< draft-ietf-dime-drmp-04.txt		draft-ietf-dime-drmp-05.txt >
	Diameter Maintenance and Extensions (DIME) S. Donovan		Diameter Maintenance and Extensions (DIME) S. Donovan
	Internet-Draft Oracle		Internet-Draft Oracle
	Intended status: Standards Track March 10, 2016		Intended status: Standards Track April 5, 2016
	Expires: September 11, 2016		Expires: October 7, 2016
	Diameter Routing Message Priority		Diameter Routing Message Priority
	draft-ietf-dime-drmp-04.txt		draft-ietf-dime-drmp-05.txt
	Abstract		Abstract
	When making routing and resource allocation decisions, Diameter nodes		When making routing and resource allocation decisions, Diameter nodes
	currently have no generic mechanism to determine the relative		currently have no generic mechanism to determine the relative
	priority of Diameter messages. This document addresses this by		priority of Diameter messages. This document addresses this by
	defining a mechanism to allow Diameter endpoints to indicate the		defining a mechanism to allow Diameter endpoints to indicate the
	relative priority of Diameter transactions. With this information		relative priority of Diameter transactions. With this information
	Diameter nodes can factor that priority into routing, resource		Diameter nodes can factor that priority into routing, resource
	allocation and overload abatement decisions.		allocation and overload abatement decisions.
	skipping to change at page 1, line 36 ¶		skipping to change at page 1, line 36 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on September 11, 2016.		This Internet-Draft will expire on October 7, 2016.
	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 32 ¶		skipping to change at page 2, line 32 ¶
	9.1. DRMP AVP . . . . . . . . . . . . . . . . . . . . . . . . 11		9.1. DRMP AVP . . . . . . . . . . . . . . . . . . . . . . . . 11
	9.2. Attribute Value Pair flag rules . . . . . . . . . . . . . 12		9.2. Attribute Value Pair flag rules . . . . . . . . . . . . . 12
	10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	10.1. AVP codes . . . . . . . . . . . . . . . . . . . . . . . 12		10.1. AVP codes . . . . . . . . . . . . . . . . . . . . . . . 12
	10.2. New registries . . . . . . . . . . . . . . . . . . . . . 12		10.2. New registries . . . . . . . . . . . . . . . . . . . . . 12
	11. Security Considerations . . . . . . . . . . . . . . . . . . . 12		11. Security Considerations . . . . . . . . . . . . . . . . . . . 12
	11.1. Potential Threat Modes . . . . . . . . . . . . . . . . . 13		11.1. Potential Threat Modes . . . . . . . . . . . . . . . . . 13
	11.2. Denial of Service Attacks . . . . . . . . . . . . . . . 14		11.2. Denial of Service Attacks . . . . . . . . . . . . . . . 14
	11.3. End-to End-Security Issues . . . . . . . . . . . . . . . 14		11.3. End-to End-Security Issues . . . . . . . . . . . . . . . 14
	12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14		12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14
	13. References . . . . . . . . . . . . . . . . . . . . . . . . . 14		13. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
	13.1. Normative References . . . . . . . . . . . . . . . . . . 14		13.1. Normative References . . . . . . . . . . . . . . . . . . 15
	13.2. Informative References . . . . . . . . . . . . . . . . . 15		13.2. Informative References . . . . . . . . . . . . . . . . . 15
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 15		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 15
	1. Introduction		1. Introduction
	The DOIC solution [RFC7683] for Diameter overload control introduces		The Diameter Overload Indication Conveyance (DOIC) solution [RFC7683]
	scenarios where Diameter routing decisions made by Diameter nodes can		for Diameter overload control introduces scenarios where Diameter
	be influenced by the overload state of other Diameter nodes. This		routing decisions made by Diameter nodes can be influenced by the
	includes the scenarios where Diameter endpoints and Diameter agents		overload state of other Diameter nodes. This includes the scenarios
	can throttle requests as a result of the target for the request being		where Diameter endpoints and Diameter agents can throttle requests as
	overloaded.		a result of the target for the request being overloaded.
