| < draft-leroux-ccamp-ctrl-saturation-00.txt | draft-leroux-ccamp-ctrl-saturation-01.txt > | |||
|---|---|---|---|---|
| CCAMP Working Group JL Le Roux | Internet Working Group J.-L. Le Roux | |||
| Internet Draft JY Mazeas | Internet Draft J.-Y. Mazeas | |||
| France Telecom | Proposed Category: Standard Track France Telecom | |||
| JP Vasseur | Expires: January 2006 J.-P. Vasseur | |||
| Sami Boutros | S. Boutros | |||
| Cisco Systems | Cisco Systems | |||
| D. Papadimitriou | ||||
| Alcatel | ||||
| Category: Standard Track | July 2005 | |||
| Expires: July 2005 February 2005 | ||||
| Procedure to handle (G)MPLS-TE control plane saturation | Procedure to handle (G)MPLS-TE control plane saturation | |||
| draft-leroux-ccamp-ctrl-saturation-00.txt | draft-leroux-ccamp-ctrl-saturation-01.txt | |||
| Status of this Memo | Status of this Memo | |||
| By submitting this Internet-Draft, I certify that any applicable | By submitting this Internet-Draft, each author represents that any | |||
| patent or IPR claims of which I am aware have been disclosed, or will | applicable patent or other IPR claims of which he or she is aware | |||
| be disclosed, and any of which I become aware will be disclosed, in | have been or will be disclosed, and any of which he or she becomes | |||
| accordance with RFC 3668. | aware will be disclosed, in accordance with Section 6 of BCP 79. | |||
| This document is an Internet-Draft and is in full conformance with | This document is an Internet-Draft and is in full conformance with | |||
| all provisions of Section 10 of RFC2026. Internet-Drafts are working | all provisions of Section 10 of RFC2026. Internet-Drafts are working | |||
| documents of the Internet Engineering Task Force (IETF), its areas, | documents of the Internet Engineering Task Force (IETF), its areas, | |||
| and its working groups. Note that other groups may also distribute | and its working groups. Note that other groups may also distribute | |||
| working documents as Internet-Drafts. | working documents as Internet-Drafts. | |||
| 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 | |||
| skipping to change at page 2, line 9 ¶ | skipping to change at page 2, line 9 ¶ | |||
| The list of current Internet-Drafts can be accessed at | The list of current Internet-Drafts can be accessed at | |||
| http://www.ietf.org/ietf/1id-abstracts.txt. | http://www.ietf.org/ietf/1id-abstracts.txt. | |||
| The list of Internet-Draft Shadow Directories can be accessed at | The list of Internet-Draft Shadow Directories can be accessed at | |||
| http://www.ietf.org/shadow.html. | http://www.ietf.org/shadow.html. | |||
| Abstract | Abstract | |||
| This document defines extensions to RSVP-TE (Resource Reservation | This document defines extensions to RSVP-TE (Resource Reservation | |||
| Protocol-Traffic Engineering) and IGP (IS-IS and OSPF), in order to | Protocol-Traffic Engineering) and IGP (IS-IS and OSPF), in order to | |||
| signal control plane resources saturation, when an LSR runs out of | notify about control plane resources saturation, when an LSR runs out | |||
| control plane resources available to support a new LSP. Such | of control plane resources available to support any additional LSP. | |||
| notification may serve as trigger for the impacted Head-end LSR to | Such notification may serve as trigger for the impacted Head-end LSR | |||
| take appropriate actions. | to take appropriate actions. | |||
| Table of Contents | Table of Contents | |||
| 1. Introduction................................................3 | 1. Terminology.................................................2 | |||
| 2. Terminology.................................................4 | 2. Introduction................................................3 | |||
| 3. RSVP-TE Saturation..........................................4 | 3. RSVP-TE Saturation..........................................4 | |||
| 4. Signalling extensions.......................................5 | 4. Signalling extensions.......................................4 | |||
| 4.1. New RSVP Error Code.........................................5 | 4.1. New RSVP Error Code.........................................4 | |||
| 4.2. Mode of operations..........................................5 | 4.2. Mode of operations..........................................5 | |||
| 4.2.1. Procedures for a saturated LSR (Transit or Tail)............5 | 4.2.1. Procedures for a saturated LSR..............................5 | |||
| 4.2.2. Procedures for a Head-End LSR...............................5 | 4.2.2. Procedures for a Head-End LSR...............................5 | |||
