RFC3487 日本語訳

Network Working Group                                     H. Schulzrinne
Request for Comments: 3487                           Columbia University
Category: Informational                                    February 2003

Network Working Group H. Schulzrinne Request for Comments: 3487 Columbia University Category: Informational February 2003

         Requirements for Resource Priority Mechanisms for the
                   Session Initiation Protocol (SIP)

Requirements for Resource Priority Mechanisms for the Session Initiation Protocol (SIP)

Status of this Memo

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Copyright Notice

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

Abstract

   This document summarizes requirements for prioritizing access to
   circuit-switched network, end system and proxy resources for
   emergency preparedness communications using the Session Initiation
   Protocol (SIP).

This document summarizes requirements for prioritizing access to circuit-switched network, end system and proxy resources for emergency preparedness communications using the Session Initiation Protocol (SIP).

Table of Contents

Table of Contents

   1.  Introduction ................................................  2
   2.  Terminology .................................................  3
   3.  Resources ...................................................  4
   4.  Network Topologies ..........................................  5
   5.  Network Models ..............................................  6
   6.  Relationship to Emergency Call Services .....................  7
   7.  SIP Call Routing ............................................  8
   8.  Policy and Mechanism ........................................  8
   9.  Requirements ................................................  9
   10. Security Requirements ....................................... 12
       10.1 Authentication and Authorization ....................... 12
       10.2 Confidentiality and Integrity .......................... 13
       10.3 Anonymity .............................................. 14
       10.4 Denial-of-Service Attacks .............................. 14
   11. Security Considerations ..................................... 15
   12. Acknowledgements ............................................ 15
   13. Normative References ........................................ 15
   14. Informative References ...................................... 15
   15. Author's Address ............................................ 16
   16. Full Copyright Statement .................................... 17

1. Introduction ................................................ 2 2. Terminology ................................................. 3 3. Resources ................................................... 4 4. Network Topologies .......................................... 5 5. Network Models .............................................. 6 6. Relationship to Emergency Call Services ..................... 7 7. SIP Call Routing ............................................ 8 8. Policy and Mechanism ........................................ 8 9. Requirements ................................................ 9 10. Security Requirements ....................................... 12 10.1 Authentication and Authorization ....................... 12 10.2 Confidentiality and Integrity .......................... 13 10.3 Anonymity .............................................. 14 10.4 Denial-of-Service Attacks .............................. 14 11. Security Considerations ..................................... 15 12. Acknowledgements ............................................ 15 13. Normative References ........................................ 15 14. Informative References ...................................... 15 15. Author's Address ............................................ 16 16. Full Copyright Statement .................................... 17

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1.  Introduction

1. Introduction

   During emergencies, communications resources including telephone
   circuits, IP bandwidth and gateways between the circuit-switched and
   IP networks may become congested.  Congestion can occur due to heavy
   usage, loss of resources caused by the natural or man-made disaster
   and attacks on the network during man-made emergencies.  This
   congestion may make it difficult for persons charged with emergency
   assistance, recovery or law enforcement to coordinate their efforts.
   As IP networks become part of converged or hybrid networks along with
   public and private circuit-switched (telephone) networks, it becomes
   necessary to ensure that these networks can assist during such
   emergencies.

During emergencies, communications resources including telephone circuits, IP bandwidth and gateways between the circuit-switched and IP networks may become congested. Congestion can occur due to heavy usage, loss of resources caused by the natural or man-made disaster and attacks on the network during man-made emergencies. This congestion may make it difficult for persons charged with emergency assistance, recovery or law enforcement to coordinate their efforts. As IP networks become part of converged or hybrid networks along with public and private circuit-switched (telephone) networks, it becomes necessary to ensure that these networks can assist during such emergencies.

   There are many IP-based services that can assist during emergencies.
   This memo only covers requirements for real-time communications
   applications involving the Session Initiation Protocol (SIP) [1],
   including voice-over-IP, multimedia conferencing and instant
   messaging/presence.

There are many IP-based services that can assist during emergencies. This memo only covers requirements for real-time communications applications involving the Session Initiation Protocol (SIP) [1], including voice-over-IP, multimedia conferencing and instant messaging/presence.

   This document takes no position as to which mode of communication is
   preferred during an emergency, as such discussion appears to be of
   little practical value.  Based on past experience, real-time
   communications is likely to be an important component of any overall
   suite of applications, particularly for coordination of emergency-
   related efforts.

This document takes no position as to which mode of communication is preferred during an emergency, as such discussion appears to be of little practical value. Based on past experience, real-time communications is likely to be an important component of any overall suite of applications, particularly for coordination of emergency- related efforts.

   As we will describe in detail below, such Session Initiation Protocol
   (SIP) [1] applications involve at least five different resources that
   may become scarce and congested during emergencies.  In order to
   improve emergency response, it may become necessary to prioritize
   access to such resources during periods of emergency-induced resource
   scarcity.  We call this "resource prioritization".

As we will describe in detail below, such Session Initiation Protocol (SIP) [1] applications involve at least five different resources that may become scarce and congested during emergencies. In order to improve emergency response, it may become necessary to prioritize access to such resources during periods of emergency-induced resource scarcity. We call this "resource prioritization".

   This document describes requirements rather than possible existing or
   new protocol features.  Although it is scoped to deal with SIP-based
   applications, this should not be taken to imply that mechanisms have
   to be SIP protocol features such as header fields, methods or URI
   parameters.

This document describes requirements rather than possible existing or new protocol features. Although it is scoped to deal with SIP-based applications, this should not be taken to imply that mechanisms have to be SIP protocol features such as header fields, methods or URI parameters.

   The document is organized as follows.  In Section 2, we explain core
   technical terms and acronyms that are used throughout the document.
   Section 3 describes the five types of resources that may be subject
   to resource prioritization.  Section 4 enumerates four network
   hybrids that determine which of these resources are relevant.  Since
   the design choices may be constrained by the assumptions placed on

The document is organized as follows. In Section 2, we explain core technical terms and acronyms that are used throughout the document. Section 3 describes the five types of resources that may be subject to resource prioritization. Section 4 enumerates four network hybrids that determine which of these resources are relevant. Since the design choices may be constrained by the assumptions placed on

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   the IP network, Section 5 attempts to classify networks into
   categories according to the restrictions placed on modifications and
   traffic classes.

the IP network, Section 5 attempts to classify networks into categories according to the restrictions placed on modifications and traffic classes.

   Since this is a major source of confusion due to similar names,
   Section 6 attempts to distinguish emergency call services placed by
   civilians from the topic of this document.

Since this is a major source of confusion due to similar names, Section 6 attempts to distinguish emergency call services placed by civilians from the topic of this document.

   Request routing is a core component of SIP, covered in Section 7.

Request routing is a core component of SIP, covered in Section 7.

   Providing resource priority entails complex implementation choices,
   so that a single priority scheme leads to a set of algorithms that
   manage queues, resource consumption and resource usage of existing
   calls.  Even within a single administrative domain, the combination
   of mechanisms is likely to vary.  Since it will also depend on the
   interaction of different policies, it appears inappropriate to have
   SIP applications specify the precise mechanisms.  Section 8 discusses
   the call-by-value (specification of mechanisms) and call-by-reference
   (invoke labeled policy) distinction.

