📄 rfc2650.txt
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about your internal routing specifics. Therefore, external routes are in general aggregated combinations of internal routes, having shorter IP prefixes where applicable according to the CIDR rules. Please see the CIDR FAQ [5] for a tutorial introduction to CIDR. It is strongly recommended that you aggregate your routes as much as possible, thereby minimizing the number of routes you inject into the global routing table and at the same time reducing the corresponding number of route objects in the IRR. While you may easily query single route objects using the whois program, and submit objects via mail to the registry robots, this becomes kind of awkward for larger sets. The RAToolSet [6] offers several tools to make handling of route objects easier. If you want to read policy data from the IRR and process it by other programs, you might be interested in using peval which is a low level policy evaluation tool. As an example, the command peval -h whois.ra.net AS3582 will give you all route objects from AS3582 registered with RADB.Meyer, et al. Informational [Page 20]RFC 2650 Using RPSL in Practice August 1999 A much more sophisticated tool from the RAToolSet to handle route objects interactively is the route object editor roe. It has a graphical user interface to view and manipulate route objects registered at any IRR. New route objects may be generated from templates and submitted to the registries. Moreover, the route objects from the databases may be compared to real life routes. Therefore, roe is highly recommended as an interface to the IRR for route objects. Further information on peval and roe is available together with the RAToolSet [6].A.4 Set Objects With routing policies it is often necessary to reference groups of autonomous systems or routes which have identical properties regarding a specific policy. To make working with such groups easier RPSL allows to combine them in set objects. There are two basic types of predefined set objects, as-set, and route-set. The RPSL set objects are described below.A.4.1 AS-SET Object Autonomous system set objects (as-set) are used to group autonomous system objects into named sets. An as-set has an RPSL name that starts with "AS-". In the example in Figure 17, an as-set called AS-NERO-PARTNERS and containing AS3701, AS4201, AS3582, AS4222, AS1798 is defined. The as-set is the RPSL replacement for the RIPE- 181 as-macro. It has been extended to include ASes in the set indirectly by referencing as set names in the aut-num objects. AS-SETs are particularly useful when specifying policies for groups such as customers, providers, or for transit. You are encouraged to register sets for these groups because it is most likely that you will treat them alike, i.e. you will have a very similar routing policy for all your customers which have an autonomous system of their own. You may as well discover that this is also true for the providers you are peering with, and it is most convenient to have the ASes combined in one as-set for which you offer transit. For example, if a transit provider specifies its import policy using its customer's as-set (i.e., its import clause for the customer contains the customer's as-set), then that customer can modify the set of ASes that its transit provider accepts from it. Again, this can be accomplished without requiring the customer or the transit provider to modify its aut-num object. as-set: AS3582:AS-PARTNERS members: AS3701, AS4201, AS3582, AS4222, AS1798 Figure 17: as-set ObjectMeyer, et al. Informational [Page 21]RFC 2650 Using RPSL in Practice August 1999 The ASes of the set are simply compiled in a comma delimited list following the members attribute of the as-set. This list may also contain other AS-SET names.A.4.2 ROUTE-SET Object A route-set is a way to name a group of routes. The syntax is similar to the as-set. A route-set has an RPSL name that starts with "RS-". The members attribute lists the members of the set. The value of a members attribute is a list of address prefixes, or route-set names. The members of the route-set are the address prefixes or the names of other route sets specified. Figure 18 presents some example route-set objects. The set rs-uo contains two address prefixes, namely 128.223.0.0/16 and 198.32.162.0/24. The set rs-bar contains the members of the set rs- uo and the address prefix 128.7.0.0/16. The set rs-martians illustrate the use of range operators. 