IDR S. Shah
Internet-Draft K. Patel
Intended status: Standards Track Cisco Systems
Expires: February 2, 2017 S. Bajaj
Juniper Network
L. Tomotaki
Verizon
M. Boucadair
Orange
August 1, 2016
Inter-domain SLA Exchange Attribute
draft-ietf-idr-sla-exchange-09.txt
Abstract
Network administrators typically enforce Quality of Service (QoS)
policies according to Service Level Agreement (SLA) with their
providers. The enforcement of such policies often relies upon
vendor-specific configuration language. Both learning of SLA, either
thru SLA documents or via some other out-of-band method, and
translating them to vendor specific configuration language is a
complex, often manual, process and prone to errors.
This document specifies an optional transitive attribute to signal
SLA parameters in-band, across administrative boundaries (considered
as Autonomous Systems (AS)), thus simplifying and facilitating some
of the complex provisioning tasks in situations where BGP is
available as a routing protocol.
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 February 2, 2017.
Shah, et al. Expires February 2, 2017 [Page 1]
Internet-Draft Inter-domain SLA Exchange August 2016
Copyright Notice
Copyright (c) 2016 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
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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. QoS Attribute Definition . . . . . . . . . . . . . . . . . . 5
3.1. QoS Attribute SubType . . . . . . . . . . . . . . . . . . 6
3.2. SLA SubType . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. SLA Content for ADVERTISE SLA Event . . . . . . . . . . . 9
3.3.1. Supported IPFIX identifiers for Traffic Class
Elements . . . . . . . . . . . . . . . . . . . . . . 13
3.3.2. Traffic Class Service types and respective TLVs . . . 14
4. Originating SLA Notification . . . . . . . . . . . . . . . . 21
4.1. SLA Contexts . . . . . . . . . . . . . . . . . . . . . . 21
4.1.1. SLA Advertisement for Point-to-Point Connection . . . 21
4.1.2. SLA Advertisement for Destination AS Multiple Hops
Away . . . . . . . . . . . . . . . . . . . . . . . . 22
5. QoS Attribute Handling at Forwarding Nodes . . . . . . . . . 22
5.1. BGP Node Capable of Processing QoS Attribute . . . . . . 23
5.2. QoS Attribute Handling at Receiver . . . . . . . . . . . 23
6. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 23
7. Deployment Considerations . . . . . . . . . . . . . . . . . . 24
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
10. Security Considerations . . . . . . . . . . . . . . . . . . . 27
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
11.1. Normative References . . . . . . . . . . . . . . . . . . 28
11.2. Informative References . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
Shah, et al. Expires February 2, 2017 [Page 2]
Internet-Draft Inter-domain SLA Exchange August 2016
1. Introduction
Typically there is a contractual Service Level Agreement (SLA) for
QoS established between a customer and a provider or between
providers [RFC7297]. This QoS SLA defines the nature of the various
traffic classes and services needed within each traffic class. The
contract may include full line-rate or sub line-rate without
additional traffic classes, or it may contain additional traffic
classes and service definitions for those traffic classes. Finer
granular traffic classes may be based on some standard code points
(e.g., based on DSCP (Differentiated Services Code Point)) or
specific set of prefixes.
Once the contractual QoS SLA is established, QoS SLA parameters are
enforced in some or all participating devices by deriving those
parameters into configuration information on respective devices. The
network administrator translates the QoS SLA to QoS policies using
router (vendor) specific provisioning language. In a multi-vendor
network, translating SLAs into technology-specific and vendor-
specific configuration requires the network administrator to consider
specific configuration of each vendor. There does not exist any
standard protocol to translate SLA agreements into technical clauses
and configurations and thus both the steps of out of band learning of
negotiated SLA and provisioning them in a vendor specific language
can be complex and error-prone.
SLA parameters may have to be exchanged through organizational
boundaries, thru SLA documents or via some other off-band method, to
an administrator provisioning actual devices. For example, to
provide voice services, the provider may negotiate QoS parameters
(like min/max rates) for such traffic classified under the EF
(Expedited Forwarding) codepoint in Diffserv-enabled [RFC2475]
networks. The Administrator at the CE (Customer Edge) not only will
have to know that provider's service for voice traffic is EF-based
but will also have to know how to implement DSCP EF classification
rule along with Low Latency Service, and possibly min/max rate
enforcement for the optimal use of bandwidth, as per vendor specific
provisioning language.
The Inter-domain exchange of QoS SLA policy described in this
document does not require any specific method for the provider in
establishing SLAs. It only requires that the provider wishes to send
the QoS SLA policy via BGP UPDATE [RFC4271] messages from the
provider to a set of receivers (BGP peers). In reaction to, a
receiving router may translate that to relevant QoS policy definition
on the device. The SLA negotiation and assurance is outside the
scope of this document.
Shah, et al. Expires February 2, 2017 [Page 3]
Internet-Draft Inter-domain SLA Exchange August 2016
This document defines a new optional BGP transitive attribute,
referred as QoS Attribute, which has as one of its sub-types the SLA
policy. The BGP node of the originating AS sends this QoS Attribute,
for prefixes this QoS SLA Policy applies to, in a BGP UPDATE message
that will be distributed to a list of destination ASes. The QoS SLA
policy can be for inbound traffic to the advertising AS or outbound
traffic from the advertising AS, or both.
Protocols and data models are being created to standardize setting
routing configuration parameters within networks. YANG data models
[RFC6020] are being developed so that NETCONF ([RFC6241] or RESTConf
([I-D.ietf-netconf-restconf]) can set these standardize in
configuration mechanisms. For ephemeral state, the I2RS protocol is
being developed to set ephemeral state. While these protocols
provide valid configuration within a domain or across domains, some
providers desire to exchange QoS parameters in-band utilizing BGP
peering relationships. This is similar to the distribution of Flow
Specification information via BGP peering relationships (see
[RFC5575] and [RFC7674]).
2. Terminology
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].
BGP Speaker: A functional component on a BGP capable device that
functions as per BGP specification.
BGP Peers: BGP Speakers adjacent to each other.
QoS Attribute Speaker: A functional component on a BGP capable device
that produces and/or processes content of the QoS Attribute. A
device that is QoS Attribute Speaker is also always a BGP Speaker.
However, a BGP Speaker not necessarily always a QoS Attribute
Speaker.
