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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) -- Missing reference section? '1' on line 13 looks like a reference -- Missing reference section? '2' on line 75 looks like a reference -- Missing reference section? '3' on line 475 looks like a reference -- Missing reference section? '4' on line 152 looks like a reference -- Missing reference section? '5' on line 550 looks like a reference Summary: 5 errors (**), 0 flaws (~~), 4 warnings (==), 8 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Benchmarking Methodology Working Group G. Trotter 2 Internet-Draft Agilent Technologies 3 Expires: January 2001 July 2000 5 Terminology for Forwarding Information Base (FIB) based Router 6 Performance Benchmarking 7 9 Status of this Memo 11 This document is an Internet-Draft and is in full conformance with 12 all provisions of Section 10 of RFC2026 [1]. 14 Internet-Drafts are working documents of the Internet Engineering 15 Task Force (IETF), its areas, and its working groups. Note that 16 other groups may also distribute working documents as Internet- 17 Drafts. 19 Internet-Drafts are draft documents valid for a maximum of six 20 months and may be updated, replaced, or obsoleted by other documents 21 at any time. It is inappropriate to use Internet- Drafts as 22 reference material or to cite them other than as "work in progress." 24 The list of current Internet-Drafts can be accessed at 25 http://www.ietf.org/ietf/1id-abstracts.txt. 27 The list of Internet-Draft Shadow Directories can be accessed at 28 http://www.ietf.org/shadow.html. 30 1. Introduction 32 This document defines terms that are to be used in a methodology 33 that determines the IP packet forwarding performance of IP routers 34 as a function of the forwarding information base installed within 35 the router. 37 The objective of this methodology is to evaluate the performance 38 levels of IP routers as forwarding information bases continue to 39 grow in size and complexity of structure. 41 This methodology utilizes the packet forwarding performance 42 measurements described in [2]; reference will also be made to the 43 associated terminology document [3] for these terms. 45 2. Overview 47 In order to measure the forwarding information base-based router 48 performance, different forwarding information bases (5.3) are 49 installed in the router. The two key elements describing the FIB 50 are the FIB size (5.5) and FIB prefix distribution (5.6). As FIB 51 sizes increase, and as FIB prefix distributions tend towards longer 52 network prefixes (5.1), then it will take more time to match the 53 destination address within an IP packet and its corresponding entry 55 Terminology for FIB based Router Performance July, 2000 57 within the FIB. The FIB-dependent throughput, latency and frame 58 loss rate (5.11, 5.12, 5.13), measured with fully meshed traffic 59 flows (5.15), will reflect the change in performance of the router. 60 Tests may need to be performed up to the maximum FIB size (5.7). 62 When configuring the router for these measurements, the routes need 63 to be manually entered into the router, or advertised via a routing 64 protocol. It may take some period of time (the FIB learning time 65 (5.8)) before the router learns all the routes. 67 When routes are advertised into the router, the routes should be 68 advertised in such a way so that route aggregation (5.14) does not 69 occur. Also, the effect of a per-interface FIB cache (5.10) needs 70 to be taken into account. 72 3. Existing Definitions 74 [3] should be consulted before attempting to make use of this 75 document. [2] contains discussions of a number of terms relevant to 76 the benchmarking of switching devices and should also be consulted. 78 4. Definition Format 80 The definition format is the equivalent to that defined in [3], and 81 is repeated here for convenience: 83 X.x Term to be defined. (e.g., Latency) 85 Definition: 86 The specific definition for the term. 88 Discussion: 89 A brief discussion about the term, it's application and any 90 restrictions on measurement procedures. 92 Measurement units: 93 The units used to report measurements of this term, if 94 applicable. 96 Issues: 97 List of issues or conditions that effect this term. 99 See Also: 100 List of other terms that are relevant to the discussion of 101 this term. 103 5. Definitions 105 5.1 Network Prefix 107 Definition: 108 See section 2.2.5, "Addressing Architecture", in [4]. 110 Terminology for FIB based Router Performance July, 2000 112 A network prefix refers to the high-order 'n' bits of an IP 113 address, identifying a particular network within which an IP 114 host is located. 116 Discussion: 117 Network prefixes are represented as a 32 bit IP address with 118 a mask indicating the number of bits representing the network 119 prefix. I.e. 141.184.128 /17 indicates that the network 120 prefix is 17 bits long. 122 Measurement units: 123 125 Issues: 127 See Also: 128 Network Prefix Length (5.2) 130 5.2 Network Prefix Length 132 Definition: 133 Refers to the length in bits of a network prefix. Network 134 prefixes, using CIDR terminology, are typically referred to 135 as 15.35.128 /17, indicating that the network prefix is 17 136 bits long. 138 Discussion: 140 Measurement units: 141 length in bits 143 Issues: 145 See Also: 146 network prefix (5.1) 147 forwarding information base prefix distribution (5.6) 149 5.3 Forwarding Information Base (FIB) 151 Definition: 152 As according to the definition in [4]: 154 "The table containing the information necessary to forward IP 155 Datagrams, in this document, is called the Forwarding 156 Information Base. At minimum, this contains the interface 157 identifier and next hop information for each reachable 158 destination network prefix." 