	With currently available mechanisms these Diameter nodes do not have		With currently available mechanisms these Diameter nodes do not have
	a mechanism to differentiate request message priorities when making		a mechanism to differentiate request message priorities when making
	these throttling decisions. As such, all requests are treated the		these throttling decisions. As such, all requests are treated the
	same, meaning that all requests have the same probability of being		same, meaning that all requests have the same probability of being
	throttled.		throttled.
	There are scenarios where treating all requests the same can cause		There are scenarios where treating all requests the same can cause
	issues. For instance it might be considered important to reduce the		issues. For instance, it might be considered important to reduce the
	probability of transactions involving first responders during a		probability of transactions involving first responders being
	period of heavy signaling resulting from a natural disaster being		throttled during overload scenarios caused, for example, by a period
	throttled during overload scenarios.		of heavy signaling resulting from a natural disaster.
	This document defines a mechanism that allows Diameter nodes to		This document defines a mechanism that allows Diameter nodes to
	indicate the relative priority of Diameter transactions. With this		indicate the relative priority of Diameter transactions. With this
	information other Diameter nodes can factor the relative priority of		information other Diameter nodes can factor the relative priority of
	requests into routing and throttling decisions.		requests into routing and throttling decisions.
	2. Terminology and Abbreviations		2. Terminology and Abbreviations
	Diversion		Diversion
	skipping to change at page 3, line 46 ¶		skipping to change at page 3, line 46 ¶
	node. Abatement actions include diversion and throttling.		node. Abatement actions include diversion and throttling.
	Priority		Priority
	The relative importance of a Diameter message. A lower priority		The relative importance of a Diameter message. A lower priority
	value implies a higher relative importance of the message.		value implies a higher relative importance of the message.
	Throttling		Throttling
	As defined in [RFC7683]. An abatement treatment that limits the		As defined in [RFC7683]. An abatement treatment that limits the
	number of requests sent by the DIOC reacting node. Throttling can		number of requests sent by the DOIC reacting node. Throttling can
	include a Diameter Client choosing to not send requests, or a		include a Diameter Client choosing to not send requests, or a
	Diameter Agent or Server rejecting requests with appropriate error		Diameter Agent or Server rejecting requests with appropriate error
	responses. In both cases the result of the throttling is a		responses. In both cases the result of the throttling is a
	permanent rejection of the transaction.		permanent rejection of the transaction.
	3. Conventions Used in This Document		3. Conventions Used in This Document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	skipping to change at page 4, line 52 ¶		skipping to change at page 4, line 52 ¶
	It is also envisioned that DRMP priority information could be used by		It is also envisioned that DRMP priority information could be used by
	Diameter endpoints to make resource allocation decisions. For		Diameter endpoints to make resource allocation decisions. For
	instance, a Diameter Server might choose to use the priority		instance, a Diameter Server might choose to use the priority
	information to treat higher priority requests ahead of lower priority		information to treat higher priority requests ahead of lower priority
	requests.		requests.
	Note: There are a number of application specific definitions		Note: There are a number of application specific definitions
	indicating various views of application level priority for		indicating various views of application level priority for
	different requests. Using these application specific priority		different requests. Using these application specific priority
	AVPs as input to throttling and other Diameter routing decisions		Attribute Value Pairs (AVPs) as input to throttling and other
	would require Diameter agents to understand all applications and		Diameter routing decisions would require Diameter agents to
	do application specific parsing of all messages in order to		understand all applications and do application specific parsing of
	determine the priority of individual messages. This is considered		all messages in order to determine the priority of individual
	an unacceptable level of complexity to put on elements whose		messages. This is considered an unacceptable level of complexity
	primary responsibility is to route Diameter messages.		to put on elements whose primary responsibility is to route
			Diameter messages.
	5. Use Cases		5. Use Cases
	This section discusses various scenarios where Diameter transactions		This section discusses various scenarios where Diameter transactions
	can benefit from the use of priority information.		can benefit from the use of priority information.
