Babel Information Model
draft-stark-babel-information-model-00

Abstract

This Babel Information Model can be used to create data models under various data modeling regimes (e.g., YANG). It allows a Babel implementation (via a management protocol such as netconf) to report on its current state and may allow some limited configuration of protocol constants.

Status of This Memo

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This Internet-Draft will expire on January 8, 2017.

Copyright Notice

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 1.1. Requirements Language
• 1.2. Notation
• 2. The Information Model
• 2.1. Definition of babel-information
• 2.2. Definition of babel-constants
• 2.3. Definition of babel-interfaces
• 2.4. Definition of babel-neighbors
• 2.5. Definition of babel-csa
• 2.6. Definition of babel-sources
• 2.7. Definition of babel-routes
• 3. References
• 3.1. Normative References
• 3.2. Informative References
• Author's Address

1. Introduction

Babel is a loop-avoiding distance-vector routing protocol defined in RFC 6126 [RFC6126]. Babel Hashed Message Authentication Code (HMAC) Cryptographic Authentication, defined in RFC 7298 [RFC7298], describes a cryptographic authentication mechanism for the Babel routing protocol. This document describes an information model for Babel (including HMAC) that can be used to created management protocol data models (such as a netconf [RFC6241] YANG data model). Other Babel extensions may be included in this document when they become working group drafts.

Due to the simplicity of the Babel protocol and the fact that it is designed to be used in non-professionally administered environments (such as home networks), most of the information model is focused on reporting status of the Babel protocol, and very little of that is considered mandatory to implement (conditional on a management protocol with Babel support being implemented). Some parameters may be configurable; however, it is up to the Babel implementation whether to allow any of these to be configured within its implementation. Where the implementation does not allow configuration of these parameters, it may still choose to expose them as read-only.

1.1. 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 RFC 2119 [RFC2119].

1.2. Notation

This document uses a programming language-like notation to define the properties of the objects of the information model. An optional property is enclosed by square brackets, [ ], and a list property is indicated by two numbers in angle brackets, <m..n>, where m indicates the minimal number of values, and n is the maximum. The symbol * for n means no upper bound.

2. The Information Model

2.1. Definition of babel-information

     object {
          int                   babel-version;
          int                   babel-self-router-id;
         [int                   babel-self-seqno;]
          string                babel-cost-comp-algorithms<1..*>;
          babel-constants-obj   babel-constants;
          babel-interfaces-obj  babel-interfaces<1..*>;
          babel-sources-obj     babel-sources<1..*>;
          babel-routes-obj      babel-routes<1..*>;
      }babel-information-obj;
            

• babel-version: the version of this implementation of the Babel protocol
• babel-self-router-id: the router-id used by this instance of the Babel protocol to identify itself
• babel-self-seqno: the current sequence number included in route updates for routes originated by this node
• babel-cost-comp-algorithm: a set of names of supported cost computation algorithms; possible values include "k-out-of-j", "ETX"
• babel-constants: a babel-constants object
• babel-interfaces: a set of babel-interface objects
• babel-sources: a set of babel-source objects
• babel-routes: a set of babel-route objects

2.2. Definition of babel-constants

     object {
          int          babel-udp-port;
         [int          babel-hello-interval-lossy;]
         [int          babel-hello-interval-lossless;]
         [int          babel-ihu-interval;]
         [int          babel-update-interval;]
         [int          babel-ihu-hold-time;]
         [int          babel-route-expiry-time;]
         [int          babel-garbage-collection-time;]
         [int          babel-max-trigger-delay;]
         [int          babel-max-normal-delay;]
         [int          babel-ack-limit;]
         [int          babel-resend-trigger-lossy-limit;]
         [int          babel-resend-trigger-lossless-limit;]        
         [int          babel-resend-normal-lossy-limit;]
         [int          babel-resend-normal-lossless-limit;]        
      }babel-constants-obj;
            