160 A forwarding information base consists of [FIB size (5.7)] 161 FIB entries (5.4). 163 Discussion: 165 Terminology for FIB based Router Performance July, 2000 167 The forwarding information base is an abstract concept used 168 to describe a database indexing network prefixes versus 169 router port identifiers. This database may, in reality, be 170 constructed in any fashion that optimizes the execution of 171 the longest prefix length match algorithm, which maps the 172 destination addresses within received IP packets against the 173 entries in the forwarding information base. 175 Measurement units: 176 178 Issues: 180 See Also: 181 forwarding information base entry (5.4) 182 forwarding information base size (5.5) 183 forwarding information base prefix distribution (5.6) 184 maximum forwarding information base size (5.7) 186 5.4 Forwarding Information Base Entry 188 Definition: 189 A single entry within a forwarding information base, 190 consisting of a network prefix and a router port identifier. 192 Discussion: 193 See (5.3). 195 Measurement units: 196 198 Issues: 200 See Also: 201 forwarding information base (5.3) 202 forwarding information base size (5.5) 203 forwarding information base prefix distribution (5.6) 204 maximum forwarding information base size (5.7) 206 5.5 Forwarding Information Base Size 208 Definition: 209 Refers to the number of forwarding information base entries 210 within a forwarding information base. 212 Discussion: 213 The number of entries within a forwarding information base is 214 one of the key elements that may influence the forwarding 215 performance of a router. Generally, the more entries within 216 the forwarding information base, the longer it could take to 217 find the longest matching network prefix within the 218 forwarding information base. 220 Terminology for FIB based Router Performance July, 2000 222 Measurement units: 223 positive integer 225 Issues: 227 See Also: 228 forwarding information base (5.3) 229 forwarding information base entry (5.4) 230 forwarding information base prefix distribution (5.6) 231 maximum forwarding information base size (5.7) 233 5.6 Forwarding Information Base Prefix Distribution 235 Definition: 236 The distribution of network prefix lengths within the 237 forwarding information base. 239 Discussion: 240 Network prefixes within the forwarding information base could 241 be all of a single network prefix length, but, more 242 realistically, the network prefix lengths will be distributed 243 across some range. 245 Individual performance measurements will be made against FIBs 246 populated with the same network prefix length, as well as 247 against FIBs with some distribution of network prefix 248 lengths. 250 The distribution of network prefix lengths will have an 251 impact on the forwarding performance of a router. The longer 252 the network prefix length, the longer it will take for a 253 router to perform the longest length prefix match algorithm, 254 and potentially the lower the performance of the router. 256 Measurement units: 257 The forwarding information base prefix distribution is 258 expressed by a list of network prefix lengths and the 259 percentage of entries within the forwarding information base 260 with a particular network prefix length. For example, a 261 forwarding information base prefix distribution is 262 represented as: 264 {[/16, 10%], [/20, 36%], [/24, 54%]} 266 This indicates that 10% of the entries within the forwarding 267 information base have a 16 bit network prefix length, 36% 268 have a 20 bit network prefix length, and 54% have a 24 bit 269 network prefix length. 271 Issues: 273 See Also: 274 forwarding information base (5.3) 276 Terminology for FIB based Router Performance July, 2000 278 forwarding information base entry (5.4) 279 forwarding information base size (5.5) 280 maximum forwarding information base size (5.7) 282 5.7 Maximum Forwarding Information Base Size 284 Definition: 285 The maximum number of forwarding information base entries 286 that can be supported within the forwarding information base. 288 Discussion: 289 It is useful to know the maximum forwarding information base 290 size for a router as it will be an indicator of the ability 291 of the router to function within the given application space, 292 and whether the router will be able to handle projected 293 network growth. 295 As a benchmarking value, it is necessary to discover this 296 value so that performance measurements can be made up to the 297 maximum possible forwarding information base size. 299 Measurement units: 300 Positive integer. 302 Issues: 303 Could this value vary with the forwarding information base 304 prefix distribution? 