Internet DRAFT - draft-ietf-idr-sla-exchange
draft-ietf-idr-sla-exchange
IDR S. Shah
Internet-Draft
Intended status: Standards Track K. Patel
Expires: August 2, 2018 Arrcus, Inc
S. Bajaj
Viptela
L. Tomotaki
Verizon
M. Boucadair
Orange
January 29, 2018
Inter-domain Traffic Conditioning Agreement (TCA) Exchange Attribute
draft-ietf-idr-sla-exchange-13.txt
Abstract
Network administrators typically enforce Quality of Service (QoS)
policies according to Traffic Conditioning Agreement (TCA) with their
providers. The enforcement of such policies often relies upon
vendor-specific configuration language. Both learning of TCA, either
thru TCA 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
TCA 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 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 August 2, 2018.
Shah, et al. Expires August 2, 2018 [Page 1]
Internet-Draft Inter-domain TCA Exchange January 2018
Copyright Notice
Copyright (c) 2018 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
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. TCA SubType . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. TCA Content for ADVERTISE TCA Event . . . . . . . . . . . 9
3.3.1. Supported IPFIX identifiers for Traffic Class
Elements . . . . . . . . . . . . . . . . . . . . . . 12
3.3.2. Traffic Class Service types and respective TLVs . . . 15
4. Originating TCA Notification . . . . . . . . . . . . . . . . 22
4.1. TCA Contexts . . . . . . . . . . . . . . . . . . . . . . 23
4.1.1. TCA Advertisement for Point-to-Point Connection . . . 23
4.1.2. TCA Advertisement for Destination AS Multiple Hops
Away . . . . . . . . . . . . . . . . . . . . . . . . 24
5. QoS Attribute Handling at Forwarding Nodes . . . . . . . . . 24
5.1. BGP Node Capable of Processing QoS Attribute . . . . . . 24
5.2. QoS Attribute Handling at Receiver . . . . . . . . . . . 25
6. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 25
7. Deployment Considerations . . . . . . . . . . . . . . . . . . 25
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
9. Security Considerations . . . . . . . . . . . . . . . . . . . 28
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 29
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
11.1. Normative References . . . . . . . . . . . . . . . . . . 29
11.2. Informative References . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
Shah, et al. Expires August 2, 2018 [Page 2]
Internet-Draft Inter-domain TCA Exchange January 2018
1. Introduction
Typically there is a contractual Traffic Conditioning Agreement (TCA)
for Quality of Service (QoS) established between a customer and a
provider or between providers [RFC7297]. This QoS TCA 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 TCA is established, QoS TCA 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 TCA to QoS policies using
router (vendor) specific provisioning language. In a multi-vendor
network, translating TCAs 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 TCA agreements into technical clauses
and configurations and thus both the steps of out of band learning of
negotiated TCA and provisioning them in a vendor specific language
can be complex and error-prone.
TCA parameters may have to be exchanged through organizational
boundaries, thru TCA 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 TCA policy described in this
document does not require any specific method for the provider in
establishing TCAs. It only requires that the provider wishes to send
the QoS TCA 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 TCA negotiation and assurance is outside the
scope of this document.
Shah, et al. Expires August 2, 2018 [Page 3]
Internet-Draft Inter-domain TCA Exchange January 2018
This document defines a new optional BGP transitive attribute,
referred as QoS Attribute, which has as one of its sub-types the TCA
policy. The BGP node of the originating AS sends this QoS Attribute,
for prefixes this QoS TCA Policy applies to, in a BGP UPDATE message
that will be distributed to a list of destination ASes. The QoS TCA
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
[RFC8040] 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", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
This document makes use of the following terms:
o BGP Speaker: A functional component on a BGP capable device that
functions as per BGP specification.
o BGP peers: BGP Speakers adjacent to each other.
o 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.
o 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
Shah, et al. Expires August 2, 2018 [Page 4]
Internet-Draft Inter-domain TCA Exchange January 2018
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 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 TCA parameters
exchange, following roles are defined further within the scope of
the QoS Attribute Speaker.
o TCA Producer: This is a QoS Attribute Speaker that produces QoS
Attribute for the TCA SubType.
o TCA Consumer: This is a QoS Attribute Speaker that is intended
receiver of QoS Attribute with the TCA 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: QoS attribute
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 August 2, 2018 [Page 5]
Internet-Draft Inter-domain TCA Exchange January 2018
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 = TCA
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 TCA 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
Shah, et al. Expires August 2, 2018 [Page 6]
Internet-Draft Inter-domain TCA Exchange January 2018
length, that contains information about a specified SubType. For
the TCA SubType the information is about sender and receiver(s),
and TCA parameters as described in Section 3.2.
