draft-nitinb-i2rs-rib-info-model-01.txt   draft-nitinb-i2rs-rib-info-model-02.txt 
Network Working Group N. Bahadur, Ed. Network Working Group N. Bahadur, Ed.
Internet-Draft R. Folkes, Ed. Internet-Draft R. Folkes, Ed.
Intended status: Informational Juniper Networks, Inc. Intended status: Informational Juniper Networks, Inc.
Expires: January 16, 2014 S. Kini Expires: February 22, 2014 S. Kini
Ericsson Ericsson
J. Medved J. Medved
Cisco Cisco
July 15, 2013 August 21, 2013
Routing Information Base Info Model Routing Information Base Info Model
draft-nitinb-i2rs-rib-info-model-01 draft-nitinb-i2rs-rib-info-model-02
Abstract Abstract
Routing and routing functions in enterprise and carrier networks are Routing and routing functions in enterprise and carrier networks are
typically performed by network devices (routers and switches) using a typically performed by network devices (routers and switches) using a
routing information base (RIB). Protocols and configuration push routing information base (RIB). Protocols and configuration push
data into the RIB and the RIB manager install state into the data into the RIB and the RIB manager install state into the
hardware; for packet forwarding. This draft specifies an information hardware; for packet forwarding. This draft specifies an information
model for the RIB to enable defining a standardized data model. Such 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 a data model can be used to define an interface to the RIB from an
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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 January 16, 2014. This Internet-Draft will expire on February 22, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Conventions used in this document . . . . . . . . . . . . 6 1.1. Conventions used in this document . . . . . . . . . . . . 6
2. RIB data . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. RIB data . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1. RIB definition . . . . . . . . . . . . . . . . . . . . . . 6 2.1. RIB definition . . . . . . . . . . . . . . . . . . . . . . 6
2.2. Routing tables . . . . . . . . . . . . . . . . . . . . . . 7 2.2. Routing instance . . . . . . . . . . . . . . . . . . . . . 7
2.3. Route . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3. Route . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4. Nexthop . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4. Nexthop . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.1. Nexthop types . . . . . . . . . . . . . . . . . . . . 10 2.4.1. Nexthop types . . . . . . . . . . . . . . . . . . . . 12
2.4.2. Nexthop list attributes . . . . . . . . . . . . . . . 11 2.4.2. Nexthop list attributes . . . . . . . . . . . . . . . 13
2.4.3. Nexthop content . . . . . . . . . . . . . . . . . . . 11 2.4.3. Nexthop content . . . . . . . . . . . . . . . . . . . 14
2.4.4. Nexthop attributes . . . . . . . . . . . . . . . . . . 12 2.4.4. Nexthop attributes . . . . . . . . . . . . . . . . . . 14
2.4.5. Nexthop vendor attributes . . . . . . . . . . . . . . 13 2.4.5. Nexthop vendor attributes . . . . . . . . . . . . . . 15
2.4.6. Special nexthops . . . . . . . . . . . . . . . . . . . 13 2.4.6. Special nexthops . . . . . . . . . . . . . . . . . . . 15
3. Reading from the RIB . . . . . . . . . . . . . . . . . . . . . 14 3. Reading from the RIB . . . . . . . . . . . . . . . . . . . . . 16
4. Writing to the RIB . . . . . . . . . . . . . . . . . . . . . . 14 4. Writing to the RIB . . . . . . . . . . . . . . . . . . . . . . 16
5. Events and Notifications . . . . . . . . . . . . . . . . . . . 14 5. Events and Notifications . . . . . . . . . . . . . . . . . . . 16
6. RIB grammar . . . . . . . . . . . . . . . . . . . . . . . . . 15 6. RIB grammar . . . . . . . . . . . . . . . . . . . . . . . . . 17
7. Using the RIB grammar . . . . . . . . . . . . . . . . . . . . 17 7. Using the RIB grammar . . . . . . . . . . . . . . . . . . . . 19
7.1. Using route preference and metric . . . . . . . . . . . . 18 7.1. Using route preference and metric . . . . . . . . . . . . 20
7.2. Using different nexthops types . . . . . . . . . . . . . . 18 7.2. Using different nexthops types . . . . . . . . . . . . . . 20
7.2.1. Tunnel nexthops . . . . . . . . . . . . . . . . . . . 18 7.2.1. Tunnel nexthops . . . . . . . . . . . . . . . . . . . 20
7.2.2. Replication lists . . . . . . . . . . . . . . . . . . 18 7.2.2. Replication lists . . . . . . . . . . . . . . . . . . 20
7.2.3. Weighted lists . . . . . . . . . . . . . . . . . . . . 19 7.2.3. Weighted lists . . . . . . . . . . . . . . . . . . . . 21
7.2.4. Protection lists . . . . . . . . . . . . . . . . . . . 19 7.2.4. Protection lists . . . . . . . . . . . . . . . . . . . 21
7.2.5. Nexthop chains . . . . . . . . . . . . . . . . . . . . 20 7.2.5. Nexthop chains . . . . . . . . . . . . . . . . . . . . 22
7.2.6. Lists of lists . . . . . . . . . . . . . . . . . . . . 20 7.2.6. Lists of lists . . . . . . . . . . . . . . . . . . . . 22
7.3. Performing multicast . . . . . . . . . . . . . . . . . . . 20 7.3. Performing multicast . . . . . . . . . . . . . . . . . . . 22
7.4. Solving optimized exit control . . . . . . . . . . . . . . 21 7.4. Solving optimized exit control . . . . . . . . . . . . . . 23
8. RIB operations at scale . . . . . . . . . . . . . . . . . . . 21 8. RIB operations at scale . . . . . . . . . . . . . . . . . . . 23
8.1. RIB reads . . . . . . . . . . . . . . . . . . . . . . . . 22 8.1. RIB reads . . . . . . . . . . . . . . . . . . . . . . . . 24
