--- 1/draft-nitinb-i2rs-rib-info-model-00.txt 2013-07-24 17:14:37.329236178 -0700 +++ 2/draft-nitinb-i2rs-rib-info-model-01.txt 2013-07-24 17:14:37.377237446 -0700 @@ -1,103 +1,109 @@ Network Working Group N. Bahadur, Ed. Internet-Draft R. Folkes, Ed. Intended status: Informational Juniper Networks, Inc. -Expires: December 27, 2013 S. Kini +Expires: January 16, 2014 S. Kini Ericsson - June 25, 2013 + J. Medved + Cisco + July 15, 2013 Routing Information Base Info Model - draft-nitinb-i2rs-rib-info-model-00 + draft-nitinb-i2rs-rib-info-model-01 Abstract Routing and routing functions in enterprise and carrier networks are typically performed by network devices (routers and switches) using a routing information base (RIB). Protocols and configuration push data into the RIB and the RIB manager install state into the hardware; for packet forwarding. This draft specifies an information - model for the RIB, to build a standardized RIB model, using which an - external entity (external to the network device) can read and write - information from/to the RIB. + model for the RIB to enable defining a standardized data model. Such + a data model can be used to define an interface to the RIB from an + entity that may even be external to the network device. This + interface can be used to support new use-cases being defined by the + IETF I2RS WG. 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 December 27, 2013. + This Internet-Draft will expire on January 16, 2014. Copyright Notice Copyright (c) 2013 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 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 - 1.1. Conventions used in this document . . . . . . . . . . . . 5 - 2. RIB data . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 2.1. RIB definition . . . . . . . . . . . . . . . . . . . . . . 5 - 2.2. Routing tables . . . . . . . . . . . . . . . . . . . . . . 6 - 2.3. Route . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 2.4. Nexthop . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 2.4.1. Nexthop types . . . . . . . . . . . . . . . . . . . . 9 - 2.4.2. Nexthop list attributes . . . . . . . . . . . . . . . 10 - 2.4.3. Nexthop content . . . . . . . . . . . . . . . . . . . 10 - 2.4.4. Nexthop attributes . . . . . . . . . . . . . . . . . . 11 - 2.4.5. Special nexthops . . . . . . . . . . . . . . . . . . . 11 - 3. Reading from the RIB . . . . . . . . . . . . . . . . . . . . . 11 - 4. Writing to the RIB . . . . . . . . . . . . . . . . . . . . . . 12 - 5. Events and Notifications . . . . . . . . . . . . . . . . . . . 12 - 6. RIB grammar . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 7. Using the RIB grammar . . . . . . . . . . . . . . . . . . . . 15 - 7.1. Using route preference and metric . . . . . . . . . . . . 15 - 7.2. Using different nexthops types . . . . . . . . . . . . . . 16 - 7.2.1. Tunnel nexthops . . . . . . . . . . . . . . . . . . . 16 - 7.2.2. Replication lists . . . . . . . . . . . . . . . . . . 16 - 7.2.3. Weighted lists . . . . . . . . . . . . . . . . . . . . 16 - 7.2.4. Protection lists . . . . . . . . . . . . . . . . . . . 17 - 7.2.5. Nexthop chains . . . . . . . . . . . . . . . . . . . . 17 - 7.2.6. Lists of lists . . . . . . . . . . . . . . . . . . . . 18 - 7.3. Solving optimized exit control . . . . . . . . . . . . . . 18 - 8. RIB operations at scale . . . . . . . . . . . . . . . . . . . 19 - 8.1. RIB reads . . . . . . . . . . . . . . . . . . . . . . . . 19 - 8.2. RIB writes . . . . . . . . . . . . . . . . . . . . . . . . 19 - 8.3. RIB events and notifications . . . . . . . . . . . . . . . 19 - 9. Security Considerations . . . . . . . . . . . . . . . . . . . 19 - 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 - 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20 - 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20 - 12.1. Normative References . . . . . . . . . . . . . . . . . . . 20 - 12.2. Informative References . . . . . . . . . . . . . . . . . . 20 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 + 1.1. Conventions used in this document . . . . . . . . . . . . 6 + 2. RIB data . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 2.1. RIB definition . . . . . . . . . . . . . . . . . . . . . . 6 + 2.2. Routing tables . . . . . . . . . . . . . . . . . . . . . . 7 + 2.3. Route . . . . . . . . . . . . . . . . . . . . . . . . . . 8 + 2.4. Nexthop . . . . . . . . . . . . . . . . . . . . . . . . . 9 + 2.4.1. Nexthop types . . . . . . . . . . . . . . . . . . . . 10 + 2.4.2. Nexthop list attributes . . . . . . . . . . . . . . . 11 + 2.4.3. Nexthop content . . . . . . . . . . . . . . . . . . . 11 + 2.4.4. Nexthop attributes . . . . . . . . . . . . . . . . . . 12 + 2.4.5. Nexthop vendor attributes . . . . . . . . . . . . . . 13 + 2.4.6. Special nexthops . . . . . . . . . . . . . . . . . . . 13 + 3. Reading from the RIB . . . . . . . . . . . . . . . . . . . . . 