QoS Attribute content is produced and processed outside the function
of the BGP Speaker and thus content of the QoS Attribute is
completely opaque to the BGP Speaker. At BGP capable device where
QoS Attribute content is produced, length and value of the QoS
Attribute is passed from QoS Attribute Speaker to the BGP Speaker
where BGP Speaker inserts the attribute into the BGP UPDATE message
with appropriate attribute flags, attribute type, and length and
value passed from the QoS Attribute Speaker. Similarly, a BGP
capable device when receives QoS Attribute in the BGP UPDATE message,
BGP Speaker extracts QoS Attribute value from the message and passes
it to the QoS Attribute Speaker where QoS Attribute Speaker processes
Shah, et al. Expires February 2, 2017 [Page 4]
Internet-Draft Inter-domain SLA Exchange August 2016
the content from that passed down value. How the content of the QoS
Attribute is passed from the QoS Attribute Speaker to the BGP Speaker
and vice versa is implementation specific.
In the context of use of QoS Attribute for SLA parameters exchange,
following roles are defined further within the scope of the QoS
Attribute Speaker.
SLA Producer: This is a QoS Attribute Speaker that produces QoS
Attribute for the SLA SubType.
SLA Consumer: This is a QoS Attribute Speaker that is intended
receiver of QoS Attribute with the SLA SubType.
3. QoS Attribute Definition
The QoS Attribute is an optional transitive attribute (TBD -
attribute code to be assigned by IANA) which is applicable to the
Source AS and NLRIs advertised in the BGP UPDATE message this
attribute is included in. The format of the QoS Attribute is shown
in Figure 1.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attr flag | Attr type QoS | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ ~
| QoS Attr length/value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+..........................
Figure 1
Attribute flags - 8-bits field
highest order bit (bit 0) - MUST be set to 1, since this is an
optional attribute
2nd higher order bit (bit 1) - MUST be set to 1, since this is a
transitive attribute
The content of the QoS Attribute is further specified with flags,
applicable to QoS Attribute content, and a SubType in a TLV form.
Shah, et al. Expires February 2, 2017 [Page 5]
Internet-Draft Inter-domain SLA Exchange August 2016
3.1. QoS Attribute SubType
The Value field of the QoS Attribute contains the following:
QoS Attribute flags
Tuple (SubType of the QoS Attribute, SubType length, SubType
value)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| QoS Attr flags| SubType | SubType length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~
| SubType value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+.........................+
Figure 2 - Format of QoS Attribute
QoS Attr flags - 8-bits field
All bits of this field are currently un-used. The space is
provided for future use. All bits MUST be set to zero when sent.
The values (0x01-0xFF) are reserved, and MUST be ignored when
received.
SubType - 8-bits field with following values:
0x00 = reserved
0x01 = SLA
0x02 - 0xf0 = reserved for future use (Standards Action)
0xf1 - 0xff = Private use
The only SubType of the QoS Attribute defined in this
specification is the SLA SubType.
SubType length - 16-bits field that specifies length of the SubType
value in number of octets.
SubType value - variable length field, as expressed in SubType
length, that contains information about a specified SubType. For
the SLA SubType the information is about sender and receiver(s),
and SLA parameters as described in Section 3.2.
Shah, et al. Expires February 2, 2017 [Page 6]
Internet-Draft Inter-domain SLA Exchange August 2016
3.2. SLA SubType
Format of the SLA SubType Value field is shown in Figure 3.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SLA SubType flags | Destination AS count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source AS (Advertiser) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| variable list of Destination AS |
~ .... ~
| .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|SLAEvnt| SLA ID | SLA length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SLA Content for SLA Event |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3 - Format of the SLA SubType of the QoS attribute
SLA SubType flags - 16-bits field
highest order bit (bit 0) -
If set to 1 indicates that SLA ID and SLA Content, specified in
this SLA SubType, is from the source AS to the list of
Destination AS specified in the same SLA SubType.
If set to 0 indicates to ignore Source AS and list of
Destination AS specified in this SLA SubType field. SLA ID and
SLA Content, specified in this SLA SubType, are intended for
the peer receiver of the BGP UPDATE message. In such a case,
on reception of such a message, QoS Attribute Speaker SHOULD
drop the QoS Attribute from the BGP UPDATE message and rest of
the BGP UPDATE message should be processed by BGP Speaker as
per BGP specification.
Rest all other bits are currently un-used.
Destination AS count - 16-bits field that specifies count of
destination ASNs present in the Destination AS list.
Shah, et al. Expires February 2, 2017 [Page 7]
Internet-Draft Inter-domain SLA Exchange August 2016
This count has no functional value when highest order bit in the
SLA SubType flags field is set to 0. When highest order bit is
set to 1 and if this count is 0 then that is an error condition
which should be handled as described in Section 6.
Source AS - 32-bits field (AS number space as defined in RFC6793)
This is the AS where SLA Content is originated from. The Source
AS MUST be of the same AS that is originating SLA ID and SLA
Content.
When highest order bit in the SLA SubType flags field is set to 0,
this Source AS value MUST be ignored. In such a case SLA ID and
SLA Content of this SLA SubType is intended for the peer receiver
of the BGP UPDATE message.
When highest order bit in the SLA SubType flags field is set to 1,
the Source AS value of 0 is illegal and thus should be considered
an error which should be handled as described in Section 6.
Destination AS list - variable length field that holds as many ASN
identifiers, each is 32-bits (AS number space is defined in
RFC6793), as specified in the Destination AS count field.
List of ASNs for which the SLA is relevant to, each of which is a
32-bit number. If Destination AS count is set to 0 then this
field MUST NOT be included.
SLA Event - 4-bits field with following values:
0x0 = reserved
0x1 = ADVERTISE
0x2 to 0xf = Reserved for future use
The only SLA Event defined in this specification is ADVERTISE.
SLA ID - 16-bits field that specifies identifier which is unique in
the scope of Source AS.
The significance of an SLA ID is in the context of the source that
is advertising SLA Content. The SLA ID is not globally unique but
it MUST be unique within the source AS.
The SLA ID applies to aggregate traffic to prefixes for a given
AFI/SAFI that share the same Source AS and SLA ID.
Shah, et al. Expires February 2, 2017 [Page 8]
Internet-Draft Inter-domain SLA Exchange August 2016
If an advertised SLA ID is different from earlier advertised one,
for the same prefix and from the same Source AS, indicates Source
AS is advertising new SLA Content to replace the previous one
advertised with the same SLA ID.