Providing resource priority entails complex implementation choices, so that a single priority scheme leads to a set of algorithms that manage queues, resource consumption and resource usage of existing calls. Even within a single administrative domain, the combination of mechanisms is likely to vary. Since it will also depend on the interaction of different policies, it appears inappropriate to have SIP applications specify the precise mechanisms. Section 8 discusses the call-by-value (specification of mechanisms) and call-by-reference (invoke labeled policy) distinction.

   Based on these discussions, Section 9 summarizes some general
   requirements that try to achieve generality and feature-transparency
   across hybrid networks.

Based on these discussions, Section 9 summarizes some general requirements that try to achieve generality and feature-transparency across hybrid networks.

   The most challenging component of resource prioritization is likely
   to be security (Section 10).  Without adequate security mechanisms,
   resource priority may cause more harm than good, so that the section
   attempts to enumerate some of the specific threats present when
   resource prioritization is being employed.

The most challenging component of resource prioritization is likely to be security (Section 10). Without adequate security mechanisms, resource priority may cause more harm than good, so that the section attempts to enumerate some of the specific threats present when resource prioritization is being employed.

2.  Terminology

2. Terminology

   CSN: Circuit-switched network, encompassing both private
      (closed) networks and the public switched telephone network
      (PSTN).

CSN: Circuit-switched network, encompassing both private (closed) networks and the public switched telephone network (PSTN).

   ETS: Emergency telecommunications service, identifying a
      communications service to be used during large-scale emergencies
      that allows authorized individuals to communicate.  Such
      communication may reach end points either within a closed network
      or any endpoint on the CSN or the Internet.  The communication
      service may use voice, video, text or other multimedia streams.

ETS: Emergency telecommunications service, identifying a communications service to be used during large-scale emergencies that allows authorized individuals to communicate. Such communication may reach end points either within a closed network or any endpoint on the CSN or the Internet. The communication service may use voice, video, text or other multimedia streams.

   Request: In this document, we define "request" as any SIP
      request.  This includes call setup requests, instant message
      requests and event notification requests.

Request: In this document, we define "request" as any SIP request. This includes call setup requests, instant message requests and event notification requests.

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3.  Resources

3. Resources

   Prioritized access to at least five resource types may be useful:

Prioritized access to at least five resource types may be useful:

   Gateway resources: The number of channels (trunks) on a CSN
      gateway is finite.  Resource prioritization may prioritize access
      to these channels, by priority queuing or preemption.

Gateway resources: The number of channels (trunks) on a CSN gateway is finite. Resource prioritization may prioritize access to these channels, by priority queuing or preemption.

   CSN resources: Resources in the CSN itself, away from the access
      gateway, may be congested.  This is the domain of traditional
      resource prioritization mechanisms such as MLPP and GETS, where
      circuits are granted to ETS communications based on queuing
      priority or preemption (if allowed by local telecommunication
      regulatory policy and local administrative procedures).  A gateway
      may also use alternate routing (Section 8) to increase the
      probability of call completion.

CSN resources: Resources in the CSN itself, away from the access gateway, may be congested. This is the domain of traditional resource prioritization mechanisms such as MLPP and GETS, where circuits are granted to ETS communications based on queuing priority or preemption (if allowed by local telecommunication regulatory policy and local administrative procedures). A gateway may also use alternate routing (Section 8) to increase the probability of call completion.

      Specifying CSN behavior is beyond the scope of this document, but
      as noted below, a central requirement is to be able to invoke all
      such behaviors from an IP endpoint.

Specifying CSN behavior is beyond the scope of this document, but as noted below, a central requirement is to be able to invoke all such behaviors from an IP endpoint.

   IP network resources: SIP may initiate voice and multimedia
      sessions.  In many cases, audio and video streams are inelastic
      and have tight delay and loss requirements.  Under conditions of
      IP network overload, emergency services applications may not be
      able to obtain sufficient bandwidth in any network.  When there
      are insufficient network resources for all users and it is not
      practical to simply add more resources, quality of service
      management is necessary to solve this problem.  This is orthogonal
      to SIP, out of the scope for SIP, and as such these requirements
      will be discussed in another document.

IP network resources: SIP may initiate voice and multimedia sessions. In many cases, audio and video streams are inelastic and have tight delay and loss requirements. Under conditions of IP network overload, emergency services applications may not be able to obtain sufficient bandwidth in any network. When there are insufficient network resources for all users and it is not practical to simply add more resources, quality of service management is necessary to solve this problem. This is orthogonal to SIP, out of the scope for SIP, and as such these requirements will be discussed in another document.

      Bandwidth used for SIP signaling itself may be subject to
      prioritization.

Bandwidth used for SIP signaling itself may be subject to prioritization.

   Receiving end system resources: End systems may include
      automatic call distribution systems (ACDs) or media servers as
      well as traditional telephone-like devices.  Gateways are also end
      systems, but have been discussed earlier.

Receiving end system resources: End systems may include automatic call distribution systems (ACDs) or media servers as well as traditional telephone-like devices. Gateways are also end systems, but have been discussed earlier.

      Since the receiving end system can only manage a finite number of
      sessions, a prioritized call may need to preempt an existing call
      or indicate to the callee that a high-priority call is waiting.
      (The precise user agent behavior is beyond the scope of this
      document and considered a matter of policy and implementation.)

Since the receiving end system can only manage a finite number of sessions, a prioritized call may need to preempt an existing call or indicate to the callee that a high-priority call is waiting. (The precise user agent behavior is beyond the scope of this document and considered a matter of policy and implementation.)

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      Such terminating services may be needed to avoid overloading, say,
      an emergency coordination center. However, other approaches beyond
      prioritization, e.g., random request dropping by geographic
      origin, need to be employed if the number of prioritized calls
      exceeds the terminating capacity.  Such approaches are beyond the
      scope of this memo.

Such terminating services may be needed to avoid overloading, say, an emergency coordination center. However, other approaches beyond prioritization, e.g., random request dropping by geographic origin, need to be employed if the number of prioritized calls exceeds the terminating capacity. Such approaches are beyond the scope of this memo.

   SIP proxy resources: While SIP proxies often have large request
      handling capacities, their capacity is likely to be smaller than
      their access network bandwidth.  (This is true in particular since
      different SIP requests consume vastly different amounts of proxy
      computational resources, depending on whether they invoke external
      services, sip-cgi [2] and CPL [3] scripts, etc.  Thus, avoiding
      proxy overload by restricting access bandwidth is likely to lead
      to inefficient utilization of the proxy.)  Therefore, some types
      of proxies may need to silently drop selected SIP requests under
      overload, reject requests, with overload indication or provide
      multiple queues with different drop and scheduling priorities for
      different types of SIP requests.  However, this is strictly an
      implementation issue and does not appear to influence the protocol
      requirements nor the on-the-wire protocol.  Thus, it is out of
      scope for the protocol requirements discussion pursued here.

