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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) ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Open Shortest Path First IGP S. Hegde 3 Internet-Draft Juniper Networks, Inc. 4 Intended status: Standards Track P. Sarkar 5 Expires: August 27, 2017 H. Gredler 6 Individual 7 M. Nanduri 8 Microsoft Corporation 9 L. Jalil 10 Verizon 11 February 23, 2017 13 OSPF Link Overload 14 draft-ietf-ospf-link-overload-05 16 Abstract 18 When a link is being prepared to be taken out of service, the traffic 19 needs to be diverted from both ends of the link. Increasing the 20 metric to the highest metric on one side of the link is not 21 sufficient to divert the traffic flowing in the other direction. 23 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to be 24 able to advertise a link being in an overload state to indicate 25 impending maintenance activity on the link. This information can be 26 used by the network devices to re-route the traffic effectively. 28 This document describes the protocol extensions to disseminate link- 29 overload information in OSPFv2 and OSPFv3. 31 Requirements Language 33 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 34 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 35 document are to be interpreted as described in RFC 2119 [RFC2119]. 37 Status of This Memo 39 This Internet-Draft is submitted in full conformance with the 40 provisions of BCP 78 and BCP 79. 42 Internet-Drafts are working documents of the Internet Engineering 43 Task Force (IETF). Note that other groups may also distribute 44 working documents as Internet-Drafts. The list of current Internet- 45 Drafts is at http://datatracker.ietf.org/drafts/current/. 47 Internet-Drafts are draft documents valid for a maximum of six months 48 and may be updated, replaced, or obsoleted by other documents at any 49 time. It is inappropriate to use Internet-Drafts as reference 50 material or to cite them other than as "work in progress." 52 This Internet-Draft will expire on August 27, 2017. 54 Copyright Notice 56 Copyright (c) 2017 IETF Trust and the persons identified as the 57 document authors. All rights reserved. 59 This document is subject to BCP 78 and the IETF Trust's Legal 60 Provisions Relating to IETF Documents 61 (http://trustee.ietf.org/license-info) in effect on the date of 62 publication of this document. Please review these documents 63 carefully, as they describe your rights and restrictions with respect 64 to this document. Code Components extracted from this document must 65 include Simplified BSD License text as described in Section 4.e of 66 the Trust Legal Provisions and are provided without warranty as 67 described in the Simplified BSD License. 69 Table of Contents 71 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 72 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3 73 3. Flooding Scope . . . . . . . . . . . . . . . . . . . . . . . 4 74 3.1. Area scope flooding . . . . . . . . . . . . . . . . . . . 4 75 3.2. Link scope flooding . . . . . . . . . . . . . . . . . . . 4 76 4. Link-Overload sub-TLV . . . . . . . . . . . . . . . . . . . . 4 77 4.1. OSPFv2 Link-overload sub-TLV . . . . . . . . . . . . . . 4 78 4.2. OSPFv3 Link-Overload sub-TLV . . . . . . . . . . . . . . 5 79 5. Elements of procedure . . . . . . . . . . . . . . . . . . . . 5 80 5.1. Point-to-point links . . . . . . . . . . . . . . . . . . 6 81 5.2. Broadcast/NBMA links . . . . . . . . . . . . . . . . . . 6 82 5.3. Point-to-multipoint links . . . . . . . . . . . . . . . . 7 83 5.4. Unnumbered interfaces . . . . . . . . . . . . . . . . . . 7 84 5.5. Hybrid Broadcast and P2MP interfaces . . . . . . . . . . 7 85 6. Backward compatibility . . . . . . . . . . . . . . . . . . . 8 86 7. Applications . . . . . . . . . . . . . . . . . . . . . . . . 8 87 7.1. Pseudowire Services . . . . . . . . . . . . . . . . . . . 8 88 7.2. Controller based Traffic Engineering Deployments . . . . 9 89 7.3. L3VPN Services and sham-links . . . . . . . . . . . . . . 10 90 7.4. Hub and spoke deployment . . . . . . . . . . . . . . . . 10 91 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 92 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 93 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 94 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 95 11.1. Normative References . . . . . . . . . . . . . . . . . . 11 96 11.2. Informative References . . . . . . . . . . . . . . . . . 12 98 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 100 1. Introduction 102 When a node is being prepared for a planned maintenance or upgrade, 103 [RFC6987] provides mechanisms to advertise the node being in an 104 overload state by setting all outgoing link costs to MAX-METRIC 105 (0xffff). These procedures are specific to the maintenance activity 106 on a node and cannot be used when a single link attached to the node 107 requires maintenance. 