| 5. Routing extensions..........................................6 | 5. Routing extensions..........................................5 | |||
| 5.1. Encoding of the Saturation TLV..............................6 | 5.1. Encoding of the Saturation TLV..............................5 | |||
| 5.2. Elements of procedure.......................................7 | 5.2. Elements of procedure.......................................6 | |||
| 6. Security Considerations.....................................7 | 5.2.1. Procedures for a Saturated LSR..............................7 | |||
| 7. Acknowledgements............................................7 | 5.2.2. Procedures for a Head-End LSR...............................7 | |||
| 8. Intellectual Property Statement.............................7 | 6. Inter-Provider considerations...............................7 | |||
| 8.1. IPR Disclosure Acknowledgement..............................8 | 7. Security Considerations.....................................8 | |||
| 9. References.................................................8 | 8. Acknowledgements............................................8 | |||
| 9. References..................................................8 | ||||
| 9.1. Normative references........................................8 | 9.1. Normative references........................................8 | |||
| 9.2. Informative references......................................9 | 9.2. Informative references......................................8 | |||
| 10. Authors' Address:...........................................9 | 10. Authors' Address:...........................................9 | |||
| 11. Intellectual Property Statement.............................9 | ||||
| Conventions used in this document | Conventions used in this document | |||
| The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | |||
| "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | |||
| document are to be interpreted as described in RFC-2119. | document are to be interpreted as described in RFC-2119. | |||
| 1. Introduction | 1. Terminology | |||
| LSR: Label Switching Router | ||||
| TE-LSP: MPLS Traffic Engineering Label Switched Path | ||||
| Head-End LSR: Head of a TE-LSP | ||||
| Tail-End LSR: Tail of a TE-LSP | ||||
| PSB: RSVP Path State Block | ||||
| RSB: RSVP Reservation State Block | ||||
| RSVP-TE Saturation: State of an LSR that cannot accept any new TE-LSP | ||||
| due to configured thresholds, or control plane limitations | ||||
| ASBR: Autonomous System Border Router | ||||
| 2. Introduction | ||||
| Many service providers have deployed RSVP-TE [RFC3209] to setup TE- | Many service providers have deployed RSVP-TE [RFC3209] to setup TE- | |||
| LSPs and achieve Traffic Engineering objectives. | LSPs and achieve Traffic Engineering objectives. | |||
| In some circumstances, MPLS-TE deployments in large networks may | In some circumstances, MPLS-TE deployments in large networks may | |||
| require maintaining a high number of TE-LSPs on transit LSRs and thus | require maintaining a high number of TE-LSPs on transit LSRs, which | |||
| instantiating a high number of RSVP states, and consuming a large | may lead to the instantiation of a high number of RSVP states and | |||
| amount of LSR resources such as memory and CPU. | hence consume a large amount of LSR control plane resources (e.g. | |||
| memory, CPU). | ||||
| Control plane capacities of an LSR (such as CPU or memory) are of | Control plane capacities of an LSR are of course not infinite and | |||
| course not infinite, and there may be some circumstances whereby an | there may be some circumstances whereby an LSR may run out of a | |||
| LSR may run out of a specific resource such as memory or CPU | specific control plane resource such as memory or CPU available for | |||
| available for the RSVP process; such resource shortage may lead to | the RSVP process; such resource shortage may lead to the inability | |||
| the inability for the LSR to support signalling of new LSPs. For | for the LSR to handle additional TE-LSPs. For instance, the LSR has | |||
| instance, the LSR has no longer enough memory to instantiate a new | no longer enough memory to instantiate a new RSVP state block (PSB, | |||
| RSVP state block (PSB, RSB [RFC2209]), and thus cannot maintain a new | RSB [RFC2209]). | |||
| LSP. In such situation, the saturated LSR should properly reject the | ||||
| LSP setup, and notify the head-end LSR about its saturation. | ||||
| Note that it may also be useful to allow the operator to limit (by | Furthermore, there may be circumstances whereby the operator may want | |||
| configuration) the maximum number of RSVP-TE sessions that can be | to limit, by configuration, the maximum number of RSVP-TE sessions | |||