14 + 4. Writing to the RIB . . . . . . . . . . . . . . . . . . . . . . 14 + 5. Events and Notifications . . . . . . . . . . . . . . . . . . . 14 + 6. RIB grammar . . . . . . . . . . . . . . . . . . . . . . . . . 15 + 7. Using the RIB grammar . . . . . . . . . . . . . . . . . . . . 17 + 7.1. Using route preference and metric . . . . . . . . . . . . 18 + 7.2. Using different nexthops types . . . . . . . . . . . . . . 18 + 7.2.1. Tunnel nexthops . . . . . . . . . . . . . . . . . . . 18 + 7.2.2. Replication lists . . . . . . . . . . . . . . . . . . 18 + 7.2.3. Weighted lists . . . . . . . . . . . . . . . . . . . . 19 + 7.2.4. Protection lists . . . . . . . . . . . . . . . . . . . 19 + 7.2.5. Nexthop chains . . . . . . . . . . . . . . . . . . . . 20 + 7.2.6. Lists of lists . . . . . . . . . . . . . . . . . . . . 20 + 7.3. Performing multicast . . . . . . . . . . . . . . . . . . . 20 + 7.4. Solving optimized exit control . . . . . . . . . . . . . . 21 + 8. RIB operations at scale . . . . . . . . . . . . . . . . . . . 21 + 8.1. RIB reads . . . . . . . . . . . . . . . . . . . . . . . . 22 + 8.2. RIB writes . . . . . . . . . . . . . . . . . . . . . . . . 22 + 8.3. RIB events and notifications . . . . . . . . . . . . . . . 22 + 9. Security Considerations . . . . . . . . . . . . . . . . . . . 22 + 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 + 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22 + 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 + 12.1. Normative References . . . . . . . . . . . . . . . . . . . 23 + 12.2. Informative References . . . . . . . . . . . . . . . . . . 23 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24 1. Introduction Routing and routing functions in enterprise and carrier networks are traditionally performed in network devices. Traditionally routers run routing protocols and the routing protocols (along with static config) populates the Routing information base (RIB) of the router. The RIB is managed by the RIB manager and it provides a north-bound interface to its clients i.e. the routing protocols to insert routes into the RIB. The RIB manager consults the RIB and decides how to @@ -131,41 +137,41 @@ | | FIB | | | | FIB | | | +-----+ | | +-----+ | +-------------+ +-------------+ Figure 1: RIB-Manager, RIB-Clients and FIB-Managers Routing protocols are inherently distributed in nature and each router makes an independent decision based on the routing data received from its peers. With the advent of newer deployment paradigms and the need for specialized applications, there is an - emerging need to guide the router's routing function ( - [I-D.atlas-i2rs-problem-statement]). Traditional protocol-based RIB - population suffices for most use cases where distributed network - control works. However there are use cases in which the network - admins today configure static routes, policies and RIB import/export - rules on the routers. There is also a growing list of use cases ( - [I-D.white-i2rs-use-case], [I-D.hares-i2rs-use-case-vn-vc] ) in which - a network admin might want to program the RIB based on data unrelated - to just routing (within that network's domain). It could be based on - routing data in adjacent domain or it could be based on load on - storage and compute in the given domain. Or it could simply be a - programmatic way of creating on-demand dynamic overlays between - compute hosts (without requiring the hosts to run traditional routing - protocols). If there was a standardized programmatic interface to a - RIB, it would fuel further networking applications targeted towards - specific niches. + emerging need to guide the router's routing function + [I-D.atlas-i2rs-problem-statement]. Traditional network-device + protocol-based RIB population suffices for most use cases where + distributed network control works. However there are use cases in + which the network admins today configure static routes, policies and + RIB import/export rules on the routers. There is also a growing list + of use cases [I-D.white-i2rs-use-case], + [I-D.hares-i2rs-use-case-vn-vc] in which a network admin might want + to program the RIB based on data unrelated to just routing (within + that network's domain). It could be based on routing data in + adjacent domain or it could be based on load on storage and compute + in the given domain. Or it could simply be a programmatic way of + creating on-demand dynamic overlays between compute hosts (without + requiring the hosts to run traditional routing protocols). If there + was a standardized programmatic interface to a RIB, it would fuel + further networking applications targeted towards specific niches. - Programming the RIB involves 2 parts - reading what's in the RIB and - adding/modifying/deleting contents of the RIB. - [I-D.white-i2rs-use-case] lists various use-cases which require read - and/or write manipulation of the