3.2. TCA SubType
Format of the TCA 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCA SubType flags | Destination AS count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source AS (Advertiser) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| variable list of Destination AS |
~ .... ~
| .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|TCAEvnt| TCA ID | TCA length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCA Content for TCA Event |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Format of the TCA SubType of the QoS attribute
TCA SubType flags - 16-bits field
Currently un-used. All bits in this field MUST be set to 0. The
field is defined for the future use.
Destination AS count - 16-bits field that specifies count of
destination ASNs present in the Destination AS list.
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 TCA Content is originated from. The Source
AS MUST be of the same AS that is originating TCA ID and TCA
Content.
Shah, et al. Expires August 2, 2018 [Page 7]
Internet-Draft Inter-domain TCA Exchange January 2018
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 TCA is relevant to, each of which is a
32-bit number.
TCA Event - 4-bits field with following values:
0x0 = reserved
0x1 = ADVERTISE
0x2 to 0xf = Reserved for future use
The only TCA Event defined in this specification is ADVERTISE.
TCA ID - 16-bits field that specifies identifier which is unique in
the scope of Source AS.
The significance of a TCA ID is in the context of the source that
is advertising TCA Content. The TCA ID is not globally unique but
it MUST be unique within the source AS.
The TCA ID applies to aggregate traffic to prefixes for a given
AFI/SAFI that share the same Source AS and TCA ID.
TCA Length - 12-bits field that specifies the length of the TCA
Content. The length is expressed in octets. The TCA Content is
optional for an advertised TCA ID. If the TCA Content need not be
there, the TCA length field MUST be set to zero in such a case.
TCA Content - A variable length field (optional field)
The TCA Content field contains TCA parameters relevant to
specified TCA SubType. Since the only defined TCA SubType is
ADVERTISE, this specification describes TCA Content only for the
ADVERTISE TCA Event.
If TCA Content field exists in a BGP UPDATE message that contains
the QoS Attribute with a TCA SubType for TCA Event ADVERTISE,
format of the TCA Content is as described in Section 3.3.
Shah, et al. Expires August 2, 2018 [Page 8]
Internet-Draft Inter-domain TCA Exchange January 2018
If the TCA Content field does not exist, then the advertised
message refers to TCA Content advertised in the previous message
for the same TCA ID. If there does not exist any prior TCA
Content to relate to the advertised TCA ID, then receiver, TCA
Consumer, can ignore the TCA advertisement and it may simply
update Destination AS count and Destination AS list.
The lack of a valid prior TCA Content field does not make this
attribute invalid, so the QoS Attribute MUST be forwarded as a
valid BGP optional transitive attribute.
3.3. TCA Content for ADVERTISE TCA Event
The only TCA Event described in this specification is ADVERTISE. The
format of TCA Content for the ADVERTISE Event is shown in Figure 4.
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 TCA in the other direction ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: TCA-Content for ADVERTISE TCA Event
Shah, et al. Expires August 2, 2018 [Page 9]
Internet-Draft Inter-domain TCA Exchange January 2018
TCA Content contains Traffic Class TLVs that is a set of Traffic
Class Elements (Classifiers) and Traffic Class Service TLVs for a
list of Traffic Classes specified by Traffic Class count. This
Traffic Class TLVs 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 TCA 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
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 TCA for the traffic in a specified direction. When
Traffic Class count is 0, for a specific direction, the rest of
the TCA 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.
Shah, et al. Expires August 2, 2018 [Page 10]
Internet-Draft Inter-domain TCA Exchange January 2018
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.
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, TCA
Consumer, receives a BGP UPDATE message with QoS Attribute for an
unsupported AFI/SAFI then TCA Consumer MAY ignore advertised TCA.
