INTERNET DRAFT M. Borella
Expires May 2000 D. Grabelsky
3Com Corp.
J. Lo
K. Tuniguchi
NEC USA
October 1999
Realm Specific IP: Protocol Specification
<draft-ietf-nat-rsip-protocol-04.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
This document presents a protocol with which to implement Realm
Specific IP (RSIP). The protocol defined herein allows negotiation
of resources between an RSIP client and server. This protocol is
designed to operate as an application and to use its own TCP or UDP
port. In particular, the protocol allows a server to allocate
addressing and control parameters to a client such that a flow policy
can be enforced at the server.
1. Introduction
Network Address Translation (NAT) has gained popularity as a method
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of separating public and private address spaces, and alleviating
network address shortages. A NAT translates the addresses of packets
leaving a first routing realm to an address from a second routing
realm, and performs the reverse function for packets entering the
first routing realm from the second routing realm. This translation
is performed transparently to the hosts in either space, and may
include modification of TCP/UDP port numbers and IP addresses in
packets that traverse the NAT.
While a NAT does not require hosts to be aware of the translation, it
will require an application layer gateway (ALG) for any protocol that
transmits IP addresses or port numbers in packet payloads (such as
FTP). Additionally, a NAT will not work with protocols that require
IP addresses and ports to remain unmodified between the source and
destination hosts, or protocols that prevent such modifications to
occur (such as some IPSEC modes, or application-layer end-to-end
encryption).
An alternative to a NAT is an architecture that allows the clients
within the first (e.g., private) routing realm to directly use
addresses and other routing parameters from the second (e.g., public)
routing realm. Thus, RSIP [RSIP-FRAME] has been defined a method for
address sharing that exhibits more transparency than NAT. In
particular, RSIP requires that an RSIP server (a router or gateway
between the two realms) assign at least one address from the second
routing realm, and perhaps some other resources, to each RSIP client.
An RSIP client is a host in the first routing realm that needs to
establish end-to-end connectivity to a host, entity or device in the
second routing realm. Thus, the second routing realm is not directly
accessible from RSIP client, but this system allows packets to
maintain their integrity from RSIP client to their destination. ALGs
are not required in the RSIP server.
RSIP requires that hosts be modified so that they place some number
of layer three, layer four or other values from those assigned by the
RSIP server in each packet bound for the second routing realm.
This draft discusses a method for assigning parameters to an RSIP
client from an RSIP server. The requirements, scope, and
applicability of RSIP, as well as its interaction with other layer 3
protocols, are discussed in a companion framework draft [RSIP-FRAME].
RSIP interaction with IPSEC is discussed in [RSIP-IPSEC].
2. Specification of Requirements
The keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
"SHALL", "SHALL NOT", "MAY" and "MAY NOT" that appear in this
document are to be interpreted as described in [RFC2119].
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3. Terminology
Private Realm
A routing realm that uses private IP addresses from the ranges
(10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) specified in
[RFC1918], or addresses that are non-routable from the Internet.
Public Realm
A routing realm with unique network addresses assigned by the
Internet Assigned Number Authority (IANA) or an equivalent address
registry.
RSIP Server
A router situated on the boundary between a private realm and a
public realm and owns one or more public IP addresses. An RSIP
server is responsible for public parameter management and
assignment to RSIP clients. An RSIP server may act as a normal NAT
router for hosts within the private realm that are not RSIP
enabled.
RSIP Client
A host within the private realm that acquires publicly unique
parameters from an RSIP server through the use of RSIP.
RSA-IP: Realm Specific Address IP
An RSIP method in which each RSIP client is allocated a unique IP
address from the public realm. Discussed in detail in [RFC2663]
RSAP-IP: Realm Specific Address and Port IP
An RSIP method in which each RSIP client is allocated an IP
address (possibly shared with other RSIP clients) and some number
of per-address unique ports from the public realm. Discussed in
detail in [RFC2663]
Binding
An association of some combination of a local IP address, one or
more local ports, a remote IP address, and a remote port with an
RSIP client.
All other terminology found in this document is consistent with that
of [RFC2663] and [RSIP-FRAME].
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4. Architecture
For simplicity, for the remainder of this document we will assume
that the RSIP clients in the first routing realm (network) use
private (e.g. see [RFC1918]) IP addresses, and that the second
routing realm (network) uses public IP addresses. The RSIP server
connects the public and private realms and contains interfaces to
both. Other NAT terminology found in this document is defined in
[RFC2663].
The diagram below describes an exemplary reference architecture for
RSIP. Some number of RSIP clients are attached via a private network
to an RSIP server, which also acts as a router or gateway between the
private and public networks. This router has been assigned some
number of public addresses that it may use or allocate for use on the
public network.
+-------------+
| RSIP client |
| 1 +--+
| 10.0.0.2 | | +-------------+
+-------------+ | 10.0.0.1 | | 149.112.240.0/24
+-----------------+ RSIP server +-------------------
+-------------+ | | |
| RSIP client | | +-------------+
| 2 +--+ private public
| 10.0.0.3 | | network network
+-------------+ |
|
| ...
5. Transport Protocol
RSIP is an application layer protocol that requires the use of a
transport layer protocol for end-to-end delivery of packets.
RSIP servers MUST support TCP, and SHOULD support UDP. Due to the
fact that RSIP may be deployed across a wide variety of network
links, RSIP clients SHOULD support TCP. However, RSIP clients MAY
support UDP instead. For RSIP clients and servers using UDP, timeout
and retransmissions MUST occur. We recommend a binary exponential
backoff scheme with an initial duration of 12.5 ms, and a maximum of
six retries (seven total attempts before failure).
Once a client and server have established a registration using either
TCP or UDP, they may not switch between the two protocols for the
duration of the registration.
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6. Client / Server Relationships
An RSIP client can be in exactly one of three fundamental
relationships with respect to an RSIP server:
Unregistered: The RSIP server does not know of the RSIP client's
existence, and it will not forward or deliver packets on behalf
of the client. The only valid RSIP-related action for a client
to perform in this state is to request registration with an
RSIP server.
Registered: The RSIP server knows of the RSIP client and has
assigned it a client ID and has specified the flow policies
that it requires of the client. However, no resources, such as
addresses or ports, have been allocated to the client, and the
server will not forward or deliver packets on behalf of the
client.
Assigned: The RSIP server has granted one or more bindings of
resources to the client. The server will forward and deliver
packets on behalf of the client.
