RFC 8350
Alternate Tunnel Encapsulation for Data Frames in Control and Provisioning of Wireless Access Points (CAPWAP)
Pages: 29
Experimental
Experimental
Part 2 of 2 – Pages 16 to 29
5. Alternate Tunnel Information Elements
This section defines the various elements described in Sections 4.1, 4.2, and 4.3. These information elements can only be included in the Alternate Tunnel Encapsulations Type message element and the IEEE 802.11 WTP Alternate Tunnel Failure Indication message element as their sub- elements.5.1. Access Router Information Elements
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 information may be an IPv4 or IPv6 address. For any Tunnel-Type, this information element SHOULD be included in the Alternate Tunnel Encapsulations Type message element. If the Alternate Tunnel Encapsulations Type message element is sent by the WTP to communicate the selected AR(s), this Access Router Information Element SHOULD be included in it. The following are the Access Router Information Elements defined in this specification. The AC can use one of them to notify the WTP about the destination information of the data tunnel. The Elements containing the AR IPv4 address MUST NOT be used if an IPv6 Data Channel with IPv6 transport is used.5.1.1. AR IPv4 List Element
This element (see Figure 12) is used by the AC to configure a WTP with the AR IPv4 address available for the WTP to establish the data tunnel for user traffic. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AR IPv4 Element Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv4 Address-1 . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv4 Address-2 . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv4 Address-N . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 12: AR IPv4 List Element
Type: 0 Length: This refers to the total length in octets of the element, excluding the Type and Length fields. AR IPv4 Address: The IPv4 address of the AR. At least one IPv4 address SHALL be present. Multiple addresses may be provided for load balancing or redundancy.5.1.2. AR IPv6 List Element
This element (see Figure 13) is used by the AC to configure a WTP with the AR IPv6 address available for the WTP to establish the data tunnel for user traffic. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AR IPv6 Element Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv6 Address-1 . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv6 Address-2 . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR IPv6 Address-N . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 13: AR IPv6 List Element Type: 1 Length: This refers to the total length in octets of the element excluding the Type and Length fields. AR IPv6 Address: The IPv6 address of the AR. At least one IPv6 address SHALL be present. Multiple addresses may be provided for load balancing or redundancy.5.2. Tunnel DTLS Policy Element
The AC distributes its Datagram Transport Layer Security (DTLS) usage policy for the CAPWAP data tunnel between a WTP and the AR. There are multiple supported options, which are represented by the bit fields below as defined in AC Descriptor message elements. The WTP MUST abide by one of the options for tunneling user traffic with AR. The Tunnel DTLS Policy Element obeys the definition in [RFC5415]. If, for reliability reasons, the AC has provided more than one AR address in the Access Router Information Element, the same Tunnel
DTLS Policy (the last one in Figure 14) is generally applied for all tunnels associated with those ARs. Otherwise, Tunnel DTLS Policy MUST be bonded together with each of the Access Router Information Elements, and the WTP will enforce the independent tunnel DTLS policy for each tunnel with a specific AR. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Tunnel DTLS Policy Element Type| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |D|C|R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |D|C|R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . ...... . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |D|C|R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 14: Tunnel DTLS Policy Element Type: 2 Length: This refers to the total length in octets of the element excluding the Type and Length fields. Reserved: A set of reserved bits for future use. All implementations complying with this protocol MUST set to 0 any bits that are reserved in the version of the protocol supported by that implementation. Receivers MUST ignore all bits not defined for the version of the protocol they support. D: DTLS-Enabled Data Channel Supported (see [RFC5415]). C: Clear Text Data Channel Supported (see [RFC5415]). R: A reserved bit for future use (see [RFC5415]). AR Information: This means Access Router Information Element. In this context, each address in AR Information MUST be one of previously specified AR addresses.
