draft-ietf-opsawg-capwap-alt-tunnel-07.txt   draft-ietf-opsawg-capwap-alt-tunnel-08.txt 
Opsawg Working Group R. Zhang Opsawg Working Group R. Zhang
Internet-Draft China Telecom Internet-Draft China Telecom
Intended status: Standards Track Z. Cao Intended status: Standards Track Z. Cao
Expires: December 10, 2016 H. Deng Expires: January 9, 2017 H. Deng
China Mobile China Mobile
R. Pazhyannur R. Pazhyannur
S. Gundavelli S. Gundavelli
Cisco Cisco
L. Xue L. Xue
J. You J. You
Huawei Huawei
June 8, 2016 July 8, 2016
Alternate Tunnel Encapsulation for Data Frames in CAPWAP Alternate Tunnel Encapsulation for Data Frames in CAPWAP
draft-ietf-opsawg-capwap-alt-tunnel-07 draft-ietf-opsawg-capwap-alt-tunnel-08
Abstract Abstract
Control and Provisioning of Wireless Access Points (CAPWAP) defines a Control and Provisioning of Wireless Access Points (CAPWAP) defines a
specification to encapsulate a station's data frames between the specification to encapsulate a station's data frames between the
Wireless Transmission Point (WTP) and Access Controller (AC). Wireless Transmission Point (WTP) and Access Controller (AC).
Specifically, the station's IEEE 802.11 data frames can be either Specifically, the station's IEEE 802.11 data frames can be either
locally bridged or tunneled to the AC. When tunneled, a CAPWAP data locally bridged or tunneled to the AC. When tunneled, a CAPWAP data
channel is used for tunneling. In many deployments encapsulating channel is used for tunneling. In many deployments encapsulating
data frames to an entity other than the AC (for example to an Access data frames to an entity other than the AC (for example to an Access
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 10, 2016. This Internet-Draft will expire on January 9, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1.1. Conventions used in this document . . . . . . . . . . . . 8 1.1. Conventions used in this document . . . . . . . . . . . . 8
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 8 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 8
2. Alternate Tunnel Encapsulation . . . . . . . . . . . . . . . . 9 2. Alternate Tunnel Encapsulation . . . . . . . . . . . . . . . . 9
2.1. Description . . . . . . . . . . . . . . . . . . . . . . . 10 2.1. Description . . . . . . . . . . . . . . . . . . . . . . . 10
3. Protocol Considerations . . . . . . . . . . . . . . . . . . . 11 3. Protocol Considerations . . . . . . . . . . . . . . . . . . . 11
3.1. Supported Alternate Tunnel Encapsulations . . . . . . . . 11 3.1. Supported Alternate Tunnel Encapsulations . . . . . . . . 11
3.2. Alternate Tunnel Encapsulations Type . . . . . . . . . . . 12 3.2. Alternate Tunnel Encapsulations Type . . . . . . . . . . . 12
3.3. IEEE 802.11 WTP Alternate Tunnel Failure Indication . . . 13 3.3. IEEE 802.11 WTP Alternate Tunnel Failure Indication . . . 13
3.4. CAPWAP based Alternate Tunnel . . . . . . . . . . . . . . 14 3.4. CAPWAP based Alternate Tunnel . . . . . . . . . . . . . . 14
3.5. PMIPv6 based Alternate Tunnel . . . . . . . . . . . . . . 15 3.5. PMIPv6 based Alternate Tunnel . . . . . . . . . . . . . . 15
3.6. Alternate Tunnel Information Elements . . . . . . . . . . 16 3.6. GRE based Alternate Tunnel . . . . . . . . . . . . . . . . 16
3.6.1. Access Router Information Elements . . . . . . . . . . 16 3.7. Alternate Tunnel Information Elements . . . . . . . . . . 16
3.6.2. IEEE 802.11 WLAN Configuration Response . . . . . . . 17 3.7.1. Access Router Information Elements . . . . . . . . . . 16
3.6.3. Tunnel DTLS Policy Element . . . . . . . . . . . . . . 17 3.7.2. IEEE 802.11 WLAN Configuration Response . . . . . . . 17
3.6.4. IEEE 802.11 Tagging Mode Policy Element . . . . . . . 18 3.7.3. Tunnel DTLS Policy Element . . . . . . . . . . . . . . 17
3.6.5. CAPWAP Transport Protocol Element . . . . . . . . . . 19 3.7.4. IEEE 802.11 Tagging Mode Policy Element . . . . . . . 18
3.6.6. GRE Key Element . . . . . . . . . . . . . . . . . . . 19 3.7.5. CAPWAP Transport Protocol Element . . . . . . . . . . 19