Architectures in which an RSIP client is associated with more than
one RSIP server are possible. In such cases, an RSIP client may be
simultaneously in different relationships with different RSIP
servers.
7. Server Flow Policy and State
Since an RSIP server is likely to reside on the boundary between two
or more different administrative domains, it is desirable to enable
an RSIP server to be able to enforce flow-based policy. In other
words, an RSIP server should have the ability to explicitly control
which local addresses and ports are used to communicate with remote
addresses and ports.
In the following, macro-flow policy refers to controlling flow policy
at the granularity level of IP addresses, while micro-flow policy
refers to controlling flow policy at the granularity of IP address
and port tuples. Of course there may be no policy at all, which
indicates that the RSIP server does not care about the flow
parameters used by RSIP clients. We consider two levels of local flow
policy and three levels of remote flow policy.
7.1. Local Flow Policy
Local flow policy determines the granularity of control that an
RSIP server has over the addressing parameters that an RSIP client
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uses for particular sessions.
Since an RSIP client must use at least an IP address allocated by
the server, the loosest level of local flow policy is macro-flow
based. Under local macro-flow policy, an RSIP client is allocated
an IP address (RSA-IP) or an IP address and one or more ports to
use with it (RSAP-IP). However, the client may use the ports as
it desires for establishing sessions with public hosts.
Under micro-flow policy, a client is allocated exactly one port at
a time. The client may request more ports, also one at a time.
This policy gives the server very tight control over local port
use, although it affords the client less flexibility.
Note that only local macro-flow policy can be used with RSA-IP,
while either local macro-flow or local micro-flow policy may be
used with RSAP-IP.
Examples of how RSIP flow policy operates are given in Appendix C.
7.2. Remote Flow Policy
Remote flow policy determines the granularity of control that an
RSIP server has over the remote (public) hosts with which an RSIP
client communicates. In particular, remote flow policy dictates
what level of detail that a client must specify addressing
parameters of a remote host before the RSIP server allows the
client to communicate with that host.
The simplest and loosest form of flow policy is no policy at all.
In other words, the RSIP server allocates addressing parameters to
the client, and the client may use these parameters to communicate
with any remote host, without specifically notifying the server.
Macro-flow policy requires that the client identify the remote
address of the host that it wishes to communicate with as part of
its request for local addressing parameters. If the request is
granted, the client MUST use the specified local parameters only
with the remote address specified, and MUST NOT communicate with
the remote address using any local parameters but the ones
allocated. However, the client may contact any port number at the
remote host without explicitly informing the server.
Micro-flow policy requires that the client identify the remote
address and port of the host that it wishes to communicate with as
part of its request for local addressing parameters. If the
request is granted, the client MUST use the specified local
parameters only with the remote address and port specified, and
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MUST NOT communicate with the remote address and port using any
local parameters but the ones allocated.
Remote flow policy is implemented in both the ingress and egress
directions, with respect to the location of the RSIP server.
7.3. Server State
An RSIP server must maintain state for all RSIP clients and their
assigned resources. The amount and type of state maintained
depends on the local and remote flow policy. The required RSIP
server state will vary based on the RSIP method, but will always
include the chosen method's demultiplexing parameters.
7.3.1. RSA-IP State
An RSIP server serving an RSIP client using the RSA-IP method
MUST maintain the following minimum state to ensure proper
mapping of incoming packets to RSIP clients:
- Client's private address
- Client's assigned public address(es)
7.3.2. RSAP-IP State
An RSIP server serving an RSIP client using the RSAP-IP method
MUST maintain the following minimum state to ensure proper
mapping of incoming packets to RSIP clients:
- Client's private address
- Client's assigned public address(es)
- Client's assigned port(s)
7.3.3. Flow State
Regardless of whether the server is using RSA-IP or RSAP-IP,
additional state is necessary if either micro-flow based or
macro-flow based remote policy is used.
If the server is using macro-flow based remote policy, the
following state must be maintained:
- Remote host's address
If the server is using micro-flow based remote policy, the
following state must be maintained:
- Remote host's address
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- Remote host's port
More state MAY be used by an RSIP server if desired. For
example, ToS/DS bytes may be recorded in order to facilitate
quality of service support.
8. Parameter Specification and Formats
In this section we define the formats for RSIP parameters. Each RSIP
message contains one or more parameters that encode the information
passed between the client and server. The general format of all
parameters consists of a 1-byte code followed by a 2-byte length as
shown below.
1 byte 2 bytes 'Length' bytes
+------+----------+--------------
| Code | Length | ...
+------+----------+--------------
The length field determines the length, in bytes, of the rest of the
parameter.
8.1. Address
Code Length Type Value
+-------+---------+--------+--------+
| 1 | 2 bytes | 1 byte | varies |
+-------+---------+--------+--------+
The address parameter contains addressing information, either an
IPv4 address or netmask, an IPv6 address or netmask, or a fully
qualified domain name (FQDN). The type field is 1 byte in length,
indicating the type of address.
Defined types are:
Type Length of value field (in bytes)
---- --------------------------------
0 Reserved 0
1 IPv4 4
2 IPv4 netmask 4
3 IPv6 16
4 IPv6 netmask 16
5 FQDN varies
For FQDN, the length of the value field will be one less than the
value of the length field.
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In some cases, it is necessary to specify a "don't care" value for
an address. This is signified by a setting the length field to 1
and omitting the value field.
8.2. Ports
Code Length Number Port Port
+-------+---------+--------+---------+ +---------+
| 2 | 2 bytes | 1 byte | 2 bytes | ... | 2 bytes |
+-------+---------+--------+---------+ +---------+
The ports parameter encodes one or more TCP or UDP ports. When a
single port is specified, the value of the number field is 1 and
there is one port field following the number field. When more
than one port is specified, the value of the number field will
indicate the total number of ports contained, and the parameter
may take one of two forms. If there is one port field, the ports
specified are considered to be contiguous starting at the port
number specified in the port field. Alternatively, there may be a
number of port fields equal to the value of the number field. The
number of port fields can be extrapolated from the length field.
In some cases, it is necessary to specify a don't care value for
one or more ports. This is accomplished by setting the length
field to 1, setting the number field to the number of ports
necessary, and omitting all port fields. The value of the number
field MUST be greater than or equal to one.
This parameter is not used with RSA-IP.