8.2. RIB writes . . . . . . . . . . . . . . . . . . . . . . . . 22 8.2. RIB writes . . . . . . . . . . . . . . . . . . . . . . . . 24
8.3. RIB events and notifications . . . . . . . . . . . . . . . 22 8.3. RIB events and notifications . . . . . . . . . . . . . . . 24
9. Security Considerations . . . . . . . . . . . . . . . . . . . 22 9. Security Considerations . . . . . . . . . . . . . . . . . . . 24
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 24
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1. Normative References . . . . . . . . . . . . . . . . . . . 23 12.1. Normative References . . . . . . . . . . . . . . . . . . . 25
12.2. Informative References . . . . . . . . . . . . . . . . . . 23 12.2. Informative References . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction 1. Introduction
Routing and routing functions in enterprise and carrier networks are Routing and routing functions in enterprise and carrier networks are
traditionally performed in network devices. Traditionally routers traditionally performed in network devices. Traditionally routers
run routing protocols and the routing protocols (along with static run routing protocols and the routing protocols (along with static
config) populates the Routing information base (RIB) of the router. config) populates the Routing information base (RIB) of the router.
The RIB is managed by the RIB manager and it provides a north-bound 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 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 into the RIB. The RIB manager consults the RIB and decides how to
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A programmatic interface to the RIB involves 2 types of operations - A programmatic interface to the RIB involves 2 types of operations -
reading what's in the RIB and adding/modifying/deleting contents of 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 the RIB. [I-D.white-i2rs-use-case] lists various use-cases which
require read and/or write manipulation of the RIB. require read and/or write manipulation of the RIB.
In order to understand what is in a router's RIB, methods like per- 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. protocol SNMP MIBs and show output screen scraping are being used.
These methods are not scalable, since they are client pull mechanisms These methods are not scalable, since they are client pull mechanisms
and not proactive push (from the router) mechanisms. Screen scraping and not proactive push (from the router) mechanisms. Screen scraping
is error prone (since output can change) and vendor dependent. is error prone (since the output format can change) and vendor
Building a RIB from per-protocol MIBs is error prone since the MIB dependent. Building a RIB from per-protocol MIBs is error prone
data represents protocol data and not the exact information that went since the MIB data represents protocol data and not the exact
into the RIB. Thus, just getting read-only RIB information from a information that went into the RIB. Thus, just getting read-only RIB
router is a hard task. information from a router is a hard task.
Adding content to the RIB from an external entity can be done today Adding content to the RIB from an external entity can be done today
using static configuration support provided by router vendors. using static configuration support provided by router vendors.
However the mix of what can be modified in the RIB varies from vendor However the mix of what can be modified in the RIB varies from vendor
to vendor and the way of configuring it is also vendor dependent. to vendor and the way of configuring it is also vendor dependent.
This makes it hard for an external entity to program a multi-vendor This makes it hard for an external entity to program a multi-vendor
network in a consistent and vendor independent way. network in a consistent and vendor independent way.
The purpose of this draft is to specify an information model for the The purpose of this draft is to specify an information model for the
RIB. Using the information model, one can build a detailed data 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 model for the RIB. And that data model could then be used by an
external entity to program a router. external entity to program a network device.
The rest of this document is organized as follows. Section 2.1 goes The rest of this document is organized as follows. Section 2 goes
into the details of what constitutes and can be programmed in a RIB. into the details of what constitutes and can be programmed in a RIB.
Section 5 provides a high-level view of the events and notifications Guidelines for reading and writing the RIB are provided in Section 3
going from a network device to an external entity, to update the and Section 4 respectively. Section 5 provides a high-level view of
external entity on asynchronous events. The RIB grammar is specified the events and notifications going from a network device to an
in Section 6. Examples of using the RIB grammar are shown in external entity, to update the external entity on asynchronous
Section 7. events. The RIB grammar is specified in Section 6. Examples of
using the RIB grammar are shown in Section 7. Section 8 covers
considerations for performing RIB operations at scale.
1.1. Conventions used in this document 1.1. 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 [RFC2119]. document are to be interpreted as described in [RFC2119].
