IS-IS Working Group | S. Litkowski |
Internet-Draft | Orange |
Intended status: Standards Track | Y. Qu |
Expires: May 7, 2017 | Cisco |
P. Sarkar | |
Individual | |
I. Chen | |
Kuatro Technologies | |
J. Tantsura | |
Individual | |
November 03, 2016 |
YANG Data Model for IS-IS Segment Routing
draft-ietf-isis-sr-yang-00
This document defines a YANG data model that can be used to configure and manage IS-IS Segment Routing ([I-D.ietf-isis-segment-routing-extensions].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
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Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.
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This Internet-Draft will expire on May 7, 2017.
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YANG [RFC6020] [RFC7950] is a data definition language used to define the contents of a conceptual data store that allows networked devices to be managed using NETCONF [RFC6241]. YANG is proving relevant beyond its initial confines, as bindings to other interfaces (e.g., ReST) and encodings other than XML (e.g., JSON) are being defined. Furthermore, YANG data models can be used as the basis for implementation of other interfaces, such as CLI and programmatic APIs.
This document defines a YANG data model that can be used to configure and manage IS-IS Segment Routing and it is an augmentation to the IS-IS YANG data model.
This document defines a model for IS-IS Segment Routing feature. It is an augmentation of the IS-IS base model.
The IS-IS SR YANG module requires support for the base segment routing module [I-D.ietf-spring-sr-yang], which defines the global segment routing configuration independent of any specific routing protocol configuration, and support of IS-IS base model [I-D.ietf-isis-yang-isis-cfg] which defines basic IS-IS configuration and state.
The figure below describes the overall structure of the isis-sr YANG module:
module: ietf-isis-sr augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis: +--rw segment-routing | +--rw enabled? boolean | +--rw bindings | +--rw advertise | | ... | +--rw receive? boolean +--rw protocol-srgb {sr:protocol-srgb}? +--rw srgb* [lower-bound upper-bound] +--rw lower-bound uint32 +--rw upper-bound uint32 augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:interfaces/isis:interface: +--rw segment-routing +--rw adjacency-sid +--rw advertise-adj-group-sid* [group-id] | ... +--rw advertise-protection? enumeration augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:interfaces/isis:interface/isis:fast-reroute: +--rw ti-lfa {ti-lfa}? +--rw enable? boolean augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:interfaces/isis:interface/isis:fast-reroute/isis:lfa/isis:remote-lfa: +--rw use-segment-routing-path? boolean {remote-lfa-sr}? augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis: +--ro segment-routing | +--ro enabled? boolean | +--ro bindings | +--ro advertise | | ... | +--ro receive? boolean +--ro protocol-srgb {sr:protocol-srgb}? +--ro srgb* [lower-bound upper-bound] +--ro lower-bound uint32 +--ro upper-bound uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:interfaces/isis:interface: +--ro segment-routing +--ro adjacency-sid +--ro advertise-adj-group-sid* [group-id] | ... +--ro advertise-protection? enumeration augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:interfaces/isis:interface/isis:adjacencies/isis:adjacency: +--ro adjacency-sid* [value] +--ro af? identityref +--ro value uint32 +--ro weight? uint8 +--ro protection-requested? boolean augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:extended-is-neighbor/isis:neighbor: +--ro sid-list* [value] +--ro flags? bits +--ro weight? uint8 +--ro neighbor-id? isis:system-id +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:mt-is-neighbor/isis:neighbor: +--ro sid-list* [value] +--ro flags? bits +--ro weight? uint8 +--ro neighbor-id? isis:system-id +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:extended-ipv4-reachability/isis:prefixes: +--ro sid-list* [value] +--ro flags? bits +--ro algorithm? uint8 +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:mt-extended-ipv4-reachability/isis:prefixes: +--ro sid-list* [value] +--ro flags? bits +--ro algorithm? uint8 +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:ipv6-reachability/isis:prefixes: +--ro sid-list* [value] +--ro flags? bits +--ro algorithm? uint8 +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp/isis:mt-ipv6-reachability/isis:prefixes: +--ro sid-list* [value] +--ro flags? bits +--ro algorithm? uint8 +--ro value uint32 augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-protocol/isis:isis/isis:database/isis:level-db/isis:lsp: +--ro segment-routing-bindings* [fec range] +--ro fec string +--ro range uint16 +--ro flags? bits +--ro weight? uint8 +--ro binding +--ro prefix-sid | ... +--ro ero-metric? uint32 +--ro ero | ... +--ro backup-ero | ... +--ro unnumbered-interface-id-ero | ... +--ro backup-unnumbered-interface-id-ero ...