8.3. Lease Time
Code Length Value
+-------+--------+---------+
| 3 | 4 | 4 bytes |
+-------+--------+---------+
The lease time parameter specifies the length, in seconds, of an
RSIP client parameter binding.
8.4. Client ID
Code Length Value
+-------+--------+---------+
| 4 | 4 | 4 bytes |
+-------+--------+---------+
The client ID parameter specifies an RSIP client ID.
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8.5. Bind ID
Code Length Value
+-------+--------+---------+
| 5 | 4 | 4 bytes |
+-------+--------+---------+
The bind ID parameter specifies an RSIP bind ID.
8.6. Tunnel Type
Code Length Value
+-------+--------+--------+
| 6 | 1 | 1 byte |
+-------+--------+--------+
The tunnel type parameter specifies the type of tunnel used
between an RSIP client and an RSIP server. Defined tunnel types
are:
Tunnel Type
-----------
0 Reserved
1 IP-IP
2 GRE
3 L2TP
8.7. RSIP Method
Code Length Value
+-------+--------+--------+
| 7 | 1 | 1 byte |
+-------+--------+--------+
The RSIP method parameter specifies an RSIP method. Defined RSIP
methods are:
RSIP method
-----------
0 Reserved
1 RSA-IP
2 RSAP-IP
3 RSA-IP with IPSEC
4 RSAP-IP with IPSEC
8.8. Error
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Code Length Value
+-------+--------+---------+
| 8 | 2 | 2 bytes |
+-------+--------+---------+
The error parameter specifies an error. The currently defined
error values are presented in Appendix A.
8.9. Flow Policy
Code Length Local Remote
+-------+--------+--------+--------+
| 9 | 2 | 1 byte | 1 byte |
+-------+--------+--------+--------+
The flow policy parameter specifies both the local and remote flow
policy.
Defined local flow policies are:
Local Flow Policy
-----------------
0 Reserved
1 Macro flows
2 Micro flows
Defined remote flow policies are:
Remote Flow Policy
------------------
0 Reserved
1 Macro flows
2 Micro flows
3 No policy
8.10. Vendor Specific Parameter
Code Length Vendor ID Subcode Value
+-------+---------+-----------+---------+--------+
| 10 | 2 bytes | 2 bytes | 2 bytes | varies |
+-------+---------+-----------+---------+--------+
The vendor specific parameter is used to encode parameters that
are defined by a particular vendor. The vendor ID field is the
vendor-specific ID assigned by IANA. Subcodes are defined and
used by each vendor as necessary. An RSIP client or server SHOULD
silently ignore vendor-specific messages that it does not
understand.
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9. Message Types
RSIP messages consist of three mandatory fields, version, message
type, and overall length, followed by one or more required
parameters, followed in turn by zero or more optional parameters. In
an RSIP message, all required parameters MUST appear in the exact
order specified below. Optional parameters MAY appear in any order.
The version number field is a single byte and specifies the RSIP
version number that is being used. The current RSIP version number
is 1.
The message type field is a single byte and specifies the message
contained in the current packet. There may be only one message per
packet. Message types given numerical assignments in Appendix B.
The overall length field is two bytes and contains the number of
bytes in the RSIP message, including the three mandatory fields.
Most parameters are only allowed to appear once in each message. The
exceptions are as follows:
- Multiple address parameters MUST appear in ASSIGN_REQUEST_RSA-IP,
ASSIGN_RESPONSE_RSA-IP, ASSIGN_REQUEST_RSAP-IP,
ASSIGN_RESPONSE_RSAP-IP, LISTEN_REQUEST and LISTEN_RESPONSE.
- Multiple ports parameters MUST appear in ASSIGN_REQUEST_RSAP-IP,
ASSIGN_RESPONSE_RSAP-IP, LISTEN_REQUEST and LISTEN_RESPONSE.
- Multiple RSIP method and tunnel type parameters MAY appear in
RESISTER_RESPONSE.
- Multiple address parameters MAY appear in QUERY_REQUEST and
QUERY_RESPONSE.
The following message types are defined in simple BNF. Required
parameters are enclosed in <> and MUST appear. Optional parameters
are enclosed in [] and MAY appear. Not all message types need to be
implemented in order to be RSIP compliant. For example, an RSIP
client and/or server may not support LISTEN_REQUEST and
LISTEN_RESPONSE, or may only support RSA-IP or RSAP-IP.
9.1. ERROR_RESPONSE
An ERROR_RESPONSE is used to provide error messages from an RSIP
server to an RSIP client. Usually, errors indicate that the RSIP
server cannot or will not perform an action or allocate resources
on behalf of the client. If the error is related to a particular
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client ID or bind ID, these associated parameters MUST be
included. Multiple errors MAY NOT be reported in the same
ERROR_RESPONSE.
<ERROR_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Error>
[Client ID]
[Bind ID]
9.2. REGISTER_REQUEST
The REGISTER_REQUEST message is used by an RSIP client to
establish registration with an RSIP server. An RSIP client MUST
register before it requests resources or services from an RSIP
server. Once an RSIP client has registered with an RSIP server,
it may not register again until it has de-registered from that
server.
<REGISTER_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
9.3. REGISTER_RESPONSE
The REGISTER_RESPONSE message is used by an RSIP server to confirm
the registration of an RSIP client, and to provide a client ID and
flow policy. The RSIP server MAY respond with one or more RSIP
methods and tunnel types that it supports.
<REGISTER_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Flow Policy>
[RSIP Method]...
[Tunnel Type]...
9.4. DE-REGISTER_REQUEST
The DE-REGISTER_REQUEST message is used by an RSIP client to de-
register with an RSIP server. If a client de-registers from the
assigned state, all of the client's bindings are revoked. The
client SHOULD NOT de-register from the unregistered state.
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<DE-REGISTER_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
9.5. DE-REGISTER_RESPONSE
The DE-REGISTER_RESPONSE message is used by an RSIP server to
confirm the de-registration of an RSIP client.
<DE-REGISTER_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
9.6. ASSIGN_REQUEST_RSA-IP
The ASSIGN_REQUEST_RSA-IP message is used by an RSIP client to
request resources to use with RSA-IP. Note that RSA-IP cannot be
used in combination with micro-flow based local policy.
The RSIP client specifies two address parameters. The RSIP client
may request a particular local address by placing that address in
the first address parameter. To indicate that it has no
preference for local address, the RSIP client may place a "don't
care" value of all zeros in the address parameter.