2. RIB data 2. RIB data
This section describes the details of a RIB. It makes forward This section describes the details of a RIB. It makes forward
references to objects in the RIB grammar (Section 6). references to objects in the RIB grammar (Section 6). A high-level
description of the RIB contents is as shown below.
routing-instance
| |
| |
0..N | | 1..N
| |
interface(s) RIB(s)
|
|
| 0..N
route(s)
2.1. RIB definition 2.1. RIB definition
A RIB is a logical construct controlled by an external entity. A RIB A RIB is an entity that contains routes. A RIB is identified by its
contains one or more routing instances. On a network device, a RIB name and a RIB is contained within a routing instance (Section 2.2).
is uniquely identified by its name. A routing instance can be in The name MUST be unique within a routing instance. All routes in a
only 1 RIB. A routing instance, in the context of the RIB given RIB MUST be of the same type (e.g. IPv4). Each RIB MUST
information model, is a collection of routing tables, interfaces, and belong to some routing instance.
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 A RIB can be tagged with a MULTI_TOPOLOGY_ID. If a routing instance
instance has control over. The routing tables specify how incoming is divided into multiple logical topologies, then the multi-topology
traffic is to be forwarded. And the routing parameters control the field is used to distinguish one topology from the other, so as to
information in the routing tables. The intersection set of keep routes from one topology independent of routes from another
interfaces of 2 routing instances MUST be the null set. In other topology.
words, an interface should not be present in 2 routing instances.
Thus a routing instance describes the routing information and If a routing instance contains multiple RIBs of the same type (e.g.
parameters across a set of interfaces. IPv4), then a MULTI_TOPOLOGY_ID MUST be associated with each such
RIB. Multiple RIBs 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
RIBs of the same type.
Each RIB can be optionally associated with a ENABLE_IP_RPF_CHECK
attribute that enables Reverse path forwarding (RPF) checks on all IP
routes in that RIB. 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.
2.2. Routing instance
A routing instance, in the context of the RIB information model, is a
collection of RIBs, 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 are associated with
this routing instance. The RIBs specify how incoming traffic is to
be forwarded. And the routing parameters control the information in
the RIBs. The intersection set of interfaces of 2 routing instances
SHOULD be the null set. In other words, an interface MUST 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. A routing instance MUST contain the following mandatory fields.
o INSTANCE_NAME: A routing instance is identified by its name, o INSTANCE_NAME: A routing instance is identified by its name,
INSTANCE_NAME. INSTANCE_NAME. This SHOULD be unique across all routing instances
o INSTANCE_DISTINGUISHER: Each routing instance must have a unique in a given network device.
o INSTANCE_DISTINGUISHER: Each routing instance MUST have a
distinguisher associated with it. It enables one to distinguish distinguisher associated with it. It enables one to distinguish
routes across routing instances. The route distinguisher SHOULD routes across routing instances. The route distinguisher MUST be
be unique across all routing instances in a given network device. unique across all routing instances in a given network device.
How the INSTANCE_DISTINGUISHER is allocated and kept unique is How the INSTANCE_DISTINGUISHER is allocated and kept unique is
outside the scope of this document. The instance distinguisher outside the scope of this document. The instance distinguisher
maps well to BGP route-distinguisher for virtual private networks maps well to BGP route-distinguisher for virtual private networks
(VPNs). However, the same concept can be used for other use-cases (VPNs). However, the same concept can be used for other use-cases
as well. as well.
o routing-table-list: This is the list of routing tables associated
with this routing instance. Each routing instance can have o rib-list: This is the list of RIBs associated with this routing
multiple tables to represent routes of different types. For instance. Each routing instance can have multiple RIBs to
example, one would put IPv4 routes in one table and MPLS routes in represent routes of different types. For example, one would put
another table. IPv4 routes in one RIB and MPLS routes in another RIB.
A routing instance MAY contain the following optional fields. A routing instance MAY contain the following optional fields.
o interface-list: This represents the list of interfaces in this o interface-list: This represents the list of interfaces associated
routing instance. The interface list helps constrain the with this routing instance. The interface list helps constrain
boundaries of packet forwarding. Packets coming on these the boundaries of packet forwarding. Packets coming on these
interfaces are directly associated with the given routing interfaces are directly associated with the given routing
instance. The interface list contains a list of identifiers, with instance. The interface list contains a list of identifiers, with
each identifier uniquely identifying an interface. each identifier uniquely identifying an interface.
o ROUTER_ID: The router-id field identifies the router. This field o ROUTER_ID: The router-id field identifies the network device in
control plane interactions with other network devices. This field
is to be used if one wants to virtualize a physical router into is to be used if one wants to virtualize a physical router into
multiple virtual routers. Each virtual router will have a unique multiple virtual routers. Each virtual router MUST have a unique
router-id. router-id. ROUTER_ID MUST be unique across all network devices in
o ISO_SYSTEM_ID: For IS-IS to operate on a router, a system a given domain.
identifier is needed. This represents the same. o as-data: This is an identifier of the administrative domain to
o as-data: The as-data fields is used when the routes in this which the routing instance belongs. The as-data fields is used
instance are to be tagged with certain autonomous system (AS) when the routes in this instance are to be tagged with certain
characteristics. The RIB manager can use AS length as one of the autonomous system (AS) characteristics. The RIB manager can use
parameters for making path selection. as-data consists of a AS AS length as one of the parameters for making route selection. as-
number and an optional Confederation AS number ([RFC5065]). data consists of a AS number and an optional Confederation AS
number ([RFC5065]).