SLA Length - 12-bits field that specifies the length of the SLA
Content. The length is expressed in octets. The SLA Content is
optional for an advertised SLA ID. If the SLA Content need not be
there, the SLA length field MUST be set to zero in such a case.
SLA Content - A variable length field (optional field)
The SLA Content field contains SLA parameters relevant to
specified SLA SubType. Since the only defined SLA SubType is
ADVERTISE, this specification describes SLA Content only for the
ADVERTISE SLA Event.
If SLA Content field exists in a BGP UPDATE message that contains
the QoS Attribute with an SLA SubType for SLA Event ADVERTISE,
format of the SLA Content is as described in Section 3.3.
If the SLA Content field does not exist, then the advertised
message refers to SLA Content advertised in the previous message
for the same SLA ID. If there does not exist any prior SLA
Content to relate to the advertised SLA ID, then receiver, SLA
Consumer, can ignore the SLA advertisement and it may simply
update Destination AS count and Destination AS list.
The lack of a valid prior SLA Content field does not make this
attribute invalid, so the QoS Attribute MUST be forwarded as a
valid BGP optional transitive attribute.
3.3. SLA Content for ADVERTISE SLA Event
The only SLA Event described in this specification is ADVERTISE. The
format of SLA Content for the ADVERTISE Event is shown in Figure 4.
Shah, et al. Expires February 2, 2017 [Page 9]
Internet-Draft Inter-domain SLA Exchange August 2016
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|dir| Traffic Class count | Class Desc Len| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~
| |
~ Traffic Class Description ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element Count | |
+-+-+-+-+-+-+-+-+ ~
| |
~ Traffic Class Element TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Count| |
+-+-+-+-+-+-+-+-+ ~
| Traffic Class Service TLVs |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Repeat from Traffic Class Description for next Traffic Class ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Repeat from direction for SLA in the other direction ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 - SLA-Content for ADVERTISE SLA Event
SLA Content contains set of Traffic Class Elements (Classifiers) and
Traffic Class Service TLVs for a list of Traffic Classes. This list
of Traffic Classes MUST be specified for one direction first and then
optionally followed by the specification for the other direction.
dir (Direction) - 2-bits field that specifies Direction of the
traffic SLA is applicable to. The following values are defined:
0x0 = reserved
0x1 = incoming, traffic to source AS from destination AS
0x2 = outgoing, traffic from source AS towards destination AS
0x3 = for future use
Shah, et al. Expires February 2, 2017 [Page 10]
Internet-Draft Inter-domain SLA Exchange August 2016
Traffic Class (Classifier Group) count - 16 bits field that
specifies number of Traffic Classes.
The value of zero (0x00) in this field is a special value which
means no SLA for the traffic in a specified direction. When
Traffic Class count is 0, for a specific direction, the rest of
the SLA Content fields MUST NOT be encoded, for that specific
direction.
Traffic Class Description Len - 8-bits field that specifies the
length of the Traffic Class Description field. The length is
expressed in octets.
The value of zero in this field indicates that no Traffic Class
Description field follows.
Traffic Class Description - variable length field, as expressed in
The Traffic Class Description Len field, MUST carry UTF-8 encoded
[RFC3629] description.
Traffic Class Elements (Classifier) Count - 8-bits field that
specifies the count of Traffic Class Elements.
The value zero (0x00) means there are no Traffic Class Elements in
the traffic class, and thus the Traffic Class is to classify rest
of the traffic not captured otherwise by other Traffic Classes in
the set for a specified direction.
Traffic Class that has 0 elements MUST be presented last in the
advertised list of Traffic Classes for a specific Direction.
Otherwise it is considered an error condition which should be
handled as described in Section 6.
The QoS Attribute advertised from a specific source MUST NOT
have more than one such Traffic Classes (Traffic Class with 0
elements count). If there are more than one such Traffic
Classes present then it is an error condition which should be
handled as described in Section 6.
Traffic Class Element TLVs - (optional) variable length field
holding as many TLVs specified by the Traffic Class Elements Count
field. Each TLV has the following format:
IPFIX Element Identifier - 8-bits field that specifies IPFIX
Identifiers listed in Table 1.
Length of Value field - 8-bits field that specifies the length,
expressed in octets, of the value field.
Shah, et al. Expires February 2, 2017 [Page 11]
Internet-Draft Inter-domain SLA Exchange August 2016
Value - A variable field that specifies a value appropriate for
the IPFIX Element Identifier. It is an error, if the value
field does not contain the appropriate format, which should be
handled as described in Section 6. Only the IPFIX elements
shown in Table 1 are supported.
Any Traffic Class Element advertised in the QoS Attribute only
applies to the advertised AFI/SAFI NLRI within the BGP UPDATE
message the QoS Attribute is contained in. If a receiver, SLA
Consumer, receives a BGP UPDATE message with QoS Attribute for an
unsupported AFI/SAFI then SLA Consumer MAY ignore advertised SLA.
SLA Consumer MAY update only Destination AS count and Destination
AS list, and then QoS Attribute and rest of the BGP UPDATE message
MUST be forwarded as per QoS Attribute and BGP protocol
specification.
Traffic Class Service Count - 8-bits field that specifies count of
Traffic Class Service TLVs.
A value of zero is a special value indicating "no bounded service"
(a.k.a., Best Effort (BE)).
Traffic Class Service TLVs - (optional) variable length field with
the following format for the TLVs
Traffic Class Service type - 16-bits field that specifies a
service type. Each service type is detailed in Section 3.3.2.
The list of available service types are,
0x00 = reserved
0x01 = TRAFFIC_CLASS_TSPEC
0x02 = L2_OVERHEAD
0x03 = MINRATE_IN_PROFILE_MARKING
0x04 = MINRATE_OUT_PROFILE_MARKING
0x05 = MAXRATE_IN_PROFILE_MARKING
0x06 = MAXRATE_OUT_PROFILE_MARKING
0x07 = DROP_THRESHOLD
0x08 = RELATIVE_PRIORITY
0x09 = SUB_TRAFFIC_CLASSES
Shah, et al. Expires February 2, 2017 [Page 12]
Internet-Draft Inter-domain SLA Exchange August 2016
Length of Value field - 08-bits field that specifies the length
of the value field. The length of the value is expressed in
octets.