If macro-flow based remote policy is used, the client MUST specify
the remote address that it will use this binding (if granted) to
contact; however, the remote port number MAY remain unspecified.
If micro-flow based remote policy is used, the client MUST specify
the remote address and port number that it will use this binding
(if granted) to contact. If no flow policy is used, the RSIP
client may place a "don't care" value of all zeros in the value
fields of the respective address and ports parameters.
<ASSIGN_REQUEST_RSA-IP> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Address (local)>
<Address (remote)>
<Ports (remote)>
[Lease Time]
[Tunnel Type]
9.7. ASSIGN_RESPONSE_RSA-IP
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The ASSIGN_RESPONSE_RSA-IP message is used by an RSIP server to
deliver parameter assignments to an RSIP client using RSA-IP. A
client-wise unique bind ID, lease time, and tunnel type must be
provided for every assignment.
If no remote flow policy is used, the RSIP server MUST use "don't
care" values for the remote address and ports parameters. If
macro-flow based remote policy is used, the remote address
parameter MUST contain the address specified in the associated
request, and the remote ports parameter MUST contain a "don't
care" value. If micro-flow based remote policy is used, the
remote address and remote ports parameters MUST contain the
address and port information specified in the associated request.
<ASSIGN_RESPONSE_RSA-IP> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
<Address (local)>
<Address (remote)>
<Ports (remote)>
<Lease Time>
<Tunnel Type>
9.8. ASSIGN_REQUEST_RSAP-IP
The ASSIGN_REQUEST_RSAP-IP message is used by an RSIP client to
request resources to use with RSAP-IP. The RSIP client specifies
two address and two port parameters, the first of each,
respectively, refer to the local address and port(s) that will be
used, and the second of each, respectively, refer to the remote
address and port(s) that will be contacted.
An RSIP client may request a particular local address by placing
that address in the value field of the first address parameter.
The RSIP client may request particular local ports by placing them
in the first port parameter. To indicate that it has no
preference for local address or ports, the RSIP client may place a
"don't care" value of zeros in the respective address or ports
parameters.
If macro-flow based remote policy is used, the client MUST specify
the remote address that it will use this binding (if granted) to
contact; however, the remote port number(s) MAY remain
unspecified. If micro-flow based remote policy is used, the
client MUST specify the remote address and port number(s) that it
will use this binding (if granted) to contact. If no flow policy
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is used, the RSIP client may place a value of all 0's in the value
fields of the respective address or port parameters.
<ASSIGN_REQUEST_RSAP-IP> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Address (local)>
<Ports (local)>
<Address (remote)>
<Ports (remote)>
[Lease Time]
[Tunnel Type]
9.9. ASSIGN_RESPONSE_RSAP-IP
The ASSIGN_RESPONSE_RSAP-IP message is used by an RSIP server to
deliver parameter assignments to an RSIP client. A client-wise
unique bind ID, lease time, and tunnel type must be provided for
every assignment.
Regardless of local flow policy, a local address and port(s) MUST
be assigned to the client. If macro-flow based local policy is
used, the client is assigned an address and one or more ports. If
micro-flow based local policy is used, the client is assigned an
address and exactly one port.
If no remote flow policy is used, the RSIP server MUST use "don't
care" values for the remote address and ports parameters. If
macro-flow based remote policy is used, the remote address
parameter MUST contain the address specified in the associated
request, and the remote ports parameter must contain a "don't
care" value. If micro-flow based remote policy is used, the
remote address and remote ports parameters MUST contain the
address and port information specified in the associated request.
<ASSIGN_RESPONSE_RSAP-IP> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
<Address (local)>
<Ports (local)>
<Address (remote)>
<Ports (remote)>
<Lease Time>
<Tunnel Type>
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9.10. EXTEND_REQUEST
The EXTEND_REQUEST message is used to request a lease extension to
a current bind. It may be used with both RSA-IP and RSAP-IP. The
client MUST specify its client ID and the bind ID in question, and
it MAY suggest a lease time to the server.
<EXTEND_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
[Lease Time]
9.11. EXTEND_RESPONSE
The EXTEND_RESPONSE message is used by an RSIP server to grant a
requested lease extension. The server MUST specify the client ID
of the client, the bind ID in question, and the new assigned lease
time.
<EXTEND_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
<Lease Time>
9.12. FREE_REQUEST
The FREE_REQUEST message is used by an RSIP client to free a
binding. The given bind ID identifies the bind to be freed.
Resources may only be freed using the granularity of a bind ID.
<FREE_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
9.13. FREE_RESPONSE
The FREE_RESPONSE message is used by an RSIP server to acknowledge
a FREE_REQUEST sent by an RSIP client.
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<FREE_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
9.14. QUERY_REQUEST
A QUERY_REQUEST message is used by an RSIP client to ask an RSIP
server whether or not a particular address or network is local or
remote. The client uses this information to determine whether to
contact the host(s) directly (in the local case), or via RSIP (in
the remote case). If the client needs to specify a subnet, it
must use two address parameters - the first indicates the network
and the second indicates the subnet mask.
<QUERY_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Address>
[Address (netmask)]
9.15. QUERY_RESPONSE
A QUERY_RESPONSE message is used by an RSIP server to answer a
QUERY_REQUEST from an RSIP client. The RSIP server MAY respond
with a list of all networks and/or addresses that are on the
private side of the network. If the server needs to specify a
subnet, it must use two address parameters - the first indicates
the network and the second indicates the subnet mask. An address
with a "don't care" value indicates that address queried is not
local.
<QUERY_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Address>
[Address (netmask)]
9.16. DEALLOCATE
A DEALLOCATE message is used by an RSIP server to force an RSIP
client to relinquish a specified binding. The client ID of the
client and the bind ID of the resources to be relinquished MUST be
included. Upon receiving a DEALLOCATE message, an RSIP client
MUST stop all use of the said resources and immediately send an OK
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response to the server.
<DEALLOCATE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
9.17. OK
An OK message MAY be used by an RSIP client to positively
acknowledge the receipt of a message from the RSIP server. The OK
message MUST be used to respond to a DEALLOCATE message from an
RSIP server. If the OK is in reference to a particular bind ID,
then that bind ID MUST appear in the message.
<OK> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
[Bind ID]
9.18. LISTEN_REQUEST
A LISTEN_REQUEST message is sent by an RSIP client that wants to
register a service on a particular IP address and port number. The
client must include its client ID, local address parameter and
ports parameters, and remote address and ports parameters. The
client MAY suggest a lease time and one or more tunnel types.
