idnits 2.17.1 draft-ietf-bmwg-fib-term-02.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** Looks like you're using RFC 2026 boilerplate. This must be updated to follow RFC 3978/3979, as updated by RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- ** Missing expiration date. The document expiration date should appear on the first and last page. ** The document seems to lack a 1id_guidelines paragraph about 6 months document validity -- however, there's a paragraph with a matching beginning. Boilerplate error? Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an Abstract section. ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. == There are 1 instance of lines with non-RFC6890-compliant IPv4 addresses in the document. If these are example addresses, they should be changed. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (July 2001) is 8314 days in the past. Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Missing reference section? '1' on line 14 looks like a reference -- Missing reference section? '2' on line 105 looks like a reference -- Missing reference section? '3' on line 593 looks like a reference -- Missing reference section? '4' on line 197 looks like a reference Summary: 6 errors (**), 0 flaws (~~), 2 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Benchmarking Methodology Working Group G. Trotter 3 Internet Draft Agilent Technologies 4 Document: draft-ietf-bmwg-fib-term-02.txt July 2001 5 Category: Informational 7 Terminology for Forwarding Information Base (FIB) based Router 8 Performance 10 Status of this Memo 12 This document is an Internet-Draft and is in full conformance with 13 all provisions of Section 10 of RFC2026 [1]. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six 21 months and may be updated, replaced, or obsoleted by other documents 22 at any time. It is inappropriate to use Internet- Drafts as 23 reference material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 Table of Contents 33 1. Introduction....................................................2 34 2. Overview........................................................2 35 3. Existing Definitions............................................2 36 4. Definition Format...............................................3 37 5. Definitions - parameters........................................3 38 5.1 Network Prefix.................................................3 39 5.2 Network Prefix Length..........................................4 40 5.3 Forwarding Information Base (FIB)..............................4 41 5.4 Forwarding Information Base Entry..............................5 42 5.5 Forwarding Information Base Size...............................5 43 5.6 Longest Length Prefix Match Algorithm..........................6 44 5.7 Forwarding Information Base Prefix Distribution................6 45 5.8 Per-Interface or Per-Card Forwarding Information Base..........7 46 5.9 Per-Interface Forwarding Information Base Cache................7 47 5.10 Route Aggregation.............................................8 48 6. Definitions - metrics...........................................9 49 6.1 Maximum Forwarding Information Base Size.......................9 50 6.2 Forwarding Information Base Learning Time.....................10 51 6.3 Forwarding Information Base-dependent Throughput..............10 52 6.4 Forwarding Information Base-dependent Latency.................11 53 6.5 Forwarding Information Base-dependent Frame Loss Rate.........11 54 7. Security Considerations........................................12 55 Terminology for FIB based Router Performance July, 2001 57 8. References.....................................................12 58 9. Acknowledgments................................................12 59 10. Author's Addresses............................................12 61 1. Introduction 63 This document defines terms that are to be used in a methodology 64 that determines the IP packet forwarding performance of IP routers 65 as a function of the forwarding information base installed within 66 the router. 68 This document is restricted to IPv4 routers. 70 The objective of this methodology is to evaluate the performance 71 levels of IP routers as forwarding information bases continue to 72 grow in size and complexity of structure. 74 This methodology utilizes the packet forwarding performance 75 measurements described in [2]; reference will also be made to the 76 associated terminology document [3] for these terms. 