ISIS Working Group S. Litkowski Internet-Draft Orange Intended status: Standards Track June 27, 2014 Expires: December 29, 2014 Yang Data Model for ISIS protocol draft-litkowski-isis-yang-isis-cfg-01 Abstract This document defines a YANG data model that can be used to configure and manage ISIS protocol. Requirements Language 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]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 29, 2014. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must Litkowski Expires December 29, 2014 [Page 1] Internet-Draft isis-cfg June 2014 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Tree diagram . . . . . . . . . . . . . . . . . . . . . . 2 2. Design of the data model . . . . . . . . . . . . . . . . . . 3 2.1. ISIS configuration . . . . . . . . . . . . . . . . . . . 5 2.2. Multitopology parameters . . . . . . . . . . . . . . . . 5 2.3. Per level parameters . . . . . . . . . . . . . . . . . . 5 2.4. Per interface parameters . . . . . . . . . . . . . . . . 6 2.5. Operational states . . . . . . . . . . . . . . . . . . . 7 3. RPC operations . . . . . . . . . . . . . . . . . . . . . . . 8 4. Notifications . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Interaction with other YANG modules . . . . . . . . . . . . . 9 6. Yang module . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 45 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 46 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46 10. Normative References . . . . . . . . . . . . . . . . . . . . 46 Appendix A. Example: NETCONF Reply . . . . . . . . . . . . 47 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 53 1. Introduction This document defines a YANG data model for ISIS routing protocol. The data model covers configuration of an ISIS routing protocol instance as well as operational states. 1.1. Tree diagram A simplified graphical representation of the data model is presented in Section 2. The meaning if the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. o Symbols after data node names: "?" means an optional node, "!" means a presence container, and "*" denotes a list and leaf-list. o Abbreviations before data node names: "rw" means configuration data (read-write), and "ro" means state data (read-only). o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). Litkowski Expires December 29, 2014 [Page 2] Internet-Draft isis-cfg June 2014 o Ellipsis ("...") stands for contents of subtrees that are not shown. 2. Design of the data model The ISIS Yang module is divided in two main containers : o isis-cfg : that contains writable configuration objects. o isis-state : that contains read-only states. The container isis-cfg and isis-state are augmenting the "routing- protocol" lists in ietf-routing module with specific ISIS parameters. The figure below describe the overall structure of the isis Yang module : module: isis augment /rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route: +--ro metric? uint32 +--ro tag* uint32 +--ro route-type? enumeration augment /rt:active-route/rt:output/rt:route: +--ro metric? uint32 +--ro tag* uint32 +--ro route-type? enumeration augment /rt:routing/rt:routing-instance/rt:routing-protocols/rt:routing-protocol: +--rw isis +--rw isis-level? isis-level +--rw nsap-address simple-iso-address +--rw ipv4-router-id? inet:ipv4-address +--rw ipv6-router-id? inet:ipv6-address +--rw reference-bandwidth? uint32 +--rw lsp-mtu? uint16 +--rw lsp-lifetime? uint16 +--rw lsp-refresh? uint16 +--rw psnp-authentication? boolean +--rw csnp-authentication? boolean +--rw hello-authentication? boolean +--rw authentication-key? string +--rw authentication-type? enumeration +--rw isis-multi-topology-cfg | ... +--rw isis-level-1-cfg | ... Litkowski Expires December 29, 2014 [Page 3] Internet-Draft isis-cfg June 2014 +--rw isis-level-2-cfg | ... +--rw overload | +--rw status? boolean | +--rw timeout? uint16 +--rw interfaces +--rw interface* [name] ... augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/rt:routing-protocol: +--ro isis-state +--ro adjacencies | +--ro adjacency* [interface] | +--ro interface string | +--ro level? isis-level | +--ro state? enumeration +--ro spf-log | +--ro event* [id] | +--ro id uint32 | +--ro spf-type? enumeration | +--ro level? isis-level | +--ro spf-delay? uint32 | +--ro schedule-timestamp? yang:timestamp | +--ro start-timestamp? yang:timestamp | +--ro end-timestamp? yang:timestamp | +--ro trigger-lsp* [lsp] | +--ro lsp isis-lsp-id | +--ro sequence? uint32 +--ro lsp-log | +--ro event* [id] | +--ro id uint32 | +--ro level? isis-level | +--ro lsp | | +--ro lsp? isis-lsp-id | | +--ro sequence? uint32 | +--ro received-timestamp? yang:timestamp +--ro database | +--ro level-1 | ... | +--ro level-2 | ... +--ro hostnames +--ro hostname* [system-id] +--ro system-id isis-system-id +--ro hostname? string Litkowski Expires December 29, 2014 [Page 4] Internet-Draft isis-cfg June 2014 2.1. ISIS configuration The ISIS configuration container is divided in : o Global parameters. o Level specific parameters (see Section 2.3). o Per interface configuration (see Section 2.4). 2.2. Multitopology parameters The multitopology section is used to enable support of MT extensions for specific address families. A boolean is associated with each topology type, defining if the topology is enabled or not. +--rw isis-multi-topology-cfg | +--rw ipv4-unicast? boolean | +--rw ipv6-unicast? boolean | +--rw ipv4-multicast? boolean | +--rw ipv6-multicast? boolean 2.3. Per level parameters The level parameter section of the ISIS instance describes the global parameters for level 1 and 2 including authentication, protocol preferences, default metrics ... Level specific parameters override parameters contained directly under isis-cfg container. Litkowski Expires December 29, 2014 [Page 5] Internet-Draft isis-cfg June 2014 +--rw isis-level-1-cfg | +--rw enabled? boolean | +--rw psnp-authentication? boolean | +--rw csnp-authentication? boolean | +--rw hello-authentication? boolean | +--rw authentication-key? string | +--rw authentication-type? enumeration | +--rw metric-type? enumeration | +--rw preference? uint8 | +--rw external-preference? uint8 | +--rw default-ipv4-unicast-metric? isis-wide-metric | +--rw default-ipv6-unicast-metric? isis-wide-metric | +--rw default-ipv4-multicast-metric? isis-wide-metric | +--rw default-ipv6-multicast-metric? isis-wide-metric +--rw isis-level-2-cfg | +--rw enabled? boolean | +--rw psnp-authentication? boolean | +--rw csnp-authentication? boolean | +--rw hello-authentication? boolean | +--rw authentication-key? string | +--rw authentication-type? enumeration | +--rw metric-type? enumeration | +--rw preference? uint8 | +--rw external-preference? uint8 | +--rw default-ipv4-unicast-metric? isis-wide-metric | +--rw default-ipv6-unicast-metric? isis-wide-metric | +--rw default-ipv4-multicast-metric? isis-wide-metric | +--rw default-ipv6-multicast-metric? isis-wide-metric 2.4. Per interface parameters The per-interface section of the ISIS instance describes the interface specific parameters. Each interface has interface-specific parameters and level-specific parameters. A level-specific parameter always override interface- specific parameter and an interface-specific parameter always override an isis global parameter (defined in isis-cfg). +--rw interfaces +--rw interface* [name] +--rw name leafref +--rw level? isis-level +--rw lsp-interval? uint16 +--rw passive? boolean +--rw csnp-interval? uint16 +--rw hello-authentication-type? enumeration +--rw hello-authentication-key? string Litkowski Expires December 29, 2014 [Page 6] Internet-Draft isis-cfg June 2014 +--rw hello-interval? uint16 +--rw hello-multiplier? uint16 +--rw hello-padding? boolean +--rw ipv4-unicast? boolean +--rw ipv6-unicast? boolean +--rw ipv4-multicast? boolean +--rw ipv6-multicast? boolean +--rw interface-type? enumeration +--rw enabled? boolean +--rw tag* uint32 +--rw level-1 | +--rw hello-authentication-type? enumeration | +--rw hello-authentication-key? string | +--rw hello-interval? uint16 | +--rw hello-multiplier? uint16 | +--rw ipv4-unicast? boolean | +--rw ipv6-unicast? boolean | +--rw ipv4-multicast? boolean | +--rw ipv6-multicast? boolean | +--rw priority? uint8 | +--rw ipv4-unicast-metric? isis-wide-metric | +--rw ipv6-unicast-metric? isis-wide-metric | +--rw ipv4-multicast-metric? isis-wide-metric | +--rw ipv6-multicast-metric? isis-wide-metric | +--rw passive? boolean +--rw level-2 +--rw hello-authentication-type? enumeration +--rw hello-authentication-key? string +--rw hello-interval? uint16 +--rw hello-multiplier? uint16 +--rw ipv4-unicast? boolean +--rw ipv6-unicast? boolean +--rw ipv4-multicast? boolean +--rw ipv6-multicast? boolean +--rw priority? uint8 +--rw ipv4-unicast-metric? isis-wide-metric +--rw ipv6-unicast-metric? isis-wide-metric +--rw ipv4-multicast-metric? isis-wide-metric +--rw ipv6-multicast-metric? isis-wide-metric +--rw passive? boolean 2.5. Operational states isis-state container provides operational states for ISIS. This container is divided in multiple components : o adjacencies : provides state information about current ISIS adjacencies. Litkowski Expires December 29, 2014 [Page 7] Internet-Draft isis-cfg June 2014 o spf-log : provides information about SPF events on the node. o lsp-log : provides information about LSP events on the node (reception of an LSP or modification of local LSP). o database : provides details on current LSDB. o hostname : provides information about system-id to hostname mappings. 3. RPC operations The "ietf-isis" module defines two RPC operations : o clear-isis-database : reset the content of a particular ISIS database and restart database synchronization with the neighbors. o clear-isis-adjacency : restart a particular set of ISIS adjacencies. rpcs: +---x clear-isis-adjacency | +--ro input | +--ro routing-instance-name rt:routing-instance-state-ref | +--ro routing-protocol-instance-name isis-instance-state-ref | +--ro isis-level? isis-level | +--ro interface? string +---x clear-isis-database +--ro input +--ro routing-instance-name rt:routing-instance-state-ref +--ro routing-protocol-instance-name isis-instance-state-ref +--ro isis-level? isis-level 4. Notifications The "ietf-isis" module a new notification "isis-adjacency-updown". This notification is triggered when an ISIS adjacency moves to Up or Down state. This notification provides details on the affected adjacency and its new state. Litkowski Expires December 29, 2014 [Page 8] Internet-Draft isis-cfg June 2014 notifications: +---n isis-adjacency-updown +--ro interface? string +--ro neighbor? string +--ro neighbor-system-id? isis-system-id +--ro isis-level? isis-level +--ro state? enumeration +--ro reason? string 5. Interaction with other YANG modules The "isis-cfg" container augments the "/rt:routing/rt:routing- instance/rt:routing-protocols/routing-protocol" container of the ietf-routing module by defining ISIS specific parameters. The "isis-state" container augments the "/rt:routing-state/ rt:routing-instance/rt:routing-protocols/routing-protocol" container of the ietf-routing module by defining ISIS specific operational states. Some ISIS specific routes attributes are added to route objects of the ietf-routing module by augmenting "/rt:routing- state/rt:ribs/rt:rib/rt:routes/rt:route" and "/rt:active- route/rt:output/rt:route". 6. Yang module file "ietf-isis@2014-06-25.yang" module ietf-isis { namespace "urn:ietf:params:xml:ns:yang:ietf-isis"; prefix isis; import ietf-routing { prefix "rt"; } import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; } organization "IETF ISIS Working Group"; Litkowski Expires December 29, 2014 [Page 9] Internet-Draft isis-cfg June 2014 contact "WG List: Editor: Stephane Litkowski "; description "The YANG module defines a generic configuration model for ISIS common across all of the vendor implementations."; revision 2014-06-25 { description " * isis-cfg renamed to isis. * Add precisions on authentication-keys in description "; reference "draft-litkowski-isis-yang-isis-01"; } revision 2014-06-20 { description " * isis-op renamed to isis-state. * Multiple instances under isis are removed. * interface-cfg grouping removed and content is directly included in container isis. * TLVxx renamed with human-readable name in isis-database. TLV reference are putted in description. * Reference to core routing module were fixed. * Namespace fixed. * Add simple-iso-address type. * area-id and system-id in isis container are merged to nsap-address. * Add isis-system-id type. * Add isis-lsp-id type. * Add remaining-lifetime leaf in isis-database. * Add TLV2 (is-neighbor) in isis-database. * Renamed some container name for consistency reason ('isis-' prefixed). * Add new identities isis-cfg and