| < draft-ietf-isis-remaining-lifetime-02.txt | draft-ietf-isis-remaining-lifetime-03.txt > | |||
|---|---|---|---|---|
| Networking Working Group L. Ginsberg | Networking Working Group L. Ginsberg | |||
| Internet-Draft P. Wells | Internet-Draft P. Wells | |||
| Intended status: Standards Track Cisco Systems | Intended status: Standards Track Cisco Systems | |||
| Expires: February 4, 2017 B. Decraene | Expires: February 9, 2017 B. Decraene | |||
| Orange | Orange | |||
| T. Przygienda | T. Przygienda | |||
| Juniper | Juniper | |||
| H. Gredler | H. Gredler | |||
| Private Contributer | Private Contributer | |||
| August 03, 2016 | August 08, 2016 | |||
| IS-IS Minimum Remaining Lifetime | IS-IS Minimum Remaining Lifetime | |||
| draft-ietf-isis-remaining-lifetime-02.txt | draft-ietf-isis-remaining-lifetime-03.txt | |||
| Abstract | Abstract | |||
| Corruption of the Remainining Lifetime Field in a Link State PDU can | Corruption of the Remainining Lifetime Field in a Link State PDU can | |||
| go undetected. In certain scenarios this may cause or exacerbate | go undetected. In certain scenarios this may cause or exacerbate | |||
| flooding storms. It is also a possible denial of service attack | flooding storms. It is also a possible denial of service attack | |||
| vector. This document defines a backwards compatible solution to | vector. This document defines a backwards compatible solution to | |||
| this problem. | this problem. | |||
| Requirements Language | Requirements Language | |||
| skipping to change at page 1, line 46 ¶ | skipping to change at page 1, line 46 ¶ | |||
| Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
| Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
| working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
| Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
| Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
| and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
| time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
| material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
| This Internet-Draft will expire on February 4, 2017. | This Internet-Draft will expire on February 9, 2017. | |||
| Copyright Notice | Copyright Notice | |||
| Copyright (c) 2016 IETF Trust and the persons identified as the | Copyright (c) 2016 IETF Trust and the persons identified as the | |||
| document authors. All rights reserved. | document authors. All rights reserved. | |||
| This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
| Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
| (http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
| publication of this document. Please review these documents | publication of this document. Please review these documents | |||
| skipping to change at page 2, line 39 ¶ | skipping to change at page 2, line 39 ¶ | |||
| 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 | 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 | |||
| 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 | 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 | |||
| 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 | 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 | |||
| 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 | 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 | |||
| 8.1. Normative References . . . . . . . . . . . . . . . . . . 7 | 8.1. Normative References . . . . . . . . . . . . . . . . . . 7 | |||
| 8.2. Informational References . . . . . . . . . . . . . . . . 8 | 8.2. Informational References . . . . . . . . . . . . . . . . 8 | |||
| Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 | Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 | |||
| 1. Problem Statement | 1. Problem Statement | |||
| Each Link State PDU (LSP) includes a Remaining Lifetime field. This | [ISO10589] defines the format of a Link State PDU (LSP) which | |||
| field is set by the originator based on local configuration and then | includes a Remaining Lifetime field. This field is set by the | |||
| decremented by all systems once the entry is stored in their Link | originator based on local configuration and then decremented by all | |||
| State PDU Database (LSPDB) consistent with the passing of time. This | systems once the entry is stored in their Link State PDU Database | |||
| allows all Intermediate Systems (ISs) to age out the LSP at | (LSPDB) consistent with the passing of time. This allows all | |||
| approximately the same time. | Intermediate Systems (ISs) to age out the LSP at approximately the | |||
| same time. | ||||
| Each LSP also has a checksum field to allow receiving systems to | Each LSP also has a checksum field to allow receiving systems to | |||
| detect errors which may have occurred during transmission. As the | detect errors which may have occurred during transmission. As the | |||
| Remaining Lifetime field changes as it is flooded and as the checksum | Remaining Lifetime field changes as it is flooded and as the checksum | |||
| field MUST NOT be altered by receiving ISs the Remaining Lifetime is | field MUST NOT be altered by receiving ISs the Remaining Lifetime is | |||
| deliberately excluded from the checksum calculation. In cases where | deliberately excluded from the checksum calculation. In cases where | |||
| cryptographic authentication is included in an LSP ([RFC5304] or | cryptographic authentication is included in an LSP ([RFC5304] or | |||
| [RFC5310]) the Remaining Lifetime field is also excluded from the | [RFC5310]) the Remaining Lifetime field is also excluded from the | |||
| hash calculation. If the Remaining Lifetime field gets corrupted | hash calculation. If the Remaining Lifetime field gets corrupted | |||
| during flooding this corruption is therefore undetectable. The | during flooding this corruption is therefore undetectable. The | |||
| consequences of such corruption depend upon how the Remaining | consequences of such corruption depend upon how the Remaining | |||
| Lifetime is altered. | Lifetime is altered. | |||
| In cases where the Remaining Lifetime becomes larger than the | In cases where the Remaining Lifetime becomes larger than the | |||
| originator intended the impact is benign. As the originator is | originator intended the impact is benign. As the originator is | |||
| responsible for refreshing the LSP before it ages out a new version | responsible for refreshing the LSP before it ages out a new version | |||
| of the LSP will be generated before the LSP ages out - so no harm is | of the LSP will be generated before the LSP ages out - so no harm is | |||
| End of changes. 6 change blocks. | ||||
| 10 lines changed or deleted | 12 lines changed or added | |||
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