TCA 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,
Shah, et al. Expires August 2, 2018 [Page 11]
Internet-Draft Inter-domain TCA Exchange January 2018
0x00 = reserved
0x01 = COMMITTED_TSPEC
0x02 = PEAK_TSPEC
0x03 = COMMITTED_IN_PROFILE_MARKING
0x04 = COMMITTED_OUT_PROFILE_MARKING
0x05 = PEAK_OUT_PROFILE_MARKING
0x06 = DROP_THRESHOLD
0x07 = RELATIVE_PRIORITY
0x08 = EFFECTIVE_MAX_RATE
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> ipfix.xml#ipfix-information-
elements). Only the IPFIX attributes listed in Table 1 are
supported. Any new attribute to be supported by TCA SubType MUST be
a Standards Action as described in IANA section.
+-----+-----------------------------+-------------------------------+
| ID | Name | Context |
+-----+-----------------------------+-------------------------------+
| 195 | ipDiffServCodePoint | Indicates the value of the |
| | | marking used in the link(s) |
| | | between the TCA Consumer and |
| | | TCA Producer domains. |
+-----+-----------------------------+-------------------------------+
| 203 | mplsTopLabelExp | Indicates the value of the |
| | | marking used in the link(s) |
| | | between the TCA Consumer and |
Shah, et al. Expires August 2, 2018 [Page 12]
Internet-Draft Inter-domain TCA Exchange January 2018
| | | TCA Producer domains. |
+-----+-----------------------------+-------------------------------+
| 244 | dot1qPriority | Indicates the value of the |
| | | marking used in the link(s) |
| | | between the TCA Consumer and |
| | | TCA Producer domains. |
+-----+-----------------------------+-------------------------------+
| 8 | sourceIPv4Address | Indicates the source IPv4 |
| | | address of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 27 | sourceIPv6Address | Indicates the source IPv6 |
| | | address of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 9 | sourceIPv4PrefixLength | Indicates the length of the |
| | | source IPv4 prefix. |
+-----+-----------------------------+-------------------------------+
| 29 | sourceIPv6PrefixLength | Indicates the length of the |
| | | source IPv6 prefix. |
+-----+-----------------------------+-------------------------------+
| 44 | sourceIPv4Prefix | Indicates the source IPv4 |
| | | prefix of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 170 | sourceIPv6Prefix | Indicates the source IPv6 |
| | | prefix of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 12 | destinationIPv4Address | Indicates the destination |
| | | IPv4 address of an aggregate |
| | | traffic over a connection |
Shah, et al. Expires August 2, 2018 [Page 13]
Internet-Draft Inter-domain TCA Exchange January 2018
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 28 | destinationIPv6Address | Indicates the destination |
| | | IPv6 address of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 13 | destinationIPv4PrefixLength | Indicates the length of the |
| | | destination IPv4 prefix. |
+-----+-----------------------------+-------------------------------+
| 30 | destinationIPv6PrefixLength | Indicates the length of the |
| | | destination IPv6 prefix. |
+-----+-----------------------------+-------------------------------+
| 45 | destinationIPv4Prefix | Indicates the destination |
| | | IPv4 prefix of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 169 | destinationIPv6Prefix | Indicates the destination |
| | | IPv6 prefix of an aggregate |
| | | traffic over a connection |
| | | subject to a TCA; the |
| | | direction is being explicitly |
| | | indicated in the ADVERTISE |
| | | Event message. |
+-----+-----------------------------+-------------------------------+
| 4 | protocolIdentifier | Indicates whether any or a |
| | | specific protocol for the |
| | | traffic class. |
+-----+-----------------------------+-------------------------------+
| 7 | sourceTransportPort | This parameter is used only |
| | | for protocols with port |
| | | identifiers. It indicates the |
| | | source port number for the |
| | | transport protocol identified |
| | | by "protocolIdentifier". |
+-----+-----------------------------+-------------------------------+
| 11 | destinationTransportPort | This parameter is used only |
| | | for protocols with port |
Shah, et al. Expires August 2, 2018 [Page 14]
Internet-Draft Inter-domain TCA Exchange January 2018
| | | identifiers. It indicates the |
| | | destination port number for |
| | | the transport protocol |
| | | identified by |
| | | "protocolIdentifier". |
+-----+-----------------------------+-------------------------------+
Table 1
3.3.2. Traffic Class Service types and respective TLVs
3.3.2.1. COMMITTED_TSPEC
The COMMITTED_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 8 octets to hold the value defined as per format
below.