SIP proxy resources: While SIP proxies often have large request handling capacities, their capacity is likely to be smaller than their access network bandwidth. (This is true in particular since different SIP requests consume vastly different amounts of proxy computational resources, depending on whether they invoke external services, sip-cgi [2] and CPL [3] scripts, etc. Thus, avoiding proxy overload by restricting access bandwidth is likely to lead to inefficient utilization of the proxy.) Therefore, some types of proxies may need to silently drop selected SIP requests under overload, reject requests, with overload indication or provide multiple queues with different drop and scheduling priorities for different types of SIP requests. However, this is strictly an implementation issue and does not appear to influence the protocol requirements nor the on-the-wire protocol. Thus, it is out of scope for the protocol requirements discussion pursued here.

      Responses should naturally receive the same treatment as the
      corresponding request.  Responses already have to be securely
      mapped to requests, so this requirement does not pose a
      significant burden.  Since proxies often do not maintain call
      state, it is not generally feasible to assign elevated priority to
      requests originating from a lower-privileged callee back to the
      higher-privileged caller.

Responses should naturally receive the same treatment as the corresponding request. Responses already have to be securely mapped to requests, so this requirement does not pose a significant burden. Since proxies often do not maintain call state, it is not generally feasible to assign elevated priority to requests originating from a lower-privileged callee back to the higher-privileged caller.

   There is no requirement that a single mechanism be used for all five
   resources.

There is no requirement that a single mechanism be used for all five resources.

4.  Network Topologies

4. Network Topologies

   We consider four types of combinations of IP and circuit-switched
   networks.

We consider four types of combinations of IP and circuit-switched networks.

   IP end-to-end: Both request originator and destination are on an
      IP network, without intervening CSN-IP gateways.  Here, any SIP
      request could be subject to prioritization.

IP end-to-end: Both request originator and destination are on an IP network, without intervening CSN-IP gateways. Here, any SIP request could be subject to prioritization.

   IP-to-CSN (IP at the start): The request originator is in the IP
      network, while the callee is in the CSN.  Clearly, this model only
      applies to SIP-originated phone calls, not generic SIP requests
      such as those supporting instant messaging services.

IP-to-CSN (IP at the start): The request originator is in the IP network, while the callee is in the CSN. Clearly, this model only applies to SIP-originated phone calls, not generic SIP requests such as those supporting instant messaging services.

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   CSN-to-IP (IP at the end): A call originates in the CSN and
      terminates, via an Internet telephony gateway, in the IP network.

CSN-to-IP (IP at the end): A call originates in the CSN and terminates, via an Internet telephony gateway, in the IP network.

   CSN-IP-CSN (IP bridging): This is a concatenation of the two
      previous ones.  It is worth calling out specifically to note that
      the two CSN sides may use different signaling protocols.  Also,
      the originating CSN endpoint and the gateway to the IP network may
      not know the nature of the terminating CSN.  Thus, encapsulation
      of originating CSN information is insufficient.

CSN-IP-CSN (IP bridging): This is a concatenation of the two previous ones. It is worth calling out specifically to note that the two CSN sides may use different signaling protocols. Also, the originating CSN endpoint and the gateway to the IP network may not know the nature of the terminating CSN. Thus, encapsulation of originating CSN information is insufficient.

   The bridging model (IP-CSN-IP) can be treated as the concatenation of
   the IP-to-CSN and CSN-to-IP cases.

The bridging model (IP-CSN-IP) can be treated as the concatenation of the IP-to-CSN and CSN-to-IP cases.

   It is worth emphasizing that CSN-to-IP gateways are unlikely to know
   whether the final destination is in the IP network, the CSN or, via
   SIP forking, in both.

It is worth emphasizing that CSN-to-IP gateways are unlikely to know whether the final destination is in the IP network, the CSN or, via SIP forking, in both.

   These models differ in the type of controllable resources, identified
   as gateway, CSN, IP network resources, proxy and receiver.  Items
   marked as (x) are beyond the scope of this document.

These models differ in the type of controllable resources, identified as gateway, CSN, IP network resources, proxy and receiver. Items marked as (x) are beyond the scope of this document.

   Topology       Gateway  CSN  IP   proxy  receiver
   _________________________________________________
   IP-end-to-end                (x)  (x)    x
   IP-to-CSN      x        x    (x)  (x)    (x)
   CSN-to-IP      x        x    (x)  (x)    x
   CSN-IP-CSN     x        x    (x)  (x)    (x)

Topology Gateway CSN IP proxy receiver _________________________________________________ IP-end-to-end (x) (x) x IP-to-CSN x x (x) (x) (x) CSN-to-IP x x (x) (x) x CSN-IP-CSN x x (x) (x) (x)

5.  Network Models

5. Network Models

   There are at least four IP network models that influence the
   requirements for resource priority.  Each model inherits the
   restrictions of the model above it.

There are at least four IP network models that influence the requirements for resource priority. Each model inherits the restrictions of the model above it.

   Pre-configured for ETS: In a pre-configured network, an ETS
      application can use any protocol carried in IP packets and modify
      the behavior of existing protocols.  As an example, if an ETS
      agency owns the IP network, it can add traffic shaping, scheduling
      or support for a resource reservation protocol to routers.

Pre-configured for ETS: In a pre-configured network, an ETS application can use any protocol carried in IP packets and modify the behavior of existing protocols. As an example, if an ETS agency owns the IP network, it can add traffic shaping, scheduling or support for a resource reservation protocol to routers.

   Transparent: In a transparent network, an ETS application can
      rely on the network to forward all valid IP packets, however, the
      ETS application cannot modify network elements.  Commercial ISP
      offer transparent networks as long as they do not filter certain
      types of packets.  Networks employing firewalls, NATs and
      "transparent" proxies are not transparent.  Sometimes, these types
      of networks are also called common-carrier networks since they
      carry IP packets without concern as to their content.

Transparent: In a transparent network, an ETS application can rely on the network to forward all valid IP packets, however, the ETS application cannot modify network elements. Commercial ISP offer transparent networks as long as they do not filter certain types of packets. Networks employing firewalls, NATs and "transparent" proxies are not transparent. Sometimes, these types of networks are also called common-carrier networks since they carry IP packets without concern as to their content.

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   SIP/RTP transparent: Networks that are SIP/RTP transparent allow
      users to place and receive SIP calls.  The network allows ingress
      and egress for all valid SIP messages, possibly subject to
      authentication.  Similarly, it allows RTP media streams in both
      directions.  However, it may block, in either inbound or outbound
      direction, other protocols such as RSVP or it may disallow non-
      zero DSCPs.  There are many degrees of SIP/RTP transparency, e.g.,
      depending on whether firewalls require inspection of SDP content,
      thus precluding end-to-end encryption of certain SIP message
      bodies, or whether only outbound calls are allowed.  Many
      firewalled corporate networks and semi-public access networks such
      as in hotels are likely to fall into this category.

SIP/RTP transparent: Networks that are SIP/RTP transparent allow users to place and receive SIP calls. The network allows ingress and egress for all valid SIP messages, possibly subject to authentication. Similarly, it allows RTP media streams in both directions. However, it may block, in either inbound or outbound direction, other protocols such as RSVP or it may disallow non- zero DSCPs. There are many degrees of SIP/RTP transparency, e.g., depending on whether firewalls require inspection of SDP content, thus precluding end-to-end encryption of certain SIP message bodies, or whether only outbound calls are allowed. Many firewalled corporate networks and semi-public access networks such as in hotels are likely to fall into this category.

