Network Working Group G. Dommety
Request for Comments: 3025 K. Leung
Category: Standards Track cisco Systems
February 2001
Mobile IP Vendor/Organization-Specific Extensions
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document defines two new extensions to Mobile IP. These
extensions will facilitate equipment vendors and organizations to
make specific use of these extensions as they see fit for research or
deployment purposes.
1. IntrodUCtion
Current specification of Mobile IP [1] does not allow for
organizations and vendors to include organization/vendor-specific
information in the Mobile IP messages. With the imminent wide scale
deployment of Mobile IP it is useful to have vendor or organization-
Specific Extensions to support this capability. This document
defines two extensions that can be used for making organization
specific extensions by vendors/organizations for their own specific
purposes.
1.1. Specification Language
The keyWords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [3].
In addition, the following words are used to signify the requirements
of the specification.
silently discard
The implementation discards the datagram without further
processing, and without indicating an error to the sender.
The implementation SHOULD provide the capability of logging
the error, including the contents of the discarded datagram,
and SHOULD record the event in a statistics counter.
2. Vendor/Organization Specific Extensions
Two Vendor/Organization Specific Extensions are described, Critical
(CVSE) and Normal (NVSE) Vendor/Organization Specific Extensions.
The basic differences between the Critical and Normal Extensions are
that when the Critical extension is encountered but not recognized,
the message containing the extension MUST be silently discarded,
whereas when a Normal Vendor/Organization Specific Extension is
encountered but not recognized, the extension SHOULD be ignored, but
the rest of the Extensions and message data MUST still be processed.
Another difference between the two is that Critical
Vendor/Organization Extension has a length field of two octets and
the NVSE has a length field of only one octet.
2.1. Critical Vendor/Organization Specific Extension (CVSE)
The format of this extension is as shown below.
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 Reserved Length
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Vendor/Org-ID
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Vendor-CVSE-Type Vendor-CVSE-Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Critical Vendor/Organization Specific Extension
Type CVSE-TYPE-NUMBER 37
Reserved Reserved for future use. MUST be set to 0 on sending,
MUST be ignored on reception.
Length Length in bytes of this extension, not including the Type
and Length bytes.
Vendor/Org-ID
The high-order octet is 0 and the low-order 3 octets are
the SMI Network Management Private Enterprise Code of the
Vendor in network byte order, as defined in the Assigned
Numbers RFC[2].
Vendor-CVSE-Type
Indicates the particular type of Vendor-CVSE-Extension.
The administration of the Vendor-CVSE-Types is done by the
Vendor.
Vendor-CVSE-Value
Vendor/organization specific data of this Vendor-CVSE-
Extension. These data fields may be published in future
RFCs. The Vendor-CVSE-Value is zero or more octets. The
length of this field can be computed from the Length Field
Value.
If an implementation does not recognize the CVSE, according to RFC
2002 [1], the entire packet is to be silently dropped.
2.2. Normal Vendor/Organization Specific Extension (NVSE)
The format of this extension is as shown below.
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 Length Reserved
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Vendor/Org-ID
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Vendor-NVSE-Type Vendor-NVSE-Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Normal Vendor/Organization Specific Extension
Type NVSE-TYPE-NUMBER 133
Length Length in bytes of this extension, not including the Type
and Length bytes.
Reserved Reserved for future use. To be set to 0.
Vendor/Org-ID
The high-order octet is 0 and the low-order 3 octets are
the SMI Network Management Private Enterprise Code of the
Vendor in network byte order, as defined in the Assigned
Numbers RFC[2].
Vendor-NVSE-Type Indicates the particular type of Vendor-NVSE-
Extension. The administration of the Vendor-NVSE-Types is
done by the Vendor.
Vendor-NVSE-Value
Vendor/organization specific data of this Vendor-NVSE-
Extension. These data fields may be published in future
RFCs. The Vendor-NVSE-Value is zero or more octets. The
length of this field can be computed from the Length
Field Value.
2.3 Vendor/Organization Specific Extensions Processing Considerations
When a Mobile IP entity receives a registration request message (or
any other request/update message) with an extension of type CVSE-
TYPE-NUMBER and recognizes it, but the extension contains an
unknown/unsupported vendor ID or Vendor-CVSE-Type, a registration
reject (or the appropriate deny message) MUST be sent with the error
code to indicate that the registration was rejected due to the
presence of an unknown CVSE.
When a Mobile IP entity receives a registration reply (or any other
mobile IP reply/acknowledgement message) with an extension of type
CVSE-TYPE-NUMBER and recognizes it, but the extensions contains an
unknown/unsupported vendor ID or Vendor-CVSE-Type, the processing is
performed as described below.