isis-state. * Add descriptions. * Add notification isis-adjacency-updown. * Add RPC clear-isis-adjacency and clear-isis-database. "; reference "draft-litkowski-isis-yang-isis-00"; } revision 2014-06-11 { description "Initial revision."; Litkowski Expires December 29, 2014 [Page 10] Internet-Draft isis-cfg June 2014 reference "draft-litkowski-netmod-isis-cfg-00"; } identity isis { base rt:routing-protocol; description "Identity for the ISIS routing protocol."; } identity isis-state { description "Identity for the ISIS routing protocol operational states."; } identity isis-adjacency-updown { description "Identity for the ISIS routing protocol adjacency state."; } identity clear-isis-database { description "Identity for the ISIS routing protocol database reset action."; } identity clear-isis-adjacency { description "Identity for the ISIS routing protocol adjacency reset action."; } typedef isis-instance-state-ref { type leafref { path "/rt:routing-state/rt:routing-instance/" +"rt:routing-protocols/rt:routing-protocol/rt:name"; } description "This type is used for leafs that reference state data of an ISIS protocol instance."; } typedef isis-level { type enumeration { enum "level-1" { description "This enum describes L1 only capability."; } enum "level-2" { description "This enum describes L2 only capability."; } Litkowski Expires December 29, 2014 [Page 11] Internet-Draft isis-cfg June 2014 enum "level-1-2" { description "This enum describes both level capability."; } } description "This type defines ISIS level of an object."; } typedef isis-lsp-id { type string { pattern '[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]' +'{4}\.[0-9][0-9]-[0-9][0-9]'; } description "This type defines isis LSP ID using pattern, system id looks like : 0143.0438.AeF0.02-01"; } typedef simple-iso-address { type string { pattern '[0-9A-Fa-f]{2}\.([0-9A-Fa-f]{4}\.){0,3}' +'[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.' +'[0-9][0-9]'; } description "This type defines simple iso address format, it looks like : area_id.systemid.nsel The area ID is at least 1 byte of AFI, and is up to 13 bytes."; } typedef isis-system-id { type string { pattern '[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.00'; } description "This type defines isis system id using pattern, system id looks like : 0143.0438.AeF0.00"; } typedef isis-wide-metric { type uint32 { range "0 .. 16777215"; } description Litkowski Expires December 29, 2014 [Page 12] Internet-Draft isis-cfg June 2014 "This type defines wide style format of ISIS metric."; } typedef isis-std-metric { type uint8 { range "0 .. 63"; } description "This type defines old style format of ISIS metric."; } grouping isis-route-content { description "This group add isis-specific route properties."; leaf metric { type uint32; description "This leaf describes isis metric of a route."; } leaf-list tag { type uint32; description "This leaf describes list of tags associated with the route."; } leaf route-type { type enumeration { enum l2-up-internal { description "Level 2 internal route and not leaked to a lower level"; } enum l1-up-internal { description "Level 1 internal route and not leaked to a lower level"; } enum l2-up-external { description "Level 2 external route and not leaked to a lower level"; } enum l1-up-external { description "Level 1 external route and not leaked to a lower level"; } enum l2-down-internal { description "Level 2 internal route and leaked to a lower level"; Litkowski Expires December 29, 2014 [Page 13] Internet-Draft isis-cfg June 2014 } enum l1-down-internal { description "Level 1 internal route and leaked to a lower level"; } enum l2-down-external { description "Level 2 external route and leaked to a lower level"; } enum l1-down-external { description "Level 1 external route and leaked to a lower level"; } } description "This leaf describes the type of isis route."; } } augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route" { when "rt:source-protocol = 'isis:isis'" { description "ISIS-specific route attributes."; } uses isis-route-content; description "This augments route object in RIB with ISIS-specific attributes."; } augment "/rt:active-route/rt:output/rt:route" { uses isis-route-content; description "ISIS-specific route attributes."; } grouping isis-prefix-ipv4-std { description "This group defines attributes of an IPv4 standard prefix."; leaf up-down { type boolean; description "This leaf expresses the value of up/down bit."; } leaf i-e { type boolean; description Litkowski Expires December 29, 2014 [Page 14] Internet-Draft isis-cfg June 2014 "This leaf expresses the value of I/E bit."; } leaf ip-prefix { type inet:ipv4-address; description "This leaf describes the IPv4 prefix"; } leaf prefix-len { type uint8; description "This leaf describes the IPv4 prefix len in bits"; } leaf default-metric { type isis-std-metric; description "This leaf describes the isis default metric value"; } container delay-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description "This leaf describes if the metric is supported."; } description "This container defines the ISIS delay metric."; } container expense-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description "This leaf describes if the metric is supported."; } description "This container defines the ISIS expense metric."; } Litkowski Expires December 29, 2014 [Page 15] Internet-Draft isis-cfg June 2014 container error-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description "This leaf describes if the metric is supported."; } description "This container defines the ISIS error metric."; } } grouping isis-prefix-ipv4-extended { description "This group defines attributes of an IPv4 extended prefix."; leaf up-down { type boolean; description "This leaf expresses the value of up/down bit."; } leaf ip-prefix { type inet:ipv4-address; description "This leaf describes the IPv4 prefix"; } leaf prefix-len { type uint8; description "This leaf describes the IPv4 prefix len in bits"; } leaf metric { type isis-wide-metric; description "This leaf describes the isis metric value"; } leaf-list tag { type uint32; description "This leaf describes a list of tags associated with the prefix."; Litkowski Expires December 29, 2014 [Page 16] Internet-Draft isis-cfg June 2014 } } grouping isis-prefix-ipv6-extended { description "This group defines attributes of an IPv6 prefix."; leaf up-down { type boolean; description "This leaf expresses the value of up/down bit."; } leaf ip-prefix { type inet:ipv6-address; description "This leaf describes the IPv6 prefix"; } leaf prefix-len { type uint8; description "This leaf describes the IPv4 prefix len in bits"; } leaf metric { type isis-wide-metric; description "This leaf describes the isis metric value"; } leaf-list tag { type uint32; description "This leaf describes a list of tags associated with the prefix."; } } grouping isis-neighbor-extended { description "This group defines attributes of an ISIS extended neighbor."; leaf neighbor-id { type isis-system-id; description "This leaf describes the system-id of the neighbor."; } leaf metric { type isis-wide-metric; description Litkowski Expires December 29, 2014 [Page 17] Internet-Draft isis-cfg June 2014 "This leaf describes the isis metric value"; } } grouping isis-neighbor { description "This group defines attributes of an ISIS standard neighbor."; leaf neighbor-id { type isis-system-id; description "This leaf describes the system-id of the neighbor."; } leaf i-e { type boolean; description "This leaf expresses the value of I/E bit."; } leaf default-metric { type isis-std-metric; description "This leaf describes the isis default metric value"; } container delay-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description "This leaf describes if the metric is supported."; } description "This container defines the ISIS delay metric."; } container expense-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description Litkowski Expires December 29, 2014 [Page 18] Internet-Draft isis-cfg June 2014 "This leaf describes if the metric is supported."; } description "This container defines the ISIS expense metric."; } container error-metric { leaf metric { type isis-std-metric; description "This leaf describes the isis delay metric value"; } leaf supported { type boolean; default "false"; description "This leaf describes if the metric is supported."; } description "This container defines the ISIS error metric."; } } grouping isis-database { description "This group defines attributes of an ISIS database (Link State DB)."; leaf lsp-id { type isis-lsp-id; description "This leaf describes the LSP ID of the LSP."; } leaf checksum { type uint16; description "This leaf describes the checksum of the LSP."; } leaf remaining-lifetime { type uint16; units "seconds"; description "This leaf describes the remaining lifetime in seconds before the LSP expiration."; } leaf sequence { type uint32; description "This leaf describes the sequence number of the LSP."; } Litkowski Expires December 29, 2014 [Page 19] Internet-Draft isis-cfg June 2014 leaf attributes { type bits { bit PARTITIONNED { description "If set, the originator supports partition repair."; } bit ATTACHED-ERROR { description "If set, the originator is attached to another area using the refered metric."; } bit ATTACHED-EXPENSE { description "If set, the originator is attached to another area using the refered metric."; } bit ATTACHED-DELAY { description "If set, the originator is attached to another area using the refered metric."; } bit ATTACHED-DEFAULT { description "If set, the originator is attached to another area using the refered metric."; } bit OVERLOAD { description "If set, the originator is overloaded, and must be avoided in path calculation."; } } description "This leaf describes attributes of the LSP."; } container is-neighbor { list neighbor { key "neighbor-id"; uses isis-neighbor-extended; description "List of neighbors."; } description "This leaf describes list of ISIS extended neighbors. ISIS reference is TLV 2."; } Litkowski Expires December 29, 2014 [Page 20] Internet-Draft isis-cfg June 2014 container authentication { leaf authentication-type { type uint8; description "This leaf describes the authentication type to be used."; } leaf authentication-key { type string; description "This leaf describes the authentication key to be used. For security reason, the authentication key MUST NOT be presented in plaintext format. Authors recommends to use MD5 hash to present the authentication-key."; } description "This container describes authentication information of the node. ISIS reference is TLV 10."; } container extended-is-neighbor { list neighbor { key "neighbor-id"; uses isis-neighbor-extended; description "List of neighbors."; } description "This container describes list of ISIS extended neighbors. ISIS reference is TLV 22."; } container ipv4-internal-reachability { list prefixes { key "ip-prefix"; uses isis-prefix-ipv4-std; description "List of prefixes."; } description "This container describes list of ipv4 internal reachability information. ISIS reference is TLV 128."; } leaf-list protocol-supported { type uint8; Litkowski Expires December 29, 2014 [Page 21] Internet-Draft isis-cfg June 2014 description "This leaf describes the list of supported protocols. ISIS reference is TLV 129."; } container ipv4-external-reachability { list prefixes { key "ip-prefix"; uses isis-prefix-ipv4-std; description "List of prefixes."; } description "This container describes list of ipv4 external reachability information. ISIS reference is TLV 130."; } leaf-list ipv4-addresses { type inet:ipv4-address; description "This leaf describes the ipv4 addresses of the node. ISIS reference is TLV 132."; } leaf ipv4-te-routerid { type inet:ipv4-address; description "This leaf describes the IPv4 Traffic Engineering router ID of the node. ISIS reference is TLV 134."; } container extended-ipv4-reachability { list prefixes { key "ip-prefix"; uses isis-prefix-ipv4-extended; description "List of prefixes."; } description "This container describes list of ipv4 extended reachability information. ISIS reference is TLV 135."; } Litkowski Expires December 29, 2014 [Page 22] Internet-Draft isis-cfg June 2014 leaf dynamic-hostname { type string; description "This leaf describes the name of the node. ISIS reference is TLV 137."; } leaf ipv6-te-routerid { type inet:ipv6-address; description "This leaf describes the IPv6 Traffic Engineering router ID of the node. ISIS reference is TLV 140."; } container mt-is-neighbor { list neighbor { key "neighbor-id"; leaf MT-ID { type uint16 { range "0 .. 4095"; } description "This leaf defines the identifier of a topology."; } uses isis-neighbor-extended; description "List of neighbors."; } description "This container describes list of ISIS multi-topology neighbors. ISIS reference is TLV 223."; } container mt-entries { list topology { key "MT-ID"; leaf MT-ID { type uint16 { range "0 .. 