109 In traffic-engineering deployments, LSPs need to be diverted from the 110 link without disrupting the services. It is useful to be able to 111 advertise the impending maintenance activity on the link and to have 112 LSP re-routing policies at the ingress to route the LSPs away from 113 the link. 115 Many OSPFv2 or OSPFv3 deployments run on overlay networks provisioned 116 by means of pseudo-wires or L2-circuits. Prior to devices in the 117 underlying network going offline for maintenance, it is useful to 118 divert the traffic away from the node before the maintenance is 119 actually scheduled. Since the nodes in the underlying network are 120 not visible to OSPF, the existing stub router mechanism described in 121 [RFC6987] cannot be used. An application specific to this use case 122 is described in Section 7.1 124 This document provides mechanisms to advertise link-overload state in 125 the flexible encodings provided by OSPFv2 Prefix/Link Attribute 126 Advertisement([RFC7684]) and RI LSA ([RFC7770]). Throughout this 127 document, OSPF is used when the text applies to both OSPFv2 and 128 OSPFv3. OSPFv2 or OSPFv3 is used when the text is specific to one 129 version of the OSPF protocol. 131 2. Motivation 133 The motivation of this document is to reduce manual intervention 134 during maintenance activities. The following objectives help to 135 accomplish this in a range of deployment scenarios. 137 1. Advertise impending maintenance activity so that traffic from 138 both directions can be diverted away from the link. 140 2. Allow the solution to be backward compatible so that nodes that 141 do not understand the new advertisement do not cause routing 142 loops. 144 3. Advertise the maintenance activity to other nodes in the network 145 so that LSP ingress routers/controllers can learn of the 146 impending maintenance activity and apply specific policies to re- 147 route the LSPs for traffic-engineering based deployments. 149 4. Allow the link to be used as last resort link to prevent traffic 150 disruption when alternate paths are not available. 152 3. Flooding Scope 154 The link-overload information can be flooded in area scoped extended 155 link LSA [RFC7684] or a link scoped RI LSA [RFC7770] or both based on 156 the needs of the application. Section 7 describes applications 157 requiring area scope as well as link scope link-overload information. 159 3.1. Area scope flooding 161 For OSPFv2, Link-Overload sub-TLV is carried in the extended Link TLV 162 as defined in [RFC7684]. 164 3.2. Link scope flooding 166 The link local scope RI LSA MAY carry the Link-Overload sub-TLV as 167 defined in Section 4. The link local scope RI-LSA corresponds to the 168 link on which the LSA arrives and there is no need to explicitly 169 specify the remote IPv4 address. The remote IPv4 address field MAY 170 be zero when the Link-Overload sub-TLV is carried in the link local 171 RI LSA. The Link-Overload sub-TLV MAY appear in any instance of the 172 link local RI-LSA. The Link-Overload sub-TLV is carried in the RI- 173 LSA for both OSPFv2 and OSPFv3. 175 4. Link-Overload sub-TLV 177 4.1. OSPFv2 Link-overload sub-TLV 179 The Link-Overload sub-TLV identifies the link being in overload 180 state. It is carried in extended Link TLV as defined in [RFC7684] or 181 link local scope RI LSA as defined in [RFC7770]. 183 0 1 2 3 184 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Type | Length | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 | Remote IP address | 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 191 Figure 1: Link-Overload sub-TLV for OSPFv2 193 Type : TBA (suggested value 4) 195 Length: 4 197 Value: Remote IPv4 address. The remote IP4 address is used to 198 identify the particular link that is in the overload state when there 199 are multiple parallel links between two nodes. 201 4.2. OSPFv3 Link-Overload sub-TLV 203 The OSPFv3 Link-Overload sub-TLV is carried in the link local scope 204 OSPFv3 RI LSA as defined in [RFC7770]. 206 0 1 2 3 207 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 209 | Type | Length | 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 Figure 2: Link-Overload sub-TLV for OSPFv3 214 Type : TBA (Suggested value 4) 216 Length: 0 218 The area scope advertisement of Link-Overload sub-TLV for OSPFv3 will 219 be described in a separate document. 