2.2. Routing tables 2.3. Route
A routing table is an entity that contains routes. A routing table A route is essentially a match condition and an action following the
is identified by its name. The name MUST be unique within a RIB. match. The match condition specifies the kind of route (IPv4, MPLS,
All routes in a given routing table MUST be of the same type (e.g. etc.) and the set of fields to match on. Figure 2 represents the
IPv4). Each routing table MUST belong to some routing instance. overall contents of a route.
A routing table can be tagged with a MULTI_TOPOLOGY_ID. If a routing artwork
instance is divided into multiple logical topologies, then the multi- route
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. Multiple tables are useful when describing multiple topology | | |
IGP (Interior Gateway Protocol) networks (see [RFC4915] and [RFC5120] 0..N | | | 0..N
). 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 route-attributes match nexthop-list
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.
2.3. Route |
|
+-------+-------+-------+--------+
| | | | |
| | | | |
A route is essentially a match condition and an action following the IPv4 IPv6 MPLS MAC Interface
match. The match condition specifies the kind of route (IPv4, MPLS,
etc.) and the set of fields to match on. This document specifies the Figure 2: Route model
following match types:
This document specifies the following match types:
o IPv4: Match on destination IP in IPv4 header o IPv4: Match on destination IP in IPv4 header
o IPv6: Match on destination IP in IPv6 header o IPv6: Match on destination IP in IPv6 header
o MPLS: Match on a MPLS tag o MPLS: Match on a MPLS tag
o MAC: Match on ethernet destination addresses o MAC: Match on ethernet destination addresses
o Interface: Match on incoming interface of packet o Interface: Match on incoming interface of packet
o IP multicast: Match on (S, G) or (*, G), where S and G are IP o IP multicast: Match on (S, G) or (*, G), where S and G are IP
prefixes prefixes
Each route can have associated with it one or more optional route Each route can have associated with it one or more optional route
attributes. attributes.
o ROUTE_PREFERENCE: This is a numerical value that allows for o ROUTE_PREFERENCE: This is a numerical value that allows for
comparing routes from different protocols. It is also known as comparing routes from different protocols (where static
administrative-distance. The lower the value, the higher the configuration is also considered a protocol for the purpose of
preference. For example there can be an OSPF route for this field). It is also known as administrative-distance. The
192.0.2.1/32 with a preference of 5. If a controller programs a lower the value, the higher the preference. For example there can
route for 192.0.2.1/32 with a preference of 2, then the controller be an OSPF route for 192.0.2.1/32 with a preference of 5. If a
entered route will be preferred by the RIB manager. Preference controller programs a route for 192.0.2.1/32 with a preference of
should be used to dictate behavior. For more examples of 2, then the controller entered route will be preferred by the RIB
preference, see Section 7.1. manager. Preference should be used to dictate behavior. For more
examples of preference, see Section 7.1.
o ROUTE_METRIC: Route preference is used for comparing routes from o ROUTE_METRIC: Route preference is used for comparing routes from
different protocols. Route metric is used for comparing routes different protocols. Route metric is used for comparing routes
learned by the same protocol. If a controller wishes to program 2 learned by the same protocol. If a controller wishes to program 2
or more routes to the same destination, then it can use the metric or more routes to the same destination, then it can use the metric
field to disambiguate the 2 routes. For more examples, see field to disambiguate the 2 routes. For more examples, see
Section 7.1. Section 7.1.
o LOCAL_ONLY: This is a boolean value. If this is present, then it o LOCAL_ONLY: This is a boolean value. If this is present, then it
means that this route should not be exported into other RIBs or means that this route should not be exported into other RIBs or
other route tables. other RIBs.
o rpf-check-interface: Reverse path forwarding (RPF) check is used o rpf-check-interface: Reverse path forwarding (RPF) check is used
to prevent spoofing and limit malicious traffic. For IP packets, to prevent spoofing and limit malicious traffic. For IP packets,
the IP source address is looked up and the rpf-check-interface the IP source address is looked up and the rpf-check-interface
associated with the route for that IP source address is found. If associated with the route for that IP source address is found. If
the incoming IP packet's interface matches one of the rpf-check- the incoming IP packet's interface matches one of the rpf-check-
interfaces, then the IP packet is forwarded based on its IP interfaces, then the IP packet is forwarded based on its IP
destination address; otherwise, the IP packet is discarded. For destination address; otherwise, the IP packet is discarded. For
MPLS routes, there is no source address to be looked up, so the MPLS routes, there is no source address to be looked up, so the
usage is slightly different. For an MPLS route, a packet with the usage is slightly different. For an MPLS route, a packet with the
specified MPLS label will only be forwarded if it is received on specified MPLS label will only be forwarded if it is received on
one of the interfaces specified by the rpf-check-interface. If no one of the interfaces specified by the rpf-check-interface. If no
rpf-check-interface is specified, then matching packets are no rpf-check-interface is specified, then matching packets are no
subject to this check. This field overrides the subject to this check. This field overrides the
ENABLE_IP_RPF_CHECK flag on the routing table and interfaces ENABLE_IP_RPF_CHECK flag on the RIB and interfaces provided in
provided in this list are used for doing the RPF check. this list are used for doing the RPF check.