3.7.6. GRE Key Element . . . . . . . . . . . . . . . . . . . 19
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
5. Security Considerations . . . . . . . . . . . . . . . . . . . 21 5. Security Considerations . . . . . . . . . . . . . . . . . . . 21
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21 6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.1. Normative References . . . . . . . . . . . . . . . . . . . 21 7.1. Normative References . . . . . . . . . . . . . . . . . . . 21
7.2. Informative References . . . . . . . . . . . . . . . . . . 22 7.2. Informative References . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
Service Providers are deploying very large Wi-Fi deployments (ranging Service Providers are deploying very large Wi-Fi deployments (ranging
from hundreds of thousands of Access Points, APs (referred to as WTPs from hundreds of thousands of Access Points, APs (referred to as WTPs
in CAPWAP terminology) to millions of APs. These networks are in CAPWAP terminology) to millions of APs. These networks are
designed to carry traffic generated from mobile users. The volume in designed to carry traffic generated from mobile users. The volume in
mobile user traffic is already very large and expected to continue mobile user traffic is already very large and expected to continue
growing rapidly. As a result, operators are looking for scalable growing rapidly. As a result, operators are looking for scalable
solutions that can meet the increasing demand. The scalability solutions that can meet the increasing demand. The scalability
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0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel-Type=4 | Info Element Length | | Tunnel-Type=4 | Info Element Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Access Router (LMA) Information Element . . Access Router (LMA) Information Element .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Alternate Tunnel Encapsulation - PMIPv6 Figure 10: Alternate Tunnel Encapsulation - PMIPv6
3.6. Alternate Tunnel Information Elements 3.6. GRE based Alternate Tunnel
Generic Routing Encapsulation mode [RFC2784] based user plane can
also be used as alternate tunnel encapsulation between the WTP and
the AR. In this scenario, a WTP and the access routers represent the
two end points of the GRE tunnel. The information elements needed
for supporting this mode are defined in Section 3.7 and
Section 3.7.6.
3.7. Alternate Tunnel Information Elements
This section defines the various elements described in Section 3.4 This section defines the various elements described in Section 3.4
and Section 3.5 and Section 3.5
3.6.1. Access Router Information Elements 3.7.1. Access Router Information Elements
The Access Router Information Elements allow the AC to notify a WTP The Access Router Information Elements allow the AC to notify a WTP
of which AR(s) are available for establishing a data tunnel. The AR of which AR(s) are available for establishing a data tunnel. The AR
information may be IPv4 address, IPv6 address, or AR domain name. If information may be IPv4 address, IPv6 address, or AR domain name. If
a WTP obtains the correct AR FQDN, the Name-to-IP address mapping is a WTP obtains the correct AR FQDN, the Name-to-IP address mapping is
handled in the WTP (see RFC2782). handled in the WTP (see RFC2782).
The following are the Access Router Information Elements defined in The following are the Access Router Information Elements defined in
this specification. The AC can use one of them to notify the this specification. The AC can use one of them to notify the
destination information of the data tunnel to the WTP. The Elements destination information of the data tunnel to the WTP. The Elements
containing the AR IPv4 address MUST NOT be used if an IPv6 data containing the AR IPv4 address MUST NOT be used if an IPv6 data
channel with IPv6 transport is used. channel with IPv6 transport is used.