306 See Also: 307 forwarding information base (5.3) 308 forwarding information base entry (5.4) 309 forwarding information base size (5.5) 310 forwarding information base prefix distribution (5.6) 312 5.8 Forwarding Information Base Learning Time 314 Definition: 315 The forwarding information base learning time is the time 316 taken for a router to receive and process received routing 317 messages, and to construct (and, possibly to distribute 318 amongst the interface cards in the router) the forwarding 319 information base. 321 Discussion: 322 It takes time for a router to construct its forwarding 323 information base. A router needs to process received routing 324 packets, build the routing information database, select the 325 best paths, build the forwarding information base and then 326 possibly distribute the forwarding information base or a 327 subset thereof to the interface cards. This entire process 328 can take several minutes with very large forwarding 329 information bases. 331 Terminology for FIB based Router Performance July, 2000 333 When performing benchmarking tests that take the forwarding 334 information base into account, time must be allocated for the 335 router to process the routing information and to install the 336 complete forwarding information base within itself, before 337 performance measurements are made. 339 Measurement units: 341 Issues: 343 See Also: 344 forwarding information base (5.3) 346 5.9 Per-Interface Forwarding Information Base 348 Definition: 349 A complete copy of the forwarding information base, installed 350 on a router's interface card to speed the destination address 351 to network prefix lookup process. 353 Discussion: 354 Router manufacturers have developed many optimizations for 355 routers, of which one optimization is to copy the forwarding 356 information base to every interface card on the router. By 357 doing this, destination address / network prefix lookups can 358 be performed on the interface, unloading a router's CPU. 360 Measurement units: 361 363 Issues: 365 See Also: 366 forwarding information base (5.3) 367 per-interface forwarding information base cache (5.10) 369 5.10 Per-Interface Forwarding Information Base Cache 371 Definition: 372 A subset of a forwarding information base, installed on a 373 router's interface card to speed the destination address / 374 network prefix lookup process. 376 Discussion: 377 Prior to installing a complete copy of the forwarding 378 information base on each interface of a router, a popular 379 technique for speeding destination address lookups is to 380 install a cache of frequently used routes on a router's 381 interface. 383 The most frequently used routes are placed in the forwarding 384 information base cache. IP packets whose destination address 385 does not match a network prefix within the per-interface 387 Terminology for FIB based Router Performance July, 2000 389 forwarding information base cache are forwarded to a router's 390 central processor for lookup in the complete forwarding 391 information base. 393 The implication for benchmarking the performance of a router 394 as a function of the forwarding information base is 395 significant. IP packets whose destination address matches an 396 entry within the per-interface forwarding information base 397 cache could be forwarded more quickly than packets whose 398 destination address does not match an entry within the per- 399 interface forwarding information base cache. 401 To create useful benchmarks, the role of a per-interface 402 forwarding cache needs to be considered. The nature of 403 benchmarking tests to measure the impact of the forwarding 404 performance of a router requires that the destination 405 addresses within IP packets transmitted into the router be 406 distributed amongst the total set of network prefixes 407 advertised into the router. This negates the role of a per- 408 interface forwarding information base cache, but serves to 409 stress the forwarding information base-based packet 410 forwarding performance of the router. 412 Measurement units: 413 415 Issues: 417 See Also: 418 forwarding information base (5.3) 419 per-interface forwarding information base (5.9) 421 5.11 Forwarding Information Base-dependent Throughput 423 Definition: 424 Throughput, as defined in [3], used in a context where the 425 forwarding information base influences the throughput. 427 Discussion: 428 This definition for FIB-dependent throughput is added to 429 distinguish the context of this measurement from that defined 430 in [3]. 432 Measurement units: 433 See [3]. 435 Issues: 437 See Also: 438 forwarding information base-dependent latency (5.12) 439 forwarding information base-dependent frame loss rate (5.13) 441 Terminology for FIB based Router Performance July, 2000 443 5.12 Forwarding Information Base-dependent Latency 445 Definition: 446 Latency, as defined in [3], used in a context where the 447 forwarding information base influences the throughput. 449 Discussion: 450 This definition for FIB-dependent latency is added to 451 distinguish the context of this measurement from that defined 452 in [3]. 454 Measurement units: 455 See [3]. 457 Issues: 459 See Also: 460 forwarding information base-dependent throughput (5.11) 461 forwarding information base-dependent frame loss rate (5.13) 463 5.13 Forwarding Information Base-dependent Frame Loss Rate 465 Definition: 466 Frame Loss Rate, as defined in [3], used in a context where 467 the forwarding information base influences the throughput. 