Value - COMMITTED_TSPEC value consists of the (r), (b) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rate (r) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Size (b) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Traffic Class COMMITTED_TSPEC
Format of Parameters (r) and (b): 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 committed-rate of the traffic class. This
Shah, et al. Expires August 2, 2018 [Page 15]
Internet-Draft Inter-domain TCA Exchange January 2018
rate indicates the minimum rate, measured in octets of IP
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 a TCA unless the traffic
class definition clearly represents a sole receiver of a TCA.
Parameter (b): indicates maximum burst size, measured in octets of
IP datagram size. Since queuing delay can be considered a
function of burst size (b) and committed-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
TCA 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.
3.3.2.2. PEAK_TSPEC
The PEAK_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 8 octets to hold the value defined as per format
below.
Value - PEAK_TSPEC value consists of the (r), (b) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rate (r) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Size (b) (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Traffic Class PEAK_TSPEC
Format of Parameters (r) and (b): are 32-bit IEEE floating point
Shah, et al. Expires August 2, 2018 [Page 16]
Internet-Draft Inter-domain TCA Exchange January 2018
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 peak-rate of the traffic class. This rate
indicates the maximum rate, measured in octets of IP 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.
Parameter (b): indicates maximum burst size, measured in octets of
IP datagram size.
When PEAK_TSPEC TLV is advertised, COMMITTED_TSPEC TLV MUST be
present in the advertisement. Advertisement of PEAK_TSPEC TLV
without COMMITTED_TSPEC TLV MUST be considered an error condition
which should be handled as described in Section 6. If committed-rate
of the TCA is 0 then rate advertised in the COMMITTED_TSPEC shall be
0. Note that existence of COMMITTED_TSPEC in TCA advertisement is
not mandatory nor is it a mandate that COMMITTED_TSPEC and PEAK_TSPEC
must always go together. COMMITTED_TSPEC TLV is optional but only
when there is no PEAK_TSPEC TLV present in the advertised TCA.
PEAK_TSPEC TLV with rate value of 0 MUST be considered an error
condition which should be handled as described in Section 6.
3.3.2.3. COMMITTED_IN_PROFILE_MARKING
This Traffic Class Service Type defines action performed, by the TCA
Producer, on packets that are compliant to the committed-rate
specified in the COMMITTED_TSPEC TLV. If committed-rate specified in
the COMMITTED_TSPEC TLV is 0 then TLV for this Traffic Class Service
Type SHOULD NOT be advertised. COMMITTED_IN_PROFILE_MARKING TLV
SHOULD be ignored by the TCA Consumer if there does not exist
COMMITTED_TSPEC TLV for the specified direction, or committed-rate
specified in the COMMITTED_TSPEC TLV is 0.
The COMMITTED_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
Shah, et al. Expires August 2, 2018 [Page 17]
Internet-Draft Inter-domain TCA Exchange January 2018
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
3.3.2.4. COMMITTED_OUT_PROFILE_MARKING
This Traffic Class Service Type defines action performed, at the TCA
Producer, on packets that are not compliant to the committed-rate
specified in the COMMITTED_TSPEC TLV, and compliant to rate specified
in the PEAK_TSPEC TLV if PEAK_TSPEC TLV exists.
The COMMITTED_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
Shah, et al. Expires August 2, 2018 [Page 18]
Internet-Draft Inter-domain TCA Exchange January 2018
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. PEAK_OUT_PROFILE_MARKING
This Traffic Class Service Type defines action performed, at the TCA
Producer, on packets that are not compliant to the max-rate specified
in the PEAK_TSPEC TLV. PEAK_OUT_PROFILE_MARKING TLV SHOULD be
ignored by the TCA Consumer if there does not exist PEAK_TSPEC TLV
for the specified direction.
The PEAK_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.
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. DROP_THRESHOLD
The DROP_THRESHOLD TLV definition:
Shah, et al. Expires August 2, 2018 [Page 19]
Internet-Draft Inter-domain TCA Exchange January 2018
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.
All advertised drop thresholds, for a specific traffic class, are
applicable to a single queue associated with that traffic class. A
threshold for a set of code-points is a logical marker where an
arrived packet is to be dropped if overall depth of a queue is beyond
a threshold of a code-point set a packet is classified into. Choice
of dropping discipline is implementation specific. If a packet can
not be classified into any of the advertised code-point set then that
means the TCA Producer is not defining any specific dropping behavior
and thus dropping behavior is subject to implementation specific of
the TCA Consumer.