In Figure 14, the last element that has no AR Information is the default tunnel DTLS policy, which provides options for any address not previously mentioned. Therefore, the AR Information field here is optional. In this element, if all ARs share the same tunnel DTLS policy, there won't be an AR Information field or its specific tunnel DTLS policy.5.3. IEEE 802.11 Tagging Mode Policy Element
In IEEE 802.11 networks, the IEEE 802.11 Tagging Mode Policy Element is used to specify how the WTP applies the QoS tagging policy when receiving 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 tagged for QoS purposes (see [RFC5416]). The IEEE 802.11 Tagging Mode Policy abides by the IEEE 802.11 WTP Quality of Service defined in Section 6.22 of [RFC5416]. If, for reliability reasons, the AC has provided more than one AR address in the Access Router Information Element, the same IEEE 802.11 Tagging Mode Policy (the last one in Figure 15) is generally applied for all tunnels associated with those ARs. Otherwise, IEEE 802.11 Tagging Mode Policy MUST be bonded together with each of the Access Router Information Elements, and the WTP will enforce the independent IEEE 802.11 Tagging Mode Policy for each tunnel with a specific AR. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tagging Mode Policy Ele. Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |P|Q|D|O|I| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |P|Q|D|O|I| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . ...... . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |P|Q|D|O|I| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 15: IEEE 802.11 Tagging Mode Policy Element
Type: 3 Length: This refers to the total length in octets of the element excluding the Type and Length fields. Reserved: A set of reserved bits for future use. P: When set, the WTP is to employ the IEEE 802.1p QoS mechanism (see [RFC5416]). Q: When the 'P' bit is set, the 'Q' bit is used by the AC to communicate to the WTP how IEEE 802.1p QoS is to be enforced (see [RFC5416]). D: When set, the WTP is to employ the DSCP QoS mechanism (see [RFC5416]). O: When the 'D' bit is set, the 'O' bit is used by the AC to communicate to the WTP how Differentiated Services Code Point (DSCP) QoS is to be enforced on the outer (tunneled) header (see [RFC5416]). I: When the 'D' bit is set, the 'I' bit is used by the AC to communicate to the WTP how DSCP QoS is to be enforced on the station's packet (inner) header (see [RFC5416]). AR Information: This means Access Router Information Element. In this context, each address in AR information MUST be one of the previously specified AR addresses. In Figure 15, the last element that has no AR information is the default IEEE 802.11 Tagging Mode Policy, which provides options for any address not previously mentioned. Therefore, the AR Information field here is optional. If all ARs share the same IEEE 802.11 Tagging Mode Policy, in this element, there will not be an AR Information field and its specific IEEE 802.11 Tagging Mode Policy.5.4. CAPWAP Transport Protocol Element
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 run over IPv6, the CAPWAP Data Channel may use either UDP or UDP-Lite. The AC specifies and configures the WTP for which the transport protocol is to be used for the CAPWAP data tunnel. The CAPWAP Transport Protocol Element abides by the definition in Section 4.6.14 of [RFC5415].
If, for reliability reasons, the AC has provided more than one AR address in the Access Router Information Element, the same CAPWAP Transport Protocol (the last one in Figure 16) is generally applied for all tunnels associated with those ARs. Otherwise, CAPWAP Transport Protocol MUST be bonded together with each of the Access Router Information Elements, and the WTP will enforce the independent CAPWAP Transport Protocol for each tunnel with a specific AR. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=4 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Transport | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Transport | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . ...... . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Transport | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 16: CAPWAP Transport Protocol Element Type: 4 Length: 1 Transport: The transport to use for the CAPWAP Data Channel. The following enumerated values are supported: 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 Control Channel is being used over IPv4 and if the AR address contained in the AR Information Element is an IPv4 address. 2 - UDP: The UDP transport protocol is to be used for the CAPWAP Data Channel. AR Information: This means Access Router Information Element. In this context, each address in AR information MUST be one of the previously specified AR addresses.