78 2. Overview 80 In order to measure the forwarding information base-based router 81 performance, different forwarding information bases (5.3) are 82 installed in the router. The two key elements describing the FIB 83 are the FIB size (5.5) and FIB prefix distribution (5.6). The 84 forwarding performance of a router may be dependent upon these two 85 primary factors, particularly if FIB prefix distributions tend 86 towards longer network prefixes (3). The FIB-dependent throughput, 87 latency and frame loss rate (6.3, 6.4, 6.5), measured with fully 88 meshed traffic flows [2], will reflect the change in performance of 89 the router. Tests may need to be performed up to the maximum FIB 90 size (6.1). 92 When configuring the router for these measurements, the routes need 93 to be manually entered into the router, or advertised via a routing 94 protocol. It may take some period of time (the FIB learning time 95 (6.2)) before the router learns all the routes. 97 When routes are advertised into the router, the routes should be 98 advertised in such a way so that route aggregation (5.10) does not 99 occur. Also, the effect of a per-interface FIB cache (5.9) needs to 100 be taken into account. 102 3. Existing Definitions 104 [3] should be consulted before attempting to make use of this 105 document. [2] contains discussions of a number of terms relevant to 106 the benchmarking of network interconnect devices and should also be 107 consulted. 109 Terminology for FIB based Router Performance July, 2001 111 4. Definition Format 113 The definition format is the equivalent to that defined in [3], and 114 is repeated here for convenience: 116 X.x Term to be defined. (e.g., Latency) 118 Definition: 119 The specific definition for the term. 121 Discussion: 122 A brief discussion about the term, it's application and any 123 restrictions on measurement procedures. 125 Measurement units: 126 The units used to report measurements of this term, if 127 applicable. 129 Issues: 130 List of issues or conditions that effect this term. 132 See Also: 133 List of other terms that are relevant to the discussion of 134 this term. 136 5. Definitions - parameters 138 This section defines parameters that would dictate the execution of 139 methodology to determine the FIB based forwarding performance of a 140 router. 142 5.1 Network Prefix 144 Definition: 146 "A network prefix is . . . a contiguous set of bits at the 147 more significant end of the address that defines a set of 148 systems; host numbers select among those systems." 150 (This definition is taken directly from section 2.2.5, 151 "Addressing Architecture", in [4].) 153 Discussion: 154 Network prefixes are represented as a 32 bit IP address with 155 a mask indicating the number of bits representing the network 156 prefix. I.e. 141.184.128 /17 indicates that the network 157 prefix is 17 bits long (i.e. the network prefix length, see 158 (5.2)). 160 Measurement units: 161 163 Issues: 165 Terminology for FIB based Router Performance July, 2001 167 See Also: 168 Network Prefix Length (5.2) 170 5.2 Network Prefix Length 172 Definition: 173 The number of bits used to define the network prefix. 174 Network prefixes, using CIDR terminology, are typically 175 referred to as 15.35.128.0 /17, indicating that the network 176 prefix is 17 bits long. 178 Discussion: 179 When referring to groups of addresses, the network prefix 180 length is often used as a means of describing groups of 181 addresses as an equivalence class. For example, 100 /16 182 addresses refers to 100 addresses whose network prefix length 183 is 16 bits. 185 Measurement units: 186 bits 188 Issues: 190 See Also: 191 network prefix (5.1) 192 forwarding information base prefix distribution (5.6) 194 5.3 Forwarding Information Base (FIB) 196 Definition: 197 As according to the definition in [4]: 199 "The table containing the information necessary to forward IP 200 Datagrams, in this document, is called the Forwarding 201 Information Base. At minimum, this contains the interface 202 identifier and next hop information for each reachable 203 destination network prefix." 205 Discussion: 206 The forwarding information base describes a database indexing 207 network prefixes versus router port identifiers. 209 A forwarding information base consists of [FIB size (6.1)] 210 FIB entries (5.4). 212 The forwarding information base is distinct from the "routing 213 table" (or, the Routing Information Base), which holds all 214 routing information received from routing peers. 216 The forwarding information base contains unique paths only 217 (i.e. does not contain secondary paths). 219 Terminology for FIB based Router Performance July, 2001 221 Measurement units: 222 224 Issues: 226 See Also: 227 forwarding information base entry (5.4) 228 forwarding information base size (5.5) 229 forwarding information base prefix distribution (5.6) 230 maximum forwarding information base size (6.1) 232 5.4 Forwarding Information Base Entry 234 Definition: 235 A single entry within a forwarding information base. This 236 entry consists of the minimum amount of information necessary 237 to make a forwarding decision on a particular packet. The 238 typical components within a forwarding information base entry 239 are a network prefix, a router port identifier and next hop 240 information. This is an entry that the router can and does 241 use to forward packets. 