If the client wants to listen on a particular address or port, it
may specify these in the address and ports parameters. Otherwise
it may leave one or both of these parameters with "don't care"
values.
If no remote flow policy is being used, the client MUST fill both
the remote address and ports parameters with "don't care" values.
If macro-flow based remote policy is used, the client MUST specify
the remote address, but MAY or MAY NOT specify the remote port(s).
If micro-flow based remote policy is used, the client MUST specify
the remote address and ports parameter.
Once a LISTEN_REQUEST has been granted, the RSIP server MUST
forward all packets destined to the address and port in question
to the client, even if the remote host address and port tuple has
not been previously contacted by the client.
LISTEN_REQUEST is not necessary for RSA-IP.
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<LISTEN_REQUEST> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Address (local)>
<Ports (local)>
<Address (remote)>
<Ports (remote)>
[Lease Time]
[Tunnel Type]...
9.19. LISTEN_RESPONSE
A LISTEN_RESPONSE message is used by an RSIP server to respond to
a LISTEN_REQUEST message from an RSIP client. The RSIP server
MUST issue a bind ID, and specify the address and port which have
been granted to the client. The server must also specify a tunnel
type and lease time.
If no remote flow policy is being used, the server MUST fill both
the remote address and ports parameters with "don't care" values.
If macro-flow based remote policy is used, the server MUST specify
the remote address, but MAY or MAY NOT specify the remote port(s).
If micro-flow based remote policy is used, the server MUST specify
the remote address and ports parameter.
<LISTEN_RESPONSE> ::= <Version>
<Message Type>
<Overall Length>
<Client ID>
<Bind ID>
<Address (local)>
<Ports (local)>
<Address (remote)>
<Ports (remote)>
<Tunnel Type>
<Lease Time>
10. Discussion
10.1. General Server Policy
There is a significant amount of RSIP server policy that may be
implemented, but is beyond the scope of this draft. We expect
that most of this policy will be site-specific or implementation-
specific and therefore do not make any recommendations. Examples
of general server policy include:
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- How ports are allocated to RSIP clients.
- Preferred length of lease times.
- How flow policy is applied to which clients.
10.2. Default Tunnel Type and RSIP Method
If an RSIP server does not specify a tunnel type or RSIP method as
part of a REGISTER_RESPONSE, the client MUST assume a tunnel type
of IP-IP and an RSIP method of RSAP-IP.
10.3. Address and Port Requests and Allocation
Regardless of local flow policy, an RSIP client may "suggest" that
it would like to use a particular local address and/or port number
in a particular binding. An RSIP server that cannot grant such a
request, because the specified resources are already in use, MAY
either (1) deny the request with an appropriate error message, or
(2) approve the request but with different values than those
suggested.
10.4. Local Servers and Flow Policy Interaction
An RSIP client may initialize a publically accessible server (such
as an FTP or HTTP server) by transmitting a LISTEN_REQUEST message
to an RSIP server and receiving a LISTEN_RESPONSE. However,
unless no remote flow policy is used, the server will have to
specify the address or address and port of a single remote host
that will be allowed to contact it. Obviously, such as
restriction is not very useful for clients that require their
servers to be accessible by any remote host.
This indicates that there is a conflict between flow-based policy
and support for servers. The main purpose of enforcing flow-based
policy for LISTEN_REQUESTs is that it allows an RSIP server tight
control over how an RSIP client uses ports and the associated
accounting. For example, an RSIP client, operating under remote
micro-flow based policy and using a protocol such as FTP, will
have to specify the address and port that it will receive FTP data
on, as well as the address and port that the server will transmit
data from, in a LISTEN_REQUEST.
In general, an RSIP server may not allow arbitrary clients to
start public servers because of the traffic and security concerns.
Thus, we recommend that if remote micro-flow based policy is used,
that an RSIP server only allow public servers on RSIP clients via
administrative override.
11. Security Considerations
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RSIP, in and of itself, does not provide security. It may provide
the illusion of security or privacy by hiding a private address
space, but security can only be ensured by the proper use of security
protocols and cryptographic techniques.
RSIP messages send between a client and server SHOULD be
authenticated. Further discussion of such authentication can be
found in [RSIP-FRAME].
Discussion of RSIP support for end-to-end IPSEC can be found in
[RSIP-IPSEC].
12. IANA Considerations
All of the below are tentative.
- RSIP port number: 4455.
- RSIP error codes (see Appendix A).
- RSIP message type codes (see Appendix B).
13. Changelog
03 to 04
- Changed "client / server state" to "client / server relationship"
in order to not overload the word "state".
- Added section on transport protocol support.
- Reduced the size of "don't care" value for Address and Port parameters.
- Removed message IDs.
- Addition of overall length field in all messages.
- Added example of an RSA-IP session.
- Divided error numbers by category.
02 to 03
- Overall re-write and editing.
- Removed a number of extraneous details that are now covered in the
framework draft.
- Moved parameter and message type codes to appendices.
- Added section on flow policy.
- Modified address and port parameters to simplify and generalize.
01 to 02:
- Added section on server state.
- Re-wrote section on parameter negotiation.
- Added details to ICMP Handling section.
- Added LISTEN_REQUEST and LISTEN_RESPONSE messages.
- Added appendix with client state diagram.
- Updated references with respect to RFC 2663.
- Clarified use/non-use of message IDs between clients and servers.
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- Added recommendation that RSIP use port 4455 for initial
implementation and testing, until further notice.
- Bumped code values up by 1, made code value of 0 reserved.
- Expanded ASSIGN_REQUEST into ASSIGN_REQUEST_ADDR for RSA-IP,
ASSIGN_REQUEST_PORT for RSAP-IP and ASSIGN_REQUEST_EXT for lease
extensions. The same expansion applies for ASSIGN_RESPONSE.
- Indicated that all RSIP parameters must not appear more than once
except for tunnel type and RSIP method in ASSIGN_REQUEST messages.
- Exactly one error is now reported in each ERROR_RESPONSE message.
00 to 01:
- Eliminated number of IP addresses and IP address range
parameters and fixed other parameters to reflect this change.
- Added IP address request message.
- Added discussion on authentication to Security Considerations
section.
- Added Miscellaneous Issues section.
- Changed all mention of "sequence number" to "message ID".