   Restricted SIP networks: In restricted SIP networks, users may
      be restricted to particular SIP applications and cannot add SIP
      protocol elements such as header fields or use SIP methods beyond
      a prescribed set.  It appears likely that 3GPP/3GPP2 networks will
      fall into this category, at least initially.

Restricted SIP networks: In restricted SIP networks, users may be restricted to particular SIP applications and cannot add SIP protocol elements such as header fields or use SIP methods beyond a prescribed set. It appears likely that 3GPP/3GPP2 networks will fall into this category, at least initially.

      A separate and distinct problem are SIP networks that
      administratively prohibit or fail to configure access to special
      access numbers, e.g., the 710 area code used by GETS.  Such
      operational failures are beyond the reach of a protocol
      specification.

A separate and distinct problem are SIP networks that administratively prohibit or fail to configure access to special access numbers, e.g., the 710 area code used by GETS. Such operational failures are beyond the reach of a protocol specification.

   It appears desirable that ETS users can employ the broadest possible
   set of networks during an emergency.  Thus, it appears preferable
   that protocol enhancements work at least in SIP/RTP transparent
   networks and are added explicitly to restricted SIP networks.

It appears desirable that ETS users can employ the broadest possible set of networks during an emergency. Thus, it appears preferable that protocol enhancements work at least in SIP/RTP transparent networks and are added explicitly to restricted SIP networks.

   The existing GETS system relies on a transparent network, allowing
   use from most unmodified telephones, while MLPP systems are typically
   pre-configured.

The existing GETS system relies on a transparent network, allowing use from most unmodified telephones, while MLPP systems are typically pre-configured.

6.  Relationship to Emergency Call Services

6. Relationship to Emergency Call Services

   The resource priority mechanisms are used to have selected
   individuals place calls with elevated priority during times when the
   network is suffering from a shortage of resources.  Generally, calls
   for emergency help placed by non-officials (e.g., "911" and "112"
   calls) do not need resource priority under normal circumstances.  If
   such emergency calls are placed during emergency-induced network
   resource shortages, the call identifier itself is sufficient to
   identify the emergency nature of the call.  Adding an indication of
   resource priority may be less appropriate, as this would require that
   all such calls carry this indicator.  Also, it opens another attack

The resource priority mechanisms are used to have selected individuals place calls with elevated priority during times when the network is suffering from a shortage of resources. Generally, calls for emergency help placed by non-officials (e.g., "911" and "112" calls) do not need resource priority under normal circumstances. If such emergency calls are placed during emergency-induced network resource shortages, the call identifier itself is sufficient to identify the emergency nature of the call. Adding an indication of resource priority may be less appropriate, as this would require that all such calls carry this indicator. Also, it opens another attack

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   mechanism, where non-emergency calls are marked as emergency calls.
   (If network elements can recognize the request URI as an emergency
   call, they would not need the resource priority mechanism.)

mechanism, where non-emergency calls are marked as emergency calls. (If network elements can recognize the request URI as an emergency call, they would not need the resource priority mechanism.)

7.  SIP Call Routing

7. SIP Call Routing

   The routing of a SIP request, i.e., the proxies it visits and the UAs
   it ends up at, may depend on the fact that the SIP request is an ETS
   request.  The set of destinations may be larger or smaller, depending
   on the SIP request routing policies implemented by proxies.  For
   example, certain gateways may be reserved for ETS use and thus only
   be reached by labeled SIP requests.

The routing of a SIP request, i.e., the proxies it visits and the UAs it ends up at, may depend on the fact that the SIP request is an ETS request. The set of destinations may be larger or smaller, depending on the SIP request routing policies implemented by proxies. For example, certain gateways may be reserved for ETS use and thus only be reached by labeled SIP requests.

8.  Policy and Mechanism

8. Policy and Mechanism

   Most priority mechanisms can be roughly categorized by whether they:

Most priority mechanisms can be roughly categorized by whether they:

   o  use a priority queue for resource attempts,

o use a priority queue for resource attempts,

   o  make additional resources available (e.g., via alternate routing
      (ACR)), or

o make additional resources available (e.g., via alternate routing (ACR)), or

   o  preempt existing resource users (e.g., calls.)

o preempt existing resource users (e.g., calls.)

   For example, in GETS, alternate routing attempts to use alternate
   GETS-enabled interexchange carriers (IXC) if it cannot be completed
   through the first-choice carrier.

For example, in GETS, alternate routing attempts to use alternate GETS-enabled interexchange carriers (IXC) if it cannot be completed through the first-choice carrier.

   Priority mechanisms may also exempt certain calls from network
   management traffic controls.

Priority mechanisms may also exempt certain calls from network management traffic controls.

   The choice between these mechanisms depends on the operational needs
   and characteristics of the network, e.g., on the number of active
   requests in the system and the fraction of prioritized calls.
   Generally, if the number of prioritized calls is small compared to
   the system capacity and the system capacity is large, it is likely
   that another call will naturally terminate in short order when a
   higher-priority call arrives.  Thus, it is conceivable that the
   priority indication can cause preemption in some network entities,
   while elsewhere it just influences whether requests are queued
   instead of discarded and what queueing policy is being applied.

The choice between these mechanisms depends on the operational needs and characteristics of the network, e.g., on the number of active requests in the system and the fraction of prioritized calls. Generally, if the number of prioritized calls is small compared to the system capacity and the system capacity is large, it is likely that another call will naturally terminate in short order when a higher-priority call arrives. Thus, it is conceivable that the priority indication can cause preemption in some network entities, while elsewhere it just influences whether requests are queued instead of discarded and what queueing policy is being applied.

   Some namespaces may inherently imply a preemption policy, while
   others may be silent on whether preemption is to be used or not,
   leaving this to local entity policy.

Some namespaces may inherently imply a preemption policy, while others may be silent on whether preemption is to be used or not, leaving this to local entity policy.

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   Similarly, the precise relationships between labels, e.g., what
   fraction of capacity is set aside for each priority level, is also a
   matter of local policy.  This is similar to how differentiated
   services labels are handled.

Similarly, the precise relationships between labels, e.g., what fraction of capacity is set aside for each priority level, is also a matter of local policy. This is similar to how differentiated services labels are handled.

9.  Requirements

9. Requirements

   In the PSTN and certain private circuit-switched networks, such as
   those run by military organizations, calls are marked in various ways
   to indicate priorities.  We call this a "priority scheme".

In the PSTN and certain private circuit-switched networks, such as those run by military organizations, calls are marked in various ways to indicate priorities. We call this a "priority scheme".

   Below are some requirements for providing a similar feature in a SIP
   environment; security requirements are discussed in Section 10.  We
   will refer to the feature as a "SIP indication" and to requests
   carrying such an indication as "labelled requests".

Below are some requirements for providing a similar feature in a SIP environment; security requirements are discussed in Section 10. We will refer to the feature as a "SIP indication" and to requests carrying such an indication as "labelled requests".