RIB. + A programmatic interface to the RIB involves 2 types of operations - + reading what's in the RIB and adding/modifying/deleting contents of + the RIB. [I-D.white-i2rs-use-case] lists various use-cases which + require read and/or write manipulation of the RIB. In order to understand what is in a router's RIB, methods like per- protocol SNMP MIBs and show output screen scraping are being used. These methods are not scalable, since they are client pull mechanisms and not proactive push (from the router) mechanisms. Screen scraping is error prone (since output can change) and vendor dependent. Building a RIB from per-protocol MIBs is error prone since the MIB data represents protocol data and not the exact information that went into the RIB. Thus, just getting read-only RIB information from a router is a hard task. @@ -177,62 +183,69 @@ This makes it hard for an external entity to program a multi-vendor network in a consistent and vendor independent way. The purpose of this draft is to specify an information model for the RIB. Using the information model, one can build a detailed data model for the RIB. And that data model could then be used by an external entity to program a router. The rest of this document is organized as follows. Section 2.1 goes into the details of what constitutes and can be programmed in a RIB. - The RIB grammar is specified in Section 6. Examples of using the RIB - grammar are shown in Section 7. Section 5 provides a high-level view - of the events and notifications going from a network device to an - external entity, to update the external entity on asynchronous - events. + Section 5 provides a high-level view of the events and notifications + going from a network device to an external entity, to update the + external entity on asynchronous events. The RIB grammar is specified + in Section 6. Examples of using the RIB grammar are shown in + Section 7. 1.1. Conventions used in this document 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 [RFC2119]. 2. RIB data This section describes the details of a RIB. It makes forward references to objects in the RIB grammar (Section 6). 2.1. RIB definition - A RIB contains one or more routing instances. On a network device, a - RIB is uniquely identified by its name. A routing instance can be in - only 1 RIB. A routing instance is a collection of routing tables, - interfaces, and routing parameters. A routing instance creates a - logical slice of the router and allows different logical slices; - across a set of routers; to communicate with other each. Layer 3 - VPNs, Layer 2 VPNs and VPLS are modeled as routing instances. The - set of interfaces indicates which interfaces this RIB has control - over. The routing tables specify how incoming traffic is to be - forwarded. And the routing parameters control the information in the - routing tables. The intersection set of interfaces of 2 routing - instances MUST be the null set. In other words, an interface should - not be present in 2 routing instances. Thus a routing instance - describes the routing policy and parameters across a set of - interfaces. + A RIB is a logical construct controlled by an external entity. A RIB + contains one or more routing instances. On a network device, a RIB + is uniquely identified by its name. A routing instance can be in + only 1 RIB. A routing instance, in the context of the RIB + information model, is a collection of routing tables, interfaces, and + routing parameters. A routing instance creates a logical slice of + the router and allows different logical slices; across a set of + routers; to communicate with other each. Layer 3 Virtual Private + Networks (VPN), Layer 2 VPNs (L2VPN) and Virtual Private Lan Service + (VPLS) can be modeled as routing instances. Note that modeling a + Layer 2 VPN using a routing instance only models the Layer-3 (RIB) + aspect and does not model any layer-2 information (like ARP) that + might be associated with the L2VPN. + + The set of interfaces indicates which interfaces this routing + instance has control over. The routing tables specify how incoming + traffic is to be forwarded. And the routing parameters control the + information in the routing tables. The intersection set of + interfaces of 2 routing instances MUST be the null set. In other + words, an interface should not be present in 2 routing instances. + Thus a routing instance describes the routing information and + parameters across a set of interfaces. A routing instance MUST contain the following mandatory fields. o INSTANCE_NAME: A routing instance is identified by its name, INSTANCE_NAME. o INSTANCE_DISTINGUISHER: Each routing instance must have a unique distinguisher associated with it. It enables one to distinguish - routes across routing instances. The route distinguisher MUST be - unique across all routing instances in a given network device. + routes across