1. If the Mobile IP entity is a transit node for the reply (i.e.,
this entity processes and sends the registration reply to another
entity) a registration reject (or the appropriate deny message) MUST
be sent with the error code to indicate that the registration was
rejected due to the presence of an unknown CVSE. For example, FA
when it receives an unknown CVSE in a registration reply from the HA,
should send a registration reject to the MN.
2. If the Mobile IP entity is not a transit node for the reply, the
reply is treated as a reject (or the appropriate deny message) due to
the presence of an unknown CVSE.
While designing enhancements wherein a CVSE is included in a reply
message, it should noted that the reply message could be discarded by
the mobile IP entity processing this message. Enhancements that
include a CVSE should take this into consideration during design.
When a Mobile IP entity receives a mobile IP related message
(registration request/reply, advertisement/solicitation, etc.) with
an extension of type NVSE-TYPE-NUMBER and recognizes it, but the
extension contains an unknown/unsupported vendor ID or Vendor-NVSE-
Type, the entire extension is skipped.
NOTE that according to RFC2002 [1], when an extension numbered
within the range 0 through 127 is encountered in a registration
message but not recognized, the message containing that extension
MUST be silently discarded. This document is compliant with the
above specification and specifies the action if the extension of type
CVSE-TYPE-NUMBER is encountered and recognized, but does not support
the vendor ID or the vendor type extension within.
2.4 Error Codes
The following error codes are defined.
Registration denied by the Foreign agent:
ERROR-FA-1 100: Unsupported Vendor-ID or
unable to interpret Vendor-CVSE-Type in the CVSE sent by the
Mobile Node to the Foreign Agent.
ERROR-FA-2 101: Unsupported Vendor-ID or
unable to interpret Vendor-CVSE-Type in the CVSE sent by the
Home Agent to the Foreign Agent.
Registration denied by the Home agent:
ERROR-HA-1 140: Unsupported Vendor-ID or
unable to interpret Vendor-CVSE-Type in the CVSE sent by the
Mobile Node to the Home Agent.
ERROR-HA-2 141: Unsupported Vendor-ID or
unable to interpret Vendor-CVSE-Type in the CVSE sent by the
Foreign Agent to the Home Agent.
3. Restrictions
Multiple TLV's with the types CVSE-TYPE-NUMBER and NVSE-TYPE-NUMBER
can be included in a message. TLVs with types CVSE-TYPE-NUMBER and
NVSE-TYPE-NUMBER can be placed anywhere after the fixed portion of
the Mobile IP message. These TLVs are eXPected to be protected by
the corresponding authenticator as necessary. Ordering of these
TLV's should not be modified by intermediate nodes.
4. IANA Considerations
The Critical Vendor/Organization Specific Extension (CVSE) as defined
in Section 2.1 and Normal Vendor/Organization Specific Extension
(NVSE) as defined in section 2.2 are proposed new extensions to the
Mobile IP protocol, defined in RFC2002 [1] and extended in RFC2356
[5].
IANA has assigned a Type value of CVSE-TYPE-NUMBER for the Critical
Vendor/Organization Specific Extension (CVSE), and a Type value of
NVSE-TYPE-NUMBER for the Normal Vendor/Organization Specific
Extension (NVSE). The numbers CVSE-TYPE-NUMBER and NVSE-TYPE-NUMBER
for the CVSE and the NVSE are taken from the numbering space defined
for Mobile IP registration extensions [1].
IANA has assigned new Foreign Agent Error Codes, ERROR-FA-1 and
ERROR-FA-2 taken from the numbering space defined for Mobile IP
Foreign Agent error codes [1]. IANA has also assigned new Home Agent
Error Codes, ERROR-HA-1 and ERROR-HA-2 taken from the numbering space
defined for Mobile IP Home Agent error codes [1].
5. Security Considerations
This document assumes that the Mobile IP messages are authenticated
using a method defined by the Mobile IP protocol. This document does
not impose any additional requirements on Mobile IP messages from a
security point of view. So this is not expected to be a security
issue.
6. Acknowledgments
The authors would like to thank TR45.4 WG, TR45.6 WG, Basavaraj
Patil, Phil Roberts, Jouni Malinen, and Patrice Calhoun for their
useful discussions.
7. References
[1] Perkins, C., "IP Mobility Support", RFC2002, October 1996.
[2] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC1700,
October 1994.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC2119, March 1997.
[4] Montenegro, G., "Reverse Tunneling for Mobile IP", RFC2344, May
1998.
[5] Montenegro, G. and V. Gupta, "Sun's SKIP Firewall Traversal for
Mobile IP", RFC2356, June 1998.
8. Authors' Addresses
Gopal Dommety
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
EMail: gdommety@cisco.com
Kent Leung
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
EMail: kleung@cisco.com
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