   Note:  Not all the following requirements are possible to meet at
   once.  They may represent in some case tradeoffs that must be
   considered by the designer.

Note: Not all the following requirements are possible to meet at once. They may represent in some case tradeoffs that must be considered by the designer.

   REQ-1: Not specific to one scheme or country: The SIP indication
      should support existing and future priority schemes.  For example,
      there are currently at least four priority schemes in widespread
      use: Q.735, also implemented by the U.S.  defense telephone
      network ("DSN" or "Autovon") and NATO, has five levels, the United
      States GETS (Government Emergency Telecommunications Systems)
      scheme with implied higher priority and the British Government
      Telephone Preference Scheme (GTPS) system, which provides three
      priority levels for receipt of dial tone.

REQ-1: Not specific to one scheme or country: The SIP indication should support existing and future priority schemes. For example, there are currently at least four priority schemes in widespread use: Q.735, also implemented by the U.S. defense telephone network ("DSN" or "Autovon") and NATO, has five levels, the United States GETS (Government Emergency Telecommunications Systems) scheme with implied higher priority and the British Government Telephone Preference Scheme (GTPS) system, which provides three priority levels for receipt of dial tone.

      The SIP indication may support these existing CSN priority schemes
      through the use of different namespaces.

The SIP indication may support these existing CSN priority schemes through the use of different namespaces.

      Private-use namespaces may also be useful for certain
      applications.

Private-use namespaces may also be useful for certain applications.

   REQ-2: Independent of particular network architecture: The SIP
      indication should work in the widest variety of SIP-based systems.
      It should not be restricted to particular operators or types of
      networks, such as wireless networks or protocol profiles and
      dialects in certain types of networks.  The originator of a SIP
      request cannot be expected to know what kind of circuit-switched
      technology is used by the destination gateway.

REQ-2: Independent of particular network architecture: The SIP indication should work in the widest variety of SIP-based systems. It should not be restricted to particular operators or types of networks, such as wireless networks or protocol profiles and dialects in certain types of networks. The originator of a SIP request cannot be expected to know what kind of circuit-switched technology is used by the destination gateway.

   REQ-3: Invisible to network (IP) layer: The SIP indication must
      be usable in IP networks that are unaware of the enhancement and
      in SIP/RTP-transparent networks.

REQ-3: Invisible to network (IP) layer: The SIP indication must be usable in IP networks that are unaware of the enhancement and in SIP/RTP-transparent networks.

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      This requirement can be translated to mean that the request has to
      be a valid SIP request and that out-of-band signaling is not
      acceptable.

This requirement can be translated to mean that the request has to be a valid SIP request and that out-of-band signaling is not acceptable.

   REQ-4: Mapping of existing schemes: Existing CSN schemes must be
      translatable to SIP-based systems.

REQ-4: Mapping of existing schemes: Existing CSN schemes must be translatable to SIP-based systems.

   REQ-5: No loss of information: For the CSN-IP-CSN case, there
      should be no loss of signaling information caused by translation
      from CSN signaling SIP and back from SIP to CSN signaling if both
      circuit-switched networks use the same priority scheme.  Loss of
      information may be unavoidable if the destination CSN uses a
      different priority scheme from the origin.

REQ-5: No loss of information: For the CSN-IP-CSN case, there should be no loss of signaling information caused by translation from CSN signaling SIP and back from SIP to CSN signaling if both circuit-switched networks use the same priority scheme. Loss of information may be unavoidable if the destination CSN uses a different priority scheme from the origin.

      One cannot assume that both CSNs are using the same signaling
      protocol or protocol version, such as ISUP, so that transporting
      ISUP objects in MIME [4,5] is unlikely to be sufficient.

One cannot assume that both CSNs are using the same signaling protocol or protocol version, such as ISUP, so that transporting ISUP objects in MIME [4,5] is unlikely to be sufficient.

   REQ-6: Extensibility: Any naming scheme specified as part of the
      SIP indication should allow for future expansion.  Expanded naming
      schemes may be needed as resource priority is applied in
      additional private networks, or if VoIP-specific priority schemes
      are defined.

REQ-6: Extensibility: Any naming scheme specified as part of the SIP indication should allow for future expansion. Expanded naming schemes may be needed as resource priority is applied in additional private networks, or if VoIP-specific priority schemes are defined.

   REQ-7: Separation of policy and mechanism: The SIP indication
      should not describe a particular detailed treatment, as it is
      likely that this depends on the nature of the resource and local
      policy.  Instead, it should invoke a particular named policy.  As
      an example, instead of specifying that a certain SIP request
      should be granted queueing priority, not cause preemption, but be
      restricted to three-minute sessions, the request invokes a certain
      named policy that may well have those properties in a particular
      implementation.  An IP-to-CSN gateway may need to be aware of the
      specific actions required for the policy, but the protocol
      indication itself should not.

REQ-7: Separation of policy and mechanism: The SIP indication should not describe a particular detailed treatment, as it is likely that this depends on the nature of the resource and local policy. Instead, it should invoke a particular named policy. As an example, instead of specifying that a certain SIP request should be granted queueing priority, not cause preemption, but be restricted to three-minute sessions, the request invokes a certain named policy that may well have those properties in a particular implementation. An IP-to-CSN gateway may need to be aware of the specific actions required for the policy, but the protocol indication itself should not.

      Even in the CSN, the same MLPP indication may result in different
      behavior for different networks.

Even in the CSN, the same MLPP indication may result in different behavior for different networks.

   REQ-8: Method-neutral: The SIP indication chosen should work for
      any SIP method, not just, say, INVITE.

REQ-8: Method-neutral: The SIP indication chosen should work for any SIP method, not just, say, INVITE.

   REQ-9: Default behavior: Network terminals configured to use a
      priority scheme may occasionally end up making calls in a network
      that does not support such a scheme.  In those cases, the protocol
      must support a sensible default behavior that treats the call no
      worse than a call that did not invoke the priority scheme.  Some
      networks may choose to disallow calls unless they have a suitable

REQ-9: デフォルトの振舞い: 優先権体系を使用するために構成されたネットワーク端末は結局、そのような体系をサポートしないネットワークで電話を時折かけるかもしれません。 それらの場合では、プロトコルは優先権体系を呼び出さなかった呼び出しほど悪くない呼び出しを扱われる実際的なデフォルト値の振舞いにサポートしなければなりません。 ネットワークの中にはaを適当にしないなら呼び出しを禁じるのを選ぶものもあるかもしれません。

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      priority marking and appropriate authentication.  This is a matter
      of local policy.

優先権のマークしていて適切な認証。 これはローカルの方針の問題です。

   REQ-10: Address-neutral: Any address or URI scheme may be a
      valid destination and must be usable with the priority scheme.
      The SIP indication cannot rely on identifying a set of destination
      addresses or URI schemes for special treatment.  This requirement
      is motivated by existing ETS systems.  For example, in GETS and
      similar systems, the caller can reach any PSTN destination with
      increased probability of call completion, not just a limited set.
      (This does not preclude local policy that allows or disallows,
      say, calls to international numbers for certain users.)