Value - a variable length field that specifies the value
appropriate for each of the Service Types. It is an error, if
this field does not contain the appropriate format, which
should be handled as described in Section 6. The format of the
value for each of the service types is described in
Section 3.3.2
3.3.1. Supported IPFIX identifiers for Traffic Class Elements
IPFIX [RFC7012] has well defined identifier set for a large number of
packet attributes; an IPFIX IANA registry maintains values for packet
classifier attributes (https://www.ietf.org/assignments/ipfix/
ipfix.xml#ipfix-information-elements). Only the IPFIX attributes
listed in Table 1 are supported. Any new attribute to be supported
by SLA SubType MUST be a Standards Action as described in IANA
section.
+----+----------------------------+
| ID | Name |
+----+----------------------------+
|195 | ipDiffServCodePoint |
|203 | mplsTopLabelExp |
|244 | dot1qPriority |
| 8 | sourceIPv4Address |
| 27 | sourceIPv6Address |
| 9 | sourceIPv4PrefixLength |
| 29 | sourceIPv6PrefixLength |
| 44 | sourceIPv4Prefix |
|170 | sourceIPv6Prefix |
| 12 | destinationIPv4Address |
| 28 | destinationIPv6Address |
| 13 | destinationIPv4PrefixLength|
| 30 | destinationIPv6PrefixLength|
| 45 | destinationIPv4Prefix |
|169 | destinationIPv6Prefix |
| 4 | protocolIdentifier |
| 7 | sourceTransportPort |
| 11 | destinationTransportPort |
+----+----------------------------+
Table 1
Shah, et al. Expires February 2, 2017 [Page 13]
Internet-Draft Inter-domain SLA Exchange August 2016
3.3.2. Traffic Class Service types and respective TLVs
3.3.2.1. TRAFFIC_CLASS_TSPEC
The TRAFFIC_CLASS_TSPEC TLV definition:
Type - 0x01
Length - 8-bits field that specifies length, expressed in octets,
of the value field. The length of the value field MUST be
specified to be 12 octets to hold the value defined as per format
below.
Value - TRAFFIC_CLASS_TSPEC value consists of the (r), (b), (p)
parameters as described in Invocation Information section of
[RFC2212] and shown in Figure 5. Note that inheriting the
definition of TSPEC (Traffic SPECification) here does not enable
RFC2212 functionality. Only the format of the Traffic
Specification is used in this specification.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Rate (r) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Size (b) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Rate (p) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5 - Traffic Class TSPEC
Format of Parameters (r), (b) and (p): are 32-bit IEEE floating
point numbers. Positive infinity is represented as an IEEE single
precision floating-point number with an exponent of all ones and a
sign mantissa of all zeros. The format of IEEE floating-point
numbers is further summarized in [RFC4506].
Parameter (r): indicates min-rate of the traffic class. This rate
indicates the minimum rate, measured in octets of Layer 2 (L2)
datagrams per second (a.k.a, bytes per second), that the service
advertiser is providing for a given class of traffic on
advertiser's hop. Note that it does not necessarily translate to
a minimum rate service to the receiver of an SLA unless the
traffic class definition clearly represents a sole receiver of an
SLA. If there is no SLA for min-rate, the value of (r) MUST be
set to 0.
Shah, et al. Expires February 2, 2017 [Page 14]
Internet-Draft Inter-domain SLA Exchange August 2016
Parameter (b): indicates maximum burst size, measured in octets of
L2 datagram size. Since queuing delay can be considered a
function of burst size (b) and min-rate (r), in presence of non-
zero parameter (r), parameter (b) represents bounded delay for the
Traffic Class. This delay is a single hop queuing delay when SLA
is to be implemented at the resource constrained bottleneck. In
other words this burst size can be considered as a buffer size.
Value of 0 for parameter (b) means the advertiser does not mandate
specific bounded delay.
Parameter (p): indicates max-rate of the traffic class. Just like
min-rate, max-rate, measured in octets of L2 datagrams per second
(a.k.a., bytes per second), field here also indicates service
provided by advertiser. If advertiser does not have any specific
value to set for a given class of traffic, it MAY be set to
physical interface line rate or any other indirect limit that may
affect this class' maximum rate. In absence of any such known
value, it MUST be set to positive infinity. Value 0 is considered
an error which should be handled as described in Section 6.
3.3.2.2. L2_OVERHEAD
The L2_OVERHEAD TLV definition:
Type - 0x02
Length - 8-bits field that specifies length, expressed in octets,
of the value field.
Value - Layer 2 overhead in octets
L2_OVERHEAD defines Layer 2 (L2) specific data in octets, on top of
IP datagram size, in a layer 2 frame. By default the rate and burst
advertised in the TRAFFIC_CLASS_TSPEC TLV are applicable to the
packet size including L2 packet overhead. For the SLA Consumer
directly connected to the SLA Producer, this overhead is the L2
overhead of the local link where advertised SLA is received.
However, in cases where advertised SLA is for a SLA Consumer multiple
hops away, L2 overhead from the source, SLA Producer, perspective may
be different from the local link L2 overhead at the receiver, SLA
Consumer. In such cases, explicit notification of size of L2
overhead from the SLA Producer suggests what per packet L2 overhead
is applicable to the rate and burst advertised in the
TRAFFIC_CLASS_TSPEC TLV. L2_OVERHEAD TLV SHOULD BE ignored by the
SLA Consumer if there does not exist TRAFFIC_CLASS_TSPEC TLV for the
specified direction.
Shah, et al. Expires February 2, 2017 [Page 15]
Internet-Draft Inter-domain SLA Exchange August 2016
Advertised L2 value of 0 means SLA advertised is for IP packet size.
3.3.2.3. MINRATE_IN_PROFILE_MARKING
This Traffic Class Service Type defines action performed, by the SLA
Producer, on packets that are compliant to the min-rate specified in
the TRAFFIC_CLASS_TSPEC TLV. If min-rate specified in the
TRAFFIC_CLASS_TSPEC TLV is 0 then TLV for this Traffic Class Service
Type SHOULD NOT be advertised. MINRATE_IN_PROFILE_MARKING TLV SHOULD
BE ignored by the SLA Consumer if there does not exist
TRAFFIC_CLASS_TSPEC TLV for the specified direction, or min-rate
specified in the TRAFFIC_CLASS_TSPEC TLV is 0.
The MINRATE_IN_PROFILE_MARKING TLV definition:
Type - 0x03
Length - 8-bits field that specifies length, expressed in octets,
of the value field. The length of the value field MUST be
specified to be 2 octets to hold the value defined as per format
below.
