DIME M. Jones Internet-Draft Bridgewater Systems Intended status: Informational October 24, 2011 Expires: April 26, 2012 Diameter Group Signaling draft-jones-diameter-group-signaling-00.txt Abstract In large network deployments, a single Diameter peer can support over a million concurrent Diameter sessions. Recent use cases have revealed the need for Diameter peers to apply the same operation to a large group of Diameter sessions concurrently. The Diameter base protocol commands operate on a single session so these use cases could result in many thousands of command exchanges in order to enforce the same operation on each session in the group. In order to reduce signaling, it would be desirable to enable bulk operations on all (or part of) the sessions managed by a Diameter peer using a single or a few command exchanges. This document specifies the Diameter protocol extensions to achieve this signaling optimization. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 26, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of Jones Expires April 26, 2012 [Page 1] Internet-Draft Diameter Group Signaling October 2011 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Grouping User Sessions . . . . . . . . . . . . . . . . . . . . 5 3.1. Group assignment at session initiation . . . . . . . . . . 5 3.2. Mid-session group assignment modifications . . . . . . . . 5 3.2.1. Client-initiated group assignment changes . . . . . . 5 3.2.2. Server-initiated group assignment changes . . . . . . 5 4. Protocol Description . . . . . . . . . . . . . . . . . . . . . 6 4.1. Session Management . . . . . . . . . . . . . . . . . . . . 6 4.1.1. Authorization Session State Machine . . . . . . . . . 6 4.1.2. Server Initiated Group Re-auth . . . . . . . . . . . . 10 4.1.3. Session Group Termination . . . . . . . . . . . . . . 10 4.1.4. Aborting a Group of Sessions . . . . . . . . . . . . . 10 4.2. Commands . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.2.1. Group-Re-Auth-Request . . . . . . . . . . . . . . . . 10 4.2.2. Group-Re-Auth-Answer . . . . . . . . . . . . . . . . . 10 4.2.3. Group-Session-Termination-Request . . . . . . . . . . 11 4.2.4. Group-Session-Termination-Answer . . . . . . . . . . . 12 4.2.5. Group-Abort-Session-Request . . . . . . . . . . . . . 13 4.2.6. Group-Abort-Session-Answer . . . . . . . . . . . . . . 13 5. AVPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.1. Session-Group-Id AVP . . . . . . . . . . . . . . . . . . . 15 5.2. Session-Group-Action AVP . . . . . . . . . . . . . . . . . 15 6. Result-Code AVP Values . . . . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 7.1. Command Codes . . . . . . . . . . . . . . . . . . . . . . 17 7.2. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 17 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 10. Normative References . . . . . . . . . . . . . . . . . . . . . 20 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 21 Jones Expires April 26, 2012 [Page 2] Internet-Draft Diameter Group Signaling October 2011 1. Introduction In large network deployments, a single Diameter peer can support over a million concurrent Diameter sessions. Recent use cases have revealed the need for Diameter peers to apply the same operation to a large group of Diameter sessions concurrently. For example, a policy decision point may need to modify the authorized quality of service for all active users having the same type of subscription. The Diameter base protocol commands operate on a single session so these use cases could result in many thousands of command exchanges in order to enforce the same operation on each session in the group. In order to reduce signaling, it would be desirable to enable bulk operations on all (or part of) the sessions managed by a Diameter peer using a single or a few command exchanges. This document describes a mechanism for grouping Diameter sessions and performing re-authentication, re-authorization, termination and abortion of groups of sessions. This document does not define a new Diameter application. Instead it defines mechanisms, commands and AVPs that may be used by any Diameter application that requires management of groups of sessions. Jones Expires April 26, 2012 [Page 3] Internet-Draft Diameter Group Signaling October 2011 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. This document uses terminology defined [RFC3588]. Jones Expires April 26, 2012 [Page 4] Internet-Draft Diameter Group Signaling October 2011 3. Grouping User Sessions Either Diameter peer may assign a session to a group. Diameter AAA applications typically assign client and server roles to the Diameter peers. In this document, a Diameter client is a node at the edge of the network that performs access control. A Diameter server is a node that performs authentication and/or authorization of the user. 3.1. Group assignment at session initiation To assign a session to a group at session initiation, a Diameter client sends a service specific auth request, e.g. NASREQ AAR [RFC4005], containing one or more client-assigned group identifiers. Assuming the user is successfully authenticated and/or authorized, the Diameter server responds with service-specific auth response, e.g. NASREQ AAA [RFC4005], containing both the client-assigned group identifiers and the server-assigned group identifiers. 