Activation of segment-routing IS-IS is done by setting the "enable" leaf to true. This triggers advertisement of segment-routing extensions based on the configuration parameters that have been setup using the base segment routing module.
The base segment routing module defines mapping server policies. By default, IS-IS will not advertise nor receive any mapping server entry. The IS-IS segment-routing module allows to advertise one or multiple mapping server policies through the "bindings/advertise/policies" leaf-list. The "bindings/receive" leaf allows to enable the reception of mapping server entries.
IS-IS SR model augments the fast-reroute container under interface. It brings the ability to activate TI-LFA (topology independent LFA) and also enhances remote LFA to use segment-routing tunneling instead of LDP.
<CODE BEGINS> file "ietf-isis-sr@2016-11-03.yang" module ietf-isis-sr { namespace "urn:ietf:params:xml:ns:" + "yang:ietf-isis-sr"; prefix isis-sr; import ietf-routing { prefix "rt"; } import ietf-segment-routing-common { prefix "sr-cmn"; } import ietf-segment-routing { prefix "sr"; } import ietf-isis { prefix "isis"; } organization "IETF ISIS Working Group"; contact "WG List: <mailto:spring@ietf.org> Editor: Stephane Litkowski <mailto:stephane.litkowski@orange.com> Acee Lindem <mailto:acee@cisco.com> Yingzhen Qu <mailto:yiqu@cisco.com> Pushpasis Sarkar <mailto:pushpasis.ietf@gmail.com> Ing-Wher Chen <mailto:ichen@kuatrotech.com> Jeff Tantsura <mailto:jefftant.ietf@gmail.com> "; description "The YANG module defines a generic configuration model for Segment routing ISIS extensions common across all of the vendor implementations."; revision 2016-11-03 { description "Initial revision."; reference "RFC XXXX"; } /* Identities */ /* Features */ feature remote-lfa-sr { description "Enhance rLFA to use SR path."; } feature ti-lfa { description "Enhance IPFRR with ti-lfa support"; } /* Groupings */ grouping adjacency-state { description "This group will extend adjacency state."; list adjacency-sid { key value; leaf af { type identityref { base rt:address-family; } description "Address-family associated with the segment ID"; } leaf value { type uint32; description "Value of the Adj-SID."; } leaf weight { type uint8; description "Weight associated with the adjacency SID."; } leaf protection-requested { type boolean; description "Describe if the adjacency SID must be protected."; } description "List of adjacency Segment IDs."; } } grouping prefix-segment-id { description "This group defines segment routing extensions for prefixes."; list sid-list { key value; leaf flags { type bits { bit readvertisment { position 7; description "If set, then the prefix to which this Prefix-SID is attached, has been propagated by the router either from another level or from redistribution."; } bit php { position 5; description "If set, then the penultimate hop MUST NOT pop the Prefix-SID before delivering the packet to the node that advertised the Prefix-SID."; } bit explicit-null { position 4; description "If set, any upstream neighbor of the Prefix-SID originator MUST replace the Prefix-SID with a Prefix-SID having an Explicit-NULL value (0 for IPv4 and 2 for IPv6) before forwarding the packet."; } bit value { position 3; description "If set, then the Prefix-SID carries a value (instead of an index). By default the flag is UNSET."; } bit local { position 2; description "If set, then the value/index carried by the Prefix-SID has local significance. By default the flag is UNSET."; } } description "Describes flags associated with the segment ID."; } leaf algorithm { type uint8; description "Algorithm to be used for path computation."; } leaf value { type uint32; description "Value of the prefix-SID."; } description "List of segments."; } } grouping adjacency-segment-id { description "This group defines segment routing extensions for adjacencies."; list sid-list { key value; leaf flags { type bits { bit address-family { position 7; description "If unset, then the Adj-SID refers to an adjacency with outgoing IPv4 encapsulation. If set then the Adj-SID refers to an adjacency with outgoing IPv6 encapsulation."; } bit backup { position 6; description "If set, the Adj-SID refers to an adjacency being protected (e.g.: using IPFRR or MPLS-FRR)"; } bit value { position 5; description "If set, then the SID carries a value (instead of an index). By default the flag is SET."; } bit