3.6.1.1. AR IPv4 List Element 3.7.1.1. AR IPv4 List Element
This Element (see Figure 11) is used by the AC to configure a WTP This Element (see Figure 11) is used by the AC to configure a WTP
with the AR IPv4 address available for the WTP to establish the data with the AR IPv4 address available for the WTP to establish the data
tunnel for user traffic. tunnel for user traffic.
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AR IPv4 Element Type | Length | | AR IPv4 Element Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 11: AR IPv4 List Element Figure 11: AR IPv4 List Element
Length: This refers to the total length in octets of the element Length: This refers to the total length in octets of the element
excluding the Type and Length fields. excluding the Type and Length fields.
AR IPv4 Address: IPv4 address of the AR. At least one IPv4 address AR IPv4 Address: IPv4 address of the AR. At least one IPv4 address
shall be present. Multiple addresses may be provided for load shall be present. Multiple addresses may be provided for load
balancing or redundancy. balancing or redundancy.
3.6.1.2. AR IPv6 List Element 3.7.1.2. AR IPv6 List Element
This Element (see Figure 12) is used by the AC to configure a WTP This Element (see Figure 12) is used by the AC to configure a WTP
with the AR IPv6 address available for the WTP to establish the data with the AR IPv6 address available for the WTP to establish the data
tunnel for user traffic. tunnel for user traffic.
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AR IPv6 Element Type | Length | | AR IPv6 Element Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 12: AR IPv6 List Element Figure 12: AR IPv6 List Element
Length: This refers to the total length in octets of the element Length: This refers to the total length in octets of the element
excluding the Type and Length fields. excluding the Type and Length fields.
AR IPv6 Address: IPv6 address of the AR. At least one IPv6 address AR IPv6 Address: IPv6 address of the AR. At least one IPv6 address
shall be present. Multiple addresses may be provided for load shall be present. Multiple addresses may be provided for load
balancing or redundancy. balancing or redundancy.
3.6.2. IEEE 802.11 WLAN Configuration Response 3.7.2. IEEE 802.11 WLAN Configuration Response
Since AC can configure a WTP with more than one AR available for the Since AC can configure a WTP with more than one AR available for the
WTP to establish the data tunnel(s) for user traffic, it may be WTP to establish the data tunnel(s) for user traffic, it may be
useful for the WTP to communicate the selected AR. To enable this, useful for the WTP to communicate the selected AR. To enable this,
the IEEE 802.11 WLAN Configuration Response may contain the AR list the IEEE 802.11 WLAN Configuration Response may contain the AR list
element containing the selected AR. element containing the selected AR.
3.6.3. Tunnel DTLS Policy Element 3.7.3. Tunnel DTLS Policy Element
The AC distributes its DTLS usage policy for the CAPWAP data tunnel The AC distributes its DTLS usage policy for the CAPWAP data tunnel
between a WTP and the AR. There are multiple supported options, between a WTP and the AR. There are multiple supported options,
represented by the bit field below as defined in AC Descriptor represented by the bit field below as defined in AC Descriptor
message elements. The WTP MUST abide by one of the options for message elements. The WTP MUST abide by one of the options for
tunneling user traffic with AR. The Tunnel DTLS Policy Element obey tunneling user traffic with AR. The Tunnel DTLS Policy Element obey
the definition in [RFC5415]. If there are more than one ARs the definition in [RFC5415]. If there are more than one ARs
information provided by the AC for reliability reasons, the same information provided by the AC for reliability reasons, the same
Tunnel DTLS Policy (see Figure 13) is generally applied for all Tunnel DTLS Policy (see Figure 13) is generally applied for all
tunnels associated with the ARs. Otherwise, Tunnel DTLS Policy MUST tunnels associated with the ARs. Otherwise, Tunnel DTLS Policy MUST
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Element. Otherwise, the same Tunnel DTLS Policy (see Figure 13) is Element. Otherwise, the same Tunnel DTLS Policy (see Figure 13) is
generally applied for all tunnels associated with the ARs configured generally applied for all tunnels associated with the ARs configured
by the AC. by the AC.