3.2. Mid-session group assignment modifications Either Diameter peer may modify the group membership of an active Diameter session. A Diameter client MAY remove the group(s) assigned to the active session by the Diameter server and vice versa. Editor's Note: It is FFS whether this document should define a default permission model limiting removal of a session from a group. For example, the server MUST NOT remove a session from a group assigned by the client. 3.2.1. Client-initiated group assignment changes To update the assigned groups mid-session, a Diameter client sends a service specific re-authorization request containing the updated list of group identifiers. Assuming the user is successfully authenticated and/or authorized, the Diameter server responds with a service-specific auth response containing the updated list of group identifiers received in the request. 3.2.2. Server-initiated group assignment changes To update the assigned groups mid-session, a Diameter server sends a Re-authorization Request (RAR) message requesting re-authorization and the client responds with a Re-authorization Answer (RAA) message. The Diameter client sends a service specific re-authorization request containing the current list of group identifiers and the Diameter server responds with a service-specific auth response containing the updated list of group identifiers. Jones Expires April 26, 2012 [Page 5] Internet-Draft Diameter Group Signaling October 2011 4. Protocol Description 4.1. Session Management 4.1.1. Authorization Session State Machine Section 8.1 in [RFC3588] defines a set of finite state machines, representing the life cycle of Diameter sessions, and which MUST be observed by all Diameter implementations that make use of the authentication and/or authorization portion of a Diameter application. This section defines the additional state transitions related to the processing of the new commands which may impact multiple sessions. The group membership is session state and therefore only those state machines from [RFC3588] in which the server is maintaining session state are relevant in this document. As in [RFC3588], the term Service-Specific below refers to a message defined in a Diameter application (e.g., Mobile IPv4, NASREQ). The following state machine is observed by a client when state is maintained on the server. State transitions which are unmodified from [RFC3588] are not repeated here. CLIENT, STATEFUL State Event Action New State --------------------------------------------------------------- Idle Client or Device Requests Send Pending access service specific auth req optionally including groups Open BASR received with Send BASA Discon Session-Group-Action with = ALL_GROUPS, Result-Code session is assigned to = SUCCESS, received group(s) and Send BSTR. client will comply with request to end the session Open BASR received with Send BASA Discon Session-Group-Action with = PER_GROUPS, Result-Code session is assigned to = SUCCESS, Jones Expires April 26, 2012 [Page 6] Internet-Draft Diameter Group Signaling October 2011 received group(s) and Send BSTR client will comply with per group request to end the session Open BASR received with Send BASA Discon Session-Group-Action with = PER_SESSION, Result-Code session is assigned to = SUCCESS, received group(s) and Send STR client will comply with per session request to end the session Open BASR received, Send BASA Open client will not comply with with request to end all session Result-Code in received group(s) != SUCCESS Discon BSTA Received Discon. Idle user/device Open BRAR received with Send BRAA, Pending Session-Group-Action Send = ALL_GROUPS, service session is assigned to specific received group(s) and group client will perform re-auth req subsequent re-auth Open BRAR received with Send BRAA, Pending Session-Group-Action Send = PER_GROUP, service session is assigned to specific received group(s) and group client will perform re-auth req subsequent re-auth per group Open BRAR received with Send BRAA, Pending Session-Group-Action Send = PER_SESSION, service session is assigned to specific received group(s) and re-auth req client will perform per session subsequent re-auth Open BRAR received and client will Send BRAA Idle not perform subsequent with re-auth Result-Code != SUCCESS, Jones Expires April 26, 2012 [Page 7] Internet-Draft Diameter Group Signaling October 2011 Discon. user/device Pending Successful service-specific Provide Open group re-authorization answer service received. Pending Failed service-specific Discon. Idle group re-authorization answer user/device received. The following state machine is observed by a server when it is maintaining state for the session. State transitions which are unmodified from [RFC3588] are not repeated here. Jones Expires April 26, 2012 [Page 8] Internet-Draft Diameter Group Signaling October 2011 SERVER, STATEFUL State Event Action New State --------------------------------------------------------------- Idle Service-specific authorization Send Open request received, and user successful is authorized service specific answer optionally including groups Open Server wants to terminate Send BASR Discon group(s) Discon BASA received Cleanup Idle Any BSTR received Send BSTA, Idle Cleanup Open Server wants to reauth Send BRAR Pending group(s) Pending BRAA received with Result-Code Update Open = SUCCESS session(s) Pending BRAA received with Result-Code Cleanup Idle != SUCCESS session(s) Open Service-specific group Send Open re-authoization request successful received and user is service authorized specific group re-auth answer Open Service-specific group Send Idle re-authorization request failed received and user is service not authorized specific group re-auth answer, cleanup Jones Expires April 26, 2012 [Page 9] Internet-Draft Diameter Group Signaling October 2011 4.1.2. Server Initiated Group Re-auth TODO: rules/restrictions governing group re-auth 4.1.3. Session Group Termination TODO: rules/restrictions governing session group termination 4.1.4. Aborting a Group of Sessions TODO: rules/restrictions governing aborting groups of session 4.2. Commands This specification extends the existing RAR, RAA, STR, STA, ASR and ASA command ABNFs. 4.2.1. Group-Re-Auth-Request The Group-Re-Auth-Request (GRAR), indicated by the Command-Code set to TBD and the message flags' 'R' bit set, may be sent by any server to the access device that is providing session service, to request that one or more groups of users be re-authenticated and/or re- authorized. ::= < Diameter Header: TBD, REQ, PXY > * { Session-Group-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Destination-Host } { Auth-Application-Id } { Re-Auth-Request-Type } [ User-Name ] [ Origin-State-Id ] * [ Proxy-Info ] * [ Route-Record ] [ Session-Group-Action ] * [ AVP ] 4.2.2. Group-Re-Auth-Answer The Group-Re-Auth-Answer (GRAA), indicated by the Command-Code set to TBD and the message flags' 'R' bit clear, is sent in response to the GRAR. The Result-Code AVP MUST be present, and indicates the disposition of the request. Jones Expires April 26, 2012 [Page 10] Internet-Draft Diameter Group Signaling October 2011 [Editor's Note: Move these detailed behaviour requirements to earlier section?] A successful GRAA message MUST be followed by an application-specific authentication and/or authorization message. The Group-Action AVP in the Group-Re-Auth-Request indicates whether a single exchange, per- group or per-session is required. If the peer receiving the GRAR has no active sessions which are assigned to the groups listed in the Session-Group-Id AVPs, it MUST return a GRAA with the Result-Code set to TBD. The Session-Group-Id AVPs in the GRAA indicate the groups for which the GRAR receiver has active sessions assigned to those groups. ::= < Diameter Header: TBD, PXY > * { Session-Group-Id } { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] [ Origin-State-Id ] [ Error-Message ] [ Error-Reporting-Host ] * [ Failed-AVP ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Host-Cache-Time ] * [ Proxy-Info ] * [ AVP ] 4.2.3. Group-Session-Termination-Request The Group-Session-Termination-Request (GSTR), indicated by the Command-Code set to TBD and the Command Flags' 'R' bit set, is sent by the access device to inform the Diameter Server that one or more groups of authenticated and/or authorized sessions are being terminated. Jones Expires April 26, 2012 [Page 11] Internet-Draft Diameter Group Signaling October 2011 ::= < Diameter Header: TBD, REQ, PXY > * { Session-Group-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Auth-Application-Id } { Termination-Cause } [ User-Name ] [ Destination-Host ] * [ Class ] [ Origin-State-Id ] * [ Proxy-Info ] * [ Route-Record ] * [ AVP ] 4.2.4. Group-Session-Termination-Answer The Group-Session-Termination-Answer (GSTA), indicated by the Command-Code set to TBD and the message flags' 'R' bit clear, is sent by the Diameter Server to acknowledge the notification that one or more groups of session have been terminated. The Result-Code AVP MUST be present, and MAY contain an indication that an error occurred while servicing the GSTR. Upon sending or receipt of the GSTA, the Diameter Server MUST release all resources for all sessions belonging to the groups indicated by the Session-Group-Id AVP. Any intermediate server in the Proxy-Chain MAY also release any resources, if necessary. ::= < Diameter Header: TBD, PXY > * { Session-Group-Id } { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] * [ Class ] [ Error-Message ] [ Error-Reporting-Host ] * [ Failed-AVP ] [ Origin-State-Id ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Max-Cache-Time ] * [ Proxy-Info ] * [ AVP ] Jones Expires April 26, 2012 [Page 12] Internet-Draft Diameter Group Signaling October 