o as-path: A route can have an as-path associated with it to o as-path: A route can have an as-path associated with it to
indicate which set of autonomous systems has to be traversed to indicate which set of autonomous systems has to be traversed to
reach the final destination. The as-path attribute can be used by reach the final destination. The as-path attribute can be used by
the RIB manager in multiple ways. The RIB manager can choose the RIB manager in multiple ways. The RIB manager can choose
paths with lower as-path length. Or the RIB manager can choose to paths with lower as-path length. Or the RIB manager can choose to
not install paths going via a particular AS. How exactly the RIB not install paths going via a particular AS. How exactly the RIB
manager uses the as-path is outside the scope of this document. manager uses the as-path is outside the scope of this document.
For details of how the as-path is formed, see Section 5.1.2 of For details of how the as-path is formed, see Section 5.1.2 of
[RFC4271] and Section 3 of [RFC5065]. [RFC4271] and Section 3 of [RFC5065].
o route-vendor-attributes: Vendors can specify vendor-specific o route-vendor-attributes: Vendors can specify vendor-specific
skipping to change at page 9, line 51 skipping to change at page 11, line 11
resolve the nexthop, then the nexthop stays in unresolved state and resolve the nexthop, then the nexthop stays in unresolved state and
is NOT a candidate for installation in the FIB. Future RIB events is NOT a candidate for installation in the FIB. Future RIB events
can cause a nexthop to get resolved (like that IP address being can cause a nexthop to get resolved (like that IP address being
advertised by an IGP neighbor). advertised by an IGP neighbor).
The RIB information model allows an external entity to program The RIB information model allows an external entity to program
nexthops that may be unresolved initially. Whenever a unresolved nexthops that may be unresolved initially. Whenever a unresolved
nexthop gets resolved, the RIB manager will send a notification of nexthop gets resolved, the RIB manager will send a notification of
the same (see Section 5 ). the same (see Section 5 ).
The overall structure and usage of a nexthop is as shown in the
figure below.
route
|
| 0..N
nexthop-list
|
+------------------+------------------+
1..N | |
| |
nexthop-list-member special-nexthop
|
|
nexthop-chain
|
1..N |
nexthop
|
+------- nexthop-attributes
|
|
+--------+------+------------------+------------------+
| | | |
| | | |
nexthop-id egress-interface logical-tunnel tunnel-encap
Nexthops can be identified by an identifier to create a level of Nexthops can be identified by an identifier to create a level of
indirection. The identifier is set by the RIB manager and returned indirection. The identifier is set by the RIB manager and returned
to the external entity on request. The RIB data-model SHOULD support to the external entity on request. The RIB data-model SHOULD support
a way to optionally receive a nexthop identifier for a given nexthop. a way to optionally receive a nexthop identifier for a given nexthop.
For example, one can create a nexthop that points to a BGP peer. The For example, one can create a nexthop that points to a BGP peer. The
returned nexthop identifier can then be used for programming routes returned nexthop identifier can then be used for programming routes
to point to the same nexthop. Given that the RIB manager has created to point to the same nexthop. Given that the RIB manager has created
an indirection for that BGP peer using the nexthop identifier, if the an indirection for that BGP peer using the nexthop identifier, if the
transport path to the BGP peer changes, that change in path will be transport path to the BGP peer changes, that change in path will be
seamless to the external entity and all routes that point to that BGP seamless to the external entity and all routes that point to that BGP
peer will automatically start going over the new transport path. peer will automatically start going over the new transport path.
Nexthop indirection using identifier could be applied to not just Nexthop indirection using identifier could be applied to not just
unicast nexthops, but even to nexthops that contain chains and nested unicast nexthops, but even to nexthops that contain chains and nested
nexthops (Section 2.4.1). nexthops (Section 2.4.1).
skipping to change at page 10, line 33 skipping to change at page 12, line 31
o Tunnel nexthops - pointing to a tunnel o Tunnel nexthops - pointing to a tunnel
o Replication lists - list of nexthops to which to replicate a o Replication lists - list of nexthops to which to replicate a
packet to packet to
o Weighted lists - for load-balancing o Weighted lists - for load-balancing
o Protection lists - for primary/backup paths o Protection lists - for primary/backup paths
o Nexthop chains - for chaining headers, e.g. MPLS label over a GRE o Nexthop chains - for chaining headers, e.g. MPLS label over a GRE
header header
o Lists of lists - recursive application of the above o Lists of lists - recursive application of the above
o Indirect nexthops - pointing to a nexthop identifier o Indirect nexthops - pointing to a nexthop identifier
o Special nexthops - for performing specific well-defined functions o Special nexthops - for performing specific well-defined functions
It is expected that all network devices will have a limit on It is expected that all network devices will have a limit on how many
recursion and not all hardware will be able to support all kinds of levels of lookup can be performed and not all hardware will be able
nexthops. RIB capability negotiation becomes very important for this to support all kinds of nexthops. RIB capability negotiation becomes
reason and a RIB data-model MUST specify a way for an external entity very important for this reason and a RIB data-model MUST specify a
to learn about the network device's capabilities. Examples of when way for an external entity to learn about the network device's
and how to use various kinds of nexthops are shown in Section 7.2. 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 Tunnel nexthops allow an external entity to program static tunnel
headers. There can be cases where the remote tunnel end-point does 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 not support dynamic signaling (e.g. no LDP support on a host) and in
those cases the external entity might want to program the tunnel those cases the external entity might want to program the tunnel
header on both ends of the tunnel. The tunnel nexthop is kept header on both ends of the tunnel. The tunnel nexthop is kept
generic with specifications provided for some commonly used tunnels. generic with specifications provided for some commonly used tunnels.