REQ-10: アドレス中立: どんなアドレスやURI体系も、有効な目的地であるかもしれなく、優先権体系で使用可能であるに違いありません。 SIP指示は特別な処理の1セットの送付先アドレスを特定するか、URI体系を当てにすることができません。 この要件は既存のETSシステムによって動機づけられています。例えば、GETSと同様のシステムでは、訪問者は限られたセットだけではなく、呼び出し完成の増強された確率でどんなPSTNの目的地にも着くことができます。 (これはそれが許容するか、または禁じるローカルの方針、たとえば呼び出しを確信しているユーザの国際的な数に排除しません。)

      Some schemes may have an open set of destinations, such as any
      valid E.164 number or any valid domestic telephone number, while
      others may only reach a limited set of destinations.

いくつかの体系には、1つのオープン・セットの目的地があるかもしれません、どんな有効なE.164番号やどんな有効な国内の電話番号のようにも、他のものは限られたセットの目的地に着くだけであるかもしれませんが。

   REQ-11: Identity-independent: The user identity, such as the
      From header field in SIP, is insufficient to identify the priority
      level of the request.  The same identity can issue non-prioritized
      requests as well as prioritized ones, with the range of priorities
      determined by the job function of the caller.  The choice of the
      priority is made based on human judgement, following a set of
      general rules that are likely to be applied by analogy rather than
      precise mapping of each condition.  For example, a particular
      circumstance may be considered similarly grave compared to one
      which is listed explicitly.

REQ-11: アイデンティティ独立者: SIPのFromヘッダーフィールドなどのように、ユーザアイデンティティは、要求の優先順位を特定するためには不十分です。 同じアイデンティティは最優先するものと同様に非最優先している要求を出すことができます、訪問者の職務権限で決定しているプライオリティの範囲で。 人間の判断に基づいて優先権の選択をします、1セットのそれぞれの状態の正確なマッピングよりむしろ類推で適用されそうな総則に従って。 例えば、明らかに記載されているものと比べて、特定の状況は荘重であると同様に考えられるかもしれません。

   REQ-12: Independent of network location: While some existing CSN
      schemes restrict the set of priorities based on the line identity,
      it is recognized that future IP-based schemes should be flexible
      enough to avoid such reliance.  Instead, a combination of
      authenticated user identity, user choice and policy determines the
      request treatment.

REQ-12: ネットワークの位置の無党派: いくつかの既存のCSN体系が系列のアイデンティティに基づくプライオリティのセットを制限している間、将来のIPベースの体系がそのような信用を避けるほどフレキシブルであるべきであると認められます。 代わりに、認証されたユーザのアイデンティティ、ユーザ選択、および方針の組み合わせは要求処理を決定します。

   REQ-13: Multiple simultaneous schemes: Some user agents will
      need to support multiple different priority schemes, as several
      will remain in use in networks run by different agencies and
      operators.  (Not all user agents will have the means of
      authorizing callers using different schemes, and thus may be
      configured at run-time to only recognize certain namespaces.)

REQ-13: 複数の同時の体系: 何人かのユーザエージェントが、複数の異なった優先権が体系であるとサポートする必要があって、数個が残りのようになるように異なった政府機関とオペレータによって経営されていたネットワークで使用のままで残ってください。 (すべてのユーザエージェントが、異なった体系を使用することで訪問者に権限を与える手段を持って、その結果、ランタイムのときにある名前空間を認識するだけであるために構成されるかもしれないというわけではありません。)

   REQ-14: Discovery: A terminal should be able to discover which,
      if any, priority namespaces are supported by a network element.
      Discovery may be explicit, where a user agent requests a list of
      the supported namespaces or it may be implicit, where it attempts
      to use a particular namespace and is then told that this namespace
      is not supported.  This does not imply that every element has to

REQ-14: 発見: 優先権名前空間がネットワーク要素によっていくらかサポートされるなら、端末はどれを発見するはずであることができるか。 発見は明白であるかもしれません、ユーザエージェントが、次に、この名前空間がサポートされないと言われた状態でサポートしている名前空間かそれのリストがそれが特定の名前空間を使用するのを試みて、あるところで暗に示されているかもしれないよう要求するところで。 これは、あらゆる要素がそうしなければならないのを含意しません。

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      support the priority scheme.  However, entities should be able
      discover whether a network element supports it or not.

優先権体系をサポートしてください。 しかしながら、実体はできるべきです。ネットワーク要素がそれをサポートするかどうか発見してください。

   REQ-15: Testing: It must be possible to test the system outside
      of emergency conditions, to increase the chances that all elements
      work during an actual emergency.  In particular, critical elements
      such as indication, authentication, authorization and call routing
      must be testable.  Testing under load is desirable.  Thus, it is
      desirable that the SIP indication is available continuously, not
      just during emergencies.

REQ-15: テストします: 非常時の状態の外でシステムを検査するのは、すべての要素が実際の非常時に働いているという可能性を増強するために可能でなければなりません。 指示や、認証や、承認や呼び出しルーティングなどの重要な要素は特に、試験できなければなりません。 負荷の下でテストするのは望ましいです。 したがって、SIP指示が非常時だけでないのに絶え間なく利用可能であることは、望ましいです。

   REQ-16: 3PCC: The system has to work with SIP third-party call
      control.

REQ-16: 3PCC: システムはSIP第三者呼び出しコントロールで動作しなければなりません。

   REQ-17: Proxy-visible: Proxies may want to use the indication to
      influence request routing (see Section 7) or impose additional
      authentication requirements.

REQ-17: 目に見えるプロキシ: プロキシは、要求ルーティング(セクション7を見る)に影響を及ぼすか、または追加認証要件を課すのに指示を使用したがっているかもしれません。

10.  Security Requirements

10. セキュリティ要件

   Any resource priority mechanism can be abused to obtain resources and
   thus deny service to other users.  While the indication itself does
   not have to provide separate authentication, any SIP request carrying
   such information has more rigorous authentication requirements than
   regular requests.  Below, we describe authentication and
   authorization aspects, confidentiality and privacy requirements,
   protection against denial of service attacks and anonymity
   requirements.  Additional discussion can be found in [6].

リソースを得て、その結果、他のユーザに対するサービスを否定するためにどんなリソース優先権メカニズムも誤用できます。 指示自体は別々の認証を提供する必要はありませんが、どんなSIPも、そのような情報を運ぶのにおいて定期的な要求より厳しい認証要件があるよう要求します。 以下では、私たちがサービス不能攻撃と匿名要件に対して認証と承認局面と秘密性とプライバシー要件、保護を説明します。 [6]で追加議論を見つけることができます。

10.1 Authentication and Authorization

10.1 認証と承認

   SEC-1: More rigorous: Prioritized access to network and end
      system resources enumerated in Section 3 imposes particularly
      stringent requirements on authentication and authorization
      mechanisms since access to prioritized resources may impact
      overall system stability and performance, not just result in theft
      of, say, a single phone call.

SEC-1: より厳しい: 最優先するリソースへのアクセスがたとえば、ただ一つの電話の窃盗で結果だけではなく、総合体系の安定性と性能に影響を与えるかもしれないので、セクション3で数え上げられたネットワークとエンドシステム資源への最優先するアクセスは特に厳しい要件を認証と承認メカニズムに課します。

      The authentication and authorization requirements for ETS calls
      are, in particular, much stronger than for emergency calls (112,
      911), where wide access is the design objective, sacrificing
      caller identification if necessary.