| maintained by an LSR, at Ingress, Transit or Egress. | that can be accepted and maintained by an LSR at the Ingress, Transit | |||
| This allows controlling the impact of RSVP-TE on other control plane | or Egress position. | |||
| entities. | ||||
| This document defines a particular state for an RSVP node, called the | This document defines a particular RSVP-TE state (referred to as the | |||
| "Saturated" state. An RSVP node is said saturated, when it cannot | "Saturated" state) whereby the LSR cannot handle any additional TE- | |||
| support an additional TE-LSP, either because the maximum number of | LSP, either because the maximum number of TE-LSPs allowed is reached | |||
| RSVP sessions configured by the operator is reached or because there | or because there is no longer enough control plane resources (CPU, | |||
| is no longer enough resources (CPU, memory,à) allocated to the RSVP | memory,à) allocated to the RSVP process to instantiate and maintain a | |||
| process, to instantiate and maintain a new session state block. There | new session state block. | |||
| may be cases, particularly in large scale RSVP-TE deployments, where | ||||
| an LSR receives a Path message for a new LSP, while it is saturated. | ||||
| This document specifies: | There may be cases, particularly in large scale RSVP-TE deployments, | |||
| - a RSVP-TE extension allowing a saturated RSVP node to reject any | where an LSR receives a Path message for a new LSP, while it is under | |||
| new LSP and notify (using a new Error code and a set of sub-codes | the Saturated state. In such situation, the LSR should simply reject | |||
| carried in a Path Error message) the head-end LSR about its | the LSP setup, and notify the head-end LSR of its control plane | |||
| saturation. | saturation state. | |||
| - IGP extensions (that complement the RSVP-TE extension) in order for | ||||
| a LSR to advertise its current saturation state (saturated or not). | ||||
| This allows head-end LSRs avoiding the set up of new TE LSP through | ||||
| saturated nodes and also allows reoptimizing TE-LSPs when a given | ||||
| node is no longer saturated. | ||||
| 2. Terminology | For that purpose, this document specifies: | |||
| LSR: Label Switching Router | - A RSVP-TE extension allowing a saturated LSR to reject any new LSP | |||
| and notify (using a new Error code and a set of sub-codes carried | ||||
| in a Path Error message) the head-end LSR about its saturation; | ||||
| TE-LSP: MPLS Traffic Engineering Label Switched Path | - IGP extensions (that complement the RSVP-TE extension) in order | |||
| for a LSR to advertise its current saturation status (saturated or | ||||
| not). This allows other head-end LSRs avoiding the set up of new | ||||
| TE LSP through saturated nodes and also discovering that a given | ||||
| node is no longer saturated. | ||||
| RSVP-TE Saturation: State of an LSR that cannot accept any new TE-LSP | These routing and signalling notifications are complementary. They | |||
| due to control plane limitations | may serve as trigger for the Head-End LSRs to take appropriate | |||
| actions. | ||||
| 3. RSVP-TE Saturation | 3. RSVP-TE Saturation | |||
| Some RSVP-TE deployment scenarios may generate a high number of RSVP | A RSVP-TE engine is usually designed such that the maximum number of | |||
| sessions on transit LSRs, and consume a significant amount of | LSPs it supports equals the total number of LSP with a resource | |||
| resources (such as memory and CPU). Depending on LSR control plane | allocation corresponding to the min LSP bandwidth (set e.g. to 2 | |||
| capacities, there may be cases where an LSR is not able to support | Mbps) configured in the context of its admission control mechanism. | |||
| any new TE LSPs for a specific amount of time. Of course, note that | However, soft-provisioning techniques (e.g. LSP established with no | |||
| such state may be transitional and this document proposes mechanism | bandwidth reservation) are challenging this rule of thumb since the | |||
| to signal that the node is no longer in such state by means of | number of supported LSPs needs now to take not only data plane | |||
| routing extensions. | resources allocation into account but also control plane resources. | |||
| An RSVP node enters the saturated state when it runs out of a | ||||
| specific resource such as the memory or CPU (globally or for the RSVP | ||||
| process) or some other constraints are reached (for the sake of | ||||
| illustration, this can be the number of transiting LSPs which can | ||||
| influence the rerouting time in case of failure with some network | ||||
| recovery techniques). | ||||
