draft-ietf-i2rs-problem-statement-02.txt		draft-ietf-i2rs-problem-statement-03.txt
	Network Working Group A. Atlas, Ed.		Network Working Group A. Atlas, Ed.
	Internet-Draft Juniper Networks		Internet-Draft Juniper Networks
	Intended status: Informational T. Nadeau, Ed.		Intended status: Informational T. Nadeau, Ed.
	Expires: December 8, 2014 Brocade		Expires: December 8, 2014 Brocade
	D. Ward		D. Ward
	Cisco Systems		Cisco Systems
	June 6, 2014		June 6, 2014
	Interface to the Routing System Problem Statement		Interface to the Routing System Problem Statement
	draft-ietf-i2rs-problem-statement-02		draft-ietf-i2rs-problem-statement-03
	Abstract		Abstract
	As modern networks grow in scale and complexity, the need for rapid		As modern networks grow in scale and complexity, the need for rapid
	and dynamic control increases. With scale, the need to automate even		and dynamic control increases. With scale, the need to automate even
	the simplest operations is important, but even more critical is the		the simplest operations is important, but even more critical is the
	ability to quickly interact with more complex operations such as		ability to quickly interact with more complex operations such as
	policy-based controls.		policy-based controls.
	In order to enable network applications to have access to and control		In order to enable network applications to have access to and control
	skipping to change at page 4, line 49		skipping to change at page 4, line 49
	+**+ objects NOT within the scope of I2RS		+**+ objects NOT within the scope of I2RS
	.... boundary of a router participating in the I2RS		.... boundary of a router participating in the I2RS
	Figure 1: I2RS model and Problem Area		Figure 1: I2RS model and Problem Area
	A critical aspect of I2RS is defining a suitable protocol or		A critical aspect of I2RS is defining a suitable protocol or
	protocols to carry messages between the I2RS Clients and the I2RS		protocols to carry messages between the I2RS Clients and the I2RS
	Agent, and defining the data-models for use with those I2RS		Agent, and defining the data-models for use with those I2RS
	protocol(s). The protocol should provide the key features specified		protocol(s). The protocol should provide the key features specified
	in Section 5. The data models should translate into a clear transfer		in Section 5. The data models should translate into a concise
	syntax that is straightforward for applications to use (e.g., a Web		transfer syntax that is straightforward for applications to use
	Services design paradigm). The information transfer should use		(e.g., a Web Services design paradigm). The information transfer
	existing transport protocols to provide the reliability, security,		should use existing transport protocols to provide the reliability,
	and timeliness appropriate for the particular data.		security, and timeliness appropriate for the particular data.
	The second critical aspect are semantic-aware data-models for		The second critical aspect are meaningful data-models for information
	information in the routing system and in a topology database. The		in the routing system and in a topology database. The data-model
	data-model should describe the meaning and relationships of the		should describe the meaning and relationships of the modeled items.
	modeled items. The data-models should be separable across different		The data-models should be separable across different features of the
	features of the managed components, versioned, and extendable. As		managed components, versioned, and extendable. As shown in Figure 1,
	shown in Figure 1, I2RS needs to interact with several logical		I2RS needs to interact with several logical components of the routing
	components of the routing element: policy database, topology		element: policy database, topology database, subscription and
	database, subscription and configuration for dynamic measuresments/		configuration for dynamic measuresments/events, routing signaling
	events, routing signaling protocols, and its RIB manager. This		protocols, and its RIB manager. This interaction is both for writing
	interaction is both for writing (e.g. to policy databases or RIB		(e.g. to policy databases or RIB manager) as well as for reading
	manager) as well as for reading (e.g. dynamic measurement or topology		(e.g. dynamic measurement or topology database). An application
	database). An application should be able to combine data from		should be able to combine data from individual routing elements to
	individual routing elements to provide network-wide data-model(s).		provide network-wide data-model(s).