0.0.0.0/0^32 are the length 32 more specifics of 0.0.0.0/0, i.e. the host routes; 224.0.0.0/3^+ are the more specifics of 224.0.0.0/3, i.e. the routes falling into the multicast address space. For more complete list of range operators please refer to RFC-2622. route-set: rs-uo members: 128.223.0.0/16, 198.32.162.0/24 route-set: rs-bar members: 128.7.0.0/16, rs-uo route-set: rs-martians remarks: routes not accepted from any peer members: 0.0.0.0/0, # default route 0.0.0.0/0^32, # host routes 224.0.0.0/3^+, # multicast routes 127.0.0.0/8^9-32, . . . Figure 18: route-set ObjectsMeyer, et al. Informational [Page 22]RFC 2650 Using RPSL in Practice August 1999B Output of RtConfig: An Example In Figure 19, you see the result of running RtConfig on the source file in Figure 11. router bgp 3582 network 128.223.0.0 ! ! NERO neighbor 198.32.162.2 remote-as 3701 no access-list 100 access-list 100 permit ip 128.223.0.0 0.0.0.0 255.255.0.0 0.0.0.0 access-list 100 deny ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255 ! no route-map AS3701-EXPORT route-map AS3701-EXPORT permit 1 match ip address 100 ! router bgp 3582 neighbor 198.32.162.2 route-map AS3701-EXPORT out ! no route-map AS3701-IMPORT route-map AS3701-IMPORT permit 1 set local-preference 1000 ! router bgp 3582 neighbor 198.32.162.2 route-map AS3701-IMPORT in ! ! WNA/VERIO neighbor 198.32.162.6 remote-as 2914 ! no route-map AS2914-EXPORT route-map AS2914-EXPORT permit 1 match ip address 100 ! router bgp 3582 neighbor 198.32.162.6 route-map AS2914-EXPORT out no ip as-path access-list 100 ip as-path access-list 100 permit ^_2914(((_[0-9]+))*_ \ (13|22|97|132|175|668|1914|2905|2914|3361|3381|3791|3937| \ 4178|4354|4571|4674|4683|5091|5303|5798|5855|5856|5881|6083 \ |6188|6971|7790|7951|8028))?$ ! no route-map AS2914-IMPORT route-map AS2914-IMPORT permit 1 match as-path 100 set local-preference 998Meyer, et al. Informational [Page 23]RFC 2650 Using RPSL in Practice August 1999 ! router bgp 3582 neighbor 198.32.162.6 route-map AS2914-IMPORT in Figure 19: Output of RtConfigSecurity Considerations This document is a tutorial to RPSL, it does not define protocols or standards that need to be secured.Endnotes (1) AS-PATH regular expressions are POSIX compliant regular expressions. (2) Discussion of RtConfig internals is beyond the scope of this document. (3) Clearly, neither of these mechanisms is sufficient to provide strong authentication or authorization. Other public key (e.g., PGP) authentication mechanisms are available from some of the IRRs.References [1] Alaettinoglu, C., Villamizar, C., Gerich, E., Kessens, D., Meyer, D., Bates, T., Karrenberg, D. and M. Terpstra, "Routing Policy Specification Language (RPSL)", RFC 2622, June 1999. [2] Bates, T., Jouanigot, J-M., Karrenberg, D., Lothberg, P. and M. Terpstra, "Representation of IP Routing Policies in the RIPE database", Technical Report ripe-81, RIPE, RIPE NCC, Amsterdam, Netherlands, February 1993. [3] T. Bates, E. Gerich, J. Joncharay, J-M. Jouanigot, D. Karrenberg, M. Terpstra, and J. Yu. Representation of IP Routing Policies in a Routing Registry, Technical Report ripe-181, RIPE, RIPE NCC, Amsterdam, Netherlands, October 1994. [4] A. M. R. Magee. RIPE NCC Database Documentation. Technical Report RIPE-157, RIPE NCC, Amsterdam, Netherlands, May 1997. [5] Hank Nussbacher. The CIDR FAQ. Tel Aviv University and IBM Israel. http://www.ibm.net.il/~hank/cidr.html [6] The RAToolSet. http://www.ra.net/ra/RAToolSet/Meyer, et al. Informational [Page 24]RFC 2650 Using RPSL in Practice August 1999 [7] Rekhter Y. and T. Li, "A Border Gateway Protocol 4 (BGP-4)", RFC 1654, July 1994. [8] RtConfig as part of the RAToolSet. http://www.ra.net/ra/RAToolSet/RtConfig.html [9] Chen, E. and T. Bates, "An Application of the BGP Community Attribute in Multi-Home Routing", RFC 1998, August 1996.Authors' Addresses David Meyer Cisco Systems EMail: dmm@cisco.com Joachim Schmitz America On-Line EMail: SchmitzJo@aol.com Carol Orange RIPE NCC EMail: orange@spiritone.com Mark Prior connect.com.au pty ltd EMail: mrp@connect.com.au Cengiz Alaettinoglu USC/Information Sciences Institute EMail: cengiz@isi.eduMeyer, et al. Informational [Page 25]RFC 2650 Using RPSL in Practice August 1999Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.Meyer, et al. Informational [Page 26]
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