Babel routing protocol B. Stark
Internet-Draft AT&T
Intended status: Informational January 2, 2018
Expires: July 6, 2018
Babel Information Model
draft-ietf-babel-information-model-01
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
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 6, 2018.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Notation . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Information Model . . . . . . . . . . . . . . . . . . . . 4
2.1. Definition of babel-information . . . . . . . . . . . . . 4
2.2. Definition of babel-constants . . . . . . . . . . . . . . 4
2.3. Definition of babel-interfaces . . . . . . . . . . . . . 5
2.4. Definition of babel-neighbors . . . . . . . . . . . . . . 6
2.5. Definition of babel-security . . . . . . . . . . . . . . 6
2.6. Definition of babel-trust . . . . . . . . . . . . . . . . 7
2.7. Definition of babel-sources . . . . . . . . . . . . . . . 7
2.8. Definition of babel-routes . . . . . . . . . . . . . . . 7
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
4. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Normative References . . . . . . . . . . . . . . . . . . 9
4.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Open Issues . . . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Babel is a loop-avoiding distance-vector routing protocol defined in
RFC 6126bis [RFC6126bis]. 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.
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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.
The object definitions use base types that are defined as follows:
base64 An opaque array of bytes.
boolean A type representing a boolean value.
counter A non-negative integer that monotonically increases.
Counters may have discontinuities and they are not
expected to persist across restarts.
credentials An opaque type representing credentials needed by a
cryptographic mechanism to secure communication. Data
models must expand this opaque type as needed and
required by the security protocols utilized.
datetime A type representing a date and time using the Gregorian
calendar. The datetime format MUST conform to RFC 3339
[RFC3339].
int A type representing signed or unsigned integer numbers.
This information model does not define a precision nor
does it make a distinction between signed and unsigned
number ranges. This type is also used to represent
enumerations.
ip-address A type representing an IP address. This type supports
both IPv4 and IPv6 addresses.
string A type representing a human-readable string consisting of
a (possibly restricted) subset of Unicode and ISO/IEC
10646 [ISO.10646] characters.
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uri A type representing a Uniform Resource Identifier as
defined in STD 66 [RFC3986].
2. The Information Model
2.1. Definition of babel-information
object {
string babel-implementation-version;
base64 babel-self-router-id;
[int babel-self-seqno;]
string babel-cost-comp-algorithms<1..*>;
babel-constants-obj babel-constants;
babel-interfaces-obj babel-interfaces<0..*>;
babel-sources-obj babel-sources<0..*>;
babel-routes-obj babel-routes<0..*>;
}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; RFC 6126bis [RFC6126bis]
describes this as an arbitrary string of 8 octets
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;
[ip-address babel-multicast-group-ipv6;]
[ip-address babel-multicast-group-ipv4;]
}babel-constants-obj;
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babel-udp-port: UDP port for sending and listening for Babel
messages; default is 6696; MAY be configurable
babel-multicast-group-ipv6: multicast group for sending and
listening to multicast announcements on IPv6; default is
ff02:0:0:0:0:0:1:6; MAY be configurable
babel-multicast-group-ipv4: multicast group for sending and
listening to multicast announcements on IPv4; default is
224.0.0.111; MAY be configurable
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-security-obj babel-security<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
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2.4. Definition of babel-neighbors
object {
ip-address babel-neighbor-address;
string babel-hello-history;
int babel-txcost;
int babel-hello-seqno;
int babel-neighbor-ihu-interval;
[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 meximum value (infinity) to
indicates 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-security
object {
string babel-security-supported;
string babel-security-enabled-protocol;
credentials babel-security-self-cred;
babel-trust-obj babel-trust<1..*>;
}babel-security-obj;
babel-security-supported: list of supported security mechanisms
babel-security-enabled-protocol: the currently enabled security
protocol; empty if none is enabled
babel-security-self-cred: the credentials this router presents to
participate in the enabled security protocol
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babel-trust-obj: a set of babel-trust objects that identify the
credentials of a router whose babel messages are trusted
2.6. Definition of babel-trust
object {
credentials babel-trust-cred;
}babel-trust-obj;
babel-trust-cred: the credentials of a router whose babel messages
can be trusted
2.7. Definition of babel-sources
object {
ip-address babel-source-prefix;
int babel-source-prefix-length;
base64 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 this entry applies to
babel-source-prefix-length: Length of the source prefix
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
2.8. Definition of babel-routes
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object {
ip-address babel-route-prefix;
int babel-route-prefix-length;
base64 babel-route-router-id;
base64 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 (expressed in IP address format) for
which this route is advertised
babel-route-prefix-length: Length of the prefix for which this
route is advertised
babel-route-router-id: router-id of the source router for which
this route is advertised
babel-route-neighbor: neighbor that advertised this route (a
router-id)
babel-route-metric: the metric with which this route was
advertised by the neighbor, or maximum value (infinity) to
indicate 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. Acknowledgements
Juliusz Chroboczek review has been very helpful in refining this
information model.
The language in the Notation section was mostly taken from RFC 8193
[RFC8193].
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4. References
4.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6126bis]
Chroboczek, J., "The Babel Routing Protocol", Work in
Progress, draft-ietf-babel-rfc6126bis, October 2017.
4.2. Informative References
[ISO.10646]
International Organization for Standardization,
"Information Technology - Universal Multiple-Octet Coded
Character Set (UCS)", ISO Standard 10646:2014, 2014.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC7298] Ovsienko, D., "Babel Hashed Message Authentication Code
(HMAC) Cryptographic Authentication", RFC 7298,
DOI 10.17487/RFC7298, July 2014,
<https://www.rfc-editor.org/info/rfc7298>.
[RFC8193] Burbridge, T., Eardley, P., Bagnulo, M., and J.
Schoenwaelder, "Information Model for Large-Scale
Measurement Platforms (LMAPs)", RFC 8193,
DOI 10.17487/RFC8193, August 2017,
<https://www.rfc-editor.org/info/rfc8193>.
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Appendix A. Open Issues
This draft must be reviewed against draft-ietf-babel-rfc6126bis.
Following are some issues where a conscious decision may be useful:
Closed by defining base64 type and using it for all router IDs:
"babel-self-router-id: Should this be an opaque 64-bit value
instead of int?"
babel-interfaces-obj: "This needs further discussion, I fear some
of these are implementation details."
Would it be useful to define some parameters for reporting
statistics or logs? [Yes, but these need to be proposed.]
Would it be useful to define some parameters specifically for
security anomalies? [Yes, but these need to be proposed.]
I created a basic security model. It's useful for single (or no)
active security mechanism; but not multiple active. OK?
Do we need a registry for the supported security mechanisms?
Author's Address
Barbara Stark
AT&T
Atlanta, GA
US
Email: barbara.stark@att.com
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