4095"; } description "This leaf defines the identifier Litkowski Expires December 29, 2014 [Page 23] Internet-Draft isis-cfg June 2014 of a topology."; } leaf attributes { type bits { bit OVERLOAD { description "If set, the originator is overloaded, and must be avoided in path calculation."; } bit ATTACHED { description "If set, the originator is attached to another area using the refered metric."; } } description "This leaf describes attributes of the LSP for the associated topology."; } description "List of topologies supported."; } description "This container describes the topology supported. ISIS reference is TLV 229."; } leaf-list ipv6-addresses { type inet:ipv6-address; description "This leaf describes the ipv6 interface addresses of the node. ISIS reference is TLV 232."; } container mt-extended-ipv4-reachability { list prefixes { key "ip-prefix"; leaf MT-ID { type uint16 { range "0 .. 4095"; } description Litkowski Expires December 29, 2014 [Page 24] Internet-Draft isis-cfg June 2014 "This leaf defines the identifier of a topology."; } uses isis-prefix-ipv4-extended; description "List of prefixes."; } description "This container describes list of ipv4 reachability information in multi-topology environment. ISIS reference is TLV 235."; } container mt-ipv6-reachability { list prefixes { key "ip-prefix"; leaf MT-ID { type uint16 { range "0 .. 4095"; } description "This leaf defines the identifier of a topology."; } uses isis-prefix-ipv6-extended; description "List of prefixes."; } description "This container describes list of ipv6 reachability information in multi-topology environment. ISIS reference is TLV 237."; } container ipv6-reachability { list prefixes { key "ip-prefix"; uses isis-prefix-ipv6-extended; description "List of prefixes."; } description "This container describes list of ipv6 reachability information. ISIS reference is TLV 236."; Litkowski Expires December 29, 2014 [Page 25] Internet-Draft isis-cfg June 2014 } container router-capabilities { leaf binary { type binary; description "This leaf describes the capability of the node. Format is binary according to the protocol encoding."; } description "This container describes the capabilities of the node. This container may be extended with detailed information. ISIS reference is TLV 242."; } } grouping isis-address-family-cfg { description "This group defines address-family-cfg global configuration for ISIS."; leaf ipv4-unicast { type boolean; description "This leaf defines if IPv4 unicast is activated."; } leaf ipv6-unicast { type boolean; description "This leaf defines if IPv6 unicast is activated."; } leaf ipv4-multicast { type boolean; description "This leaf defines if IPv4 multicast is activated."; } leaf ipv6-multicast { type boolean; description "This leaf defines if IPv6 multicast is activated."; } } grouping isis-interface-hello-cfg { description "This group defines hello interface parameters for ISIS."; leaf hello-authentication-type { Litkowski Expires December 29, 2014 [Page 26] Internet-Draft isis-cfg June 2014 type enumeration { enum none { description "No authentication used."; } enum plaintext { description "Plain text password used."; } enum message-digest { description "MD5 digest used."; } } description "This leaf describes the authentication type to be used in hello messages."; } leaf hello-authentication-key { type string; description "This leaf describes the authentication key to be used in hello messages. For security reason, the authentication key MUST NOT be presented in plaintext format upon a get-config reply. Authors recommends to use MD5 hash to present the authentication-key"; } leaf hello-interval { type uint16; units "seconds"; description "This leaf defines the interval of hello messages."; } leaf hello-multiplier { type uint16; description "This leaf defines the number of hello failed to be received before declaring the adjacency down."; } } grouping isis-interface-level-cfg { description "This group defines level specific configuration for ISIS interfaces."; uses isis-interface-hello-cfg; uses isis-address-family-cfg; Litkowski Expires December 29, 2014 [Page 27] Internet-Draft isis-cfg June 2014 leaf priority { type uint8 { range "0 .. 127"; } description "This leaf describes the priority of the interface for DIS election."; } leaf ipv4-unicast-metric { type isis-wide-metric; description "This leaf describes the IPv4 unicast metric of the interface."; } leaf ipv6-unicast-metric { type isis-wide-metric; description "This leaf describes the IPv6 unicast metric of the interface."; } leaf ipv4-multicast-metric { type isis-wide-metric; description "This leaf describes the IPv4 multicast metric of the interface."; } leaf ipv6-multicast-metric { type isis-wide-metric; description "This leaf describes the IPv6 multicast metric of the interface."; } leaf passive { type boolean; default "false"; description "This leaf defines if interface is in passive mode (ISIS not running, but network is advertised)."; } } grouping isis-authentication-cfg { description "This group defines authentication configuration for ISIS."; leaf psnp-authentication { type boolean; Litkowski Expires December 29, 2014 [Page 28] Internet-Draft isis-cfg June 2014 default "true"; description "This leaf describes if PSNP messages must be authenticated."; } leaf csnp-authentication { type boolean; default "true"; description "This leaf describes if CSNP messages must be authenticated."; } leaf hello-authentication { type boolean; default "true"; description "This leaf describes if HELLO messages must be authenticated."; } leaf authentication-key { type string; description "This leaf describes the authentication key to be used. For security reason, the authentication key MUST NOT be presented in plaintext format upon a get-config reply. Authors recommends to use MD5 hash to present the authentication-key";"; } leaf authentication-type { type enumeration { enum none { description "No authentication used."; } enum plaintext { description "Plain text password used."; } enum message-digest { description "MD5 digest used."; } } description "This leaf describes the authentication type to be used."; } } Litkowski Expires December 29, 2014 [Page 29] Internet-Draft isis-cfg