469 Discussion: 470 This definition for FIB-dependent frame loss rate is added to 471 distinguish the context of this measurement from that defined 472 in [3]. 474 Measurement units: 475 See [3]. 477 Issues: 479 See Also: 480 forwarding information base-dependent throughput (5.11) 481 forwarding information base-dependent latency (5.12) 483 5.14 Route Aggregation 485 Definition: 486 The ability of a router to collapse many forwarding 487 information base entries into a single entry. 489 Discussion: 490 A router may aggregate routes in a forwarding information 491 base into a single entry to conserve space. 493 When advertising routes into a router to perform benchmarking 494 tests as a function of the forwarding information base 496 Terminology for FIB based Router Performance July, 2000 498 installed within the router, it is necessary to ensure that a 499 router does not aggregate routes. 501 Thus, when routes are advertised to the router or installed 502 statically, care must be taken to ensure that the router does 503 not aggregate routes. 505 For example, if advertising a set of /24 network prefixes 506 into a particular port on the router, 256 consecutive /24 507 routes, sharing a common leading 16 bits, should not be 508 advertised on a single port. If this is done, then the 509 router will install a single entry within the forwarding 510 information base indicating that all networks matching a 511 particular /16 network prefix are accessible through one 512 particular entry. 514 Measurement units: 515 517 Issues: 519 See Also: 521 5.15 Fully Meshed Traffic Flows 523 Definition: 524 A traffic mesh that fully exercises the forwarding table 525 continuously in the router under test. 527 Discussion: 528 In order to stress the forwarding information base lookup 529 mechanisms within the router, packets need to be delivered on 530 every interface such that every entry within the forwarding 531 information base is accessed. 533 This implies that the set of destination addresses used by IP 534 packets delivered to each interface of the router matches the 535 set of all network prefixes advertised into the router. That 536 is, IP packets are sent into every interface such that IP 537 packets are directed through to every network advertised on 538 every other interface on the router. 540 Fully meshed traffic flows ensure that the forwarding 541 information base or per-interface forwarding information 542 bases are fully and continuously exercised. 544 Measurement units: 545 547 Issues: 549 See Also: 550 fully meshed traffic (section 3.3.3 in [5]) 552 Terminology for FIB based Router Performance July, 2000 554 6. Security Considerations 556 As this document is solely for the purpose of providing metric 557 methodology and describes neither a protocol nor a protocols 558 implementation, there are no security considerations associated with 559 this document. 561 7. References 563 1 Bradner, S., "The Internet Standards Process -- Revision 3", BCP 564 9, RFC 2026, October 1996. 565 2 Bradner, S., McQuaid, J., "Benchmarking Methodology for Network 566 Interconnect Devices", RFC 2544, March 1999 567 3 Bradner, S., "Benchmarking Terminology for Network 568 Interconnection Devices", RFC 1242, July 1991 569 4 Baker, F., "Requirements for IP Version 4 Routers", RFC 1812, 570 June 1995 571 5 Mandeville, R., "Benchmarking Terminology for LAN Switching 572 Devices", RFC 2285, February 1998 574 8. Acknowledgments 576 9. Author's Addresses 578 Guy Trotter 579 Agilent Technologies (Canada) Inc. 580 #2500 4710 Kingsway 581 Burnaby, British Columbia 582 Canada 583 V5H 4M2 584 Phone: +1 604 454 3516 585 Email: Guy_Trotter@agilent.com 587 Full Copyright Statement 589 "Copyright (C) The Internet Society (2000). All Rights Reserved. 591 This document and translations of it may be copied and furnished to 592 others, and derivative works that comment on or otherwise explain it 593 or assist in its implementation may be prepared, copied, published 594 and distributed, in whole or in part, without restriction of any 595 kind, provided that the above copyright notice and this paragraph 596 are included on all such copies and derivative works. However, this 597 document itself may not be modified in any way, such as by removing 598 the copyright notice or references to the Internet Society or other 599 Internet organizations, except as needed for the purpose of 600 developing Internet standards in which case the procedures for 601 copyrights defined in the Internet Standards process must be 602 followed, or as required to translate it into languages other than 603 English. 605 Terminology for FIB based Router Performance July, 2000 607 The limited permissions granted above are perpetual and will not be 608 revoked by the Internet Society or its successors or assigns. This 609 document and the information contained herein is provided on an "AS 610 IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK 611 FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT 612 NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN 613 WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 614 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.