ETS呼び出しのための認証と承認要件は緊急通報(112、911)よりはるかに必要なら、広いアクセスが設計目標であるところで訪問者識別を犠牲にするのに特に強いです。

   SEC-2: Attack protection: Under certain emergency conditions,
      the network infrastructure, including its authentication and
      authorization mechanism, may be under attack.  Thus,
      authentication and authorization must be able to survive such
      attacks and defend the resources against these attacks.

SEC-2: 保護を攻撃してください: ある非常時の条件のもとでは、その認証と承認メカニズムを含むネットワークインフラは攻撃されているかもしれません。 したがって、認証と承認は、そのような攻撃を乗り切っていて、これらの攻撃に対してリソースを防御できなければなりません。

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      Mechanisms to delegate authentication and to authenticate as early
      as possible are required.  In particular, the number of packets
      and the amount of other resources such as computation or storage
      that an unauthorized user can consume needs to be minimized.

メカニズム、認証を代表として派遣して、できるだけ早く認証する、必要です。 特に、パケットの数と権限のないユーザが消費できる計算かストレージなどの他のリソースの量は、最小にされる必要があります。

      Unauthorized users must not be able to block CSN resources, as
      they are likely to be more scarce than packet resources. This
      implies that authentication and authorization must take place on
      the IP network side rather than using, say, a CSN circuit to
      authenticate the caller via a DTMF sequence.

権限のないユーザはCSNリソースを妨げることができるはずがありません、それらがパケットリソースより少ない傾向があるときに。 これは、認証と承認必須がDTMF系列で訪問者を認証するのにたとえばCSN回路を使用するよりIPネットワーク側でむしろ行われるのを含意します。

      Given the urgency during emergency events, normal statistical
      fraud detection may be less effective, thus placing a premium on
      reliable authentication.

非常時のイベントの間の緊急を考えて、通常の統計的な詐欺の検出はそれほど有効でないかもしれません、その結果、信頼できる認証を尊重します。

      SIP nodes should be able to independently verify the authorization
      of requests to receive prioritized service and not rely on
      transitive trust within the network.

SIPノードは、独自に最優先するサービスを受けるという要求の承認について確かめて、ネットワークの中で遷移的な信頼を当てにするはずであることができません。

   SEC-3: Independent of mechanism: Any indication of the resource
      priority must be independent of the authentication mechanism,
      since end systems will impose different constraints on the
      applicable authentication mechanisms. For example, some end
      systems may only allow user input via a 12-digit keypad, while
      others may have the ability to acquire biometrics or read
      smartcards.

SEC-3: メカニズムの無党派: リソース優先権のどんなしるしも認証機構から独立しているに違いありません、エンドシステムが異なった規制を適切な認証機構に課すので。例えば、いくつかのエンドシステムが12ケタのキーパッドを通してユーザ入力を許すだけであるかもしれません、他のものには、生体認証を習得するか、またはスマートカードを読む能力があるかもしれませんが。

   SEC-4: Non-trusted end systems: Since ETS users may use devices
      that are not their own, systems should support authentication
      mechanisms that do not require the user to reveal her secret, such
      as a PIN or password, to the device.

SEC-4: 非信じられたエンドシステム: ETSユーザがそれら自身のでないデバイスを使用するかもしれないので、システムは、認証がユーザが秘密を打ち明けるのを必要としないメカニズムであるとサポートするはずです、暗証番号やパスワードのように、デバイスに。

   SEC-5: Replay: The authentication mechanisms must be resistant
      to replay attacks.

SEC-5: 以下を再演してください。 認証機構は反射攻撃に抵抗力があるに違いありません。

   SEC-6: Cut-and-paste: The authentication mechanisms must be
      resistant to cut-and-paste attacks.

SEC-6: カットアンドペースト: 認証機構はカットアンドペースト攻撃に抵抗力があるに違いありません。

   SEC-7: Bid-down: The authentication mechanisms must be resistant
      to bid down attacks.

SEC-7: 下に付け値: 認証機構は、攻撃の下側に入札するために抵抗力がなければなりません。

10.2 Confidentiality and Integrity

10.2 秘密性と保全

   SEC-8: Confidentiality: All aspects of ETS are likely to be
      sensitive and should be protected from unlawful intercept and
      alteration.  In particular, requirements for protecting the
      confidentiality of communications relationships may be higher than
      for normal commercial service.  For SIP, the To, From,

SEC-8: 秘密性: ETSの全面は、敏感であることがありそうであり、不法なインタセプトと変更から保護されるべきです。 コミュニケーション関係の秘密性を保護するための要件は通常の商業サービスより特に、高いかもしれません。 一口のために

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      Organization, Subject, Priority and Via header fields are examples
      of particularly sensitive information.  Callers may be willing to
      sacrifice confidentiality if the only alternative is abandoning
      the call attempt.

組織、Subject、Priority、およびViaヘッダーフィールドは特に機密の情報に関する例です。 唯一の選択肢が呼び出し試みを捨てることであるなら、訪問者は、秘密性を犠牲にしても構わないと思っているかもしれません。

      Unauthorized users must not be able to discern that a particular
      request is using a resource priority mechanism, as that may reveal
      sensitive information about the nature of the request to the
      attacker.  Information not required for request routing should be
      protected end-to-end from intermediate SIP nodes.

権限のないユーザは、特定の要求がリソース優先権メカニズムを使用しているのを裁量できるはずがありません、それが要求の本質に関する機密情報を攻撃者に明らかにするとき。 要求ルーティングに必要でない情報は、保護された中間的SIPノードからの終わりから終わりであるべきです。

      The act of authentication, e.g., by contacting a particular
      server, itself may reveal that a user is requesting prioritized
      service.

サービスを最優先させましたそのaユーザが、要求している認証の行為、例えば、連絡するのによる特定のサーバ自体が、明らかにするかもしれない。

      SIP allows protection of header fields not used for request
      routing via S/MIME, while hop-by-hop channel confidentiality can
      be provided by TLS or IPsec.

SIPは要求ルーティングにS/MIMEで使用されないヘッダーフィールドの保護を許します、TLSかIPsecがホップごとのチャンネル秘密性を提供できますが。

10.3 Anonymity

10.3 匿名

   SEC-9: Anonymity: Some users may wish to remain anonymous to the
      request destination.  For the reasons noted earlier, users have to
      authenticate themselves towards the network carrying the request.
      The authentication may be based on capabilities and noms, not
      necessarily their civil name.

SEC-9: 匿名: 要求の目的地に匿名を希望するユーザもいるかもしれません。 より早く注意された理由で、ユーザは要求を運ぶネットワークに向かって自分たちを認証しなければなりません。 認証は必ず彼らの民間名前ではなく、能力とnomsに基づくかもしれません。

      Clearly, they may remain anonymous towards the request
      destination, using the network-asserted identity and general
      privacy mechanisms [7,8].