+-----+---------------------+
| ID | Name |
+-----+---------------------+
| 195 | ipDiffServCodePoint |
| 203 | mplsTopLabelExp |
| 244 | dot1qPriority |
+-----+---------------------+
Table 3
Shah, et al. Expires August 2, 2018 [Page 20]
Internet-Draft Inter-domain TCA Exchange January 2018
3.3.2.7. 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 classification 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 should be advertised with the same value.
A higher priority class of traffic to be served without pre-empted by
lower priority class of traffic for more than a packet time at the
configured rate.
For a system that implements WRR only (i.e., no priority queuing), it
is possible to use a hierarchical WRR scheduling to achieve a
behavior close to priority queueing where a root scheduling node has
two child nodes. One child node is a queue assigned with a maximum
possible value of a weight and advertised rate of highest priority
Traffic Class as output bandwidth. The other child node is a
scheduling node serving group of rest other advertised Traffic
Classes (in the form of queues or yet another level of hierarchical
WRR scheduler). Note that implementation specifics are out of the
scope of this specification and this is an example to highlight how
relative priority attribute can be relevant and treated by a system
that implements only WRR. A system may choose to implement alternate
methods to achieve a similar behavior.
3.3.2.8. EFFECTIVE_MAX_RATE
The EFFECTIVE_MAX_RATE TLV definition:
Type - 0x02
Shah, et al. Expires August 2, 2018 [Page 21]
Internet-Draft Inter-domain TCA Exchange January 2018
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 5 octets to hold the value defined as per format
below.
Value - Contains value of rate and per packet overhead
Aggregate max rate - 32-bits IEEE floating point number
Per packet overhead - 8-bits specifying value of overhead
octets
Aggregate max rate indicates rate measured based on combined octets
of packet's IP datagram size and advertised per packet overhead.
A packet traversing from the TCA Producer to the TCA Consumer or
vice-versa may see packet overhead, additional octets on top of IP
datagram size, difference between the Producer and the Consumer sent
or received over a physical link. In cases, where advertised TCA is
for a Consumer where total traffic between Consumer and Producer is
to be capped to a specific sub-rate of a physical link, due to packet
overhead differences between Producer and Consumer, sum of traffic
from each TRAFFIC CLASS may overrun that total cap causing undesired
behavior. In such cases, Producer can explicitly notify this TLV in
advertised TCA.
4. Originating TCA Notification
The QoS Attribute for the TCA SubType MUST only be added to the BGP
UPDATE message at the node that is TCA Producer. Any QoS Attribute
Speaker, in the path to the TCA Consumer MUST NOT modify content of
that attribute except modification of the Destination AS list.
QoS Attribute with the TCA SubType SHOULD NOT be advertised
periodically just for the purpose of KEEPALIVE between TCA Producer
and TCA Consumer. Some sort of TCA policy change, at the TCA
Producer, may be considered as a trigger for the advertisement.
For any modified TCA policy at the TCA Producer, the TCA Producer
MUST re-advertise the entire set of TCA parameters. There is no
provision to advertise partial set of TCA parameters. Announcing a
TCA ID different from an earlier advertised one, for the same prefix
and from the same Source AS, indicates Source AS is advertising new
TCA Content to replace the previous one advertised with the same TCA
ID.
Shah, et al. Expires August 2, 2018 [Page 22]
Internet-Draft Inter-domain TCA Exchange January 2018
In order to withdraw a given TCA between TCA Producer and TCA
Consumer, the TCA Produced MUST sent TCA Content with the same TCA
ID, AS Source, and NLRI prefix, as were used to advertise earlier TCA
parameters, and the Traffic Class count MUST be set to 0.
4.1. TCA Contexts
4.1.1. TCA Advertisement for Point-to-Point Connection
In certain cases, the advertisement of a TCA 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 a TCA Producer can uniquely identify physical/virtual link
in order to establish the context for the advertised TCA 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 TCA 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
address, establishes TCA context for the aggregate traffic through
CE-to-PE link.
The TCA advertised in the QoS Attribute in the BGP UPDATE message
from PE to CE, with PE's AS number and any other prefix, means TCA
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 TCA exchange does not have to be limited to the IP
address family (IPv4 and IPv6). TCA 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 TCA
SubType, is triggered for a point-to-point connection (physical or
logical), the Source AS number in the TCA SubType SHOULD be set to
Shah, et al. Expires August 2, 2018 [Page 23]
Internet-Draft Inter-domain TCA Exchange January 2018
TCA Producer's AS number and destination AS number SHOULD be set to
AS number of BGP peer's that is targeted TCA Consumer.