June 2014 grouping isis-level-cfg { description "This group defines level specific global configuration for ISIS."; leaf enabled { type boolean; default "true"; description "This leaf defines the status of the administrative status of the level (Active / not active)."; } uses isis-authentication-cfg; leaf metric-type { type enumeration { enum wide-only { description "Advertise new metric style only (RFC5305)"; } enum old-only { description "Advertise old metric style only (RFC1195)"; } enum both { description "Advertise both metric styles"; } } description "This leaf describes the type of metric to be generated. Wide-only means only new metric style is generated, old-only means that only old style metric is generated, and both means that both are advertised."; } leaf preference { type uint8; description "This leaf defines the protocol preference."; } leaf external-preference { type uint8; description "This leaf defines the protocol preference for external routes."; } leaf default-ipv4-unicast-metric { type isis-wide-metric; description Litkowski Expires December 29, 2014 [Page 30] Internet-Draft isis-cfg June 2014 "This leaf defines the IPv4 unicast default metric."; } leaf default-ipv6-unicast-metric { type isis-wide-metric; description "This leaf defines the IPv6 unicast default metric."; } leaf default-ipv4-multicast-metric { type isis-wide-metric; description "This leaf defines the IPv4 multicast default metric."; } leaf default-ipv6-multicast-metric { type isis-wide-metric; description "This leaf defines the IPv6 multicast default metric."; } } augment "/rt:routing/rt:routing-instance/rt:routing-protocols/" +"rt:routing-protocol" { when "rt:type = 'isis:isis'" { description "This augment is only valid when routing protocol instance type is isis."; } description "This augments a routing protocol instance with ISIS specific parameters."; container isis { leaf isis-level { type isis-level; default "level-1-2"; description "This leaf describes the type of ISIS node. A node can be level-1-only, level-2-only or level-1-2. "; } leaf nsap-address { type simple-iso-address; description "This leaf defines the NSAP address of the node in a simple format. This parameter is mandatory."; } leaf ipv4-router-id { type inet:ipv4-address; description Litkowski Expires December 29, 2014 [Page 31] Internet-Draft isis-cfg June 2014 "Router ID value that would be used in TLV134."; } leaf ipv6-router-id { type inet:ipv6-address; description "Router ID value that would be used in TLV234."; } leaf reference-bandwidth { type uint32; units "bps"; description "This leaf defines the bandwidth for calculating metric."; } leaf lsp-mtu { type uint16; units "bytes"; default 1492; description "This leaf describes the maximum size of a LSP PDU in bytes."; } leaf lsp-lifetime { type uint16; units "seconds"; description "This leaf describes the lifetime of the router LSP in seconds."; } leaf lsp-refresh { type uint16; units "seconds"; description "This leaf describes the refresh interval of the router LSP in seconds."; } uses isis-authentication-cfg; container isis-multi-topology-cfg { uses isis-address-family-cfg; description "This container describes activation of MT extensions for supporting new address families."; } container isis-level-1-cfg { Litkowski Expires December 29, 2014 [Page 32] Internet-Draft isis-cfg June 2014 uses isis-level-cfg; description "Defines configuration parameters of level 1."; } container isis-level-2-cfg { uses isis-level-cfg; description "Defines configuration parameters of level 2."; } container overload { leaf status { type boolean; description "This leaf defines the overload status."; } leaf timeout { type uint16; units "seconds"; description "This leaf defines the timeout in seconds of the overload condition."; } description "This leaf describes if the router is set to overload state."; } container interfaces { list interface { key "name"; leaf name { type leafref { path "/rt:routing/rt:routing-instance/" +"rt:interfaces/rt:interface/rt:name"; } description "Reference to the interface within the routing-instance."; } leaf level { type isis-level; default "level-1-2"; description "This leaf defines the associated ISIS level of the interface."; Litkowski Expires December 29, 2014 [Page 33] Internet-Draft isis-cfg June 2014 } leaf lsp-interval { type uint16; units "milliseconds"; description "This leaf defines the interval between LSP transmissions in msec"; } leaf passive { type boolean; default "false"; description "This leaf defines if interface is in passive mode (ISIS not running, but network is advertised)."; } leaf csnp-interval { type uint16; units "seconds"; description "This leaf defines the interval of CSNP messages."; } uses isis-interface-hello-cfg; leaf hello-padding { type boolean; description "This leaf defines if ISIS Hellos would be padded up to MTU size."; } uses isis-address-family-cfg; leaf interface-type { type enumeration { enum broadcast { description "Broadcast interface type. Would result in DIS election."; } enum point-to-point { description "Point to point interface type."; } } description Litkowski Expires December 29, 2014 [Page 34] Internet-Draft isis-cfg June 2014 "This leaf defines the type of adjacency to be established on the interface. This is affecting the type of hello message that would be used."; } leaf enabled { type boolean; default "true"; description "This leaf describes the administrative status of the ISIS interface."; } leaf-list tag { type uint32; description "This leaf defines list of tags associated with the interface."; } container level-1 { uses isis-interface-level-cfg; description "This container defines the level 1 specific configuration of the interface."; } container level-2 { uses isis-interface-level-cfg; description "This container defines the level 2 specific configuration of the interface."; } description "List of ISIS interfaces."; } description "This container defines ISIS interface specific configuration objects."; } description "This container defines ISIS specific configuration objects."; } Litkowski Expires December 29, 2014 [Page 35] Internet-Draft isis-cfg June 2014 } augment "/rt:routing-state/rt:routing-instance/" +"rt:routing-protocols/rt:routing-protocol" { when "rt:type = 'isis:isis'" { description "This augment is only valid when routing protocol instance type is isis."; } description "This augments routing protocol instance states with ISIS specific parameters."; container isis-state { config false; container adjacencies { list adjacency { key interface; leaf interface { type string; description "This leaf describes the name of the interface."; } leaf level { type uint8 { range "1 .. 