	5.1. First Responder Related Signaling		5.1. First Responder Related Signaling
	Natural disasters can result in a considerable increase in usage of		Natural disasters can result in a considerable increase in usage of
	network resources. This can be made worse if the disaster results in		network resources. This can be made worse if the disaster results in
	skipping to change at page 6, line 12 ¶		skipping to change at page 6, line 12 ¶
	emergency calls, this signaling should also be given preferential		emergency calls, this signaling should also be given preferential
	treatment when possible.		treatment when possible.
	5.3. Differentiated Services		5.3. Differentiated Services
	Operators may desire to differentiate network-based services by		Operators may desire to differentiate network-based services by
	providing a service level agreement that includes preferential		providing a service level agreement that includes preferential
	Diameter routing behavior. This might, for example, be modeled as		Diameter routing behavior. This might, for example, be modeled as
	Platinum, Gold and Silver levels of service.		Platinum, Gold and Silver levels of service.
	In this scenario an operator might offer a Platinum SLA the includes		In this scenario an operator might offer a Platinum SLA that includes
	ensuring that all signaling for a customer who purchases the Platinum		ensuring that all signaling for a customer who purchases the Platinum
	service being marked as having a higher priority than signaling		service being marked as having a higher priority than signaling
	associated with Gold and Silver customers.		associated with Gold and Silver customers.
	5.4. Application Specific Priorities		5.4. Application Specific Priorities
	There are scenarios within Diameter applications where it might be		There are scenarios within Diameter applications where it might be
	appropriate to give a subset of the transactions for the application		appropriate to give a subset of the transactions for the application
	a higher priority than other transactions for that application.		a higher priority than other transactions for that application.
	skipping to change at page 6, line 48 ¶		skipping to change at page 6, line 48 ¶
	There are also scenarios where the priority of requests for		There are also scenarios where the priority of requests for
	individual command codes within an application depends on the context		individual command codes within an application depends on the context
	that exists when the request is sent. There isn't always information		that exists when the request is sent. There isn't always information
	in the message from which this context can be determined by Diameter		in the message from which this context can be determined by Diameter
	nodes other than the node that originates the request.		nodes other than the node that originates the request.
	This is similar to the scenario where a series of requests are needed		This is similar to the scenario where a series of requests are needed
	to access a network service. It is different in that the series of		to access a network service. It is different in that the series of
	requests involve different application command codes. In this		requests involve different application command codes. In this
	scenario it is requests with the same command code that have		scenario requests with the same command code have different implied
	different implied priorities.		priorities.
	One example of this is in the 3GPP application [S6a] where a ULR		One example of this is in the 3GPP application [S6a] where an
	request resulting from an MME (Mobility Management Entity)		Update Location Request (ULR) request resulting from an MME
	restoration procedure might be given a higher priority than a ULR		(Mobility Management Entity) restoration procedure might be given
	(Update Location Request) resulting from an initial attach.		a higher priority than a ULR (Update Location Request) resulting
			from an initial attach.
	6. Theory of Operation		6. Theory of Operation
	This section outlines the envisioned usage of DRMP.		This section outlines the envisioned usage of DRMP.
	The expected behavior depends on the role (request sender, agent or		The expected behavior depends on the role (request sender, agent or
	request handler) of the Diameter node handling the request.		request handler) of the Diameter node handling the request.
	The following behavior is expected during the flow of a Diameter		The following behavior is expected during the flow of a Diameter
	transaction.		transaction.
	skipping to change at page 8, line 34 ¶		skipping to change at page 8, line 34 ¶
	answers for higher priority transactions are given preferential		answers for higher priority transactions are given preferential
	treatment to lower priority transactions. When forwarding the		treatment to lower priority transactions. When forwarding the
	answer messages, agents generally do not modify the priority		answer messages, agents generally do not modify the priority
	information present in the received answer messages nor include		information present in the received answer messages nor include
	the priority information when absent in the received answer		the priority information when absent in the received answer
	messages. However, in some scenarios, agents can modify the		messages. However, in some scenarios, agents can modify the
	priority information, for example, edge agents modifying the		priority information, for example, edge agents modifying the
	priority values set by an adjacent operator. There might be		priority values set by an adjacent operator. There might be
	other scenarios where a Diameter endpoint does not support the		other scenarios where a Diameter endpoint does not support the
	DRMP mechanism and agents insert the priority information for		DRMP mechanism and agents insert the priority information for
	that non supporting endpoint.		that non-supporting endpoint.