It is expected that the data-model will model these tunnel types with It is expected that the data-model will model these tunnel types with
complete accuracy. complete accuracy.
skipping to change at page 11, line 45 skipping to change at page 13, line 43
distribution is done is up to the network device and not in the distribution is done is up to the network device and not in the
scope of the document. In other words, traffic should always be scope of the document. In other words, traffic should always be
load-balanced even if there is a failure. After a failure, the load-balanced even if there is a failure. After a failure, the
external entity SHOULD re-program the nexthop list with updated external entity SHOULD re-program the nexthop list with updated
weights so as to get a deterministic behavior among the remaining weights so as to get a deterministic behavior among the remaining
list members. To perform equal load-balancing, one MAY specify a list members. To perform equal load-balancing, one MAY specify a
weight of "0" for all the member nexthops. The value "0" is weight of "0" for all the member nexthops. The value "0" is
reserved for equal load-balancing and if applied, MUST be applied reserved for equal load-balancing and if applied, MUST be applied
to all member nexthops. to all member nexthops.
A nexthop list MAY contain elements that have both
PROTECTION_PREFERENCE and LOAD_BALANCE_WEIGHT set. When both are
set, it means under normal operation the network device should load
balance the traffic over all nexthops with a protection preference of
1. And when all nexthops with a protection preference of 1 are down
(or unavailable), then traffic MUST be load balanced over elements
with protection preference of 2.
2.4.3. Nexthop content 2.4.3. Nexthop content
At the lowest level, a nexthop can point to a: At the lowest level, a nexthop can point to a:
o identifier: This is an identifier returned by the network device o identifier: This is an identifier returned by the network device
representing another nexthop or another nexthop chain. representing another nexthop or another nexthop chain.
o EGRESS_INTERFACE: This represents a physical, logical or virtual o EGRESS_INTERFACE: This represents a physical, logical or virtual
interface on the network device. interface on the network device.
o address: This can be an IP address or MAC address or ISO address. 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 * An optional RIB name can also be specified to indicate the RIB
table in which the address is to be looked up further. One can in which the address is to be looked up further. One can use
use the table name field to direct the packet from one domain the RIB name field to direct the packet from one domain into
into another domain. For example, a MPLS packet coming in on another domain. For example, a MPLS packet coming in on an
an interface would be looked up in a MPLS routing table and the interface would be looked up in a MPLS RIB and the nexthop for
nexthop for that could indicate that we strip the MPLS label that could indicate that we strip the MPLS label and do a
and do a subsequent IPv4 lookup in an IPv4 table. By default subsequent IPv4 lookup in an IPv4 RIB. By default the RIB will
the table will be the same in which the route lookup was be the same in which the route lookup was performed.
performed.
* An optional egress interface can be specified to indicate which * An optional egress interface can be specified to indicate which
interface to send the packet out on. The egress interface is interface to send the packet out on. The egress interface is
useful when the network device contains Ethernet interfaces and useful when the network device contains Ethernet interfaces and
one needs to perform an ARP lookup for the IP packet. one needs to perform an ARP lookup for the IP packet.
o tunnel encap: This can be an encap representing an IP tunnel or o tunnel encap: This can be an encap representing an IP tunnel or
MPLS tunnel or others as defined in this document. An optional MPLS tunnel or others as defined in this document. An optional
egress interface can be specified to indicate which interface to egress interface can be specified to indicate which interface to
send the packet out on. The egress interface is useful when the send the packet out on. The egress interface is useful when the
network device contains Ethernet interfaces and one needs to network device contains Ethernet interfaces and one needs to
perform an ARP lookup for the IP packet. perform an ARP lookup for the IP packet.
o logical tunnel: This can be a MPLS LSP or a GRE tunnel (or others 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 as defined in this document), that is represented by a unique
identifier (E.g. name). identifier (E.g. name).
o ROUTING_TABLE_NAME: This is a routing table that exists in the o RIB_NAME: A nexthop pointing to a RIB indicates that the route
RIB. A nexthop pointing to a table indicates that the route lookup needs to continue in the specified RIB. This is a way to
lookup needs to continue in the specified table. This is a way to
perform chained lookups. perform chained lookups.