| A saturated LSR MUST reject the setup of a new TE-LSP, and SHOULD | An RSVP node enters the Saturated state when it runs out of specific | |||
| maintain already established TE-LSPs. | control plane resource such as the memory or CPU (globally or for the | |||
| RSVP process) or above a pre-configured threshold or when a pre- | ||||
| configured maximum number of LSPs allowed is reached. Criteria to | ||||
| trigger such saturated state are local to the LSR and outside of the | ||||
| scope of this document. | ||||
| Note that it is recommended to introduce some hysteresis for | Note that it is recommended to introduce some hysteresis for | |||
| saturation state transition, in order to avoid oscillations. | saturation state transition, so as to avoid oscillations. | |||
| For instance in case the number of TE-LSPs is bounded, two thresholds | For instance if the number of TE-LSPs is bounded (by configuration), | |||
| could be configured: | two thresholds should be configured: An upper-threshold and a lower- | |||
| The upper-threshold: An LSR enters the saturated when the number | threshold with upper-threshold > lower-threshold. An LSR enters the | |||
| of TE-LSPs reaches the upper-threshold. | saturated state when the number of TE-LSPs reaches the upper- | |||
| The lower-threshold: An LSR leaves the saturated state when the | threshold and leaves the saturated state when it goes down the lower- | |||
| number of TE-LSPs goes below the lower-threshold. | threshold. | |||
| 4. Signalling extensions | 4. Signalling extensions | |||
| 4.1. New RSVP Error Code | 4.1. New RSVP Error Code | |||
| This document specifies a new Error Code (suggested value | This document specifies a new Error Code (suggested value | |||
| to be confirmed by IANA) for the RSVP ERROR_SPEC object: | to be confirmed by IANA) for the RSVP ERROR_SPEC object: | |||
| 26 Control Plane Saturation | 26 Control Plane Saturation | |||
| The following defines error values sub-codes for the new Control | The following defines error values sub-codes for the new Control | |||
| Plane Saturation Error Code: | Plane Saturation Error Code: | |||
| 1 Saturation unspecified | 1 Saturation unspecified | |||
| 2 Memory saturation | 2 Memory saturation | |||
| 3 CPU saturation | 3 CPU saturation | |||
| 4 Max number of LSPs reached | ||||
| 100-255 Proprietary | 100-255 Reserved | |||
| Procedures are detailed in section 4.2 below. | Procedures are detailed in section 4.2 below. | |||
| 4.2. Mode of operations | 4.2. Mode of operations | |||
| 4.2.1. Procedures for a saturated LSR (Transit or Tail) | 4.2.1. Procedures for a saturated LSR | |||
| On receipt of a Path message for a new LSP, a saturated LSR compliant | On receipt of a Path message for a new LSP, a saturated LSR compliant | |||
| with this document MUST reject the LSP setup and send back a Path | with this document SHOULD reject the LSP setup and send back a | |||
| Error Message with the Error Code "Saturation" and optionally a sub- | PathErr Message with the Path_State_Removed flag set in the | |||
| code mentioning the reasons for the saturation. | ERROR_SPEC object, with the Error Code "Saturation" and optionally an | |||
| Error sub-code value mentioning the reasons for the saturation. | ||||
| The Error node address carried within the ERROR_SPEC object MUST be | ||||
| set to the TE router id. | ||||
| 4.2.2. Procedures for a Head-End LSR | The address carried within the ERROR_SPEC object SHOULD be set to the | |||
| TE router id of the saturated node. The IF_ID ERROR_SPEC object MAY | ||||
| be used in case saturation can be determined as coming from a given | ||||
| adjacency. | ||||
| On receipt of a Path Error message with the Error Code "Saturation" | To avoid inability of the saturated node to generate PathErr | |||
| and with the PSR flag not set, the Head-End LSR SHOULD send a Path | messages, it is expected that the locally pre-configured threshold on | |||
| Tear message for the LSP. | control plane resources is such that it allows generation of such | |||
| messages. | ||||
| The head-end LSR should trigger the computation of a new path | 4.2.2. Procedures for a Head-End LSR | |||
| avoiding the saturated node, and it may also choose to avoid the | ||||
| saturated node for future LSPs. An implementation may decide to | ||||
| signal some of its TE LSPs along the saturated node upon the | ||||
| expiration of some timer. | ||||
| The head-end should not reroute already established LSPs passing | On receipt of a PathErr message with the Error Code "Saturation" and | |||
| through the saturated node. | with the Path_State_Removed flag not set, the Head-End LSR SHOULD | |||
| send a PathTear message for the rejected LSP. | ||||