2011 4.2.5. Group-Abort-Session-Request The Group-Abort-Session-Request (GASR), indicated by the Command-Code set to TBD and the message flags' 'R' bit set, may be sent by any server to the access device that is providing session service, to request that the sessions identified by the Session-Group-Id be stopped. ::= < Diameter Header: TBD, REQ, PXY > * { Session-Group-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Destination-Host } { Auth-Application-Id } [ User-Name ] [ Origin-State-Id ] * [ Proxy-Info ] * [ Route-Record ] [ Group-Action ] * [ AVP ] 4.2.6. Group-Abort-Session-Answer The Group-Abort-Session-Answer (GASA), indicated by the Command-Code set to TBD and the message flags' 'R' bit clear, is sent in response to the GASR. The Result-Code AVP MUST be present, and indicates the disposition of the request. If the sessions identified by Session-Group-Id in the GASR were successfully terminated, Result-Code is set to DIAMETER_SUCCESS. If the session is not currently active, Result-Code is set to DIAMETER_UNKNOWN_SESSION_ID. If the access device does not stop the session for any other reason, Result-Code is set to DIAMETER_UNABLE_TO_COMPLY. [Editor's Note: Move these detailed behaviour requirements to earlier section.] A successful GASA message MUST be followed by one or more STR or GSTR to the authorizing server. The Group-Action AVP in the Group-Abort- Session-Request indicates whether a GSTR per group of sessions, a GSTR per group or an STR per session is required. If the peer receiving the GASR has no active sessions which are assigned the groups listed in the Session-Group-Id AVPs, it MUST return a GASA with the Result-Code set to TBD. Jones Expires April 26, 2012 [Page 13] Internet-Draft Diameter Group Signaling October 2011 The Session-Group-Id AVPs in the GASA indicate the groups for which the GASR receiver has active sessions assigned to those groups. ::= < Diameter Header: TBD, PXY > * { Session-Group-Id } { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] [ Origin-State-Id ] [ Error-Message ] [ Error-Reporting-Host ] * [ Failed-AVP ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Max-Cache-Time ] * [ Proxy-Info ] * [ AVP ] Jones Expires April 26, 2012 [Page 14] Internet-Draft Diameter Group Signaling October 2011 5. AVPs +--------------------+ | AVP Flag rules | +----+---+------+----+ AVP | | |SHOULD|MUST| Attribute Name Code Value Type |MUST|MAY| NOT | NOT| +---------------------------------------+----+---+------+----+ |Session-Group-Id TBD OctetString | | P | | V | |Session-Group-Action TBD Enumerated | | P | | V | +---------------------------------------+----+---+------+----+ AVPs for the Diameter Group Signaling 5.1. Session-Group-Id AVP 5.2. Session-Group-Action AVP The Session-Group-Action AVP (AVP Code TBD) is of type Enumerated and specifies how the peer SHOULD issue follow up exchanges in response to a command which impacts mulitple sessions. The following values are supported: ALL_GROUPS (0) Follow up exchanges should be performed with a single message exchange for all impacted groups. PER_GROUP (1) Follow up exchanges should be performed with a message exchange for each impacted group. PER_SESSION (2) Follow up exchanges should be performed with a message exchange for each impacted session. Jones Expires April 26, 2012 [Page 15] Internet-Draft Diameter Group Signaling October 2011 6. Result-Code AVP Values This section defines new Result-Code [RFC3588] values that MUST be supported by all Diameter implementations that conform to this specification. [Editor's Note: Group specific error values may need to be added here.] Jones Expires April 26, 2012 [Page 16] Internet-Draft Diameter Group Signaling October 2011 7. IANA Considerations This section contains the namespaces that have either been created in this specification or had their values assigned to existing namespaces managed by IANA. 7.1. Command Codes This specification requires IANA to register the following new Commands from the Command Code namespace defined in [RFC3588]. o Group-Re-Auth-Request/Answer o Group-Session-Termination-Request/Answer o Group-Abort-Session-Request/Answer The commands are defined in Section 4.2. 7.2. AVP Codes This specification requires IANA to register the following new AVPs from the AVP Code namespace defined in [RFC3588]. o Session-Group-Id o Session-Group-Action The AVPs are defined in Section 5. Jones Expires April 26, 2012 [Page 17] Internet-Draft Diameter Group Signaling October 2011 8. Security Considerations TODO Jones Expires April 26, 2012 [Page 18] Internet-Draft Diameter Group Signaling October 2011 9. Acknowledgments Jones Expires April 26, 2012 [Page 19] Internet-Draft Diameter Group Signaling October 2011 10. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter Network Access Server Application", RFC 4005, August 2005. Jones Expires April 26, 2012 [Page 20] Internet-Draft Diameter Group Signaling October 2011 Author's Address Mark Jones Bridgewater Systems Email: mark@azu.ca Jones Expires April 26, 2012 [Page 21]