2.4.4. Nexthop attributes 2.4.4. Nexthop attributes
Certain information is encoded implicitly in the nexthop and does not Certain information is encoded implicitly in the nexthop and does not
need to be specified by the controller. For example, when a IP need to be specified by the controller. For example, when a IP
packet is forwarded out, the IP TTL is decremented by default. Same packet is forwarded out, the IP TTL is decremented by default. Same
applies for an MPLS packet. Similarly, when an IP packet is sent applies for an MPLS packet. Similarly, when an IP packet is sent
over an ethernet interface, any ARP processing is handled implicitly over an ethernet interface, any ARP processing is handled implicitly
by the network device and does not need to be programmed by an by the network device and does not need to be programmed by an
skipping to change at page 14, line 33 skipping to change at page 16, line 33
RIBs created by that entity. The network device administrator MAY RIBs created by that entity. The network device administrator MAY
allow writes to other RIBs by an external entity through access lists allow writes to other RIBs by an external entity through access lists
on the network device. The details of access lists are outside the on the network device. The details of access lists are outside the
scope of this document. scope of this document.
When writing an object to a RIB, the external entity SHOULD try to When writing an object to a RIB, the external entity SHOULD try to
write all dependencies of the object prior to sending that object. write all dependencies of the object prior to sending that object.
The data-model MUST support requesting identifiers for nexthops and The data-model MUST support requesting identifiers for nexthops and
collecting the identifiers back in the response. collecting the identifiers back in the response.
Route programming in the RIB SHOULD result in a return code that Route programming in the RIB MUST result in a return code that
contains the following attributes: contains the following attributes:
o Installed - Yes/No (Indicates whether the route got installed in o Installed - Yes/No (Indicates whether the route got installed in
the FIB) the FIB)
o Active - Yes/No (Indicates whether a route is fully resolved and o Active - Yes/No (Indicates whether a route is fully resolved and
is a candidate for selection) is a candidate for selection)
o Reason - E.g. Not authorized o Reason - E.g. Not authorized
The data-model MUST specify which objects are modify-able objects. A The data-model MUST specify which objects are modify-able objects. A
modify-able object is one whose contents can be changed without modify-able object is one whose contents can be changed without
having to change objects that depend on it and without affecting any having to change objects that depend on it and without affecting any
data forwarding. To change a non-modifiable object, one will need to data forwarding. To change a non-modifiable object, one will need to
skipping to change at page 15, line 16 skipping to change at page 17, line 16
notifications. A brief list of suggested notifications is as below: notifications. A brief list of suggested notifications is as below:
o Route change notification, with return code as specified in o Route change notification, with return code as specified in
Section 4 Section 4
o Nexthop resolution status (resolved/unresolved) notification o Nexthop resolution status (resolved/unresolved) notification
6. RIB grammar 6. RIB grammar
This section specifies the RIB information model in Routing Backus- This section specifies the RIB information model in Routing Backus-
Naur Form [RFC5511]. Naur Form [RFC5511].
<rib> ::= <RIB_NAME> <routing-instance> [<routing-instance> ...]
<routing-instance> ::= <INSTANCE_NAME> <INSTANCE_DISTINGUISHER> <routing-instance> ::= <INSTANCE_NAME> <INSTANCE_DISTINGUISHER>
[<interface-list>] <routing-table-list> [<interface-list>] <rib-list>
[<ROUTER_ID>] [<ISO_SYSTEM_ID>] [<ROUTER_ID>] [<as-data>]
[<as-data>]
<as-data> ::= <AS_NUMBER> [<CONFEDERATION_AS>] <as-data> ::= <AS_NUMBER> [<CONFEDERATION_AS>]
<interface-list> ::= (<INTERFACE_IDENTIFIER> ...) <interface-list> ::= (<INTERFACE_IDENTIFIER> ...)
<routing-table-list> ::= (<routing-table> ...) <rib-list> ::= (<rib> ...)