local { position 4; description "If set, then the value/index carried by the SID has local significance. By default the flag is SET."; } bit set { position 3; description "When set, the S-Flag indicates that the Adj-SID refers to a set of adjacencies"; } } description "Describes flags associated with the segment ID."; } leaf weight { type uint8; description "The value represents the weight of the Adj-SID for the purpose of load balancing."; } leaf neighbor-id { type isis:system-id; description "Describes the system ID of the neighbor associated with the SID value. This is only used on LAN adjacencies."; } leaf value { type uint32; description "Value of the Adj-SID."; } description "List of segments."; } } grouping segment-routing-binding-tlv { list segment-routing-bindings { key "fec range"; leaf fec { type string; description "IP (v4 or v6) range to be bound to SIDs."; } leaf range { type uint16; description "Describes number of elements to assign a binding to."; } leaf flags { type bits { bit address-family { position 7; description "If unset, then the Prefix FEC carries an IPv4 Prefix. If set then the Prefix FEC carries an IPv6 Prefix."; } bit mirror { position 6; description "Set if the advertised SID/path corresponds to a mirrored context. "; } bit flooding { position 5; description "If the S bit is set(1), the IS-IS Router CAPABILITY TLV MUST be flooded across the entire routing domain. If the S bit is not set(0), the TLV MUST NOT be leaked between levels. This bit MUST NOT be altered during the TLV leaking."; } bit down { position 4; description "When the IS-IS Router CAPABILITY TLV is leaked from level-2 to level-1, the D bit MUST be set. Otherwise, this bit MUST be clear. IS-IS Router capability TLVs with the D bit set MUST NOT be leaked from level-1 to level-2. This is to prevent TLV looping. "; } bit attached { position 3; description "The originator of the SID/Label Binding TLV MAY set the A bit in order to signal that the prefixes and SIDs advertised in the SID/Label Binding TLV are directly connected to their originators. "; } } description "Flags of the binding."; } leaf weight { type uint8; description "Weight of the path for loadbalancing purpose."; } container binding { container prefix-sid { uses prefix-segment-id; description "Binding prefix SID to the range."; } leaf ero-metric { type uint32; description "Cost of ERO path."; } container ero { leaf address-family { type identityref { base rt:address-family; } description "Address-family."; } leaf loose { type boolean; description "Set to true, if hop is a loose hop."; } leaf address { type string; description "IP address of a node on the path."; } description "Binding ERO path to the range."; } container backup-ero { leaf address-family { type identityref { base rt:address-family; } description "Address-family."; } leaf loose { type boolean; description "Set to true, if hop is a loose hop."; } leaf address { type string; description "IP address of a node on the path."; } description "Binding backup ERO path to the range."; } container unnumbered-interface-id-ero { leaf router-id { type string; description "Router ID of the node owning the interface."; } leaf interface-id { type uint32; description "Interface ID on which the path is built."; } description "Binding a path over unnumbered interface."; } container backup-unnumbered-interface-id-ero { leaf router-id { type string; description "Router ID of the node owning the interface."; } leaf interface-id { type uint32; description "Interface ID on which the path is built."; } description "Binding a backup path over unnumbered interface."; } description "Bindings associated with the range."; } description "This container describes list of SID/Label bindings. ISIS reference is TLV 149."; } description "Defines binding TLV for database."; } /* Cfg */ augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis" { when "/rt:routing/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses sr:controlplane-cfg; container protocol-srgb { if-feature sr:protocol-srgb; uses sr-cmn:srgb-cfg; description "Per-protocol SRGB."; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:interfaces/isis:interface" { when "/rt:routing/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses sr:igp-interface-cfg; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:interfaces/isis:interface"+ "/isis:fast-reroute" { when "/rt:routing/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS IP FRR with TILFA."; container ti-lfa { if-feature ti-lfa; leaf enable { type boolean; description "Enables TI-LFA computation."; } description "TILFA configuration."; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:interfaces/isis:interface"+ "/isis:fast-reroute/isis:lfa/isis:remote-lfa" { when "/rt:routing/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS remoteLFA config with use of segment-routing path."; leaf use-segment-routing-path { if-feature remote-lfa-sr; type boolean; description "force remote LFA to use segment routing path instead of LDP path."; } } /* Operational states */ augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses sr:controlplane-cfg; container protocol-srgb { if-feature sr:protocol-srgb; uses sr-cmn:srgb-cfg; description "Per-protocol SRGB."; } } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:interfaces/isis:interface" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses sr:igp-interface-cfg; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:interfaces/isis:interface" + "/isis:adjacencies/isis:adjacency" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses adjacency-state; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:extended-is-neighbor/isis:neighbor" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB neighbor."; uses adjacency-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:mt-is-neighbor/isis:neighbor" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB neighbor."; uses adjacency-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:extended-ipv4-reachability/isis:prefixes" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:mt-extended-ipv4-reachability/isis:prefixes" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:ipv6-reachability/isis:prefixes" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp"+ "/isis:mt-ipv6-reachability/isis:prefixes" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-segment-id; } augment "/rt:routing-state/" + "rt:control-plane-protocols/rt:control-plane-protocol"+ "/isis:isis/isis:database/isis:level-db/isis:lsp" { when "/rt:routing-state/rt:control-plane-protocols/"+ "rt:control-plane-protocol/rt:type = 'isis:isis'" { description "This augment ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB."; uses segment-routing-binding-tlv; } /* Notifications */ } <CODE ENDS>
Configuration and state data defined in this document are designed to be accessed via the NETCONF protocol [RFC6241].
As IS-IS is an IGP protocol (critical piece of the network), ensuring stability and security of the protocol is mandatory for the network service.
Authors recommends to implement NETCONF access control model ([RFC6536]) to restrict access to all or part of the configuration to specific users.
Authors would like to thank Derek Yeung, Acee Lindem, Yi Yang for their major contributions to the draft.
TBD.
The IANA is requested to assign two new URIs from the IETF XML registry ([RFC3688]). Authors are suggesting the following URI:
URI: urn:ietf:params:xml:ns:yang:ietf-isis-sr Registrant Contact: IS-IS WG XML: N/A, the requested URI is an XML namespace
This document also requests one new YANG module name in the YANG Module Names registry ([RFC6020]) with the following suggestion :
name: ietf-isis-sr namespace: urn:ietf:params:xml:ns:yang:ietf-isis-sr prefix: isis-sr reference: RFC XXXX
[I-D.ietf-isis-segment-routing-extensions] | Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., Litkowski, S., Decraene, B. and j. jefftant@gmail.com, "IS-IS Extensions for Segment Routing", Internet-Draft draft-ietf-isis-segment-routing-extensions-09, October 2016. |
[I-D.ietf-isis-yang-isis-cfg] | Litkowski, S., Yeung, D., Lindem, A., Zhang, Z. and L. Lhotka, "YANG Data Model for IS-IS protocol", Internet-Draft draft-ietf-isis-yang-isis-cfg-13, October 2016. |
[I-D.ietf-spring-sr-yang] | Litkowski, S., Qu, Y., Sarkar, P. and J. Tantsura, "YANG Data Model for Segment Routing", Internet-Draft draft-ietf-spring-sr-yang-05, October 2016. |
[RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
[RFC3688] | Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004. |
[RFC6020] | Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010. |
[RFC6241] | Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011. |
[RFC6536] | Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012. |
[RFC7950] | Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016. |