D: DTLS-Enabled Data Channel Supported (see [RFC5415]). D: DTLS-Enabled Data Channel Supported (see [RFC5415]).
C: Clear Text Data Channel Supported (see [RFC5415]). C: Clear Text Data Channel Supported (see [RFC5415]).
R: A reserved bit for future use abide (see [RFC5415]). R: A reserved bit for future use abide (see [RFC5415]).
3.6.4. IEEE 802.11 Tagging Mode Policy Element 3.7.4. IEEE 802.11 Tagging Mode Policy Element
In 802.11 networks, IEEE 802.11 Tagging Mode Policy Element is used In 802.11 networks, IEEE 802.11 Tagging Mode Policy Element is used
to specify how the WTP apply the QoS tagging policy when receiving to specify how the WTP apply the QoS tagging policy when receiving
the packets from stations on a particular radio. When the WTP sends the packets from stations on a particular radio. When the WTP sends
out the packet to data channel to the AR(s), the packets have to be out the packet to data channel to the AR(s), the packets have to be
tagged for QoS purposes (see [RFC5416]). tagged for QoS purposes (see [RFC5416]).
The IEEE 802.11 Tagging Mode Policy abides the IEEE 802.11 WTP The IEEE 802.11 Tagging Mode Policy abides the IEEE 802.11 WTP
Quality of Service defined in Section 6.22 of [RFC5416]. Quality of Service defined in Section 6.22 of [RFC5416].
3.6.5. CAPWAP Transport Protocol Element 3.7.5. CAPWAP Transport Protocol Element
The CAPWAP data tunnel supports both UDP and UDP-Lite (see RFC3828). The CAPWAP data tunnel supports both UDP and UDP-Lite (see RFC3828).
When run over IPv4, UDP is used for the CAPWAP data channels. When When run over IPv4, UDP is used for the CAPWAP data channels. When
run over IPv6, the CAPWAP data channel may use either UDP or UDP- run over IPv6, the CAPWAP data channel may use either UDP or UDP-
lite. The AC specifies and configure the WTP for which transport lite. The AC specifies and configure the WTP for which transport
protocol is to be used for the CAPWAP data tunnel. protocol is to be used for the CAPWAP data tunnel.
The CAPWAP Transport Protocol Element abides the definition in The CAPWAP Transport Protocol Element abides the definition in
Section 4.6.14 of [RFC5415]. Section 4.6.14 of [RFC5415].
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following enumerated values are supported: following enumerated values are supported:
1 - UDP-Lite: The UDP-Lite transport protocol is to be used for the 1 - UDP-Lite: The UDP-Lite transport protocol is to be used for the
CAPWAP Data channel. Note that this option MUST NOT be used if the CAPWAP Data channel. Note that this option MUST NOT be used if the
CAPWAP Control channel is being used over IPv4 and AR address is IPv4 CAPWAP Control channel is being used over IPv4 and AR address is IPv4
contained in the AR Information Element. contained in the AR Information Element.
2 - UDP: The UDP transport protocol is to be used for the CAPWAP Data 2 - UDP: The UDP transport protocol is to be used for the CAPWAP Data
channel. channel.
3.6.6. GRE Key Element 3.7.6. GRE Key Element
If a WTP receives the GRE Key Element in the Alternate Tunnel If a WTP receives the GRE Key Element in the Alternate Tunnel
Encapsulation message element for GRE selection, the WTP must insert Encapsulation message element for GRE selection, the WTP must insert
the GRE Key to the encapsulation packet (see [RFC2890]). An AR the GRE Key to the encapsulation packet (see [RFC2890]). An AR
acting as decapsulating tunnel endpoint identifies packets belonging acting as decapsulating tunnel endpoint identifies packets belonging
to a traffic flow based on the Key value. to a traffic flow based on the Key value.
The GRE Key Element field contains a four octet number defined in The GRE Key Element field contains a four octet number defined in
[RFC2890]. [RFC2890].
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Key Element Type | Length | | GRE Key Element Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Key | | GRE Key |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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