243 Discussion: 244 See (5.3). 246 Measurement units: 247 249 Issues: 251 See Also: 252 forwarding information base (5.3) 253 forwarding information base size (5.5) 254 forwarding information base prefix distribution (5.6) 255 maximum forwarding information base size (6.1) 257 5.5 Forwarding Information Base Size 259 Definition: 260 Refers to the number of forwarding information base entries 261 within a forwarding information base. 263 Discussion: 264 The number of entries within a forwarding information base is 265 one of the key elements that may influence the forwarding 266 performance of a router. Generally, the more entries within 267 the forwarding information base, the longer it could take to 268 find the longest matching network prefix within the 269 forwarding information base. 271 Measurement units: 272 Number of routes 273 Terminology for FIB based Router Performance July, 2001 275 Issues: 277 See Also: 278 forwarding information base (5.3) 279 forwarding information base entry (5.4) 280 forwarding information base prefix distribution (5.6) 281 maximum forwarding information base size (6.1) 283 5.6 Longest Length Prefix Match Algorithm 285 Definition: 286 An algorithm that a router uses to quickly match destination 287 addresses within received IP packets to exit interfaces on 288 the router. 290 Discussion: 292 Measurement Units: 293 295 Issues: 297 See Also: 299 5.7 Forwarding Information Base Prefix Distribution 301 Definition: 302 The distribution of network prefix lengths within the 303 forwarding information base. 305 Discussion: 306 Network prefixes within the forwarding information base could 307 be all of a single network prefix length, but, more 308 realistically, the network prefix lengths will be distributed 309 across some range. 311 Individual performance measurements will be made against FIBs 312 populated with the same network prefix length, as well as 313 against FIBs with some distribution of network prefix 314 lengths. 316 The distribution of network prefix lengths may have an impact 317 on the forwarding performance of a router. The longer the 318 network prefix length, the longer it will take for a router 319 to perform the longest length prefix match algorithm, and 320 potentially the lower the performance of the router. 322 Measurement units: 323 The forwarding information base prefix distribution is 324 expressed by a list of network prefix lengths and the 325 percentage of entries within the forwarding information base 326 with a particular network prefix length. For example, a 327 Terminology for FIB based Router Performance July, 2001 329 forwarding information base prefix distribution is 330 represented as: 332 {[/16, 100], [/20, 360], [/24, 540]} 334 This indicates that 100 of the entries within the forwarding 335 information base have a 16 bit network prefix length, 360 336 have a 20 bit network prefix length, and 540 have a 24 bit 337 network prefix length. 339 Issues: 341 See Also: 342 forwarding information base (5.3) 343 forwarding information base entry (5.4) 344 forwarding information base size (5.5) 345 maximum forwarding information base size (6.1) 347 5.8 Per-Interface or Per-Card Forwarding Information Base 349 Definition: 350 A complete copy of the forwarding information base, installed 351 on a router's card or individual physical interface to speed 352 the destination address to network prefix lookup process. 354 Discussion: 355 Router manufacturers have developed many optimizations for 356 routers, of which one optimization is to copy the forwarding 357 information base to every interface or interface card on the 358 router. By doing this, destination address / network prefix 359 lookups can be performed on the interface or card, unloading 360 a router's CPU. 362 Measurement units: 363 365 Issues: 367 See Also: 368 forwarding information base (5.3) 369 per-interface forwarding information base cache (5.9) 371 5.9 Per-Interface Forwarding Information Base Cache 373 Definition: 374 A subset of a forwarding information base, installed on a 375 router's interface card to speed the destination address / 376 network prefix lookup process. 378 Discussion: 379 Prior to installing a complete copy of the forwarding 380 information base on each interface of a router, a popular 381 technique for speeding destination address lookups is to 382 Terminology for FIB based Router Performance July, 2001 384 install a cache of frequently used routes on a router's 385 interface. 