| 5. Routing extensions | 5. Routing extensions | |||
| It is obviously desirable to augment the signaling extensions by | It is desirable to augment the signaling extensions by specific link | |||
| routing notifications ([ISIS-TE], [OSPF-TE]) that would allow an LSR | state routing ([ISIS] and [OSPF]) extensions that would allow an LSR | |||
| to advertise the state of its RSVP process (saturated or not). This | to advertise the state of its RSVP process (saturated or not). This | |||
| information could then be taken into account by all LSRs (and not | information could then be taken into account by all LSRs (and not | |||
| only LSRs on the path of a rejected LSPs), in order to avoid a | only LSRs on the path of a rejected LSPs), in order to avoid a | |||
| saturated node when computing the path of a new TE-LSP, and also to | saturated node when computing the path of a new TE-LSP, and also to | |||
| automatically discover when a node is no longer saturated and | automatically discover when a node is no longer saturated. | |||
| potentially trigger appropriate TE-LSP reoptimisation. | ||||
| A new TLV is defined for OSPF and ISIS, named the ôSaturation TLVö, | A new TLV is defined for OSPF and ISIS, named the ôSaturation TLVö, | |||
| to be included in the Router Information LSA for OSPF [OSPF-CAP] and | to be included in the Router Information LSA for OSPF [OSPF-CAP] and | |||
| in the CAPABILITY TLV for ISIS [ISIS-CAP]. | in the CAPABILITY TLV for ISIS [ISIS-CAP]. | |||
| This TLV contains a set of 32 bit flags. Currently only one flag is | The TLV structure consists of a fixed 8 bit flags field. Currently 4 | |||
| defined, to indicate if the LSR is saturated or not. | flags are defined, to indicate if the LSR is saturated or not as well | |||
| as the reasons for the saturation. | ||||
| 5.1. Encoding of the Saturation TLV | 5.1. Encoding of the Saturation TLV | |||
| This document defines a new TLV, the Saturation TLV, allowing an LSR | This document defines a new TLV (named the Saturation TLV) allowing | |||
| advertising if its control plane is saturated or not, where, | an LSR advertising if its control plane is saturated or not, where, | |||
| -With OSPF, the Saturation TLV is a TLV of the Router Information | - With OSPF, the Saturation TLV is a TLV of the Router Information | |||
| LSA defined in [OSPF-CAP], and its TLV type is TBD. | LSA defined in [OSPF-CAP]. The TLV type is TBD (To be assigned | |||
| -With ISIS, the Saturation TLV is a sub-TLV of the ISIS CAPABILITY | by IANA). | |||
| TLV defined in [ISIS-CAP], and its sub-TLV type is TBD. | - With ISIS, the Saturation TLV is a sub-TLV of the ISIS | |||
| CAPABILITY TLV defined in [ISIS-CAP]. The sub-TLV type is TBD | ||||
| (To be assigned by IANA). | ||||
| All relevant generic TLV encoding rules (including TLV format, | All relevant generic TLV encoding rules (including TLV format, | |||
| padding and alignment, as well as IEEE floating point format | padding and alignment, as well as IEEE floating point format | |||
| encoding) defined in [OSPF] and [ISIS] are applicable to this new | encoding) defined in [OSPF] and [ISIS] are applicable to this new | |||
| sub-TLV. | sub-TLV. | |||
| The Saturation TLV is a series of 32 bit flags. Its format is | The Saturation TLV is a series of 8 bit flags. Its format is | |||
| illustrated below: | illustrated below: | |||
| 0 1 2 3 | 0 1 2 3 4 5 6 7 | |||
| 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 | +-+-+-+-+-+-+-+-+ | |||
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |S|C|M|N| Res | | |||
| |S| Reserved | | +-+-+-+-+-+-+-+-+ | |||
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ||||
| Four bits are currently defined: | ||||
| Only one bit is currently defined: | ||||
| -S bit: When set this indicates that the node is saturated and | -S bit: When set this indicates that the node is saturated and | |||
| cannot support new TE-LSPs. When not set this indicates that the node | cannot support any new TE-LSP. When not set this | |||
| is not saturated and can support new TE-LSPs. | indicates that the node is not saturated and can support | |||
| new TE-LSPs. | ||||
| -C bit: When set this indicates that the saturation is due to | ||||
| CPU overload. | ||||
| -M bit: When set this indicates that the saturation is due to | ||||
| memory shortage . | ||||
| -N bit: When set this indicates that the maximum number of LSPs | ||||
| allowed is reached. | ||||
| New flags may be defined in the future to indicate the reasons for | C, M or N are not exclusive. They can be set only if S is set. | |||
| the saturation. | If S is set and other flags are cleared this means that the reason | |||