Value - contains the Marking code-point type and value
Marking code-point type - 8-bits IPFIX Element Identifier.
Marking code-point value - 8-bits code-point number.
The marking code-point type of 0x00 is a drop identifier. When
marking code-point type value is 0x00 (that is drop), the marking
code-point value in this case has no meaning and thus the value in
this field should be ignored.
The following table lists the supported IPFIX Identifiers. Any value
other than 0 or identifier from the following table is an error
condition which should be handled as described in Section 6.
+----+----------------------------+
| ID | Name |
+----+----------------------------+
|195 | ipDiffServCodePoint |
|203 | mplsTopLabelExp |
|244 | dot1qPriority |
+----+----------------------------+
Table 2
Shah, et al. Expires February 2, 2017 [Page 16]
Internet-Draft Inter-domain SLA Exchange August 2016
3.3.2.4. MINRATE_OUT_PROFILE_MARKING
This Traffic Class Service Type defines action performed, at the SLA
Producer, on packets that are not compliant to the min-rate specified
in the TRAFFIC_CLASS_TSPEC TLV. If min-rate specified in the
TRAFFIC_CLASS_TSPEC TLV is 0 then TLV for this Traffic Class Service
Type SHOULD NOT be advertised. MINRATE_OUT_PROFILE_MARKING TLV
SHOULD BE ignored by the SLA Consumer if there does not exist
TRAFFIC_CLASS_TSPEC TLV for the specified direction, or min-rate
specified in the TRAFFIC_CLASS_TSPEC TLV is 0.
The MINRATE_OUT_PROFILE_MARKING TLV definition:
Type - 0x04
Length - 8-bits field that specifies length, expressed in octets,
of the value field. The length of the value field MUST be
specified to be 2 octets to hold the value defined as per format
below.
Value - contains the Marking code-point type and value
Marking code-point type - 8-bits IPFIX Element Identifier
Marking code-point value - 8-bits code-point number
The marking code-point type of 0x00 is a drop identifier. When
marking code-point type value is 0x00 (that is drop), the marking
code-point value in this case has no meaning and thus the value in
this field should be ignored.
Table 2 lists the supported IPFIX Identifiers. Any value other than
0 or identifier from the Table 2 is an error condition which should
be handled as described in Section 6.
3.3.2.5. MAXRATE_IN_PROFILE_MARKING
This Traffic Class Service Type defines action performed, at the SLA
Producer, on packets that are compliant to the max-rate specified in
the TRAFFIC_CLASS_TSPEC TLV. MAXRATE_IN_PROFILE_MARKING TLV SHOULD
BE ignored by the SLA Consumer if there does not exist
TRAFFIC_CLASS_TSPEC TLV for the specified direction.
The MAXRATE_IN_PROFILE_MARKING TLV definition:
Type - 0x05
Shah, et al. Expires February 2, 2017 [Page 17]
Internet-Draft Inter-domain SLA Exchange August 2016
Length - 8-bits field that specifies length, expressed in octets,
of the value field. The length of the value field MUST be
specified to be 2 octets to hold the value defined as per format
below.
Value - contains the Marking code-point type and value
Marking code-point type - 8-bits IPFIX Element Identifier
Marking code-point value - 8-bits code-point number
The marking code-point type of 0x00 is a drop identifier. When
marking code-point type value is 0x00 (that is drop), the marking
code-point value in this case has no meaning and thus the value in
this field should be ignored.
Table 2 lists the supported IPFIX Identifiers. Any value other than
0 or identifier from the Table 2 is an error condition which should
be handled as described in Section 6.
3.3.2.6. MAXRATE_OUT_PROFILE_MARKING
This Traffic Class Service Type defines action performed, at the SLA
Producer, on packets that are not compliant to the max-rate specified
in the TRAFFIC_CLASS_TSPEC TLV. MAXRATE_OUT_PROFILE_MARKING TLV
SHOULD BE ignored by the SLA Consumer if there does not exist
TRAFFIC_CLASS_TSPEC TLV for the specified direction.
The MAXRATE_OUT_PROFILE_MARKING TLV definition:
Type - 0x06
Length - 8-bits field that specifies length, expressed in octets,
of the value field. The length of the value field MUST be
specified to be 2 octets to hold the value defined as per format
below.
Value - contains the Marking code-point type and value
Marking code-point type - 8-bits IPFIX Element Identifier
Marking code-point value - 8-bits code-point number
The marking code-point type of 0x00 is a drop identifier. When
marking code-point type value is 0x00 (that is drop), the marking
code-point value in this case has no meaning and thus the value in
this field should be ignored.
Shah, et al. Expires February 2, 2017 [Page 18]
Internet-Draft Inter-domain SLA Exchange August 2016
Table 2 lists the supported IPFIX Identifiers. Any value other than
0 or identifier from the Table 2 is an error condition which should
be handled as described in Section 6.
3.3.2.7. Precedence between MINRATE and MAXRATE
The precedence between MINRATE_IN_PROFILE_MARKING,
MINRATE_OUT_PROFILE_MARKING, MAXRATE_IN_PROFILE_MARKING, and
MAXRATE_OUT_PROFILE_MARKING when all four are advertised is:
- MINRATE_IN_PROFILE_MARKING takes highest precedence (that is
over MAXRATE_IN_PROFILE_MARKING),
- MAXRATE_IN_PROFILE_MARKING takes precedence over
MINRATE_OUT_PROFILE_MARKING, and
- MAXRATE_OUT_PROFILE_MARKING takes precedence over
MINRATE_OUT_PROFILE_MARKING
3.3.2.8. DROP_THRESHOLD
The DROP_THRESHOLD TLV definition:
Type - 0x07
Length - 8-bits field that specifies length, expressed in octets,
of the value field.
Value - Count of drop thresholds, followed by content for each
drop threshold in the form of (code-point type, count of code-
points, list of code-points, threshold value).
Count of drop thresholds - 8-bits field that specifies number
of drop thresholds specified in this TLV. Content of each drop
threshold is to follow following format
Code-point type - 8-bits IPFIX Element Identifier from the list
shown in Table 6.
Count of code-points - 8-bits field that specifies number of
code-point values to follow for a specified code-point type.
List of code-points - each code-point value is specified in
size of 8 bits and thus total size for this field is 8 bits
multiplied by as many number of code-points specified.