387 The most frequently used routes are placed in the forwarding 388 information base cache. IP packets whose destination address 389 does not match a network prefix within the per-interface 390 forwarding information base cache are forwarded to a router's 391 central processor for lookup in the complete forwarding 392 information base. 394 The implication for benchmarking the performance of a router 395 as a function of the forwarding information base is 396 significant. IP packets whose destination address matches an 397 entry within the per-interface forwarding information base 398 cache could be forwarded more quickly than packets whose 399 destination address does not match an entry within the per- 400 interface forwarding information base cache. 402 To create useful benchmarks, the role of a per-interface 403 forwarding cache needs to be considered. The nature of 404 benchmarking tests to measure the impact of the forwarding 405 performance of a router requires that the destination 406 addresses within IP packets transmitted into the router be 407 distributed amongst the total set of network prefixes 408 advertised into the router. This negates the role of a per- 409 interface forwarding information base cache, but serves to 410 stress the forwarding information base-based packet 411 forwarding performance of the router. 413 Measurement units: 414 416 Issues: 418 See Also: 419 forwarding information base (5.3) 420 per-interface forwarding information base (5.8) 422 5.10 Route Aggregation 424 Definition: 425 The ability of a router to collapse many forwarding 426 information base entries into a single entry. 428 Discussion: 429 A router may aggregate routes in a forwarding information 430 base into a single entry to conserve space. 432 When advertising routes into a router to perform benchmarking 433 tests as a function of the forwarding information base 434 installed within the router, it is necessary to ensure that a 435 router does not aggregate routes. 437 Terminology for FIB based Router Performance July, 2001 439 Thus, when routes are advertised to the router or installed 440 statically, care must be taken to ensure that the router does 441 not aggregate routes. 443 For example, if advertising a set of /24 network prefixes 444 into a particular port on the router, 256 consecutive /24 445 routes, sharing a common leading 16 bits, should not be 446 advertised on a single port. If this is done, then the 447 router will install a single entry within the forwarding 448 information base indicating that all networks matching a 449 particular /16 network prefix are accessible through one 450 particular entry. 452 Route aggregation on a router can be turned off, but routes 453 should still be advertised into the router in such a manner 454 as to avoid route aggregation. 456 Measurement units: 457 459 Issues: 461 See Also: 463 6. Definitions - metrics 465 This section defines the metrics, or results, that would 466 characterized the FIB based forwarding performance of a router. 468 6.1 Maximum Forwarding Information Base Size 470 Definition: 471 The maximum number of forwarding information base entries 472 that can be supported within the forwarding information base. 473 The Maximum Forwarding Information Base Size is the size over 474 which all entries can and are used to forward traffic. 476 Discussion: 477 It is useful to know the maximum forwarding information base 478 size for a router as it will be an indicator of the ability 479 of the router to function within the given application space, 480 and whether the router will be able to handle projected 481 network growth. 483 As a benchmarking value, it is necessary to discover this 484 value so that performance measurements can be made up to the 485 maximum possible forwarding information base size. 487 Measurement units: 488 Number of routes 490 Issues: 492 Terminology for FIB based Router Performance July, 2001 494 Could this value vary with the forwarding information base 495 prefix distribution? 497 See Also: 498 forwarding information base (5.3) 499 forwarding information base entry (5.4) 500 forwarding information base size (5.5) 501 forwarding information base prefix distribution (5.6) 503 6.2 Forwarding Information Base Learning Time 505 Definition: 506 The time a router takes to process received routing messages, 507 and to construct (and, possibly to distribute amongst the 508 interface cards in the router) the forwarding information 509 base. This is measured from the time at which a router is 510 presented with the first routing message, through to when it 511 can forward packets using any entry in the forwarding 512 information base. 514 Discussion: 515 It takes time for a router to construct its forwarding 516 information base. A router needs to process received routing 517 packets, build the routing information database, select the 518 best paths, build the forwarding information base and then 519 possibly distribute the forwarding information base or a 520 subset thereof to the interface cards. This entire process 521 can take several minutes with very large forwarding 522 information bases. 