routing instances. The route distinguisher SHOULD + be unique across all routing instances in a given network device. How the INSTANCE_DISTINGUISHER is allocated and kept unique is outside the scope of this document. The instance distinguisher maps well to BGP route-distinguisher for virtual private networks (VPNs). However, the same concept can be used for other use-cases as well. o routing-table-list: This is the list of routing tables associated with this routing instance. Each routing instance can have multiple tables to represent routes of different types. For example, one would put IPv4 routes in one table and MPLS routes in another table. @@ -263,24 +276,24 @@ IPv4). Each routing table MUST belong to some routing instance. A routing table can be tagged with a MULTI_TOPOLOGY_ID. If a routing instance is divided into multiple logical topologies, then the multi- topology field is used to distinguish one topology from the other, so as to keep routes from one topology independent of routes from another topology. If a routing instance contains multiple tables of the same type (e.g. IPv4), then a MULTI_TOPOLOGY_ID MUST be associated with each such - table. In other words, multiple tables MUST be used only when there - are multiple topologies. In a given routing instance, - MULTI_TOPOLOGY_ID MUST be unique across routing tables of the same - type. + table. Multiple tables are useful when describing multiple topology + IGP (Interior Gateway Protocol) networks (see [RFC4915] and [RFC5120] + ). In a given routing instance, MULTI_TOPOLOGY_ID MUST be unique + across routing tables of the same type. Each route table can be optionally associated with a ENABLE_IP_RPF_CHECK attribute that enables Reverse path forwarding (RPF) checks on all IP routes in that table. Reverse path forwarding (RPF) check is used to prevent spoofing and limit malicious traffic. For IP packets, the IP source address is looked up and the rpf interface(s) associated with the route for that IP source address is found. If the incoming IP packet's interface matches one of the rpf interface(s), then the IP packet is forwarded based on its IP destination address; otherwise, the IP packet is discarded. @@ -289,20 +302,22 @@ A route is essentially a match condition and an action following the match. The match condition specifies the kind of route (IPv4, MPLS, etc.) and the set of fields to match on. This document specifies the following match types: o IPv4: Match on destination IP in IPv4 header o IPv6: Match on destination IP in IPv6 header o MPLS: Match on a MPLS tag o MAC: Match on ethernet destination addresses o Interface: Match on incoming interface of packet + o IP multicast: Match on (S, G) or (*, G), where S and G are IP + prefixes Each route can have associated with it one or more optional route attributes. o ROUTE_PREFERENCE: This is a numerical value that allows for comparing routes from different protocols. It is also known as administrative-distance. The lower the value, the higher the preference. For example there can be an OSPF route for 192.0.2.1/32 with a preference of 5. If a controller programs a route for 192.0.2.1/32 with a preference of 2, then the controller entered route will be preferred by the RIB manager. Preference @@ -387,24 +402,25 @@ 2.4.1. Nexthop types This document specifies a very generic, extensible and recursive grammar for nexthops. Nexthops can be o Unicast nexthops - pointing to an interface o Tunnel nexthops - pointing to a tunnel o Replication lists - list of nexthops to which to replicate a packet to o Weighted lists - for load-balancing o Protection lists - for primary/backup paths - o Nexthop chains - chaining headers, e.g. MPLS label over a GRE + o Nexthop chains - for chaining headers, e.g. MPLS label over a GRE header o Lists of lists - recursive application of the above o Indirect nexthops - pointing to a nexthop identifier + o Special nexthops - for performing specific well-defined functions It is expected that all network devices will have a limit on recursion and not all hardware will be able to support all kinds of nexthops. RIB capability negotiation becomes very important for this reason and a RIB data-model MUST specify a way for an external entity to learn about the network device's capabilities. Examples of when and how to use various kinds of nexthops are shown in Section 7.2. Tunnel nexthops allow an external entity to program static tunnel headers. There can be cases where the remote tunnel end-point does not support dynamic signaling (e.g. no LDP support on a host) and in @@ -456,29 +472,46 @@ list members. To perform equal load-balancing, one MAY specify a weight of "0" for all the member nexthops. The value "0" is reserved for equal load-balancing and if applied, MUST be applied to all member nexthops. 