	6. Answer handler - The answer handler uses the same method as the		6. Answer handler - The answer handler uses the same method as the
	agent to determine the priority of the answer message. By		agent to determine the priority of the answer message. By
	default the handler of the answer message uses the priority saved		default the handler of the answer message uses the priority saved
	in the transaction's state. Priority information in the answer		in the transaction's state. Priority information in the answer
	message is used when present. The priority is used when		message is used when present. The priority is used when
	allocating resources for processing that occurs after the receipt		allocating resources for processing that occurs after the receipt
	of the answer message.		of the answer message.
	7. Extensibility		7. Extensibility
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	understand application specific AVPs.		understand application specific AVPs.
	When available, Diameter nodes SHOULD use routing priority		When available, Diameter nodes SHOULD use routing priority
	information included in the DRMP AVP when making Diameter overload		information included in the DRMP AVP when making Diameter overload
	throttling decisions.		throttling decisions.
	Diameter agents MAY use routing priority information included in the		Diameter agents MAY use routing priority information included in the
	DRMP AVP when relaying request and answer messages. This includes		DRMP AVP when relaying request and answer messages. This includes
	the selection of routes and the ordering of messages relayed.		the selection of routes and the ordering of messages relayed.
	The priority information included in the DRMP AVP in request		Note: The priority information included in the DRMP AVP in request
	messages applies to both the request message and, by default,		messages applies to both the request message and, by default,
	answer message associated with the transaction.		answer message associated with the transaction.
	While done only in exceptional circumstances, Diameter agents MAY		While done only in exceptional circumstances, Diameter agents MAY
	modify priority information when relaying request and answer		modify priority information when relaying request and answer
	messages.		messages.
	There might be scenarios where a Diameter agent does modify		Note: There might be scenarios where a Diameter agent does modify
	priority information. For instance, an edge agent might need to		priority information. For instance, an edge agent might need to
	modify the priority values set by an adjacent operator.		modify the priority values set by an adjacent operator.
	While done only in exceptional circumstances, Diameter agents MAY add		While done only in exceptional circumstances, Diameter agents MAY add
	priority information when relaying request and answer messages.		priority information when relaying request and answer messages.
	There might be scenarios where a Diameter endpoint does not		Note: There might be scenarios where a Diameter endpoint does not
	support the DRMP mechanism and agents insert priority information		support the DRMP mechanism and agents insert priority information
	for that non supporting endpoint.		for that non-supporting endpoint.
	Diameter endpoints MAY use routing priority information included in		Diameter endpoints MAY use routing priority information included in
	the DRMP AVP when making resource allocation decisions for the		the DRMP AVP when making resource allocation decisions for the
	transaction associated with the request message that contains the		transaction associated with the request message that contains the
	DRMP information.		DRMP information.
	Diameter endpoints MAY use routing priority information included in		Diameter endpoints MAY use routing priority information included in
	the DRMP AVP when making resource allocation decisions for the		the DRMP AVP when making resource allocation decisions for the
	transaction associated with the answer messages using the DRMP		transaction associated with the answer messages using the DRMP
	information associated with the transaction.		information associated with the transaction.
	skipping to change at page 11, line 20 ¶		skipping to change at page 11, line 20 ¶
	9. Attribute Value Pairs		9. Attribute Value Pairs
	This section describes the encoding and semantics of the Diameter		This section describes the encoding and semantics of the Diameter
	Overload Indication Attribute Value Pairs (AVPs) defined in this		Overload Indication Attribute Value Pairs (AVPs) defined in this
	document.		document.