- Reformatted References section.
- Added reference to RSIP framework draft.
- Separated request and response messages, then renumbered them.
- Required that all RSIP implementations support IP-IP tunneling
and RSA-IP.
- Modified message semantics slightly.
- Added appendix with protocol example.
- Added address and port resource error messages.
- Specified that multiple error responses may be returned in the
same ERROR_RESPONSE message.
- RSIP method may now be specified per binding, so that different
methods can be used when connecting to different external systems.
- Synched up terminology with the latest NAT terminology draft.
- Added mention of RSIP servers also implementing a NAT as a
fallback.
- Added DEALLOCATE and OK messages.
- Tunneling now negotiated per bind rather than per-registration.
14. Acknowledgements
The authors would like to specifically thank Gabriel Montenegro, Pyda
Srisuresh, Dan Nessett, Gary Jaszewski, and Rick Cobb for their
input. The IETF NAT working group as a whole has been extremely
helpful in the ongoing development of RSIP.
15. Appendix A: RSIP Error Numbers
This section provides descriptions for the error values in the RSIP
error parameter. These error values are preliminary and are very
likely to change over time as implementations are tested.
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All errors are grouped into the following categories:
100's: General errors.
101: UNKNOWN_ERROR. An error that cannot be identified has
occurred. This error should be used when all other error
messages are inappropriate.
102: USE_TCP. A client has attempted to use UDP on a server that
only supports TCP.
200's: Parameter and message errors. The server uses these errors
when it detects that a parameter or message is malformed, as well
as when it does not understand a parameter or message.
201: MISSING_PARAM. The request does not contain a required
parameter.
202: DUPLICATE_PARAM. The request contains an illegal duplicate
parameter.
203: EXTRA_PARAM. The request contains a parameter that it should
not.
204: ILLEGAL_PARAM. The server does not understand a parameter
code. not.
205: BAD_PARAM. A parameter is malformed.
206: ILLEGAL_MESSAGE. The server does not understand the message
type.
207: BAD_MESSAGE. A message is malformed.
300's: Permission and policy errors. The server uses these errors
when a client has attempted to do something that it is not
permitted to do, or something that violated server policy.
301: REGISTER_FIRST. The RSIP client has attempted to request or
use resources without registering.
302: ALREADY_REGISTERED. The client has attempted to register
again without first de-registering.
303: ALREADY_UNREGISTERED. The client has attempted to de-register
but it is already in the unregistered state.
304: BAD_CLIENT_ID. The client has referred to itself with the
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wrong Client ID.
305: BAD_BIND_ID. The request refers to a Bind ID that is not
valid for the client.
306: REMOTE_ADDR_UNALLOWED. The server will not allow the client
to establish a session to the specified remote address.
307: REMOTE_ADDRPORT_UNALLOWED. The server will not allow the
client to establish a session to the specified remote address /
port tuple.
400's: Resource allocation errors. The server uses these errors when
it needs to indicate to a client that a particular resource is not
available. These errors MUST NOT be used when a client attempts
to use resources that it does not have permission to use - in such
a case, a 300 error is to be used.
401: ADDR_UNAVAILABLE. The server was not able to allocate a local
IP address.
402: PORT_UNAVAILABLE. The server was not able to allocate
port(s).
403: REQUESTED_ADDR_UNAVAILABLE. The server was not able to
allocate the local IP address specified by the client.
404: REQUESTED_PORT_UNAVAILABLE. The server was not able to
allocate the port or ports specified by the client.
500's: IPSEC errors. All errors specific to RSIP / IPSEC operation.
See [RSIP-IPSEC].
16. Appendix B: Message Type Values
This section defines the values assigned to RSIP message types.
These values are preliminary and are very likely to change over time
as implementations are tested.
1 ERROR_RESPONSE
2 REGISTER_REQUEST
3 REGISTER_RESPONSE
4 DE-REGISTER_REQUEST
5 DE-REGISTER_RESPONSE
6 ASSIGN_REQUEST_RSA-IP
7 ASSIGN_RESPONSE_RSA-IP
8 ASSIGN_REQUEST_RSAP-IP
9 ASSIGN_RESPONSE_RSAP-IP
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10 EXTEND_REQUEST
11 EXTEND_RESPONSE
12 FREE_REQUEST
13 FREE_RESPONSE
14 QUERY_REQUEST
15 QUERY_RESPONSE
16 DEALLOCATE
17 OK
18 LISTEN_REQUEST
19 LISTEN_RESPONSE
17. Appendix C: Example RSIP client/server transactions
In this appendix, we present an exemplary series of annotated
transactions between an RSIP client and an RSIP server. All client
to server traffic is denote by `C --> S' and all server to client
traffic is denoted by `S --> C'. Parameter values are denoted inside
of parentheses. Versions, message types, and overall lengths are not
included in order to save space. "Don't care" values are indicated
by 0's.
A ports parameter is represented by the number of ports followed by
the port numbers, separated by dashes. For example, 2-1012-1013
indicates two ports, namely 1012 and 1013, while 16-10000 indicates
16 ports, namely 10000-10015, and 4-0 indicates four ports, but the
sender doesn't care where they are.
IPv4 addresses are assumed.
17.1. RSAP-IP with Local Macro-flow Based Policy and No Remote Flow
Policy
This example exhibits the loosest policy framework for RSA-IP.
C --> S: REGISTER_REQUEST ()
The client attempts to register with the server.
S --> C: REGISTER_RESPONSE (Client ID = 1, Local Flow Policy =
Macro, Remote Flow policy = None)
The server responds, assigning a Client ID of 1, local macro-
flow based policy and no remote flow policy. No RSIP method is
indicated, so RSAP-IP is assumed. No tunnel type is indicated,
so IP-IP is assumed.
C --> S: ASSIGN_REQUEST_RSAP-IP: (Client ID = 1, Address (local) =
0, Ports (local) = 4-0, Address (remote) = 0, Ports (remote) =
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0, Lease Time = 3600)
The client requests an address and four ports to use with it,
but doesn't care which address or ports are assigned. The
client does not specify the remote address or ports either.
The client suggests a lease time of 3600 seconds.
S --> C: ASSIGN_RESPONSE_RSAP-IP: (Client ID = 1, Bind ID = 1,
Address (local) = 149.112.240.156, Ports (local) = 4-1234,
Address (remote) = 0, Ports (remote) = 0, Lease Time = 1800,
Tunnel Type = IP-IP)
The server responds by indicating that a bind ID of 1 has been
assigned to IP address 149.112.240.156 with ports 1234-1237.