2.4.3. Nexthop content At the lowest level, a nexthop can point to a: o identifier: This is an identifier returned by the network device representing another nexthop or another nexthop chain. - o INTERFACE_IDENTIFIER: This represents a physical, logical or - virtual interface on the network device. + + o EGRESS_INTERFACE: This represents a physical, logical or virtual + interface on the network device. o address: This can be an IP address or MAC address or ISO address. - An optional table name can also be specified to indicate the table - in which the address is to be looked up further. By default the - table will be the same in which the route lookup was performed. + * An optional table name can also be specified to indicate the + table in which the address is to be looked up further. One can + use the table name field to direct the packet from one domain + into another domain. For example, a MPLS packet coming in on + an interface would be looked up in a MPLS routing table and the + nexthop for that could indicate that we strip the MPLS label + and do a subsequent IPv4 lookup in an IPv4 table. By default + the table will be the same in which the route lookup was + performed. + * An optional egress interface can be specified to indicate which + interface to send the packet out on. The egress interface is + useful when the network device contains Ethernet interfaces and + one needs to perform an ARP lookup for the IP packet. o tunnel encap: This can be an encap representing an IP tunnel or - MPLS tunnel or others as defined in this document - + MPLS tunnel or others as defined in this document. An optional + egress interface can be specified to indicate which interface to + send the packet out on. The egress interface is useful when the + network device contains Ethernet interfaces and one needs to + perform an ARP lookup for the IP packet. + o logical tunnel: This can be a MPLS LSP or a GRE tunnel (or others + as defined in this document), that is represented by a unique + identifier (E.g. name). o ROUTING_TABLE_NAME: This is a routing table that exists in the RIB. A nexthop pointing to a table indicates that the route lookup needs to continue in the specified table. This is a way to perform chained lookups. 2.4.4. Nexthop attributes Certain information is encoded implicitly in the nexthop and does not need to be specified by the controller. For example, when a IP packet is forwarded out, the IP TTL is decremented by default. Same @@ -487,21 +520,49 @@ by the network device and does not need to be programmed by an external device. A nexthop can have some attributes associated with it. The purpose of the attributes is to either override implicit behavior (like that related to TTL processing) or to guide the network device to perform something specific. Vendor specific attributes can also be specified. The details of vendor specific attributes is outside the scope of this document. -2.4.5. Special nexthops +2.4.4.1. Nexthop flags + + Nexthop flags in a nexthop is an optional attribute that is used to + denote specific connotation to hardware. Two common types of + operations are specified using nexthop flags. + o NO_DECREMENT_TTL: This indicates that the IPv4 time-to-live field + in an IPv4 packet MUST NOT be decremented before the packet is + forwarded. This may be applied one when an IPv4 packet is + encapsulated in a tunnel (E.g. MPLS) and one wants to hide the + fact that the packet is going through a tunnel. + o NO_PROPAGATE_TTL: This indicates that the IPv4 time-to-live field + in an IPv4 packet MUST NOT be propagated into an equivalent field, + when the IPv4 packet is tunneled. For example, if the IPv4 packet + is tunneled over MPLS, then the network device should use the + default time-to-live value for the outer MPLS header. This field + can also be used to indicate that when a tunnel terminates, one + does not propagate the outer header's time-to-live value into the + inner header. So, on MPLS tunnel termination, one does not + propagate the MPLS TTL value into the IPv4 header. + The TTL nexthop flags can be used to simulate a Pipe model for + tunnels. See [RFC3443] for a detailed understanding of Pipe model + and Uniform model. + +2.4.5. Nexthop vendor attributes + + This field has been defined for vendor specific extensions. The + contents of this field are beyond the scope of this document. + +2.4.6. Special nexthops This document specifies certain special nexthops. The purpose of each of them is explained below: o DISCARD: This indicates that the network device should drop the packet and increment a drop counter. o DISCARD_WITH_ERROR: This indicates that the network device should drop the packet, increment a drop counter and send back an appropriate error message (like ICMP error). o RECEIVE: This indicates that that the traffic is destined for the network device. For example, protocol packets or OAM packets. @@ -560,52 +621,58 @@ manager to an external entity when some event