4.1.2. TCA Advertisement for Destination AS Multiple Hops Away
When advertised TCA is not for the BGP peer of a TCA Producer, the
Source AS field, in the TCA SubType, MUST be set. The list of
destination AS(es) also MUST be set, in the TCA SubType, to avoid
flooding of the QoS Attribute data in the network beyond those
destinations. Destination AS(es) is a list of TCA Consumers the
advertised TCA is intended for.
If a new prefix is learned and traffic with this new prefix is
subject to TCA 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 a TCA ID that was
advertised earlier. This BGP UPDATE message does not require to have
the whole TCA Content. The TCA ID is sufficient to relate TCA
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.
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 TCA 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 TCA 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.
Shah, et al. Expires August 2, 2018 [Page 24]
Internet-Draft Inter-domain TCA Exchange January 2018
5.2. QoS Attribute Handling at Receiver
Once QoS Attribute with the TCA SubType is received at intended
receiver (TCA Consumer) , processing of advertised TCA Content is
optional for the TCA Consumer. TCA Consumer MAY just trim the
Destination AS list as per rules described in this specification,
without processing any other content of the Attribute. If Receiver
chooses to process advertised TCA content, it may encounter errors
beyond the ones described in this document, errors like
unavailability of resources if Receiver chooses to implement policies
for advertised TCA. In such a case Receiver MAY simply log a
message. QoS attribute still MUST be forwarded as per rules defined
in this document and rest of the BGP UPDATE message MUST be processed
as per BGP specification. 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 TCA policy
change, propagating BGP UPDATE message beyond intended TCA Consumers
is not necessary. If the TCA 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 TCA 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
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 TCA
parameters to a Customer Edge (CE) in cases where eBGP is deployed
between PE and CE. The TCA parameters may already be provisioned by
the provider on the PE device (facing CE). This provisioned TCA
parameters are then advertised thru proposed QoS Attribute to the CE
device. The CE device may read the QoS Attribute and TCA SubType
content to implement the QoS policy on the device.
Contracted TCA from PE to CE may be full line-rate or sub line-rate
or finer granular controlled services. The advertised TCA can be
useful when contracted service is sub-rate of a link and/or when for
Shah, et al. Expires August 2, 2018 [Page 25]
Internet-Draft Inter-domain TCA Exchange January 2018
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
TCA_ADVERTISE: AS2 to AS3
NLRI = PE ip address
Figure 7: - Example 1
Another use case can be to advertise TCAs among different network
sites within one Enterprise network. In Hub and Spoke deployments,
Administrator may define TCAs at spoke and advertise QoS TCA
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 TCA to AS3 in the context of that tunnel
ip address.
AS 2
_______________ ________
/ \ / \
_____ / \-----| Spoke2 |
/ \ / \ \________/
| Hub |-----| Provider | ________
\______/ \ / / \
\ /-----| Spoke1 |
AS 3 \_______________/ \________/
AS 1
TCA_ADVERTISE: AS2 to AS3
NLRI = AS2 tunnel address
TCA_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, TCA parameters
may be advertised from one to the other.
Shah, et al. Expires August 2, 2018 [Page 26]
Internet-Draft Inter-domain TCA Exchange January 2018
8. 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
TCA 0x01
Reserved 0x02-0xf0 (Standards Action)
Private use 0xf1-0xff
IANA is requested to create a registry for QoS Attribute TCA 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 TCA 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 TCA
Direction. This is the direction in forwarding path, advertised QoS
TCA is applicable to. This is a 2-bit registry. Values for QoS
Attribute TCA direction are:
QoS Attribute TCA Direction
===========================
Reserved 0x0
To source AS from destination AS 0x1
From source AS to destination AS 0x2
Reserved (Standards Action) 0x3
QoS Attribute TCA Traffic Class Element Types will be referring to
existing IPFIX IANA types as listed in Table 1. While IPFIX registry
Shah, et al. Expires August 2, 2018 [Page 27]
Internet-Draft Inter-domain TCA Exchange January 2018
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 TCA 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:
Traffic Class Service Type Value
============================ ======
Reserved 0x00
COMMITTED_TSPEC 0x01
PEAK_TSPEC 0x02
COMMITTED_IN_PROFILE_MARKING 0x03
COMMITTED_OUT_PROFILE_MARKING 0x04
PEAK_OUT_PROFILE_MARKING 0x05
DROP_THRESHOLD 0x06
RELATIVE_PRIORITY 0x07
EFFECTIVE_MAX_RATE 0x08
Standards Action 0x09 - 0x3FFF
FCFS 0x4000 - 0x4FF0
9. 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. Means to prevent route hijacking SHOULD be
enabled. Such means include RPKI based origin validation [RFC7115]
and BGP Path validation (e.g., [I-D.ietf-sidr-bgpsec-protocol]).