In Figure 16, the last element that has no AR information is the default CAPWAP Transport Protocol, which provides options for any address not previously mentioned. Therefore, the AR Information field here is optional. If all ARs share the same CAPWAP Transport Protocol, in this element, there will not be an AR Information field and its specific CAPWAP Transport Protocol.5.5. GRE Key Element
If a WTP receives the GRE Key Element in the Alternate Tunnel Encapsulations Type message element for GRE selection, the WTP MUST insert the GRE Key to the encapsulation packet (see [RFC2890]). An AR acting as a decapsulating tunnel endpoint identifies packets belonging to a traffic flow based on the Key value. The GRE Key Element field contains a 4-octet number defined in [RFC2890]. If, for reliability reasons, the AC has provided more than one AR address in the Access Router Information Element, a GRE Key Element MAY be bonded together with each of the Access Router Information Elements, and the WTP will enforce the independent GRE Key for each tunnel with a specific AR. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GRE Key Element Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GRE Key | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GRE Key | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . ...... . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 17: GRE Key Element Type: 5 Length: This refers to the total length in octets of the element excluding the Type and Length fields.
GRE Key: The Key field contains a 4-octet number that is inserted by the WTP according to [RFC2890]. AR Information: This means Access Router Information Element. In this context, it SHOULD be restricted to a single address and MUST be the address of one of previously specified AR addresses. Any address not explicitly mentioned here does not have a GRE key.5.6. IPv6 MTU Element
If AC has chosen a tunneling mechanism based on IPv6, it SHOULD support the minimum IPv6 MTU requirements [RFC8200]. This issue is described in [ARCH-TUNNELS]. AC SHOULD inform the WTP about the IPv6 MTU information in the Tunnel Info Element field. If, for reliability reasons, the AC has provided more than one AR address in the Access Router Information Element, an IPv6 MTU Element MAY be bonded together with each of the Access Router Information Elements, and the WTP will enforce the independent IPv6 MTU for each tunnel with a specific AR. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 MTU Element Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Minimum IPv6 MTU | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Minimum IPv6 MTU | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . AR Information . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 18: IPv6 MTU Element Type: 6 Length: This refers to the total length in octets of the element excluding the Type and Length fields. Minimum IPv6 MTU: The field contains a 2-octet number indicating the minimum IPv6 MTU in the tunnel.
AR Information: This means Access Router Information Element. In this context, each address in AR information MUST be one of previously specified AR addresses.6. IANA Considerations
Per this document, IANA has registered the following values in the existing "CAPWAP Message Element Type" registry, defined in [RFC5415]. o 54: Supported Alternate Tunnel Encapsulations Type as defined in Section 3.1. o 55: Alternate Tunnel Encapsulations Type as defined in Section 3.2. o 1062: IEEE 802.11 WTP Alternate Tunnel Failure Indication as defined in Section 3.3. Per this document, IANA has created a registry called "Alternate Tunnel-Types" under "CAPWAP Parameters". This specification defines the Alternate Tunnel Encapsulations Type message element. This element contains a field Tunnel-Type. The namespace for the field is 16 bits (0-65535). This specification defines values 0 through 6 and can be found in Section 3.2. Future allocations of values in this namespace are to be assigned by IANA using the "Specification Required" policy [RFC8126]. The registry format is given below. Description Value Reference CAPWAP 0 [RFC5415] [RFC5416] L2TP 1 [RFC2661] L2TPv3 2 [RFC3931] IP-IP 3 [RFC2003] PMIPv6-UDP 4 [RFC5844] GRE 5 [RFC2784] GTPv1-U 6 [TS.3GPP.29.281]
