFC2784] and encapsulating the multicast 245 protocols across the interface. The routing configuration is 246 basically unchanged: Instead of BGP (SAFI2) across the native IP 247 multicast link between AD-1 and AD-2, BGP (SAFI2) is now run across 248 the GRE tunnel. 250 Advantages of this configuration: 252 o Highly efficient use of bandwidth in both domains although not 253 as efficient as the fully native multicast Use Case. 255 o Fewer devices in the path traversed by the multicast stream 256 when compared to unicast transmissions. 258 o Ability to support only partial IP multicast deployments in AD- 259 1 and/or AD-2. 261 o GRE is an existing technology and is relatively simple to 262 implement. 264 Disadvantages of this configuration: 266 o Per Use Case 3.1, current router technology cannot count the 267 number of end users or the number bytes transmitted. 269 o GRE tunnel requires manual configuration. 271 o GRE must be in place prior to stream starting. 273 o GRE is often left pinned up 275 Architectural Requirements for this Configuration: 277 R3.2-1 through R3.2-4 are the same as requirements R.3.1-1 through 278 R.3.1-4 defined in Use Case 3.1. 280 R3.2-5: GRE tunnels will be manually configured at peering points to 281 support multicast delivery between domains. 283 R3.1-6 The GRE tunnel (tunnel server) in source network must be 284 configured to only advertise the routes to the Content Sources (not 285 the entire network). Otherwise content that should not be in tunnel 286 may go through tunnel (e.g. content not part of an agreed CDN 287 partnership). 289 3.3. Peering Point Enabled with an AMT - Both Domains Multicast 290 Enabled 292 Both administrative domains in this Use Case are assumed to be 293 native multicast enabled here; however the peering point is not. The 294 peering point is enabled with an Automatic Multicast Tunnel. The 295 basic configuration is depicted in Figure 2. 297 ------------------- ------------------- 298 / AD-1 \ / AD-2 \ 299 / (Multicast Enabled) \ / (Multicast Enabled) \ 300 / \ / \ 301 | +----+ | | | 302 | | | +------+ | | +------+ | +----+ 303 | | CS |------>| AR |-|---------|->| AG |-------------|-->| EU | 304 | | | +------+ | I1 | +------+ |I2 +----+ 305 \ +----+ / \ / 306 \ / \ / 307 \ / \ / 308 ------------------- ------------------- 310 AR = AMT Relay 311 AG = AMT Gateway 312 I1 = AMT Interconnection between P-CDN and S-CDN 313 I2 = S-CDN and EU Multicast Connection 315 Figure 2 - AMT Interconnection between AD-1 and AD-2 317 Advantages of this configuration: 319 o Highly efficient use of bandwidth in AD-1. 321 o AMT is an existing technology and is relatively simple to 322 implement. Attractive properties of AMT include the following: 324 o Dynamic interconnection between Gateway-Relay pair across 325 the peering point. 327 o Ability to serve clients and servers with differing 328 policies. 330 Disadvantages of this configuration: 332 o Per Use Case 3.1 (AD-2 is native multicast), current router 333 technology cannot count the number of end users or the number 334 bytes transmitted. 336 o Additional devices (AMT Gateway and Relay pairs) may be 337 introduced into the path if these services are not incorporated 338 in the existing routing nodes. 340 o Currently undefined mechanisms to select the AR from the AG 341 automatically. 343 Architectural Requirements for this Configuration: 345 R3.3-1 through R3.3-4 are the same as requirements R.3.1-1 through 346 R.3.1-4 defined in Use Case 3.1. 348 R3.3-5: AMT Relay and Gateway pair needs to be established at 349 peering points to support multicast delivery between domains. The 350 AMT tunnel will then configure dynamically across the peering point 351 once the Gateway in AD-2 receives the (S,G) information from the EU. 353 3.4. Peering Point Enabled with an AMT - AD-2 Not Multicast Enabled 355 In this AMT Use Case, the second administrative domain AD-2 is not 356 multicast enabled. This implies that the interconnection between AD- 357 2 and the End User is also not multicast enabled as depicted in 358 Figure 3. 360 ------------------- ------------------- 361 / P-CDN \ / S-CDN \ 362 / (Multicast Enabled) \ / (Non-Multicast \ 363 / \ / Enabled) \ 364 | +----+ | | | 365 | | | +------+ | | | +----+ 366 | | CS |------>| AR |-|---------|-----------------------|-->|EU/G| 367 | | | +------+ | | |I2 +----+ 368 \ +----+ / \ / 369 \ / \ / 370 \ / \ / 371 ------------------- ------------------- 373 (Note: Diff-marks for the figure have been removed to improve 374 viewing) 376 CS = Content Source 377 AR = AMT Relay 378 EU/G = Gateway client embedded in EU device 379 I2 = AMT Tunnel Connecting EU/G to AR in AD-1 through Non-Multicast 380 Enabled AD-2. 382 Figure 3 - AMT Tunnel Connecting AD-1 AMT Relay and EU Gateway 384 This Use Case is equivalent to having unicast distribution of the 385 application through AD-2. The total number of AMT tunnels would be 386 equal to the total number of End Users requesting the application. 