	9.1. DRMP AVP		9.1. DRMP AVP
	The DRMP (AVP code TBD1) is of type Enumerated. The value of the AVP		The DRMP (AVP code TBD1) is of type Enumerated. The value of the AVP
	indicates the routing message priority for the transaction. The		indicates the routing message priority for the transaction. The
	following values are initially defined:		following values are defined:
	PRIORITY_15 15 PRIORITY_15 is the lowest priority.		PRIORITY_15 15 PRIORITY_15 is the lowest priority.
	PRIORITY_14 14 PRIORITY_14 is a higher priority than PRIORITY_15 and		PRIORITY_14 14 PRIORITY_14 is a higher priority than PRIORITY_15 and
	a lower priority than PRIORITY_13.		a lower priority than PRIORITY_13.
	PRIORITY_13 13 PRIORITY_13 is a higher priority than PRIORITY_14 and		PRIORITY_13 13 PRIORITY_13 is a higher priority than PRIORITY_14 and
	a lower priority than PRIORITY_12.		a lower priority than PRIORITY_12.
	PRIORITY_12 12 PRIORITY_12 is a higher priority than PRIORITY_13 and		PRIORITY_12 12 PRIORITY_12 is a higher priority than PRIORITY_13 and
	skipping to change at page 12, line 46 ¶		skipping to change at page 12, line 46 ¶
	AVP codes are allocated from the 'Authentication, Authorization, and		AVP codes are allocated from the 'Authentication, Authorization, and
	Accounting (AAA) Parameters' AVP Codes registry.		Accounting (AAA) Parameters' AVP Codes registry.
	10.2. New registries		10.2. New registries
	There are no new IANA registries introduced by this document.		There are no new IANA registries introduced by this document.
	11. Security Considerations		11. Security Considerations
	DRMP gives Diameter nodes the ability to influence which requests are		DRMP gives Diameter nodes the ability to influence which requests are
	are throttled during overload scenarios. Improper use of the DRMP		throttled during overload scenarios. Improper use of the DRMP
	mechanism could result in the malicious Diameter node gaining		mechanism could result in the malicious Diameter node gaining
	preferential treatment, by reducing the probability of its requests		preferential treatment, by reducing the probability of its requests
	being throttled, over other Diameter nodes. This would be achieved		being throttled, over other Diameter nodes. This would be achieved
	by the malicious node inserting artificially high priority values.		by the malicious node inserting artificially high priority values.
	Diameter does not include features to provide end-to-end		Diameter does not include features to provide end-to-end
	authentication, integrity protection, or confidentiality. This opens		authentication, integrity protection, or confidentiality. This opens
	the possibility that malicious or compromised agents in the path of a		the possibility that malicious or compromised agents in the path of a
	request could modify the DRMP AVP to reflect a priority different		request could modify the DRMP AVP to reflect a priority different
	than that asserted by the sender of the request.		than that asserted by the sender of the request.
	11.1. Potential Threat Modes		11.1. Potential Threat Modes
	The Diameter protocol involves transactions in the form of requests		The Diameter protocol involves transactions in the form of requests
	and answers exchanged between clients and servers. These clients and		and answers exchanged between clients and servers. These clients and
	servers may be peers, that is, they may share a direct transport		servers may be peers, that is, they may share a direct transport
	(e.g., TCP or SCTP) connection, or the messages may traverse one or		(e.g., Transmission Control Protocol (TCP) or Stream Control
	more intermediaries, known as Diameter Agents. Diameter nodes use		Transmission Protocol (SCTP)) connection, or the messages may
	TLS, DTLS, or IPsec to authenticate peers, and to provide		traverse one or more intermediaries, known as Diameter Agents.
			Diameter nodes use Transport Layer Security (TLS), Datagram Transport
			Layer Security (DTLS), or IPsec to authenticate peers, and to provide
	confidentiality and integrity protection of traffic between peers.		confidentiality and integrity protection of traffic between peers.
	Nodes can make authorization decisions based on the peer identities		Nodes can make authorization decisions based on the peer identities
	authenticated at the transport layer.		authenticated at the transport layer.