Burst value - This is a fixed size 32-bits IEEE floating point
number that specifies burst value in unit of bytes.
Shah, et al. Expires February 2, 2017 [Page 19]
Internet-Draft Inter-domain SLA Exchange August 2016
+----+----------------------------+
| ID | Name |
+----+----------------------------+
|195 | ipDiffServCodePoint |
|203 | mplsTopLabelExp |
|244 | dot1qPriority |
+----+----------------------------+
Table 3
3.3.2.9. RELATIVE_PRIORITY
The RELATIVE_PRIORITY TLV definition:
Type - 0x08
Length - 8-bits field that specifies length, expressed in octets,
of the value field. Given supported range of priority values in
this specification, the length of the value field MUST be limited
to and thus MUST be specified exactly as 1 octet.
Value - A value from range of 0 - 255. Lower the value means
higher the priority
Relative priority indicates scheduling priority of this traffic
class. Voice traffic, for example, which requires lowest latency
compared to any other traffic, may have lowest value advertised in
relative priority. For two different traffic classification groups
where one application group may be considered more important than the
other but from a scheduling perspective does not require to be
distinguished with a different priority, relative priority for those
classification groups may be advertised with the same value.
3.3.2.10. SUB_TRAFFIC_CLASSES
The SUB_TRAFFIC_CLASSES TLV definition:
Type - 0x09
Length - 16-bits field that specifies total length, expressed in
octets, of a subset of Traffic Class TLVs encoded in the value
field
Value - A subset of Traffic Class TLVs
For SLAs where a specific Traffic Class may further be defined by a
subset of more granular Traffic Classes, each with its own set of
Shah, et al. Expires February 2, 2017 [Page 20]
Internet-Draft Inter-domain SLA Exchange August 2016
Traffic Class Elements and Service types definitions,
SUB_TRAFFIC_CLASSES service type SHOULD be used to specify them.
4. Originating SLA Notification
The QoS Attribute for the SLA SubType MUST only be added to the BGP
UPDATE message at the node that is SLA Producer. Any QoS Attribute
Speaker, in the path to the SLA Consumer MUST NOT modify content of
that attribute except modification of the Destination AS list.
QoS Attribute with the SLA SubType SHOULD NOT be advertised
periodically just for the purpose of KEEPALIVE between SLA Producer
and SLA Consumer. Some sort of SLA policy change, at the SLA
Producer, may be considered as a trigger for the advertisement.
For any modified SLA policy at the SLA Producer, SLA Producer MUST
re-advertise the entire set of SLA parameters. There is no provision
to advertise partial set of SLA parameters. If modified SLA policy
is to mean no SLA between SLA Producer and SLA Consumer, then SLA
Content MUST be sent with the same SLA ID with the same AS Source and
NLRI prefix, as were used to advertise earlier SLA parameters, and
the Traffic Class count set to 0.
4.1. SLA Contexts
4.1.1. SLA Advertisement for Point-to-Point Connection
In certain cases, the advertisement of an SLA is intended to relate
to aggregate traffic over a point-to-point connection between a
specific destination and a specific source. A point-to-point
connection may be a physical link or a virtual link (e.g. a tunnel).
In such cases, a BGP UPDATE message with source AS number and NLRI
prefix as an IP address of an SLA Producer can uniquely identify
physical/virtual link in order to establish the context for the
advertised SLA for that point to point link.
In the simplest case where Provider (e.g., PE) and Customer (e.g.,
CE) devices are directly connected via a physical link and have only
a single link between them, the CE can uniquely identify the
forwarding link to the PE with the following:
o AS number of the PE,
o NLRI prefix being an IP address of the PE, that is the next hop
address from CE to PE.
The SLA advertised in the QoS Attribute in the BGP UPDATE message
sent from the PE to a CE, along with the PE's AS number and PE's IP
Shah, et al. Expires February 2, 2017 [Page 21]
Internet-Draft Inter-domain SLA Exchange August 2016
address, establishes SLA context for the aggregate traffic through
CE-to-PE link.
The SLA advertised in the QoS Attribute in the BGP UPDATE message
from PE to CE, with PE's AS number and any other prefix, means SLA
for that specific prefix based traffic, a subset of traffic through
CE-to-PE link.
Even though this example is in the context of IP prefixes, QoS
Attribute's SLA exchange does not have to be limited to the IP
address family (IPv4 and IPv6). SLA advertisement is generic to all
forms of NLRI types that are supported by the BGP specification (like
IPv4, IPv6, VPN-IPv4, VPN-IPv6).
When BGP UPDATE message with the QoS Attribute, containing SLA
SubType, is triggered for a point-to-point connection (physical or
logical), the Source AS number in the SLA SubType SHOULD BE set to
SLA Producer's AS number and destination AS number SHOULD BE set to
AS number of BGP peer's that is targeted SLA Consumer.
Alternatively, highest order bit in the SLA SubType flags MAY BE set
to ignore Source AS and destination AS values from the SLA SubType
content since SLA advertised is meant specifically for the BGP peer.
4.1.2. SLA Advertisement for Destination AS Multiple Hops Away
When advertised SLA is not for the BGP peer of an SLA Producer, the
Source AS field, in the SLA SubType, MUST be set. The list of
destination AS(es) also MUST be set, in the SLA SubType, to avoid
flooding of the QoS Attribute data in the network beyond those
destinations. Destination AS(es) is a list of SLA Consumers the
advertised SLA is intended for.
If a new prefix is learned and traffic with this new prefix is
subject to SLA parameters that have already been advertised before
for other existing prefixes, then the BGP UPDATE for this new prefix
MAY include QoS Attribute containing just an SLA ID that was
advertised earlier. This BGP UPDATE message does not require to have
the whole SLA Content. The SLA ID is sufficient to relate SLA
parameters to new advertised prefixes.
5. QoS Attribute Handling at Forwarding Nodes
The propagation of the QoS Attribute in the BGP UPDATE messages
depends on the rules detailed in the following sub-sections.
Shah, et al. Expires February 2, 2017 [Page 22]
Internet-Draft Inter-domain SLA Exchange August 2016
5.1. BGP Node Capable of Processing QoS Attribute
If a BGP peer is also a QoS Attribute Speaker, it MAY process the QoS
Attribute. If BGP UPDATE message has a QoS Attribute with a list of
destination ASes, QoS Attribute Speaker MAY trim the list and adjust
the count of the destination AS to exclude ones that are not required
in further announcement of BGP UPDATE messages.