Any remote host may be communicated with, using any remote port
number. The lease time has been assigned to be 1800 seconds,
and the tunnel type is confirmed to be IP-IP.
The client is now able to communicate with any host on the
public network using these resources.
C --> S: QUERY_REQUEST: (Client ID = 1, Address = 10.20.60.0,
Address (netmask) 255.255.255.0)
The client asks the server if the network 10.20.60.0 is local.
S --> C: QUERY_RESPONSE: (Client ID = 1, Address = 10.20.60.0,
Address (netmask) = 255.255.255.0)
The server responds indicating that the network in question is
local.
C --> S: ASSIGN_REQUEST_RSAP-IP: (Client ID = 1, Address (local) =
149.112.240.156, Ports (local) = 8-1238, Address (remote) = 0,
Ports (remote) = 0, Lease Time = 1800)
The client requests eight more particular ports for use with
RSAP-IP with the same address. A lease of 1800 seconds is
requested. IP-IP tunneling is implied by default.
S --> C: ASSIGN_RESPONSE_RSAP-IP: (Client ID = 1, Bind ID = 2,
Address (local) = 149.112.240.156, Ports (local) = 8-1305,
Address (remote) = 0, Ports (remote) = 0, Lease Time = 1800)
The server grants the request with the same address, but with a
different set of ports. IP-IP tunneling is implied by default.
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C --> S: FREE_REQUEST (Client ID = 1, Bind ID = 1)
The client frees bind ID 1; i.e., ports 1234-1237 from IP
address 149.112.240.156. Note that the address itself is still
assigned to the client because the client is still assigned
ports 1305-1314.
S --> C: FREE_RESPONSE (Client ID = 1, Bind ID = 1)
The server acknowledges that Bind ID 1 has been freed.
C --> S: EXTEND_REQUEST (Client ID = 1, Bind ID = 2, Lease Time =
1800)
The client request that the lease on bind ID 1 be extended for
1800 seconds.
S --> C: EXTEND_RESPONSE (Client ID = 1, Bind ID = 2, Lease Time =
1800)
The server confirms the request.
S --> C: DEALLOCATE (Client ID = 1, Bind ID = 2)
The server forces the client to deallocate the resources of
bind ID 2.
C --> S: OK (Client ID = 1, Bind ID 2)
The client acknowledges that the resources have been
deallocated.
C --> S: DE-REGISTER_REQUEST (Client ID = 1)
The client de-registers with the sever.
S --> C: REGISTER_RESPONSE (Client ID = 1)
The server acknowledges that the client has de-registered.
17.2. RSAP-IP with Local Micro-flow Based Policy and Remote Micro-
flow Based Policy
This example exhibits the strictest policy framework for RSAP-IP.
C --> S: REGISTER_REQUEST ()
The client attempts to register with the server.
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S --> C: REGISTER_RESPONSE (Client ID = 5, Local Flow Policy =
Micro, Remote Flow policy = Micro, RSIP Method = RSAP-IP, RSIP
Method = RSA-IP, Tunnel Type = IP-IP, Tunnel Type = GRE)
The server responds, assigning a Client ID of 5, local micro-
flow based policy and remote micro-flow based policy. Both
RSAP-IP and RSA-IP are supported. Both IP-IP and GRE tunnel
types are supported.
C --> S: ASSIGN_REQUEST_RSAP-IP: (Client ID = 5, Address (local) =
0, Ports (local) = 0, Address (remote) = 38.196.73.6, Ports
(remote) = 21, Lease Time = 600, Tunnel Type = IP-IP)
The client requests a local address and a port assignment to
use with it. The client indicates that it wants to contact
host 38.196.73.6 at port 21 (FTP control). The client requests
a lease time of 600 seconds and a tunnel type of IP-IP.
S --> C: ASSIGN_RESPONSE_RSAP-IP: (Client ID = 5, Bind ID = 1,
Address (local) = 149.112.240.156, Ports (local) = 2049,
Address (remote) = 38.196.73.6, Ports (remote) = 21, Lease Time
= 600, Tunnel Type = IP-IP)
The server responds by indicating that a bind ID of 1 has been
assigned to IP address 149.112.240.156 with port 2049. Only
host 38.196.73.6 at port 21 may be contacted. The lease time
has been assigned to be 600 seconds, and the tunnel type is
confirmed to be IP-IP.
C --> S: LISTEN_REQUEST: (Client ID = 5, Address (local) =
149.112.240.156, Ports (local) = 2050, Address (remote) =
38.196.73.6, Ports (remote) = 20)
The client requests a listen port 2050 at the same address that
it has been assigned. Only host 38.196.73.6 from ports 20 (FTP
data) will be able to contact it.
S --> C: LISTEN_RESPONSE: (Client ID = 5, Address (local) =
149.112.240.156, Ports (local) = 2050, Address (remote) =
38.196.73.6, Ports (remote) = 20, Lease Time = 600, Tunnel Type
= IP-IP)
The server confirms the request and assigns a lease time of 600
seconds and a tunnel type of IP-IP.
C --> S: DE-REGISTER_REQUEST (Client ID = 5)
The client de-registers with the sever.
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S --> C: REGISTER_RESPONSE (Client ID = 5)
The server acknowledges that the client has de-registered. All
of the client's bindings have been implicitly revoked.
17.3. RSA-IP with Local Macro-flow Based Policy and Remote Macro-
flow based Policy
This example exhibits a medium level of control for RSA-IP.
C --> S: REGISTER_REQUEST ()
The client attempts to register with the server.
S --> C: REGISTER_RESPONSE (Client ID = 3, Local Flow Policy =
Macro, Remote Flow policy = Macro, RSIP Method = RSAP-IP, RSIP
Method = RSA-IP, Tunnel Type = IP-IP, Tunnel Type = L2TP)
The server responds, assigning a Client ID of 3, local macro-
flow based policy and remote macro-flow based policy. Both
RSAP-IP and RSA-IP are supported. Both IP-IP and L2TP tunnel
types are supported.
C --> S: ASSIGN_REQUEST_RSA-IP: (Client ID = 3, Address (local) =
0, Address (remote) = www.foo.com, Ports (remote) = 0, Lease
Time = 3600, Tunnel Type = IP-IP)
The client requests a local address and indicates that it wants
to contact host www.foo.com.
