Network Working Group E. Lear
Internet-Draft J. Henry
Intended status: Experimental Cisco Systems
Expires: January 9, 2020 July 08, 2019
Bandwidth Profiling Extensions for MUD
draft-lear-opsawg-mud-bw-profile-01
Abstract
Manufacturer Usage Descriptions (MUD) are a means by which devices
can establish expectations about how they are intended to behave, and
how the network should treat them. Earlier work focused on access
control. This draft specifies a means by which manufacturers can
express to deployments what form of bandwidth profile devices are
expected to have with respect to specific services.
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 https://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 January 9, 2020.
Copyright Notice
Copyright (c) 2019 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
(https://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
include Simplified BSD License text as described in Section 4.e of
Lear & Henry Expires January 9, 2020 [Page 1]
Internet-Draft MUD QoS July 2019
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Envisioned Uses . . . . . . . . . . . . . . . . . . . . . 3
1.2. Limitations . . . . . . . . . . . . . . . . . . . . . . . 3
1.3. What devices would use this extension? . . . . . . . . . 3
2. The ietf-mud-bw-profile model extension . . . . . . . . . . . 4
2.1. The mud-qos YANG model . . . . . . . . . . . . . . . . . 4
3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
4.1. Manufacturer Attempts to Exhaust Available Bandwidth . . 7
4.2. Device lies about what it is to get more bandwidth . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. Normative References . . . . . . . . . . . . . . . . . . 8
6.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Changes from Earlier Versions . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Devices connecting to networks will often exhibit certain nominal
behaviors that can be described. In addition, sometimes device
require particular network behaviors such as appropriate quality-of-
service treatment. Manufacturer Usage Descriptions [RFC8520] discuss
how to characterize access control requirements, for instance. As
just mentioned, access control requirements are not the only
requirements device manufacturers may wish to specify. This memo
defines an extension to the MUD YANG model by which manufacturers can
characterize the traffic exchanged with a Thing, and specify how much
bandwidth is required by a device or may be expected of a device over
some period of time for each given service it uses.
Network deployments may use this information in two ways:
o Provisioning of bandwidth based on device requirements;
o Facilitating proper traffic characterization and marking by the
network infrastructure
o Policing of devices to not permit them to exceed design
requirements. In particular, a device that is transmitting a DSCP
value that exceeds the expected value, or that manifests unusual
transmission patterns, should be viewed with great suspicion.
Lear & Henry Expires January 9, 2020 [Page 2]
Internet-Draft MUD QoS July 2019
The basis of the model is that services may be identified by access-
lists, and that each service can then be assigned an attendant
bandwidth expectation in terms of either bits-per-second or packets-
per-second. In addition, a DSCP marking can be specified.
When a service is identified by access lists, each access list is
appended to the existing access list entries. N.B., as a reminder,
acl names in MUD files are scoped solely to those files, and may
conflict with acl names in _other_ MUD files.
1.1. Envisioned Uses
A luminaire may require a few packets per minute of a predictable
payload size (e.g. keepalives), and may expect that traffic to be
sent in the background, as one or more keepalive packet loss would
not impede the luminaire functions. Additionally, when a virtual
'light switch' changes its state, a burst of 3 to 4 packets over a
well-defined port are expected, with a QoS marking of OAM. Last,
occasional firmware updates may bring an exchange of a few kilobytes
marked as best effort.
A smoke detector may require at most 1 packet per second at best
effort (keepalive), except when there is a problem, at which point it
may send a frame upstream to a specific port and of a specified
payload size, with a DSCP marking of EF.
A coffee maker may be designed never set DSCP to anything other than
AF13 (even when it's empty, perish the thought), nor may it ever use
more than 5 packets of 120 bytes payload per minute, even if it has a
fault.
A different coffee maker may be designed to set DSCP to EF if the it
has caught fire.
1.2. Limitations
Not every device can be easily profiled. Not every service on every
device may be easily profiled. A manufacturer may use this extension
to describe those services that _are_ easily profile, and omit
services that the device offers or uses that are not easily profiled.
The local deployment is cautioned not to assume that a service not
profiled is in some way anomalous, even when other services are.
1.3. What devices would use this extension?
The MUD manager remains a key component of this system. To begin
with, it is the component that retrieves the MUD file, and would
identify the extension. From that point, different implementation
Lear & Henry Expires January 9, 2020 [Page 3]
Internet-Draft MUD QoS July 2019
decisions can be made. For instance, the MUD manager or associated
infrastructure can retain the mapping between devices and MUD-URLs.
A dispatch function could be implemented wherever that mapping is
housed, such that either enforcement or monitoring functions can be
invoked. Enforcement functions would almost certainly begin with
some form of telemetry on access switches, routers or firewalls.
That same telemetry might be exported to an IPFIX analyzer [RFC7011]
that might report anomalies.
2. The ietf-mud-bw-profile model extension
To extend MUD the "qos" extension is added as an element to the
"extensions" node when a MUD file is generated.