| for the saturation is unspecified. | ||||
| Note that new flags may be defined in the future. | ||||
| The absence of the saturation TLV means that the saturation status is | ||||
| unspecified. | ||||
| 5.2. Elements of procedure | 5.2. Elements of procedure | |||
| A router MUST originate a new IS-IS LSP/OSPF LSA whenever a | A router SHOULD originate a new IS-IS LSP/OSPF LSA whenever a | |||
| saturation state change occurs or whenever required by the | saturation state change occurs or whenever required by the | |||
| regular IS-IS/OSPF procedure (LSP/LSA refresh). | regular IS-IS/OSPF procedure (LSP/LSA refresh). | |||
| It is expected that a proper implementation will support dampening | ||||
| algorithms so as to dampen IGP flooding, thus preserving the IGP | ||||
| scalability. | ||||
| A saturated node MUST originate LSPs/LSAs with the S bit of the | The flooding scope of this saturation state advertisement SHOULD be | |||
| Saturation TLV set. | limited to a single IGP area. This implies that this TLV SHOULD be | |||
| carried within an OSPF type 10 Router Information LSAs or within an | ||||
| ISIS CAPIBILITY TLV with the S flag cleared. | ||||
| Note that a head-end LSR computing a path of a TE-LSP should avoid | Note that a saturation satus change MAY trigger CSPF computation, but | |||
| saturated nodes. Note also that when a head-end LSR detects that a | MUST not trigger normal SPF computation. | |||
| node on the path of an already established TE-LSP, becomes saturated, | ||||
| it should not reroute this TE-LSP. | ||||
| Once an LSR leaves the saturation state, the condition of which are | 5.2.1. Procedures for a Saturated LSR | |||
| implementation specific, it MUST originate LSPs/LSAs with the S bit | ||||
| of the Saturation TLV cleared. An implementation may decide to | ||||
| originate an LSP/LSP with the S bit of its Saturation TLV cleared for | ||||
| a configurable amount of time and then decide not to include the | ||||
| saturation TLV in its LSA/LSP. | ||||
| Note that when a head-End LSR detects that an LSR is no longer | Once an LSR enters the saturation state, the conditions of which are | |||
| saturated it may try to reoptimize TE-LSPs, should the path along the | implementation specific, it SHOULD originate LSPs/LSAs with the S bit | |||
| no-longer saturated node be optimal. This procedure may be delayed, | of the Saturation TLV set and potentially with one or more "reason" | |||
| potentially using some LSP setup jittering between head-end LSRs, in | bits set. | |||
| order to avoid a signalling storm that may again saturate the node, | ||||
| that is, to avoid TE-LSP routing oscillations. | ||||
| 6. Security Considerations | Once a LSR leaves the saturation state, the conditions of which are | |||
| implementation specific, it SHOULD originate LSPs/LSAs with all bits | ||||
| of the Saturation TLV cleared. | ||||
| This document does not raise any new security issue. | 5.2.2. Procedures for a Head-End LSR | |||
| 7. Acknowledgements | A head-end LSR computing a path of a TE-LSP should avoid saturated | |||
| nodes. | ||||
| We would like to thank Thomas Morin and Bruno Decraene for the really | Note also that when a head-end LSR detects that a node on the path of | |||
| useful comments and suggestions, and Muthurajah Sivabalan, Rudy | an already established TE-LSP, becomes saturated, it should not | |||
| Figaro, David Ward, Reshad Rahman, and Stefano Previdi for their | reroute this TE-LSP. | |||
| input and contributions to the IGP extensions. | ||||
| 8. Intellectual Property Statement | Note that when a head-End LSR detects that an LSR is no longer | |||
| saturated it may re-use this LSR for establishing new TE LSPs, and | ||||
| may try to reoptimize some TE-LSPs, should the path along the no- | ||||
| longer saturated LSR be desirable. | ||||
| This procedure may be delayed, potentially using some LSP setup | ||||
| jittering between head-end LSRs, in order to avoid a signalling storm | ||||
| that may again saturate the node, that is, to avoid TE-LSP routing | ||||
| oscillations. | ||||
| The IETF takes no position regarding the validity or scope of any | Note that the procedures discussed above are local implementation | |||
| Intellectual Property Rights or other rights that might be claimed to | issues. | |||
| pertain to the implementation or use of the technology described in | ||||
| this document or the extent to which any license under such rights | ||||
| might or might not be available; nor does it represent that it has | ||||
| made any independent effort to identify any such rights. Information | ||||
| on the procedures with respect to rights in RFC documents can be | ||||