明確に、ネットワークによって断言されたアイデンティティと一般的なプライバシーメカニズム[7、8]を使用して、彼らは要求の目的地に向かって匿名のままで残るかもしれません。

10.4 Denial-of-Service Attacks

10.4 サービス不能攻撃

   SEC-10: Denial-of-service: ETS systems are likely to be subject
        to deliberate denial-of-service attacks during certain
        types of emergencies.  DOS attacks may be launched on the
        network itself as well as its authentication and
        authorization mechanism.

SEC-10: サービスの否定: ETSシステムはあるタイプの非常時にサービス不能攻撃を熟考するためになることがある傾向があります。 DOS攻撃はその認証と承認メカニズムと同様にネットワーク自体で着手されるかもしれません。

   SEC-11: Minimize resource use by unauthorized users: Systems
        should minimize the amount of state, computation and
        network resources that an unauthorized user can command.

SEC-11: 権限のないユーザによるリソース使用を最小にしてください: システムは権限のないユーザが命令することができる状態、計算、およびネットワーク資源の量を最小にするはずです。

   SEC-12: Avoid amplification: The system must not amplify attacks
        by causing the transmission of more than one packet or SIP
        request to a network address whose reachability has not
        been verified.

SEC-12: 増幅を避けてください: システムは、1つ以上のパケットかSIP要求の伝達を可到達性が確かめられていないネットワーク・アドレスに引き起こすことによって、攻撃を増幅してはいけません。

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11.  Security Considerations

11. セキュリティ問題

   Section 10 discusses the security issues related to priority
   indication for SIP in detail and derives requirements for the SIP
   indicator.  As discussed in Section 6, identification of priority
   service should avoid multiple concurrent mechanisms, to avoid
   allowing attackers to exploit inconsistent labeling.

セクション10は、SIPのために詳細に優先権指示に関連する安全保障問題について論じて、SIPインディケータのために要件を引き出します。 セクション6で議論するように、優先サービスの識別は攻撃者が無節操なラベリングを利用するのを許容するのを避けるために複数の同時発生のメカニズムを避けるべきです。

12.  Acknowledgements

12. 承認

   Ran Atkinson, Fred Baker, Scott Bradner, Ian Brown, Ken Carlberg,
   Janet Gunn, Kimberly King, Rohan Mahy and James Polk provided helpful
   comments.

役に立つコメントであるならアトキンソン、フレッド・ベイカー、スコット・ブラドナー、イアン・ブラウン、ケンCarlberg、ジャネット・ガン、キンバリー・キング、Rohanマーイ、およびジェイムズ・ポークを車で送りました。

13.  Normative References

13. 引用規格

   [1]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
        Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
        Session Initiation Protocol", RFC 3261, June 2002.

[1] ローゼンバーグ、J.、Schulzrinne、H.、キャマリロ、G.、ジョンストン、A.、ピーターソン、J.、スパークス、R.、ハンドレー、M.、およびE.学生は「以下をちびちび飲みます」。 「セッション開始プロトコル」、RFC3261、2002年6月。

14.  Informative References

14. 有益な参照

   [2]  Lennox, J., Schulzrinne, H. and J. Rosenberg, "Common Gateway
        Interface for SIP", RFC 3050, January 2001.

[2] レノックスとJ.とSchulzrinneとH.とJ.ローゼンバーグ、「一口のための共通ゲートウェイインターフェイス」、RFC3050、2001年1月。

   [3]  Lennox J. and H. Schulzrinne, "CPL: A language for user control
        of internet telephony services", Work in Progress.

[3] レノックスJ.とH.Schulzrinne、「CPL:」 「インターネット電話サービスのユーザコントロールのための言語」、ProgressのWork。

   [4]  Zimmerer, E., Peterson, J., Vemuri, A., Ong, L., Audet, F.,
        Watson, M. and M. Zonoun, "MIME media types for ISUP and QSIG
        objects", RFC 3204, December 2001.

[4]ZimmererとE.とピーターソンとJ.とVemuriとA.、オングとL.とAudetとF.とワトソンとM.とM.Zonoun、「ISUPとQSIGオブジェクトのためのMIMEメディアタイプ」RFC3204(2001年12月)。

   [5]  Vemuri, A. and J. Peterson, "Session Initiation Protocol for
        Telephones (SIP-T): (SIP-T)", BCP 63, RFC 3372, September 2002.

[5] Vemuri、A.、およびJ.ピーターソン、「セッション開始は電話(一口T)のために議定書を作ります」。 (一口T)「BCP63、RFC3372、2002年9月」

   [6]  Brown, I., "A security framework for emergency communications",
        Work in Progress.

[6] ブラウン、I.、「非常時のコミュニケーションのためのセキュリティフレームワーク」、ProgressのWork。

   [7]  Peterson, J., "A Privacy Mechanism for the Session Initiation
        Protocol (SIP)", RFC 3323, November 2002.

[7] ピーターソン、J.、「セッション開始プロトコル(一口)のためのプライバシーメカニズム」、RFC3323、2002年11月。

   [8]  Watson, M., "Short Term Requirements for Network Asserted
        Identity", RFC 3324, November 2002.

[8] ワトソン、M.、「ネットワークの断言されたアイデンティティのための短期間要件」、RFC3324、2002年11月。

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15.  Author's Address

15. 作者のアドレス

   Henning Schulzrinne
   Dept. of Computer Science
   Columbia University
   1214 Amsterdam Avenue
   New York, NY 10027
   USA

コンピュータサイエンスコロンビア大学1214アムステルダムAvenueニューヨーク10027ニューヨーク(米国)のヘニングSchulzrinne部

   EMail: schulzrinne@cs.columbia.edu

メール: schulzrinne@cs.columbia.edu

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16.  Full Copyright Statement

16. 完全な著作権宣言文

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Copyright(C)インターネット協会(2003)。 All rights reserved。

   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.

それに関するこのドキュメントと翻訳は、コピーして、それが批評するか、またはそうでなければわかる他のもの、および派生している作品に提供するか、または準備されているかもしれなくて、コピーされて、発行されて、全体か一部分配された実装を助けるかもしれません、どんな種類の制限なしでも、上の版権情報とこのパラグラフがそのようなすべてのコピーと派生している作品の上に含まれていれば。 しかしながら、このドキュメント自体は何らかの方法で変更されないかもしれません、インターネット協会か他のインターネット組織の版権情報か参照を取り除くのなどように、それを英語以外の言語に翻訳するのが著作権のための手順がインターネットStandardsプロセスで定義したどのケースに従わなければならないか、必要に応じてさもなければ、インターネット標準を開発する目的に必要であるのを除いて。

   The limited permissions granted above are perpetual and will not be
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上に承諾された限られた許容は、永久であり、インターネット協会、後継者または案配によって取り消されないでしょう。

   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.

このドキュメントとそして、「そのままで」という基礎とインターネットの振興発展を目的とする組織に、インターネット・エンジニアリング・タスク・フォースが速達の、または、暗示しているすべての保証を放棄するかどうかというここにことであり、他を含んでいて、含まれて、情報の使用がここに侵害しないどんな保証も少しもまっすぐになるという情報か市場性か特定目的への適合性のどんな黙示的な保証。

Acknowledgement

承認

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

RFC Editor機能のための基金は現在、インターネット協会によって提供されます。

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