2"; } description "This leaf describes the associated ISIS level of the interface. The value of the level can only be 1 or 2."; } leaf state { type enumeration { enum "Up" { description "This state describes that adjacency is established."; } enum "Down" { description "This state describes that adjacency is NOT established."; } enum "Init" { Litkowski Expires December 29, 2014 [Page 36] Internet-Draft isis-cfg June 2014 description "This state describes that adjacency is establishing."; } } description "This leaf describes the state of the interface."; } description "List of operational adjacencies."; } description "This container lists the adjacencies of the local node."; } container spf-log { list event { key id; leaf id { type uint32; description "This leaf defines the event identifier. This is a purely internal value."; } leaf spf-type { type enumeration { enum full { description "Computation done is a Full SPF."; } enum incremental { description "Computation done is an incremental SPF."; } enum route-only { description "Computation done is a reachability computation only."; } } description "This leaf describes the type of computation used."; } Litkowski Expires December 29, 2014 [Page 37] Internet-Draft isis-cfg June 2014 leaf level { type uint8 { range "1 .. 2"; } description "This leaf describes the level affected bytes the computation."; } leaf spf-delay { type uint32; units "milliseconds"; description "This leaf describes the SPF delay that was used for this event."; } leaf schedule-timestamp { type yang:timestamp; description "This leaf describes the timestamp when the computation was scheduled."; } leaf start-timestamp { type yang:timestamp; description "This leaf describes the timestamp when the computation was started."; } leaf end-timestamp { type yang:timestamp; description "This leaf describes the timestamp when the computation was ended."; } list trigger-lsp { key "lsp"; leaf lsp { type isis-lsp-id; description "This leaf describes the LSPID of the LSP."; } leaf sequence { type uint32; description "This leaf describes the sequence number of the LSP."; } description Litkowski Expires December 29, 2014 [Page 38] Internet-Draft isis-cfg June 2014 "This leaf describes list of LSPs that triggered the computation."; } description "List of computation events."; } description "This container lists the SPF computation events."; } container lsp-log { list event { key id; leaf id { type uint32; description "This leaf defines the event identifier. This is a purely internal value."; } leaf level { type uint8 { range "1 .. 2"; } description "This leaf describes the level affected bytes the computation."; } container lsp { leaf lsp { type isis-lsp-id; description "This leaf describes the LSPID of the LSP."; } leaf sequence { type uint32; description "This leaf describes the sequence number of the LSP."; } description "This container describes the received LSP , in case of local LSP update the local LSP ID is referenced."; } Litkowski Expires December 29, 2014 [Page 39] Internet-Draft isis-cfg June 2014 leaf received-timestamp { type yang:timestamp; description "This leaf describes the timestamp when the LSP was received. In case of local LSP update, the timestamp refers to the local LSP update time."; } description "List of LSP events."; } description "This container lists the LSP reception events. Local LSP modification are also contained in the list."; } container database { container level-1 { list lsp { key lsp-id; uses isis-database; description "List of LSPs in LSDB."; } description "This container describes the list of LSPs in the level-1 database."; } container level-2 { list lsp { key lsp-id; uses isis-database; description "List of LSPs in LSDB."; } description "This container describes the list of LSPs in the level-2 database."; } description "This container describes ISIS Link State Litkowski Expires December 29, 2014 [Page 40] Internet-Draft isis-cfg June 2014 databases."; } container hostnames { list hostname { key system-id; leaf system-id { type isis-system-id; description "This leaf describes the system-id associated with the hostname."; } leaf hostname { type string; description "This leaf describes the hostname associated with the system ID."; } description "List of system-id/hostname associations"; } description "This container describes the list of binding between system-id and hostnames."; } description "This container defines various ISIS states objects."; } } /* RPC methods */ rpc clear-isis-adjacency { description "This RPC request clears a particular set of ISIS adjacencies. If the operation fails for ISIS internal reason, then error-tag and error-app-tag should be set to a meaningful value."; input { leaf routing-instance-name { type rt:routing-instance-state-ref; mandatory "true"; description Litkowski Expires December 29, 2014 [Page 41] Internet-Draft isis-cfg June 2014 "Name of the routing instance whose ISIS information is being queried. If the routing instance with name equal to the value of this parameter doesn't exist, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'routing-instance-not-found'."; } leaf routing-protocol-instance-name { type isis-instance-state-ref; mandatory "true"; description "Name of the ISIS protocol instance whose ISIS information is being queried. If the ISIS instance with name equal to the value of this parameter doesn't exist, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'routing-protocol-instance-not-found'."; } leaf isis-level { type isis-level; description "ISIS level of the adjacency to be cleared. If ISIS level is level-1-2, both level 1 and level 2 adjacencies would be cleared. If the value provided is different from the one authorized in the enum type, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'bad-isis-level'. "; } leaf interface { type string; description "Name of the ISIS interface. If the ISIS interface with name equal to the value of this parameter doesn't exist, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'isis-interface-not-found'."; } Litkowski Expires December 29, 2014 [Page 42] Internet-Draft