221 5. Elements of procedure 223 The Link-Overload sub-TLV indicates that the link identified by the 224 sub-TLV is overloaded. The node that has the link to be taken out of 225 service SHOULD originate the Link-Overload sub-TLV in the Extended 226 Link TLV in the Extended Link Opaque LSA as defined in [RFC7684] for 227 OSPFv2. The Link-Overload information is carried as a property of 228 the link and is flooded across the area. This information can be 229 used by ingress routers or controllers to take special actions. An 230 application specific to this use case is described in Section 7.2. 232 The precise action taken by the remote node at the other end of the 233 link identified as overloaded depends on the link type. 235 5.1. Point-to-point links 237 The node that has the link to be taken out of service SHOULD set 238 metric of the link to MAX-METRIC (0xffff) and re- originate the 239 Router-LSA. The TE metric SHOULD be set to MAX-TE-METRIC -1 240 (0xfffffffe) and the node SHOULD re-originate the TE Link Opaque 241 LSAs. When a Link-Overload sub-TLV is received for a point-to-point 242 link, the remote node SHOULD identify the local link which 243 corresponds to the overloaded link and set the metric to MAX-METRIC 244 (0xffff)and the remote node SHOULD re-originate the router-LSA with 245 the changed metric. The TE metric SHOULD be set to MAX-TE-METRIC -1 246 (0xfffffffe) and the TE opaque LSA for the link SHOULD be re- 247 originated with new value. 249 Extended link opaque LSAs and the Extended link TLV are not scoped 250 for multi-topology [RFC4915]. In multi-topology deployments 251 [RFC4915], the Link-Overload sub-TLV carried in an Extended Link 252 opaque LSA corresponds to all the topologies the link belongs to. 253 The receiver node SHOULD change the metric in the reverse direction 254 corresponding to all the topologies to which the reverse link belongs 255 and re-originate the Router LSA as defined in [RFC4915]. 257 When the originator of the Link-Overload sub-TLV purges the Extended 258 Link Opaque LSA or re-originates it without the Link-Overload sub- 259 TLV, the remote node must re-originate the appropriate LSAs with the 260 metric and TE metric values set to their original values. 262 5.2. Broadcast/NBMA links 264 Broadcast or NBMA networks in OSPF are represented by a star topology 265 where the Designated Router (DR) is the central point to which all 266 other routers on the broadcast or NBMA network connect logically. As 267 a result, routers on the broadcast or NBMA network advertise only 268 their adjacency to the DR. Routers that do not act as DR do not form 269 or advertise adjacencies with each other. For the Broadcast links, 270 the MAX-METRIC on the remote link cannot be changed since all the 271 neighbours are on same link. Setting the link cost to MAX-METRIC 272 would impact paths going via all neighbours. 274 The node that has the link to be taken out of service SHOULD set 275 metric of the link to MAX-METRIC(0xffff) and re-originate the Router- 276 LSA. The TE metric SHOULD be set to MAX-TE-METRIC -1(0xfffffffe) and 277 the node SHOULD re-originate the TE Link Opaque LSAs. For a 278 broadcast link, the two part metric as described in [RFC8042] is 279 used. The node originating the Link-Overload sub-TLV MUST set the 280 metric in the Network-to-Router Metric sub-TLV to MAX-METRIC 0xffff 281 for OSPFv2 and OSPFv3 and re-originate the LSAs the TLV is carried- 282 in. The nodes that receive the two part metric should follow the 283 procedures described in [RFC8042]. The backward compatibility 284 procedures described in [RFC8042] should be followed to ensure loop 285 free routing. 287 5.3. Point-to-multipoint links 289 Operation for the point-to-multipoint links is similar to the point- 290 to-point links. When a Link-Overload sub-TLV is received for a 291 point-to-multipoint link the remote node SHOULD identify the 292 neighbour which corresponds to the overloaded link and set the metric 293 to MAX-METRIC (0xffff). The remote node MUST re-originate the 294 Router-LSA with the changed metric and flood into the OSPF area. 296 5.4. Unnumbered interfaces 298 Unnumbered interface do not have a unique IP addresses and borrow 299 address from other interfaces. [RFC2328] describes procedures to 300 handle unnumbered interfaces in the context of the Router LSA. We 301 apply a similar procedure to the Extended Link TLV carrying the Link- 302 Overload sub-TLV in to handle unnumbered interfaces. The link-data 303 field in the Extended Link TLV carries the interface-id instead of 304 the IP address. The Link-Overload sub-TLV carries the remote 305 interface-id in the remote-ip-address field if the interface is 306 unnumbered. Procedures to obtain interface-id of the remote side are 307 defined in [RFC4203]. 