• babel-udp-port: UDP port for sending and listening for Babel messages; MAY be configurable
• babel-hello-interval-lossy: Hello Interval default for lossy links in milliseconds; MAY be configurable
• babel-hello-interval-lossless: Hello Interval default for lossless links in milliseconds; MAY be configurable
• babel-ihu-interval: IHU Interval default as multiples of Hello interval
• babel-update-interval: Update Interval default as multiples of Hello interval
• babel-ihu-hold-time: IHU Hold Time default as multiples of Hello interval
• babel-route-expiry-time: IHU Interval default as multiples of Hello interval
• babel-garbage-collection-time: Garbage Collection time default as multiples of Update interval
• babel-max-trigger-delay: Maximum delay to wait before sending a triggered update in milliseconds
• babel-max-normal-delay: Maximum delay to wait before sending a non-triggered message in milliseconds
• babel-ack-limit: Threshold for requesting acknowledgements on an interface (do not request acknowledgements if there are more than this many neighbors on the interface); MAY be configurable
• babel-resend-trigger-lossy-limit: Resend limit of triggered updates on lossy links (can this be the same, whether or not acknowledgements are requested?)
• babel-resend-trigger-lossless-limit: Resend limit of triggered updates on lossless links (can this be the same, whether or not acknowledgements are requested?)
• babel-resend-normal-lossy-limit: Resend limit of normal messages on lossy links
• babel-resend-normal-lossless-limit: Resend limit of normal messages on lossless links

2.3. Definition of babel-interfaces

     object {
          uri                  babel-interface-reference;
         [int                  babel-interface-seqno;]
         [int                  babel-interface-hello-interval;]
         [int                  babel-interface-update-interval;]
          boolean              babel-request-trigger-ack;
          boolean              babel-lossy-link;
         [int                  babel-external-cost;]
          babel-neighbors-obj  babel-neighbors<1..*>;
         [babel-csa-obj        babel-csa<1..*>;]
      }babel-interfaces-obj;
            

• babel-interface-reference: reference to an interface object as defined by the data model
• babel-interface-seqno: the current sequence number in use for this interface
• babel-interface-hello-interval: the current hello interval in use for this interface
• babel-interface-update-interval: the current update interval in use for this interface
• babel-request-trigger-ack: requests acknowledgement of triggered updates (if number of neighbors less than babel-ack-limit); MAY be configurable
• babel-lossy-link: indicates (if true) that the link of this interface is considered lossy; MAY be configurable
• babel-external-cost: external input to cost of link of this interface (need to determine how to express this);MUST be configurable if implemented

2.4. Definition of babel-neighbors

     object {
          some address format  babel-neighbor-address;
          string               babel-hello-history;
          int                  babel-txcost;
          int                  babel-hello-seqno;
          int                  babel-neighbor-ihu-interval;
         [int                  babel-neighbor-router-id;]
         [int                  babel-rxcost]
      }babel-neighbors-obj;
            

• babel-neighbor-address: (IPv4 or v6) address the neighbor sends messages from
• babel-hello-history: the Hello history (do we want a human readable format?)
• babel-txcost: transmission cost value from the last IHU packet received from this neighbor, or FFFF hexadecimal (infinity) if the IHU hold timer for this neighbor has expired
• babel-hello-seqno: expected Hello sequence number
• babel-neighbor-ihu-interval: current IHU interval for this neighbor
• babel-router-id: router-id of the neighbor
• babel-rxcost: reception cost calculated for this neighbor

2.5. Definition of babel-csa

     object {
          string               placeholder;
    }babel-csa-obj;
            

• placeholder: this section to be filled in, in the future

2.6. Definition of babel-sources

     object {
          (prefix, plen)       babel-source-prefix;
          int                  babel-source-router-id;
          int                  babel-source-seqno;
          int                  babel-source-metric;
         [int                  babel-source-garbage-collection-time;]
      }babel-sources-obj;
            

• babel-source-prefix: Prefix (with prefix length)
• babel-source-router-id: router-id of the router originating this prefix
• babel-source-seqno: last sequence number used by this source
• babel-source-metric: this source's feasibility distance
• babel-source-garbage-collection-time: garbage-collection timer for this source

2.7. Definition of babel-routes

     object {
          (prefix, plen)       babel-route-prefix;
          int                  babel-route-router-id;
          int                  babel-route-neighbor;
          int                  babel-route-metric;
          int                  babel-route-seqno;
          ip address           babel-route-next-hop;
          boolean              babel-route-selected;
      }babel-routes-obj;
            

• babel-route-prefix: Prefix (with prefix length) for which this route is advertised
• babel-route-router-id: router-id of the router originating this prefix
• babel-route-neighbor: neighbor that advertised this route (is this a router-id ?)
• babel-route-metric: the metric with which this route was advertised by the neighbor, or FFFF hexadecimal (infinity) for a recently retracted route
• babel-route-seqno: the sequence number with which this route was advertised
• babel-route-next-hop: the next-hop address of this route
• babel-route-selected: a boolean flag indicating whether this route is selected, i.e., whether it is currently being used for forwarding and is being advertised

3. References

3.1. Normative References

3.2. Informative References

Author's Address