occurs on the network device. A RIB data-model MUST support sending asynchronous notifications. A brief list of suggested notifications is as below: o Route change notification, with return code as specified in Section 4 o Nexthop resolution status (resolved/unresolved) notification 6. RIB grammar This section specifies the RIB information model in Routing Backus- - Naur Form ([RFC5511]). + Naur Form [RFC5511]. ::= [ ...] ::= [] [] [] [] ::= [] ::= ( ...) ::= ( ...) - ::= - + ::= [ ... ] [] [ENABLE_IP_RPF_CHECK] ::= | | | - ::= - [] + ::= + [] [] ::= | | | | ::= + [] ::= - ::= ( ... ) + [] + ::= ::= ( ) ::= + ::= + + ::= + + ::= [] [] [] [] ::= | | ::= [] [] ::= ( ) [ ...] ::= | | @@ -622,38 +690,42 @@ ([ ... ] )) ::= ( | ) [] ::= [] [] ::= ( ...) ::= | - ::= ( | | - ( [] - []) | - ( [] - [) | + ::= ( | | + ( + ([] | [])) | + ( []) | + | ) [] [] ::= | ::= ( ) | ( ) | ( ) | ( ) + ::= | | ( [] []) ::= <> + ::= + ::= | | | | + ::= ( ) | ( ) | ( ) | ( ) | ( ) | ( ) ::= [] [] @@ -807,38 +878,58 @@ 7.2.6. Lists of lists Lists of lists is a complex construct. One example of usage of such a construct is to replicate traffic to multiple destinations, with high availability. In other words, for each destination you have a primary and backup nexthop (replication list) to ensure there is no traffic drop in case of a failure. So the outer list is a list of destinations and the inner lists are replication lists of primary/ backup nexthops. -7.3. Solving optimized exit control +7.3. Performing multicast + + IP multicast involves matching a packet on (S, G) or (*, G), where + both S (source) and G (group) are IP prefixes. Following the match, + the packet is replicated to one or more recipients. How the + recipients subscribe to the multicast group is outside the scope of + this document. + + In PIM-based multicast, the packets are IP forwarded on an IP + multicast tree. The downstream nodes on each point in the multicast + tree is one or more IP addresses. These can be represented as a + replication list ( Section 7.2.2 ). + + In MPLS-based multicast, the packets are forwarded on a point to + multipoint (P2MP) label-switched path (LSP). The nexthop for a P2MP + LSP can be represented in the nexthop grammar as a + (P2MP LSP identifier) or a replication list ( Section 7.2.2) of + , with each tunnel encap representing a single mpls + downstream nexthop. + +7.4. Solving optimized exit control In case of optimized exit control, a controller wants to control the edge device (and optionally control the outgoing interface on that edge device) that is used by a server to send traffic out. This can be easily achieved by having the controller program the edge router (Eg. 192.0.2.10) and the server along the following lines: Server: ::= ( ) ::= <198.51.100.1/16> - ( ) ( ) + ( ) ::- <198.51.100.1/16> - ( <192.0.2.10> ) ( <100>) + ( <192.0.2.10> ) Edge Router: ::= ::= ( <100>) In the above case, the label 100 identifies the egress interface on the edge router. 8. RIB operations at scale @@ -901,41 +992,53 @@ 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 12.2. Informative References [I-D.atlas-i2rs-problem-statement] Atlas, A., Nadeau, T., and D. Ward, "Interface to the Routing System Problem Statement", - draft-atlas-i2rs-problem-statement-00 (work in progress), - February 2013. + draft-atlas-i2rs-problem-statement-01 (work in progress), + July 2013. [I-D.hares-i2rs-use-case-vn-vc] Hares, S., "Use Cases for Virtual Connections on Demand (VCoD) and Virtual Network on Demand using Interface to Routing System", draft-hares-i2rs-use-case-vn-vc-00 (work in progress), February 2013. [I-D.white-i2rs-use-case] White, R., Hares, S., and R. Fernando, "Use Cases for an Interface to the Routing System", draft-white-i2rs-use-case-00 (work in progress), February 2013. + [RFC3443] Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing + in Multi-Protocol Label Switching (MPLS) Networks", + RFC 3443, January 2003. + [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. + [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. + Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", + RFC 4915, June 2007. + [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous System Confederations for BGP", RFC 5065, August 2007. + [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi + Topology (MT) Routing in Intermediate System to + Intermediate Systems (IS-ISs)", RFC 5120, February 2008. + [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax Used to Form Encoding Rules in Various Routing Protocol Specifications", RFC 5511, April 2009. Authors' Addresses Nitin Bahadur (editor) Juniper Networks, Inc. 1194 N. Mathilda Avenue Sunnyvale, CA 94089 @@ -952,10 +1055,15 @@ US Phone: +1 408 745 2000 Email: ronf@juniper.net URI: www.juniper.net Sriganesh Kini Ericsson Email: sriganesh.kini@ericsson.com + + Jan Medved + Cisco + + Email: jmedved@cisco.com