309 5.5. Hybrid Broadcast and P2MP interfaces 311 Hybrid Broadcast and P2MP interfaces represent a broadcast network 312 modeled as P2MP interfaces. [RFC6845] describes procedures to handle 313 these interfaces. Operation for the Hybrid interfaces is similar to 314 the P2MP interfaces. When a Link-Overload sub-TLV is received for a 315 hybrid link the remote node SHOULD identify the neighbour which 316 corresponds to the overloaded link and set the metric to MAX-METRIC 317 (0xffff). All the remote nodes connected to originator MUST re- 318 originate the Router-LSA with the changed metric and flood into the 319 OSPF area. 321 6. Backward compatibility 323 The mechanism described in the document is fully backward compatible. 324 It is required that the originator of the Link-Overload sub-TLV as 325 well as the node at the remote end of the link identified as 326 overloaded understand the extensions defined in this document. In 327 the case of broadcast links, the backward compatibility procedures as 328 described in [RFC8042] are applicable. 330 7. Applications 332 7.1. Pseudowire Services 334 Many service providers offer pseudo-wire services to customers using 335 L2 circuits. The IGP protocol that runs in the customer network 336 would also run over the pseudo-wire to create seamless private 337 network for the customer. Service providers want to offer overload 338 kind of functionality when the PE device is taken-out for 339 maintenance. The provider should guarantee that the PE is taken out 340 for maintenance only after the service is successfully diverted on an 341 alternate path. There can be large number of customers attached to a 342 PE node and the remote end-points for these pseudo-wires are spread 343 across the service provider's network. It is a tedious and error- 344 prone process to change the metric for all pseudo-wires in both 345 directions. The link-overload feature simplifies the process by 346 increasing the metric on the link in the reverse direction as well so 347 that traffic in both directions is diverted away from the PE 348 undergoing maintenance. The Link-Overload feature allows the link to 349 be used as a last resort link so that traffic is not disrupted when 350 alternative paths are not available. 352 Private VLAN 353 ======================================= 354 | | 355 | | 356 | ------PE3---------------PE4------CE3 357 | / \ 358 | / \ 359 CE1---------PE1----------PE2---------CE2 360 | \ 361 | \ 362 | ------CE4 363 | | 364 | | 365 | | 366 ================================= 367 Private VLAN 369 Figure 3: Pseudowire Services 371 In the example shown in Figure 3, when the PE1 node is going for 372 maintenance, service providers set the PE1 to overload state. The 373 PE1 going in overload state triggers all the CEs (In this example 374 CE1)connected to the PE to set their pseudowire links passing via PE1 375 to link-overload state. The mechanisms used to communicate between 376 PE1 and CE1 is outside the scope of this document. CE1 sets the 377 link-overload state on its private VLAN connecting CE3, CE2 and CE4 378 and modifies the metric to MAX_METRIC and floods the information, the 379 remote end of the link at CE3, CE2, and CE4 also set the metric on 380 the link to MAX-METRIC and the traffic from both directions gets 381 diverted away from the link. 383 7.2. Controller based Traffic Engineering Deployments 385 In controller-based deployments where the controller participates in 386 the IGP protocol, the controller can also receive the link-overload 387 information as a warning that link maintenance is imminent. Using 388 this information, the controller can find alternate paths for traffic 389 which use the affected link. The controller can apply various 390 policies and re-route the LSPs away from the link undergoing 391 maintenance. If there are no alternate paths satisfying the traffic 392 engineering constraints, the controller might temporarily relax those 393 constraints and put the service on a different path. 395 _____________ 396 | | 397 -------------| Controller |-------------- 398 | |____________ | | 399 | | 400 |--------- Primary Path ------------------| 401 PE1---------P1----------------P2---------PE2 402 | | 403 | | 404 |________P3________| 406 Alternate Path 408 Figure 4: Controller based Traffic Engineering 410 In the above example, PE1->PE2 LSP is set-up to satisfy a constraint 411 of 10 Gbps bandwidth on each link. The links P1->P3 and P3->P2 have 412 only 1 Gbps capacity and there is no alternate path satisfying the 413 bandwidth constraint of 10GB. When P1->P2 link is being prepared for 414 maintenance, the controller receives the link-overload information, 415 as there is no alternate path available which satisfies the 416 constraints, controller chooses a path that is less optimal and 417 temporarily sets up an alternate path via P1->P3->P2. Once the 418 traffic is diverted, the P1->P2 link can be taken out of service for 419 maintenance/upgrade. 