| found in BCP 78 and BCP 79. | ||||
| Copies of IPR disclosures made to the IETF Secretariat and any | 6. Inter-Provider considerations | |||
| assurances of licenses to be made available, or the result of an | ||||
| attempt made to obtain a general license or permission for the use of | ||||
| such proprietary rights by implementers or users of this | ||||
| specification can be obtained from the IETF on-line IPR repository at | ||||
| http://www.ietf.org/ipr. | ||||
| The IETF invites any interested party to bring to its attention any | For confidentially purpose in an inter-provider MPLS-TE context (see | |||
| copyrights, patents or patent applications, or other proprietary | [INTER-AS-REQ]), a provider may desire to hide to other providers, a | |||
| rights that may cover technology that may be required to implement | saturation that could occur in its own network. For that purpose an | |||
| this standard. Please address the information to the IETF at ietf- | ASBR may modify the RSVP error code/sub-code before forwarding the | |||
| ipr@ietf.org. | PathErr message to an upstream provider. For instance, if a provider | |||
| wants to hide the reason for the saturation, it should update the | ||||
| error sub-code to 1. If the provider wants to entirely hide the | ||||
| saturation, it may change the error code. Note that this is a local | ||||
| policy-based decision. | ||||
| 8.1. IPR Disclosure Acknowledgement | 7. Security Considerations | |||
| By submitting this Internet-Draft, I certify that any applicable | This document does not raise any new security issue. | |||
| patent or other IPR claims of which I am aware have been disclosed, | ||||
| or will be disclosed, and any of which I become aware will be | 8. Acknowledgements | |||
| disclosed, in accordance with RFC 3668. | ||||
| We would like to thank Thomas Morin, Bruno Decraene, Adrian Farrel, | ||||
| Arthi Ayyangar, Muthurajah Sivabalan, Rudy Figaro, David Ward, Reshad | ||||
| Rahman, and Stefano Previdi for the really useful comments and | ||||
| suggestions. | ||||
| 9. References | 9. References | |||
| 9.1. Normative references | 9.1. Normative references | |||
| [RFC] Bradner, S., 'Key words for use in RFCs to indicate | [RFC] Bradner, S., 'Key words for use in RFCs to indicate | |||
| requirements levels', RFC 2119, March 1997. | requirements levels', RFC 2119, March 1997. | |||
| [RFC3667] Bradner, S., 'IETF Rights in Contributions', BCP 78, | ||||
| RFC 3667, February 2004. | ||||
| [RFC3668] Bradner, S., Ed., 'Intellectual Property Rights in IETF | ||||
| Technology', BCP 79, RFC 3668, February 2004. | ||||
| [TE-REQ] Awduche et. al., 'Requirements for Traffic Engineering | [BCP79] Bradner, S., Ed., 'Intellectual Property Rights in IETF | |||
| over MPLS', RFC2702. | Technology', BCP 79, RFC 3979, March 2005. | |||
| [RSVP] Braden, R., Zhang, L., Berson, S., Herzog, S. and S. Jamin, | [RSVP] Braden, R., Zhang, L., Berson, S., Herzog, S. and S. Jamin, | |||
| 'Resource ReSerVation Protocol (RSVP) -- Version 1, Functional | 'Resource ReSerVation Protocol (RSVP) -- Version 1, Functional | |||
| Specification', RFC 2205, September 1997. | Specification', RFC 2205, September 1997. | |||
| [RSVP-TE] Awduche, D., Berger, L., Gan, D., Li, T., | ||||
| Srinivasan, V. and G. Swallow, 'RSVP-TE: Extensions | ||||
| to RSVP for LSP Tunnels', RFC 3209, December 2001. | ||||
| [RFC2209] Braden, R., Zhang, L., 'Resource ReSerVation Protocol | [RFC2209] Braden, R., Zhang, L., 'Resource ReSerVation Protocol | |||
| (RSVP) -- Version 1 Message Processing Rules', RFC2209, | (RSVP) -- Version 1 Message Processing Rules', RFC2209, September | |||
| September 1997. | 1997. | |||
| [ISIS] "Intermediate System to Intermediate System Intra-Domain | [RSVP-TE] Awduche, D., Berger, L., Gan, D., Li, T., | |||
| Routing Exchange Protocol " ISO 10589. | Srinivasan, V. and G. Swallow, 'RSVP-TE: Extensions to RSVP for LSP | |||
| Tunnels', RFC 3209, December 2001. | ||||
| [ISIS-TE] Smit, H., Li, T., 'Intermediate System to Intermediate | [ISIS] "Intermediate System to Intermediate System Intra-Domain | |||
| System (IS-IS)Extensions for Traffic Engineering (TE)', | Routing Exchange Protocol " ISO 10589. | |||
| RFC3784, June 2004 | ||||
| [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. | [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. | |||
| [OSPF-TE] Katz, D., Kompella, K., Yeung, D., 'Traffic Engineering | ||||
| (TE) Extensions to OSPF Version 2', RFC3630, September 2003 | ||||
| 9.2. Informative references | ||||
| [ISIS-CAP] Vasseur, J.P., Aggarwal, R., Shen, N. et al. "IS-IS | [ISIS-CAP] Vasseur, J.P., Aggarwal, R., Shen, N. et al. "IS-IS | |||