524 When performing benchmarking tests that take the forwarding 525 information base into account, time must be allocated for the 526 router to process the routing information and to install the 527 complete forwarding information base within itself, before 528 performance measurements are made. 530 Measurement units: 531 Prefixes per second. 533 Issues: 535 See Also: 536 forwarding information base (5.3) 538 6.3 Forwarding Information Base-dependent Throughput 540 Definition: 541 Throughput, as defined in [3], used in a context where the 542 forwarding information base influences the throughput. 544 Discussion: 546 Terminology for FIB based Router Performance July, 2001 548 This definition for FIB-dependent throughput is added to 549 distinguish the context of this measurement from that defined 550 in [3]. 552 Measurement units: 553 See [3]. 555 Issues: 557 See Also: 558 forwarding information base-dependent latency (6.4) 559 forwarding information base-dependent frame loss rate (6.5) 561 6.4 Forwarding Information Base-dependent Latency 563 Definition: 564 Latency, as defined in [3], used in a context where the 565 forwarding information base influences the throughput. 567 Discussion: 568 This definition for FIB-dependent latency is added to 569 distinguish the context of this measurement from that defined 570 in [3]. 572 Measurement units: 573 See [3]. 575 Issues: 577 See Also: 578 forwarding information base-dependent throughput (6.3) 579 forwarding information base-dependent frame loss rate (6.5) 581 6.5 Forwarding Information Base-dependent Frame Loss Rate 583 Definition: 584 Frame Loss Rate, as defined in [3], used in a context where 585 the forwarding information base influences the throughput. 587 Discussion: 588 This definition for FIB-dependent frame loss rate is added to 589 distinguish the context of this measurement from that defined 590 in [3]. 592 Measurement units: 593 See [3]. 595 Issues: 597 See Also: 598 forwarding information base-dependent throughput (6.3) 599 forwarding information base-dependent latency (6.4) 600 Terminology for FIB based Router Performance July, 2001 602 7. Security Considerations 604 As this document is solely for the purpose of providing metric 605 methodology and describes neither a protocol nor a protocols 606 implementation, there are no security considerations associated with 607 this document. 609 8. References 611 1 Bradner, S., "The Internet Standards Process -- Revision 3", BCP 612 9, RFC 2026, October 1996. 613 2 Bradner, S., McQuaid, J., "Benchmarking Methodology for Network 614 Interconnect Devices", RFC 2544, March 1999 615 3 Bradner, S., "Benchmarking Terminology for Network 616 Interconnection Devices", RFC 1242, July 1991 617 4 Baker, F., "Requirements for IP Version 4 Routers", RFC 1812, 618 June 1995 620 9. Acknowledgments 622 10. Author's Addresses 624 Guy Trotter 625 Agilent Technologies (Canada) Inc. 626 #2500 4710 Kingsway 627 Burnaby, British Columbia 628 Canada 629 V5H 4M2 630 Phone: +1 604 454 3516 631 Email: Guy_Trotter@agilent.com 633 Full Copyright Statement 635 "Copyright (C) The Internet Society (2000). All Rights Reserved. 637 This document and translations of it may be copied and furnished to 638 others, and derivative works that comment on or otherwise explain it 639 or assist in its implementation may be prepared, copied, published 640 and distributed, in whole or in part, without restriction of any 641 kind, provided that the above copyright notice and this paragraph 642 are included on all such copies and derivative works. However, this 643 document itself may not be modified in any way, such as by removing 644 the copyright notice or references to the Internet Society or other 645 Internet organizations, except as needed for the purpose of 646 developing Internet standards in which case the procedures for 647 copyrights defined in the Internet Standards process must be 648 followed, or as required to translate it into languages other than 649 English. 651 Terminology for FIB based Router Performance July, 2001 653 The limited permissions granted above are perpetual and will not be 654 revoked by the Internet Society or its successors or assigns. This 655 document and the information contained herein is provided on an "AS 656 IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK 657 FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT 658 NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN 659 WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 660 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.