isis-cfg June 2014 } } rpc clear-isis-database { description "This RPC request clears a particular ISIS database. If the operation fails for ISIS internal reason, then error-tag and error-app-tag should be set to a meaningful value."; input { leaf routing-instance-name { type rt:routing-instance-state-ref; mandatory "true"; description "Name of the routing instance whose ISIS information is being queried. If the routing instance with name equal to the value of this parameter doesn't exist, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'routing-instance-not-found'."; } leaf routing-protocol-instance-name { type isis-instance-state-ref; mandatory "true"; description "Name of the ISIS protocol instance whose ISIS information is being queried. If the ISIS instance with name equal to the value of this parameter doesn't exist, then this operation SHALL fail with error-tag 'data-missing' and error-app-tag 'routing-protocol-instance-not-found'."; } leaf isis-level { type isis-level; description "ISIS level of the adjacency to be cleared. If ISIS level is level-1-2, both level 1 and level 2 adjacencies would be cleared. If the value provided is different from the one authorized in the enum type, then this operation SHALL fail with error-tag 'data-missing' Litkowski Expires December 29, 2014 [Page 43] Internet-Draft isis-cfg June 2014 and error-app-tag 'bad-isis-level'. "; } } } /* Notifications */ notification isis-adjacency-updown { leaf interface { type string; description "Describes the interface of the adjacency"; } leaf neighbor { type string; description "Describes the name of the neighbor. If the name of the neighbor is not available, the field would be empty."; } leaf neighbor-system-id { type isis-system-id; description "Describes the system-id of the neighbor."; } leaf isis-level { type isis-level; description "Describes the ISIS level of the adjacency."; } leaf state { type enumeration { enum "Up" { description "This state describes that adjacency is established."; } enum "Down" { description "This state describes that adjacency is no more established."; } } Litkowski Expires December 29, 2014 [Page 44] Internet-Draft isis-cfg June 2014 description "This leaf describes the new state of the ISIS adjacency."; } leaf reason { type string; description "If the adjacency is going to DOWN, this leaf provides a reason for the adjacency going down. The reason is provided as a text. If the adjacency is going to UP, no reason is provided."; } description "This notification is sent when an ISIS adjacency moves to Up state or to Down state."; } } 7. Security Considerations Configuration and state data defined in this document are designed to be accessed via the NETCONF protocol [RFC6241]. As ISIS 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. Access control to RPCs is also critical as RPC permits to clear protocol datastructures that would definitively impact the network service. This kind of RPC needs only to be used in specific cases by well-known experienced users. Authors consider that all the configuration is considered as sensitive/vulnerable as well as RPCs. But security teams can decide to open some part of the configuration to less experienced users depending on the internal organization, for example : o User FullWrite : would access to the whole data model. This kind of profile may be restricted to few experienced people. Litkowski Expires December 29, 2014 [Page 45] Internet-Draft isis-cfg June 2014 o User PartialWrite : would only access to configuration part within /isis/interfaces/interface. So this kind of profile is restricted to creation/modification/deletion of interfaces. This profile does not have access to RPC. o User Read : would only access to state part /isis-state. Unauthorized access to configuration or RPC may cause high damages to the network service. The /isis-state/database may contain authentication information. As presented in the description of the /isis-state/database/level- 1/lsp/authentication/authentication-key, the authentication MUST never be presented in plaintext format for security reason. Authors recommends the usage of MD5 to present the authentication-key. Some authentication-key may also be present in the /isis configuration. When configuring ISIS using the NETCONF protocol, authors recommends the usage of secure transport of NETCONF using SSH ([RFC6242]). 8. Acknowledgements 9. IANA Considerations 10. Normative References [I-D.ietf-netmod-routing-cfg] Lhotka, L., "A YANG Data Model for Routing Management", draft-ietf-netmod-routing-cfg-15 (work in progress), May 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, June 2011. Litkowski Expires December 29, 2014 [Page 46] Internet-Draft isis-cfg June 2014 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012. Appendix A. Example: NETCONF Reply This section gives an example of a reply to the NETCONF request for a device that implements the data model defined in this document. The example is written in XML. eth0 10.0.0.1 30 lo0 192.168.0.2 32 eth0 up 2014-12-02T12:14:25.123Z 100 10 0 Litkowski Expires December 29, 2014 [Page 47] Internet-Draft isis-cfg June 2014 0 0 0 0 541 100 0 0 0 0 10.0.0.1 30 lo0 up 2014-12-02T12:14:25.123Z 100 10 0 0 0 0 0 541 100 0 0 0 0 192.168.0.2 32 Litkowski Expires December 29, 2014 [Page 48] Internet-Draft isis-cfg June 2014 rtr1 1 192.0.2.1 eth0 ISIS1 isis:isis eth0 2 Up 18979 full 2 150 1403612245 1403612399 1403612420 0000.1245.1245.01-01 125458 1245 2 0000.1245.1245.01-01 Litkowski Expires December 29, 2014 [Page 49] Internet-Draft isis-cfg June 2014 125458 1403612420 0000.1245.1245.01-01 1245 45 125458 0000.1245.9999.00 100 204 192.168.0.2 192.168.0.2 false 32 30490 200 rtr1 Litkowski Expires December 29, 2014 [Page 50] Internet-Draft isis-cfg June 2014 0000.1245.9999.00 rtr1 ipv4-master 1 v4ur:ipv4-unicast 124554657 eth0 isis:isis 2013-07-02T18:02:45+01:00 10.0.0.0/24 750 l2-up-internal rtr1 192.0.2.1 eth0 Litkowski Expires December 29, 2014 [Page 51] Internet-Draft isis-cfg June 2014 lo0 ISIS1 isis:isis level-2 49.0002.0000.1245.9999.00 65535 65000 f567acafcd6578861df5683268$ plaintext true wide-only 11111111 eth0 100 10 point-to-point 200 lo0 Litkowski Expires December 29, 2014 [Page 52] Internet-Draft isis-cfg June 2014 1 true Author's Address Stephane Litkowski Orange Email: stephane.litkowski@orange.com Litkowski Expires December 29, 2014 [Page 53]