Per this document, IANA has created a registry called "Alternate Tunnel Sub-elements" under "CAPWAP Parameters". This specification defines the Alternate Tunnel Sub-elements. Currently, these information elements can only be included in the Alternate Tunnel Encapsulations Type message element with the IEEE 802.11 WTP Alternate Tunnel Failure Indication message element as its sub- elements. These information elements contain a Type field. The namespace for the field is 16 bits (0-65535). This specification defines values 0 through 6 in Section 5. This namespace is managed by IANA, and assignments require an Expert Review [RFC8126]. Description Value AR IPv4 List 0 AR IPv6 List 1 Tunnel DTLS Policy 2 IEEE 802.11 Tagging Mode Policy 3 CAPWAP Transport Protocol 4 GRE Key 5 IPv6 MTU 67. Security Considerations
This document introduces three new CAPWAP WTP message elements. These elements are transported within CAPWAP Control messages as the existing message elements. Therefore, this document does not introduce any new security risks to the control plane compared to [RFC5415] and [RFC5416]. In the data plane, if the encapsulation type selected itself is not secured, it is suggested to protect the tunnel by using known secure methods, such as IPsec.8. References
8.1. Normative References
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003, DOI 10.17487/RFC2003, October 1996, <https://www.rfc-editor.org/info/rfc2003>. [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>. [RFC2661] Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn, G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"", RFC 2661, DOI 10.17487/RFC2661, August 1999, <https://www.rfc-editor.org/info/rfc2661>.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, DOI 10.17487/RFC2784, March 2000, <https://www.rfc-editor.org/info/rfc2784>. [RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE", RFC 2890, DOI 10.17487/RFC2890, September 2000, <https://www.rfc-editor.org/info/rfc2890>. [RFC3828] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., Ed., and G. Fairhurst, Ed., "The Lightweight User Datagram Protocol (UDP-Lite)", RFC 3828, DOI 10.17487/RFC3828, July 2004, <https://www.rfc-editor.org/info/rfc3828>. [RFC3931] Lau, J., Ed., Townsley, M., Ed., and I. Goyret, Ed., "Layer Two Tunneling Protocol - Version 3 (L2TPv3)", RFC 3931, DOI 10.17487/RFC3931, March 2005, <https://www.rfc-editor.org/info/rfc3931>. [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, Ed., "Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification", RFC 5415, DOI 10.17487/RFC5415, March 2009, <https://www.rfc-editor.org/info/rfc5415>. [RFC5416] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, Ed., "Control and Provisioning of Wireless Access Points (CAPWAP) Protocol Binding for IEEE 802.11", RFC 5416, DOI 10.17487/RFC5416, March 2009, <https://www.rfc-editor.org/info/rfc5416>. [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, <https://www.rfc-editor.org/info/rfc8200>.
8.2. Informative References
[ARCH-TUNNELS] Touch, J. and M. Townsley, "IP Tunnels in the Internet Architecture", Work in Progress, draft-ietf-intarea- tunnels-08, January 2018. [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, DOI 10.17487/RFC5213, August 2008, <https://www.rfc-editor.org/info/rfc5213>. [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010, <https://www.rfc-editor.org/info/rfc5844>. [RFC5845] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung, "Generic Routing Encapsulation (GRE) Key Option for Proxy Mobile IPv6", RFC 5845, DOI 10.17487/RFC5845, June 2010, <https://www.rfc-editor.org/info/rfc5845>. [RFC7494] Shao, C., Deng, H., Pazhyannur, R., Bari, F., Zhang, R., and S. Matsushima, "IEEE 802.11 Medium Access Control (MAC) Profile for Control and Provisioning of Wireless Access Points (CAPWAP)", RFC 7494, DOI 10.17487/RFC7494, April 2015, <https://www.rfc-editor.org/info/rfc7494>. [TS.3GPP.29.281] 3GPP, "General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)", 3GPP TS 29.281, V13.1.0, March 2016.
Contributors
The authors would like to thank Andreas Schultz, Hong Liu, Yifan Chen, Chunju Shao, Li Xue, Jianjie You, Jin Li, Joe Touch, Alexey Melnikov, Kathleen Moriarty, Mirja Kuehlewind, Catherine Meadows, and Paul Kyzivat for their valuable comments.Authors' Addresses
Rong Zhang China Telecom No.109 Zhongshandadao avenue Guangzhou 510630 China Email: zhangr@gsta.com Rajesh S. Pazhyannur Cisco 170 West Tasman Drive San Jose, CA 95134 United States of America Email: rpazhyan@cisco.com Sri Gundavelli Cisco 170 West Tasman Drive San Jose, CA 95134 United States of America Email: sgundave@cisco.com Zhen Cao Huawei Xinxi Rd. 3 Beijing 100085 China Email: zhencao.ietf@gmail.com
Hui Deng Huawei Xinxi Rd. 3 Beijing 100085 China Email: denghui02@gmail.com Zongpeng Du Huawei No.156 Beiqing Rd. Z-park, HaiDian District Beijing 100095 China Email: duzongpeng@huawei.com