	When agents are involved, this presents an effectively transitive		When agents are involved, this presents an effectively transitive
	trust model. That is, a Diameter client or server can authorize an		trust model. That is, a Diameter client or server can authorize an
	agent for certain actions, but it must trust that agent to make		agent for certain actions, but it must trust that agent to make
	appropriate authorization decisions about its peers, and so on.		appropriate authorization decisions about its peers, and so on.
	Since confidentiality and integrity protection occurs at the		Since confidentiality and integrity protection occurs at the
	transport layer, agents can read, and perhaps modify, any part of a		transport layer, agents can read, and perhaps modify, any part of a
	skipping to change at page 14, line 10 ¶		skipping to change at page 14, line 12 ¶
	have a potentially greater impact in this scenario as the priority		have a potentially greater impact in this scenario as the priority
	indication impacts the handling of all requests at all times,		indication impacts the handling of all requests at all times,
	independent of the overload status of Diameter nodes in the Diameter		independent of the overload status of Diameter nodes in the Diameter
	network.		network.
	11.2. Denial of Service Attacks		11.2. Denial of Service Attacks
	The DRMP mechanism does not open direct denial of service attack		The DRMP mechanism does not open direct denial of service attack
	vectors. Rather, it introduces a mechanism where a node can gain		vectors. Rather, it introduces a mechanism where a node can gain
	unwarranted preferential treatment. It also introduces a mechanism		unwarranted preferential treatment. It also introduces a mechanism
	where a node can get degrated service in the scenario where a rogue		where a node can get degraded service in the scenario where a rogue
	agent changes the priority value included in messages.		agent changes the priority value included in messages.
	11.3. End-to End-Security Issues		11.3. End-to End-Security Issues
	The lack of end-to-end integrity features makes it difficult to		The lack of end-to-end integrity features in Diameter [RFC6733] makes
	establish trust in DRMP AVPs received from non-adjacent nodes. Any		it difficult to establish trust in DRMP AVPs received from non-
	agents in the message path may insert or modify DRMP AVPs. Nodes		adjacent nodes. Any agents in the message path may insert or modify
	must trust that their adjacent peers perform proper checks on		DRMP AVPs. Nodes must trust that their adjacent peers perform proper
	overload reports from their peers, and so on, creating a transitive-		checks on overload reports from their peers, and so on, creating a
	trust requirement extending for potentially long chains of nodes.		transitive-trust requirement extending for potentially long chains of
	Network operators must determine if this transitive trust requirement		nodes. Network operators must determine if this transitive trust
	is acceptable for their deployments. Nodes supporting DRMP MUST give		requirement is acceptable for their deployments. Nodes supporting
	operators the ability to select which peers are trusted to deliver		DRMP MUST give operators the ability to select which peers are
	DRMP AVPs, and whether they are trusted to forward the DRMP AVPs from		trusted to deliver DRMP AVPs, and whether they are trusted to forward
	non-adjacent nodes. Diameter nodes MUST strip DRMP AVPs from		the DRMP AVPs from non-adjacent nodes. Diameter nodes MUST strip
	messages received from peers that are not trusted for DRMP purposes.		DRMP AVPs from messages received from peers that are not trusted for
			DRMP purposes.
	It is expected that work on end-to-end Diameter security might make		It is expected that work on end-to-end Diameter security might make
	it easier to establish trust in non-adjacent nodes for DRMP purposes.		it easier to establish trust in non-adjacent nodes for DRMP purposes.
	Readers should be reminded, however, that the DRMP mechanism allows		Readers should be reminded, however, that the DRMP mechanism allows
	Diameter agents to modify AVPs in existing messages that are		Diameter agents to modify AVPs in existing messages that are
	originated by other nodes. If end-to-end security is enabled, there		originated by other nodes. If end-to-end security is enabled, there
	is a risk that such modification could violate integrity protection.		is a risk that such modification could violate integrity protection.
	The details of using any future Diameter end-to-end security		The details of using any future Diameter end-to-end security
	mechanism with DRMP will require careful consideration, and are		mechanism with DRMP will require careful consideration, and are
	beyond the scope of this document.		beyond the scope of this document.
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