A QoS Attribute Speaker MUST drop SLA SubType from the QoS Attribute,
if there are no more ASes left in the QoS Attribute's destination
list. The rest of the QoS Attribute contents may be forwarded if
there exist other SubTypes of QoS Attribute and forwarding rules meet
other SubTypes requirements. If there is no other SubTypes in that
QoS Attribute content then QoS Attribute Speaker MUST drop the entire
QoS Attribute all together. BGP Speaker MAY announce further other
attributes and NLRI information, if they meet rules defined by other
attributes and BGP specification.
Except extracting the entire SLA SubType of the QoS Attribute and
trimming the list of Destination AS list, all other content MUST NOT
be modified by any QoS Attribute Speaker or BGP Speaker in the path
of a BGP UPDATE message.
5.2. QoS Attribute Handling at Receiver
Once QoS Attribute with the SLA SubType is received at intended
receiver (SLA Consumer) , processing of advertised SLA Content is
optional for the SLA Consumer. SLA Consumer MAY just trim the
Destination AS list as per rules described in this specification,
without processing any other content of the Attribute. If intended
receiver is not a QoS Attribute Speaker than BGP Speaker MUST forward
this attribute without any change if rest of the BGP UPDATE message
also meets forwarding rules as per BGP specification.
When BGP UPDATE messages are triggered only as a result of SLA policy
change, propagating BGP UPDATE message beyond intended SLA Consumers
is not necessary. If the SLA Consumer device implementations are
capable of policy based filtering, it may implement a policy to
filter such BGP UPDATE messages based on prefixes and QoS Attribute
containing SLA SubType.
6. Error Handling
Error conditions, while processing of the QoS Attribute content, MUST
be handled with the approach of attribute discard as described in
[RFC7606]. Processing of QoS Attribute content is done by QoS
Attribute Speaker and thus in case of errors, resulting in attribute
discard, QoS Attribute Speaker SHOULD convey such indication to the
Shah, et al. Expires February 2, 2017 [Page 23]
Internet-Draft Inter-domain SLA Exchange August 2016
BGP Speaker and rest of the BGP message SHOULD BE processed by the
BGP Speaker as per BGP specification.
7. Deployment Considerations
One of the use cases is for a provider to advertise contracted SLA
parameters to a Customer Edge (CE) in cases where eBGP is deployed
between PE and CE. The SLA parameters may already be provisioned by
the provider on the PE device (facing CE). This provisioned SLA
parameters are then advertised thru proposed QoS Attribute to the CE
device. The CE device may read the QoS Attribute and SLA SubType
content to implement the QoS policy on the device.
Contracted SLA from PE to CE may be full line-rate or sub line-rate
or finer granular controlled services. The advertised SLA can be
useful when contracted service is sub-rate of a link and/or when for
finer granular traffic classes that are controlled (e.g. voice, video
services may be capped to certain rate).
_______________
__________ / \
/ \ / \
/ \ / \
|CustomerSite|-----| Provider |
\ C/E P\E /
\__________/ \ /
\_______________/
AS 3 AS 2
SLA_ADVERTISE: AS2 to AS3
NLRI = PE ip address
Figure 6 - Example 1
Another use case can be to advertise SLAs among different network
sites within one Enterprise network. In Hub and Spoke deployments,
Administrator may define SLAs at spoke and advertise QoS SLA
parameters to the Hub thru BGP updates. In Figure 7, each spoke (AS1
and AS2) are connected to Hub (AS3) via a VPN tunnel. As shown in
Figure 7, AS2 can advertise SLA to AS3 in the context of that tunnel
ip address.
Shah, et al. Expires February 2, 2017 [Page 24]
Internet-Draft Inter-domain SLA Exchange August 2016
AS 2
_______________ ________
/ \ / \
_____ / \-----| Spoke2 |
/ \ / \ \________/
| Hub |-----| Provider | ________
\______/ \ / / \
\ /-----| Spoke1 |
AS 3 \_______________/ \________/
AS 1
SLA_ADVERTISE: AS2 to AS3
NLRI = AS2 tunnel address
SLA_ADVERTISE: AS1 to AS3
NLRI = AS1 tunnel address
Figure 7 - Example 2
Deployment options are not limited to involving CEs, PE-to-CE or CE-
to-CE, only. For any contract between two providers, SLA parameters
may be advertised from one to the other.
8. Acknowledgements
Thanks to Fred Baker, David Black, Sue Hares, Benoit Claise and
Alvaro Retana for their suggestions and to Christian Jacquenet, Ken
Briley, Rahul Patel, Fred Yip, Lou Berger, Brian Carpenter, Bertrand
Duvivier, Bruno Decraene for the review.
9. IANA Considerations
This document defines a new BGP optional transitive path attribute,
called QoS Attribute. IANA action is required to allocate a new
code-point in the BGP path Attributes registry.
IANA is requested to create a registry for QoS Attribute SubTypes.
This is a registry of 1 octet value, divided into two pools.One pool
of numbers to be assigned on a standards action/early allocation
basis. The initial assignments are as shown below. The other pool
is for the private use,available range for which is as shown below.
QoS Attribute SubTypes
======================
Reserved 0x00
SLA 0x01
Reserved 0x02-0xf0 (Standards Action)
Private use 0xf1-0xff
Shah, et al. Expires February 2, 2017 [Page 25]
Internet-Draft Inter-domain SLA Exchange August 2016
IANA is requested to create a registry for QoS Attribute SLA SubType
flags. This is registry for 8-bits. The initial assignments are as
shown below.
QoS Attribute SLA SubType Flags
===============================
Highest order bit (bit 0) - to indicate source and destination AS context
Reserved - bits 1 to 15 (Standards Action)
IANA is requested to create a registry for QoS Attribute SLA Event
Types. This is a registry of 4-bits value, divided into two pools.
One pool of numbers to be assigned on a standards action/early
allocation basis. One pool of numbers to be assigned on a standards
action/early allocation basis. The initial assignments are as shown
below. The other pool is for the private use, available range for
which is as shown below.