	3. Standard Data-Models of Routing State for Installation		3. Standard Data-Models of Routing State for Installation
	There is a need to be able to precisely control routing and signaling		There is a need to be able to precisely control routing and signaling
	state based upon policy or external measures. This can range from		state based upon policy or external measures. This can range from
	simple static routes to policy-based routing to static multicast		simple static routes to policy-based routing to static multicast
	replication and routing state. This means that, to usefully model		replication and routing state. This means that, to usefully model
	next-hops, the data model employed needs to handle next-hop		next-hops, the data model employed needs to handle next-hop
	indirection and recursion (e.g. a prefix X is routed like prefix Y)		indirection and recursion (e.g. a prefix X is routed like prefix Y)
	as well as different types of tunneling and encapsulation. The		as well as different types of tunneling and encapsulation. The
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	Efforts to provide this level of control have focused on		Efforts to provide this level of control have focused on
	standardizing data models that describe the forwarding plane (e.g.		standardizing data models that describe the forwarding plane (e.g.
	ForCES [RFC3746]). I2RS posits that the routing system and a		ForCES [RFC3746]). I2RS posits that the routing system and a
	router's OS provide useful mechanisms that applications could		router's OS provide useful mechanisms that applications could
	usefully harness to accomplish application-level goals.		usefully harness to accomplish application-level goals.
	In addition to interfaces to the RIB layer, there is a need to		In addition to interfaces to the RIB layer, there is a need to
	configure the various routing and signaling protocols with differing		configure the various routing and signaling protocols with differing
	dynamic state based upon application-level policy decisions. The		dynamic state based upon application-level policy decisions. The
	range desired is not available via MIBs at the present time.		range desired is not available via MIB modules at the present time.
	4. Learning Router Information		4. Learning Router Information
	A router has information that applications may require so that they		A router has information that applications may require so that they
	can understand the network, verify that programmed state is installed		can understand the network, verify that programmed state is installed
	in the forwarding plane, measure the behavior of various flows, and		in the forwarding plane, measure the behavior of various flows, and
	understand the existing configuration and state of the router. I2RS		understand the existing configuration and state of the router. I2RS
	provides a framework so that applications can register for		provides a framework so that applications can register for
	asynchronous notifications and can make specific requests for		asynchronous notifications and can make specific requests for
	information.		information.
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	mechanism such as IPFIX [RFC5470] may be the facilitator for		mechanism such as IPFIX [RFC5470] may be the facilitator for
	delivering the data, the need for an application to be able to		delivering the data, the need for an application to be able to
	dynamically request that measurements be taken and data delivered is		dynamically request that measurements be taken and data delivered is
	critical.		critical.
	There are a wide range of events that applications could use for		There are a wide range of events that applications could use for
	either verification of router state before other network state is		either verification of router state before other network state is
	changed (e.g. that a route has been installed), to act upon changes		changed (e.g. that a route has been installed), to act upon changes
	to relevant routes by others, or upon router events (e.g. link up/		to relevant routes by others, or upon router events (e.g. link up/
	down). While a few of these (e.g. link up/down) may be available via		down). While a few of these (e.g. link up/down) may be available via
	MIB Notifications today, the full range is not - nor is there the		MIB notifications today, the full range is not - nor has there been
	standardized ability to set up the router to trigger different		successfully deployed the standardized ability to set up the router
	actions upon an event's occurrence so that a rapid reaction can be		to trigger different actions upon an event's occurrence so that a
	accomplished.		rapid reaction can be accomplished.
	5. Desired Aspects of a Protocol for I2RS		5. Desired Aspects of a Protocol for I2RS
	This section describes required aspects of a protocol that could		This section describes required aspects of a protocol that could
	support I2RS. Whether such a protocol is built upon extending		support I2RS. Whether such a protocol is built upon extending
	existing mechanisms or requires a new mechanism requires further		existing mechanisms or requires a new mechanism requires further
	investigation.		investigation.
	The key aspects needed in an interface to the routing system are:		The key aspects needed in an interface to the routing system are:
	Multiple Simultaneous Asynchronous Operations: A single application		Multiple Simultaneous Asynchronous Operations: A single application
	should be able to send multiple independent operations via I2RS		should be able to send multiple independent atomic operations via
	without being required to wait for each to complete before sending		I2RS without being required to wait for each to complete before
	the next.		sending the next.