S --> C: ERROR_RESPONSE: (Error = REMOTE_ADDR_UNALLOWED, Client ID
= 3)
The server indicates that the client is not permitted to
establish communication with www.foo.com.
C --> S: ASSIGN_REQUEST_RSA-IP: (Client ID = 3, Address (local) =
0, Address (remote) = www.bar.com, Ports (remote) = 0, Lease
Time = 3600, Tunnel Type = IP-IP)
The client requests a local address and indicates that it wants
to contact host www.bar.com.
S --> C: ASSIGN_RESPONSE_RSA-IP: (Client ID = 3, Bind ID = 1,
Address (local) = 149.112.240.17, Address (remote) =
www.bar.com, Ports (remote) = 0, Lease Time = 3600, Tunnel Type
= IP-IP)
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The server responds by granting local IP address 149.112.240.17
to the client, and permitting it to communicate with
www.bar.com, at any port. Requested lease time and tunnel type
are also granted.
C --> S: DE-REGISTER_REQUEST (Client ID = 3)
The client de-registers with the sever.
S --> C: REGISTER_RESPONSE (Client ID = 3)
The server acknowledges that the client has de-registered. All
of the client's bindings have been implicitly revoked.
18. Appendix D: Example RSIP client state diagram
This appendix provides an exemplary diagram of RSIP client state.
The client begins in the unregistered state. We assume that for UDP,
if a message is lost, the client will timeout and retransmit another
copy of it. We recommend a 7-fold binary exponential backoff timer
for retransmissions, with the first timeout occurring after 12.5 ms.
This diagram does not include transitions for the LISTEN_REQUEST
message or the DEALLOCATE message.
send
+------------+ REGISTER_REQUEST +------------+
| |----------------->|Registration|<-- timeout/send
+--->|Unregistered|<-----------------| Pending |--- REGISTER_REQUEST
| | | 7th timeout/recv +------------+
| +------------+ ERROR_RESPONSE |
| ^ |
| |7th timeout/recv |recv timeout/send
| |DE-REGISTER_RESPONSE |REGISTER_RESPONSE QUERY_REQUEST
| | | ^ |
| | send DE- v send | |
| +----------------+ REGISTER_REQUEST+----------+QUERY_REQUEST +----------+
| | Registered |<----------------| |-------------->|Registered|
| | De-registration| |Registered| | Query |
| | Pending |---------------->| |<--------------| Pending |
| +----------------+ recv +----------+ 7th timeout/ +----------+
| | ^ ERROR_RESPONSE ^ | recv
| | | | | QUERY_RESPONSE or
| timeout/send | | ERROR_RESPONSE
| DE-REGISTER_REQUEST 7th timeout/recv| |
| ERROR_RESPONSE | |
| +----------------+ | |
| |Go to Registered| | |send
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| +----------------+ | |ASSIGN_REQUEST
| ^ timeout/send | |
| |Yes FREE_REQUEST | |
| + | | | |
| + + v | | v
| + + 7th timeout/ +--------+ +----------+
| + Are all + recv | Free | |Assignment|<--timeout/send
| + resources +<-----------|Pending | | Pending |---ASSIGN_REQUEST
| + freed? + FREE_RESPONSE+--------+ +----------+
| + + ^ | |
| + + | | |
| + | | |recv
| |No send | |recv |ASSIGN_RESPONSE
| v ERROR_REQUEST| |ERROR_ |
| +---------------+ | |RESPONSE |
| | Go to Assigned| | | |
| +---------------+ | | | 7th timeout/recv
| recv | | | QUERY_RESPONSE or
| +---------------+ERROR_RESPONSE | v v ERROR_RESPONSE+-------------+
| | Assigned |-------------->+-------------+------------->| Assigned |
+>|De-registration| | Assigned | | Query |
| Pending |<--------------+-------------+<-------------| Pending |
+---------------+ send ^ | send +-------------+
^ | DE-REGISTER_REQUEST | | QUERY_REQUEST ^ |
| | | | | |
timeout/send 7th/timeout/recv | |send | |
DE-REGISTER_ ASSIGN_RESPONSE | |ASSIGN_REQUEST timeout/send
REQUEST or ERROR_RESPONSE| | QUERY_REQUEST
| |
| v
+----------+
| Assigned |
|Assignment|
| Pending |
+----------+
^ |
| |
timeout/send
ASSIGN_REQUEST
19. References
[RFC1918] Y. Rekhter, B. Moskowitz, D. Karrenberg, G. J. de Groot,
and E. Lear, "Address Allocation for Private Internets," RFC 1918,
Feb. 1996.
[RFC2119] S. Bradner, "Key words for use in RFCs to indicate
requirement levels," RFC 2119, Mar. 1997.
Borella et al. Expires May 2000 [Page 32]
INTERNET-DRAFT Realm Specific IP: Protocol Specification November 1999
[RFC2663] P. Srisuresh and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations," RFC 2663, Aug.
1999.
[RSIP-FRAME] M. Borella, J. Lo, D. Grabelsky, and G. Montenegro,
"Realm Specific IP: Framework," Internet Draft <draft-ietf-nat-
rsip-framework-02.txt>, Oct. 1999 (work in progress).
[RSIP-IPSEC] G. Montenegro and M. Borella, "RSIP Support for End-to-
end IPSEC," <draft-ietf-nat-rsip-ipsec-01.txt>, work in progress,
Oct. 1999.
20. Authors' Addresses
Michael Borella
3Com Corp.
1800 W. Central Rd.
Mount Prospect IL 60056
(847) 342-6093
mike_borella@3com.com
David Grabelsky
3Com Corp.
1800 W. Central Rd.
Mount Prospect IL 60056
(847) 222-2483
david_grabelsky@3com.com
Jeffrey Lo
NEC USA
C&C Research Labs.
110 Rio Robles
San Jose, CA 95134
(408) 943-3033
jlo@ccrl.sj.nec.com
Kunihiro Taniguchi
NEC USA
C&C Research Labs.
110 Rio Robles
San Jose, CA 95134
(408) 943-3031
taniguti@ccrl.sj.nec.com
21. Copyright Statement
Copyright (c) The Internet Society (1999). All Rights Reserved.
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INTERNET-DRAFT Realm Specific IP: Protocol Specification November 1999
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Borella et al. Expires May 2000 [Page 34]