| extensions for advertising router information", draft- | extensions for advertising router information", draft-ietf-isis- | |||
| vasseur-isis-caps-02.txt, work in progress. | caps-03.txt, work in progress. | |||
| [OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur, | [OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur, | |||
| J.P., "Extensions to OSPF for advertising Optional Router | J.P., "Extensions to OSPF for advertising Optional Router | |||
| Capabilities", draft-ietf-ospf-cap-05.txt, work in progress. | Capabilities", draft-ietf-ospf-cap-07.txt, work in progress. | |||
| 9.2. Informative references | ||||
| [INTER-AS-REQ] Zhang, R., Vasseur, J.P., "MPLS Inter-AS Traffic | ||||
| Engineering requirements", draft-ietf-tewg-interas-mpls-te-req- | ||||
| 09.txt, work in progress | ||||
| 10. Authors' Address: | 10. Authors' Address: | |||
| Jean-Louis Le Roux | Jean-Louis Le Roux | |||
| France Telecom | France Telecom | |||
| 2, avenue Pierre-Marzin | 2, avenue Pierre-Marzin | |||
| 22307 Lannion Cedex | 22307 Lannion Cedex | |||
| France | France | |||
| jeanlouis.leroux@francetelecom.com | jeanlouis.leroux@francetelecom.com | |||
| skipping to change at page 10, line 8 ¶ | skipping to change at page 9, line 34 ¶ | |||
| Boxborough, MA 01719 | Boxborough, MA 01719 | |||
| USA | USA | |||
| Email: jpv@cisco.com | Email: jpv@cisco.com | |||
| Sami Boutros | Sami Boutros | |||
| Cisco Systems | Cisco Systems | |||
| 2000 Innovation Drive, Kanata, | 2000 Innovation Drive, Kanata, | |||
| Ontario, Canada K2K 3E8 | Ontario, Canada K2K 3E8 | |||
| sboutros@cisco.com | sboutros@cisco.com | |||
| Full Copyright Statement | Dimitri Papadimitriou | |||
| Alcatel | ||||
| Francis Wellensplein 1, | ||||
| B-2018 Antwerpen, Belgium | ||||
| Email: dimitri.papdimitriou@alcatel.be | ||||
| Copyright (C) The Internet Society (2005). This document is subject | 11. Intellectual Property Statement | |||
| to the rights, licenses and restrictions contained in BCP 78, and | ||||
| except as set forth therein, the authors retain all their rights. | The IETF takes no position regarding the validity or scope of any | |||
| Intellectual Property Rights or other rights that might be claimed to | ||||
| pertain to the implementation or use of the technology described in | ||||
| this document or the extent to which any license under such rights | ||||
| might or might not be available; nor does it represent that it has | ||||
| made any independent effort to identify any such rights. Information | ||||
| on the procedures with respect to rights in RFC documents can be | ||||
| found in BCP 78 and BCP 79. | ||||
| Copies of IPR disclosures made to the IETF Secretariat and any | ||||
| assurances of licenses to be made available, or the result of an | ||||
| attempt made to obtain a general license or permission for the use of | ||||
| such proprietary rights by implementers or users of this | ||||
| specification can be obtained from the IETF on-line IPR repository at | ||||
| http://www.ietf.org/ipr. | ||||
| The IETF invites any interested party to bring to its attention any | ||||
| copyrights, patents or patent applications, or other proprietary | ||||
| rights that may cover technology that may be required to implement | ||||
| this standard. Please address the information to the IETF at | ||||
| ietf-ipr@ietf.org. | ||||
| Disclaimer of Validity | ||||
| This document and the information contained herein are provided on an | This document and the information contained herein are provided on an | |||
| "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS | "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS | |||
| OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET | OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET | |||
| ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, | ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, | |||
| INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE | INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE | |||
| INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED | INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED | |||
| WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. | WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. | |||
| Copyright Statement | ||||
| Copyright (C) The Internet Society (2005). This document is subject | ||||
| to the rights, licenses and restrictions contained in BCP 78, and | ||||
| except as set forth therein, the authors retain all their rights. | ||||
| End of changes. 69 change blocks. | ||||
| 224 lines changed or deleted | 273 lines changed or added | |||
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