421 7.3. L3VPN Services and sham-links 423 Many service providers offer L3VPN services to customers and CE-PE 424 links run OSPF [RFC4577]. When PE goes for maintenance, all the 425 links on the PE can be set to link-overlaod state which will gurantee 426 that the traffic from CEs also gets diverted. The interaction 427 between OSPF and BGP is outside the scope of this document. 429 Another useful usecase is when ISPs provide sham-link services to 430 customers [RFC4577].When PE goes for maintenance, all sham-links on 431 the PE can be set to link-overload state and traffic can be divered 432 from both ends without having to touch the configurations on the 433 remote end of the sham-links. 435 7.4. Hub and spoke deployment 437 OSPF is largely deployed in Hub and Spoke deployments with a number 438 of spokes connecting to the Hub. It is a general practice to deploy 439 multiple Hubs with all spokes connecting to these Hubs to achieve 440 redundancy. When a Hub node goes down for maintenance, all links on 441 the Hub can be set to link-overload state and traffic gets divered 442 from spoke sites as well without having to make configuration changes 443 on the spokes. 445 8. Security Considerations 447 This document does not introduce any further security issues other 448 than those discussed in [RFC2328] and [RFC5340]. 450 9. IANA Considerations 452 This specification updates one OSPF registry: 454 OSPF Extended Link TLVs Registry 456 i) TBD - Link-Overload sub-TLV 458 OSPFV3 Router Link TLV Registry 460 i) TBD - Link-Overload sub-TLV 462 OSPF RI TLV Registry 464 i) TBD - Link-Overload sub-TLV 466 BGP-LS Link NLRI Registry [RFC7752] 468 i)TBD - Link-Overload sub-TLV 470 10. Acknowledgements 472 Thanks to Chris Bowers for valuable inputs and edits to the document. 473 Thanks to Jeffrey Zhang and Acee Lindem for inputs. Thanks to 474 Karsten Thomann for careful review and inputs on the applications 475 where link-overload is useful. 477 11. References 479 11.1. Normative References 481 [RFC6845] Sheth, N., Wang, L., and J. Zhang, "OSPF Hybrid Broadcast 482 and Point-to-Multipoint Interface Type", RFC 6845, 483 DOI 10.17487/RFC6845, January 2013, 484 . 486 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 487 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 488 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 489 2015, . 491 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 492 S. Ray, "North-Bound Distribution of Link-State and 493 Traffic Engineering (TE) Information Using BGP", RFC 7752, 494 DOI 10.17487/RFC7752, March 2016, 495 . 497 [RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and 498 S. Shaffer, "Extensions to OSPF for Advertising Optional 499 Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, 500 February 2016, . 502 [RFC8042] Zhang, Z., Wang, L., and A. Lindem, "OSPF Two-Part 503 Metric", RFC 8042, DOI 10.17487/RFC8042, December 2016, 504 . 506 11.2. Informative References 508 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 509 Requirement Levels", BCP 14, RFC 2119, 510 DOI 10.17487/RFC2119, March 1997, 511 . 513 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 514 DOI 10.17487/RFC2328, April 1998, 515 . 517 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 518 Support of Generalized Multi-Protocol Label Switching 519 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 520 . 522 [RFC4577] Rosen, E., Psenak, P., and P. Pillay-Esnault, "OSPF as the 523 Provider/Customer Edge Protocol for BGP/MPLS IP Virtual 524 Private Networks (VPNs)", RFC 4577, DOI 10.17487/RFC4577, 525 June 2006, . 527 [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. 528 Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", 529 RFC 4915, DOI 10.17487/RFC4915, June 2007, 530 . 532 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 533 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 534 . 536 [RFC6987] Retana, A., Nguyen, L., Zinin, A., White, R., and D. 537 McPherson, "OSPF Stub Router Advertisement", RFC 6987, 538 DOI 10.17487/RFC6987, September 2013, 539 . 541 Authors' Addresses 543 Shraddha Hegde 544 Juniper Networks, Inc. 545 Embassy Business Park 546 Bangalore, KA 560093 547 India 549 Email: shraddha@juniper.net 551 Pushpasis Sarkar 552 Individual 554 Email: pushpasis.ietf@gmail.com 556 Hannes Gredler 557 Individual 559 Email: hannes@gredler.at 561 Mohan Nanduri 562 Microsoft Corporation 563 One Microsoft Way 564 Redmond, WA 98052 565 US 567 Email: mnanduri@microsoft.com 569 Luay Jalil 570 Verizon 572 Email: luay.jalil@verizon.com