QoS Attribute SLA Event Types
=============================
Reserved 0x0
ADVERTISE 0x1
Reserved 0x2 - 0xc (Standards Action)
Private use 0xd - 0xf
IANA is requested to create a registry to define QoS Attribute SLA
Direction. This is the direction in forwarding path, advertised QoS
SLA is applicable to. This is a 2-bit registry. Values for QoS
Attribute SLA direction are:
QoS Attribute SLA Direction
===========================
Reserved 0x0
To source AS from destination AS 0x1
From source AS to destination AS 0x2
Reserved (Standards Action) 0x3
QoS Attribute SLA Traffic Class Element Types will be referring to
existing IPFIX IANA types as listed in Table 1. While IPFIX registry
is maintained by IANA out of scope of this specification, the use of
IPFIX identifiers for this specification are limited to what is
described in Table 1. Any new addition of IPFIX identifiers to this
table should be a Standards Action.
IANA is requested to create a registry for QoS Attribute SLA Traffic
Class Service Types. This is a registry of 2 octet values, to be
assigned on a standards action/early allocation basis. The initial
assignments are:
Shah, et al. Expires February 2, 2017 [Page 26]
Internet-Draft Inter-domain SLA Exchange August 2016
Traffic Class Service Type Value
============================ ======
Reserved 0x00
TRAFFIC_CLASS_TSPEC 0x01
L2_OVERHEAD 0x02
MINRATE_IN_PROFILE_MARKING 0x03
MINRATE_OUT_PROFILE_MARKING 0x04
MAXRATE_IN_PROFILE_MARKING 0x05
MAXRATE_OUT_PROFILE_MARKING 0x06
DROP_THRESHOLD 0x07
RELATIVE_PRIORITY 0x08
SUB_TRAFFIC_CLASSES 0x09
Standards Action 0x0A - 0x3FFF
FCFS 0x4000 - 0x4FF0
10. Security Considerations
BGP security vulnerabilities analysis is documented in [RFC4272]
while BGP-related security considerations are discussed in [RFC4271].
Also, the reader may refer to [RFC7132] for more details about BGP
path threat model. Rest of the content in this section discusses
additional privacy and security considerations that are applicable to
the attribute defined in this document.
The information conveyed in the QoS Attribute SLA SubType reveals
sensitive data that should not be exposed publicly to non-authorized
parties. Deployment considerations mainly target use of QoS
Attribute and SLA SubType in managed networks and those where a trust
relationship is in place (Customer to Provider, or Provider to
Provider). It is NOT RECOMMENDED to enable this attribute at the
scale of the Internet unless if means to prevent leaking sensitive
information are enforced.
The attribute may be advertised by a misbehaving node to communicate
SLA parameters that are not aligned with the SLA agreements. Though
the enforcement of SLA parameters is outside the scope of this
document, it is RECOMMENDED that the SLA Consumer to enforce a set of
validation checks before translating the SLA parameters conveyed in
the QoS attributes into provisioning actions. Such validations MAY
rely on SLA parameters lime the origin AS or SLA ID, like generating
SLA ID using pseudo-random schemes [RFC4086].
Means to prevent route hijacking SHOULD BE considered. Such means
include RPKI based origin validation [RFC7115] and BGP Path
validation (e.g., [I-D.ietf-sidr-bgpsec-protocol]).
Shah, et al. Expires February 2, 2017 [Page 27]
Internet-Draft Inter-domain SLA Exchange August 2016
11. References
11.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212,
DOI 10.17487/RFC2212, September 1997,
<http://www.rfc-editor.org/info/rfc2212>.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 2434,
DOI 10.17487/RFC2434, October 1998,
<http://www.rfc-editor.org/info/rfc2434>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <http://www.rfc-editor.org/info/rfc3629>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<http://www.rfc-editor.org/info/rfc4272>.
[RFC4506] Eisler, M., Ed., "XDR: External Data Representation
Standard", STD 67, RFC 4506, DOI 10.17487/RFC4506, May
2006, <http://www.rfc-editor.org/info/rfc4506>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012,
<http://www.rfc-editor.org/info/rfc6793>.
[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model
for IP Flow Information Export (IPFIX)", RFC 7012,
DOI 10.17487/RFC7012, September 2013,
<http://www.rfc-editor.org/info/rfc7012>.
Shah, et al. Expires February 2, 2017 [Page 28]
Internet-Draft Inter-domain SLA Exchange August 2016
[RFC7115] Bush, R., "Origin Validation Operation Based on the
Resource Public Key Infrastructure (RPKI)", BCP 185,
RFC 7115, DOI 10.17487/RFC7115, January 2014,
<http://www.rfc-editor.org/info/rfc7115>.
[RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security",
RFC 7132, DOI 10.17487/RFC7132, February 2014,
<http://www.rfc-editor.org/info/rfc7132>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015,
<http://www.rfc-editor.org/info/rfc7606>.
11.2. Informative References
[I-D.ietf-netconf-restconf]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", draft-ietf-netconf-restconf-15 (work in
progress), July 2016.
[I-D.ietf-sidr-bgpsec-protocol]
Lepinski, M. and K. Sriram, "BGPsec Protocol
Specification", draft-ietf-sidr-bgpsec-protocol-17 (work
in progress), June 2016.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<http://www.rfc-editor.org/info/rfc2475>.
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<http://www.rfc-editor.org/info/rfc4086>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<http://www.rfc-editor.org/info/rfc6020>.
Shah, et al. Expires February 2, 2017 [Page 29]
Internet-Draft Inter-domain SLA Exchange August 2016
[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,
<http://www.rfc-editor.org/info/rfc6241>.
[RFC7297] Boucadair, M., Jacquenet, C., and N. Wang, "IP
Connectivity Provisioning Profile (CPP)", RFC 7297,
DOI 10.17487/RFC7297, July 2014,
<http://www.rfc-editor.org/info/rfc7297>.
[RFC7674] Haas, J., Ed., "Clarification of the Flowspec Redirect
Extended Community", RFC 7674, DOI 10.17487/RFC7674,
October 2015, <http://www.rfc-editor.org/info/rfc7674>.
Authors' Addresses
Shitanshu Shah
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
US
Email: svshah@cisco.com
Keyur Patel
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
US
Email: keyupate@cisco.com
Sandeep Bajaj
Juniper Network
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Email: sbajaj@juniper.net
Shah, et al. Expires February 2, 2017 [Page 30]
Internet-Draft Inter-domain SLA Exchange August 2016
Luis Tomotaki
Verizon
400 International
Richardson, TX 75081
US
Email: luis.tomotaki@verizon.com
Mohamed Boucadair
Orange
Rennes
35000
France
Email: mohamed.boucadair@orange.com
Shah, et al. Expires February 2, 2017 [Page 31]