	Very Fine Granularity of Data Locking for Writing: When an I2RS		Very Fine Granularity of Data Locking for Writing: When an I2RS
	operation is processed, it is required that the data locked for		operation is processed, it is required that the data locked for
	writing is very granular (e.g. a particular prefix and route)		writing is very granular (e.g. a particular prefix and route)
	rather than extremely coarse, as is done for writing		rather than extremely coarse, as is done for writing
	configuration. This should improve the number of concurrent I2RS		configuration. This should improve the number of concurrent I2RS
	operations that are feasible and reduce blocking delays.		operations that are feasible and reduce blocking delays.
	Multi-Headed Control: Multiple applications may communicate to the		Multi-Headed Control: Multiple applications may communicate to the
	same I2RS agent in a minimally coordinated fashion. It is		same I2RS agent in a minimally coordinated fashion. It is
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	events, acknowledgements, failures, operations, etc. can be sent		events, acknowledgements, failures, operations, etc. can be sent
	at any time by both the router and the application. The I2RS is		at any time by both the router and the application. The I2RS is
	not a pure pull-model where only the application queries to pull		not a pure pull-model where only the application queries to pull
	responses.		responses.
	High-Throughput: At a minimum, the I2RS Agent and associated router		High-Throughput: At a minimum, the I2RS Agent and associated router
	should be able to handle a considerable number of operations per		should be able to handle a considerable number of operations per
	second (for example 10,000 per second to handle many individual		second (for example 10,000 per second to handle many individual
	subscriber routes changing simultaneously).		subscriber routes changing simultaneously).
	Responsive: Within a sub-second time-scale, it should be possible		Low-Latency: Within a sub-second time-scale, it should be possible
	to complete simple operations (e.g. reading or writing a single		to complete simple operations (e.g. reading or writing a single
	prefix route).		prefix route).
	Multi-Channel: It should be possible for information to be		Multi-Channel: It should be possible for information to be
	communicated via the interface from different components in the		communicated via the interface from different components in the
	router without requiring going through a single channel. For		router without requiring going through a single channel. For
	example, for scaling, some exported data or events may be better		example, for scaling, some exported data or events may be better
	sent directly from the forwarding plane, while other interactions		sent directly from the forwarding plane, while other interactions
	may come from the control-plane. Thus a single TCP session would		may come from the control-plane. Thus a single TCP session would
	not be a good match.		not be a good match.
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	information about devices, including their routing systems. However,		information about devices, including their routing systems. However,
	SNMP is very rarely used to configure a device or any of its systems		SNMP is very rarely used to configure a device or any of its systems
	for reasons that vary depending upon the network operator. Some		for reasons that vary depending upon the network operator. Some
	example reasons include complexity, the lack of desired configuration		example reasons include complexity, the lack of desired configuration
	semantics (e.g., configuration "roll-back", "sandboxing" or		semantics (e.g., configuration "roll-back", "sandboxing" or
	configuration versioning), and the difficulty of using the semantics		configuration versioning), and the difficulty of using the semantics
	(or lack thereof) as defined in the MIB modules to configure device		(or lack thereof) as defined in the MIB modules to configure device
	features. Therefore, SNMP is not considered as a candidate solution		features. Therefore, SNMP is not considered as a candidate solution
	for the problems motivating I2RS.		for the problems motivating I2RS.
	Finally, the IETF's Network Configuration (or NetConf) protocol has		Finally, the IETF's Network Configuration (or NETCONF) protocol has
	made many strides at overcoming most of the limitations around		made many strides at overcoming most of the limitations around
	configuration that were just described. However, the lack of		configuration that were just described. However, the initial lack of
	standard data models have hampered the adoption of NetConf.		standard data models have hampered the adoption of NETCONF.
	Naturally, I2RS may help define needed information and data models.		Naturally, I2RS may help define needed information and data models.
	Additional extensions to handle multi-headed control may need to be		Additional extensions to handle multi-headed control may need to be
	added to NetConf and/or appropriate data models.		added to NETCONF and/or appropriate data models.
	Authors' Addresses		Authors' Addresses
	Alia Atlas (editor)		Alia Atlas (editor)
	Juniper Networks		Juniper Networks
	10 Technology Park Drive		10 Technology Park Drive
	Westford, MA 01886		Westford, MA 01886
	USA		USA
	Email: akatlas@juniper.net		Email: akatlas@juniper.net
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