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 TCA SubType reveals
sensitive data that should not be exposed publicly to non-authorized
parties. Deployment considerations mainly target use of QoS
Attribute and TCA SubType in managed networks and those where a trust
relationship is in place (Customer to Provider, or Provider to
Provider). Administrators MUST disable this attribute to be sent to
a remote peer which whom no trust relationship is in place. Both TCA
Producer and Consumer SHOULD NOT publish valid TCA IDs to non-
authorized nodes.
Shah, et al. Expires August 2, 2018 [Page 28]
Internet-Draft Inter-domain TCA Exchange January 2018
The attribute may be advertised by a misbehaving node to communicate
TCA parameters that are not aligned with the TCA agreements. The
enforcement of TCA parameters is outside the scope of this document.
The attribute defined in this document may be used by a misbehaving
node for denial-of-service (e.g., inadequately rate-limit or drop
some critical traffic). As a mitigation, a BGP peer MUST accept this
attribute only from trusted BGP peers. For example, ACLs may be
configured to identify the trusted ASes that are allowed to send the
attribute. Further, administrators of a TCA Consumer's domain are
RECOMMENDED to generate TCA ID using pseudo-random schemes [RFC4086].
Using robust TCA IDs make it hard to guess a valid TCA.
10. 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, David Black, and Ron Bonica for the review.
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,
<https://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,
<https://www.rfc-editor.org/info/rfc2212>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <https://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,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4506] Eisler, M., Ed., "XDR: External Data Representation
Standard", STD 67, RFC 4506, DOI 10.17487/RFC4506, May
2006, <https://www.rfc-editor.org/info/rfc4506>.
Shah, et al. Expires August 2, 2018 [Page 29]
Internet-Draft Inter-domain TCA Exchange January 2018
[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model
for IP Flow Information Export (IPFIX)", RFC 7012,
DOI 10.17487/RFC7012, September 2013,
<https://www.rfc-editor.org/info/rfc7012>.
[RFC7115] Bush, R., "Origin Validation Operation Based on the
Resource Public Key Infrastructure (RPKI)", BCP 185,
RFC 7115, DOI 10.17487/RFC7115, January 2014,
<https://www.rfc-editor.org/info/rfc7115>.
[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,
<https://www.rfc-editor.org/info/rfc7606>.
11.2. Informative References
[I-D.ietf-sidr-bgpsec-protocol]
Lepinski, M. and K. Sriram, "BGPsec Protocol
Specification", draft-ietf-sidr-bgpsec-protocol-22 (work
in progress), January 2017.
[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,
<https://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,
<https://www.rfc-editor.org/info/rfc4086>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/info/rfc4272>.
[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,
<https://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,
<https://www.rfc-editor.org/info/rfc6020>.
Shah, et al. Expires August 2, 2018 [Page 30]
Internet-Draft Inter-domain TCA Exchange January 2018
[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>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012,
<https://www.rfc-editor.org/info/rfc6793>.
[RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security",
RFC 7132, DOI 10.17487/RFC7132, February 2014,
<https://www.rfc-editor.org/info/rfc7132>.
[RFC7297] Boucadair, M., Jacquenet, C., and N. Wang, "IP
Connectivity Provisioning Profile (CPP)", RFC 7297,
DOI 10.17487/RFC7297, July 2014,
<https://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, <https://www.rfc-editor.org/info/rfc7674>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
Authors' Addresses
Shitanshu Shah
Email: shitanshu_shah@hotmail.com
Keyur Patel
Arrcus, Inc
Email: keyur@arrcus.com
Sandeep Bajaj
Viptela
Shah, et al. Expires August 2, 2018 [Page 31]
Internet-Draft Inter-domain TCA Exchange January 2018
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 August 2, 2018 [Page 32]