387 The peering point thus needs to accommodate the total number of AMT 388 tunnels between the two domains. Each AMT tunnel can provide the 389 data usage associated with each End User. 391 Advantages of this configuration: 393 o Highly efficient use of bandwidth in AD-1. 395 o AMT is an existing technology and is relatively simple to 396 implement. Attractive properties of AMT include the following: 398 o Dynamic interconnection between Gateway-Relay pair across 399 the peering point. 401 o Ability to serve clients and servers with differing 402 policies. 404 o Each AMT tunnel serves as a count for each End User and is also 405 able to track data usage (bytes) delivered to the EU. 407 Disadvantages of this configuration: 409 o Additional devices (AMT Gateway and Relay pairs) are introduced 410 into the transport path. 412 o Assuming multiple peering points between the domains, the EU 413 Gateway needs to be able to find the "correct" AMT Relay in AD- 414 1. 416 Architectural Requirements for this Configuration: 418 R3.4-1 through R3.4-3 are the same as requirements R.3.1-1 through 419 R.3.1-3 defined in Use Case 3.1. 421 R3.4-4: Proper procedures shall exist to enable the AMT Gateway at 422 End User device to find the correct AMT Relay in AD-1 across the 423 peering points. At a minimum, the application client in the EU 424 device will supply the (S,G) information to the Gateway for this 425 purpose. 427 R3.3-5: Relevant information on the multicast streams delivered to 428 End Users in AD-2 via AMT tunnels shall be collected by the tunnels 429 per existing AMT capabilities. 431 A variation of this Use Case can be constructed as follows: 433 o Single AMT tunnel across peering point. 435 o Strategic location of AMT Gateways at Exit Routers in AD-2 and 436 an AMT Relay at AD-2 side of Peering Point. This reduces the 437 total number of unicast streams across AD-2 equal to the total 438 number of exit routers in AD-2. 440 o Co-Location of AMT Relays with the AMT Gateways at the Exit 441 Routers. This permits the AMT Gateway at the End User device 442 application client to establish a shorter AMT tunnel with the 443 AMT Relay at the appropriate Exit Router. 445 The advantage for such a chained set of AMT tunnels is that the 446 total number of unicast streams across AD-2 is significantly reduced 447 thus freeing up bandwidth. The negative aspect is that several AMT 448 tunnels will need to dynamically configure by the various AMT 449 Gateways based solely on the (S,G) information received from the 450 application client at the EU device. 452 The requirements for this scenario are the same as the simpler case 453 defined in this section. Only the dynamic configurations will become 454 more complicated for setting up the correct set of tunnel chains. 456 4. Supporting Functionality 458 Supporting functions and related interfaces over the peering point 459 that enable the multicast transport of the application are listed in 460 this section. Critical information parameters that need to be 461 exchanged in support of these functions are enumerated along with 462 guidelines as appropriate. Specific interface functions for 463 consideration are as follows. 465 4.1. Network Transport and Security Guidelines 467 4.2. Routing Aspects and Related Guidelines 469 4.3. Back Office Functions - Billing and Logging Guidelines 470 4.4. Operations - Service Performance and Monitoring Guidelines 472 4.5. Reliability Models/Service Assurance Guidelines 474 4.6. Provisioning Guidelines 476 In order to find right relay there is a need for a small/light 477 implementation of an AMT DNS in source network. 479 4.7. Client Models 481 4.8. Addressing Guidelines 483 5. Security Considerations 485 (Include discussion on DRM, AAA, Network Security) 487 6. IANA Considerations 488 7. Conclusions 490 8. References 492 8.1. Normative References 494 [RFC2784] D. Farinacci, T. Li, S. Hanks, D. Meyer, P. Traina, 495 "Generic Routing Encapsulation (GRE)", RFC 2784, March 2000 497 [IETF-ID-AMT] G. Bumgardner, "Automatic Multicast Tunneling", draft- 498 ietf-mboned-auto-multicast-13, April 2012, Work in progress 500 [RFC4604] H. Holbrook, et al, "Using Internet Group Management 501 Protocol Version 3 (IGMPv3) and Multicast Listener Discovery 502 Protocol Version 2 (MLDv2) for Source Specific Multicast", RFC 4604, 503 August 2006 505 [RFC4607] H. Holbrook, et al, "Source Specific Multicast", RFC 4607, 506 August 2006 508 8.2. Informative References 510 9. Acknowledgments 511 Authors' Addresses 513 Percy S. Tarapore 514 AT&T 515 Phone: 1-732-420-4172 516 Email: tarapore@att.com 518 Robert Sayko 519 AT&T 520 Phone: 1-732-420-3292 521 Email: rs1983@att.com 523 Greg Shepherd 524 Cisco 525 Phone: 526 Email: shep@cisco.com 528 Toerless Eckert 529 Cisco 530 Phone: 531 Email: eckert@cisco.com 533 Ram Krishnan 534 Brocade 535 Phone: 536 Email: ramk@brocade.com