The model augmentation appears as follows:
module: ietf-mud-bw-profile
augment /mud:mud/mud:to-device-policy:
+--rw bw-params
+--rw service* [name]
+--rw name string
+--rw timeframe uint32
+--rw pps? uint32
+--rw bps? uint64
+--rw dscp? inet:dscp
+--rw aclname? -> /acl:acls/acl/name
augment /mud:mud/mud:from-device-policy:
+--rw bw-params
+--rw service* [name]
+--rw name string
+--rw timeframe uint32
+--rw pps? uint32
+--rw bps? uint64
+--rw dscp? inet:dscp
+--rw aclname? -> /acl:acls/acl/name
2.1. The mud-qos YANG model
<CODE BEGINS>file "ietf-mud-bw-profile@2019-07-08.yang"
module ietf-mud-bw-profile {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-mud-bw-profile";
prefix mud-qos;
import ietf-access-control-list {
prefix acl;
}
import ietf-inet-types {
Lear & Henry Expires January 9, 2020 [Page 4]
Internet-Draft MUD QoS July 2019
prefix inet;
}
import ietf-mud {
prefix mud;
}
organization
"IETF OPSAWG (Ops Area) Working Group";
contact
"WG Web: http://tools.ietf.org/wg/opsawg/
WG List: opsawg@ietf.org
Author: Eliot Lear
lear@cisco.com
Author: Jerome Henry
jerhenry@cisco.com
";
description
"This YANG module augments the ietf-mud model to provide the
network with some understanding as to the QoS requirements and
anticipated behavior of a device.
The to-device-policy and from-device-policy containers are
augmented with one additional container, which expresses how many
packets per second a device is expected to transmit, how much
bandwidth it is expected to use, and what QoS is required, and
how much bandwidth is to be expected to be prioritized. An
access-list is further specified to indicate how QoS should be
marked on ingress and egress.
Copyright (c) 2016,2017,2018 IETF Trust and the persons
identified as the document authors. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision 2019-07-08 {
description
"Initial proposed standard.";
reference "RFC XXXX: Bandwidth Descriptions for MUD Specification";
}
grouping mud-bw-params {
Lear & Henry Expires January 9, 2020 [Page 5]
Internet-Draft MUD QoS July 2019
description
"QoS and Bandwidth additions for MUD";
container bw-params {
description
"Expected Bandwidth to/from device";
list service {
key "name";
description
"a list of services that are being described.";
leaf name {
type string;
description
"Service Name";
}
leaf timeframe {
type uint32;
mandatory true;
description
"the period of time in seconds one
expects a service to burst at described rates";
}
leaf pps {
type uint32;
description
"number of packets per second to be expected.";
}
leaf bps {
type uint64;
description
"number of bits per second to be expected.";
}
leaf dscp {
type inet:dscp;
description
"The DSCP that packets for this service should
treated with. N.B., just because the manufacturer
wants this, doesn't mean it will get it. However,
manufacturers who do set the DSCP value in their
packets SHOULD indicate that in this description.
This field differs from the dscp field in the matches
portion of the access-list in that here the field is
populated when the manufacturer states what the nominal
value of the DSCP field MAY be, and how much bandwidth
can be used when it is set. Note that it is possible
that the same service may use multiple DSCP values,
depending on the circumstances. In this case, service
entry MUST be made.";
Lear & Henry Expires January 9, 2020 [Page 6]
Internet-Draft MUD QoS July 2019
}
leaf aclname {
type leafref {
path "/acl:acls/acl:acl/acl:name";
}
description
"The name of the ACL that will match packets
for a given service.";
}
}
}
}
augment "/mud:mud/mud:to-device-policy" {
description
"add inbound QoS parameters";
uses mud-bw-params;
}
augment "/mud:mud/mud:from-device-policy" {
description
"add outbound QoS parameters";
uses mud-bw-params;
}
}
<CODE ENDS>
3. Examples
TBD
4. Security Considerations
4.1. Manufacturer Attempts to Exhaust Available Bandwidth
An attacking manufacturer claims a device would require substantial
bandwidth or QoS for use. This attack would be effected when a
device is installed into a local deployment and its MUD file
interpreted. The impact of a device demanding excessive bandwidth
could be overprovisioning of the network or denial of service to
other uses.
This attack is remediated by a human being reviewing the bandwidth
consumption projections suggested by the MUD file when they are in
some way beyond the norm for any device being installed.
Lear & Henry Expires January 9, 2020 [Page 7]
Internet-Draft MUD QoS July 2019
4.2. Device lies about what it is to get more bandwidth
If the device is emitting a MUD-URL via insecure, it is possible for
an attacker to modify it. Devices emitting such URLs should already
receive additional scrutiny from administrators as they are
onboarded. This mechanism SHOULD NOT be used to admit devices into
privileged queues without them having been securely admitted to the
network, through means such as IEEE 802.1X.
5. IANA Considerations
The IANA is requested to add "qos" to the MUD extensions registry as
follows:
Extension Name: MUD
Standard reference: This document
6. References
6.1. Normative References
[RFC8520] Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
Description Specification", RFC 8520,
DOI 10.17487/RFC8520, March 2019,
<https://www.rfc-editor.org/info/rfc8520>.
6.2. Informative References
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/info/rfc7011>.
Appendix A. Changes from Earlier Versions
Draft -01:
o Very modest changes.
Draft -00:
o Initial revision
Lear & Henry Expires January 9, 2020 [Page 8]
Internet-Draft MUD QoS July 2019
Authors' Addresses
Eliot Lear
Cisco Systems
Richtistrasse 7
Wallisellen CH-8304
Switzerland
Phone: +41 44 878 9200
Email: lear@cisco.com
Jerome Henry
Cisco Systems
170 W. Tasman Dr.
San Jose, CA 95134
United States
Email: ofriel@cisco.com
Lear & Henry Expires January 9, 2020 [Page 9]