<routing-table> ::= <ROUTING_TABLE_NAME> <table-family> <rib> ::= <RIB_NAME> <rib-family>
[<route> ... ] [<MULTI_TOPOLOGY_ID>] [<route> ... ] [<MULTI_TOPOLOGY_ID>]
[ENABLE_IP_RPF_CHECK] [ENABLE_IP_RPF_CHECK]
<table-family> ::= <IPV4_TABLE_FAMILY> | <IPV6_TABLE_FAMILY> | <rib-family> ::= <IPV4_RIB_FAMILY> | <IPV6_RIB_FAMILY> |
<MPLS_TABLE_FAMILY> | <IEEE_MAC_TABLE_FAMILY> <MPLS_RIB_FAMILY> | <IEEE_MAC_RIB_FAMILY>
<route> ::= <match> <nexthop-list> <route> ::= <match> <nexthop-list>
[<route-attributes>] [<route-attributes>]
[<route-vendor-attributes>] [<route-vendor-attributes>]
<match> ::= <ipv4-route> | <ipv6-route> | <mpls-route> | <match> ::= <ipv4-route> | <ipv6-route> | <mpls-route> |
<mac-route> | <interface-route> <mac-route> | <interface-route>
<ipv4-route> ::= <IPV4_ADDRESS> <IPV4_PREFIX_LENGTH>
[<multicast-source-ipv4-address>] <ipv4-route> ::= <ipv4-prefix> [<multicast-source-ipv4-address>]
<ipv6-route> ::= <IPV6_ADDRESS> <IPV6_PREFIX_LENGTH> <ipv4-prefix> ::= <IPV4_ADDRESS> <IPV4_ADDRESS_LENGTH>
[<multicast-source-ipv6-address>]
<ipv6-route> ::= <ipv6-prefix> [<multicast-source-ipv6-address>]
<ipv6-prefix> ::= <IPV6_ADDRESS> <IPV6_PREFIX_LENGTH>
<mpls-route> ::= <MPLS> <MPLS_LABEL> <mpls-route> ::= <MPLS> <MPLS_LABEL>
<mac-route> ::= <IEEE_MAC> ( <MAC_ADDRESS> ) <mac-route> ::= <IEEE_MAC> ( <MAC_ADDRESS> )
<interface-route> ::= <INTERFACE> <INTERFACE_IDENTIFIER> <interface-route> ::= <INTERFACE> <INTERFACE_IDENTIFIER>
<multicast-source-ipv4-address> ::= <IPV4_ADDRESS> <multicast-source-ipv4-address> ::= <IPV4_ADDRESS>
<IPV4_PREFIX_LENGTH> <IPV4_PREFIX_LENGTH>
<multicast-source-ipv6-address> ::= <IPV6_ADDRESS> <multicast-source-ipv6-address> ::= <IPV6_ADDRESS>
<IPV6_PREFIX_LENGTH> <IPV6_PREFIX_LENGTH>
<route-attributes> ::= [<ROUTE_PREFERENCE>] [<ROUTE_METRIC>] <route-attributes> ::= [<ROUTE_PREFERENCE>] [<ROUTE_METRIC>]
[<LOCAL_ONLY>] [<LOCAL_ONLY>]
[<address-family-route-attributes>] [<address-family-route-attributes>]
<address-family-route-attributes> ::= <ip-route-attributes> | <address-family-route-attributes> ::= <ip-route-attributes> |
<mpls-route-attributes> | <mpls-route-attributes> |
<ethernet-route-attributes> <ethernet-route-attributes>
skipping to change at page 16, line 37 skipping to change at page 18, line 39
([<nexthop-list-member> ... ] <nexthop-list> )) ([<nexthop-list-member> ... ] <nexthop-list> ))
<nexthop-list-member> ::= (<nexthop-chain> | <nexthop-list-member> ::= (<nexthop-chain> |
<nexthop-chain-identifier> ) <nexthop-chain-identifier> )
[<nexthop-list-member-attributes>] [<nexthop-list-member-attributes>]
<nexthop-list-member-attributes> ::= [<PROTECTION_PREFERENCE>] <nexthop-list-member-attributes> ::= [<PROTECTION_PREFERENCE>]
[<LOAD_BALANCE_WEIGHT>] [<LOAD_BALANCE_WEIGHT>]
<nexthop-chain> ::= (<nexthop> ...) <nexthop-chain> ::= (<nexthop> ...)
<nexthop-chain-identifier> ::= <NEXTHOP_NAME> | <NEXTHOP_ID> <nexthop-chain-identifier> ::= <NEXTHOP_NAME> | <NEXTHOP_ID>
<nexthop> ::= (<nexthop-identifier> | <EGRESS_IDENTIFIER> | <nexthop> ::= (<nexthop-identifier> | <EGRESS_INTERFACE> |
(<nexthop-address> (<nexthop-address>
([<ROUTING_TABLE_NAME>] | [<EGRESS_INTERFACE>])) | ([<RIB_NAME>] | [<EGRESS_INTERFACE>])) |
(<tunnel-encap> [<EGRESS_INTERFACE>]) | (<tunnel-encap> [<EGRESS_INTERFACE>]) |
<logical-tunnel> | <logical-tunnel> |
<ROUTING_TABLE_NAME>) <RIB_NAME>)
[<nexthop-attributes>] [<nexthop-attributes>]
[<nexthop-vendor-attributes>] [<nexthop-vendor-attributes>]
<nexthop-identifier> ::= <NEXTHOP_NAME> | <NEXTHOP_ID> <nexthop-identifier> ::= <NEXTHOP_NAME> | <NEXTHOP_ID>
<nexthop-address> ::= (<IPv4> <ipv4-address>) | <nexthop-address> ::= (<IPv4> <ipv4-address>) |
(<IPV6> <ipv6-address>) | (<IPV6> <ipv6-address>) |
(<IEEE_MAC> <IEEE_MAC_ADDRESS>) | (<IEEE_MAC> <IEEE_MAC_ADDRESS>) |
(<ISO> <ISO_ADDRESS>) (<ISO> <ISO_ADDRESS>)
<special-nexthop> ::= <DISCARD> | <DISCARD_WITH_ERROR> | <special-nexthop> ::= <DISCARD> | <DISCARD_WITH_ERROR> |
(<RECEIVE> [<COS_VALUE>] [<rate-limiter>]) (<RECEIVE> [<COS_VALUE>] [<rate-limiter>])
<rate-limiter> ::= <> <rate-limiter> ::= <>
<logical-tunnel> ::= <tunnel-type> <TUNNEL_NAME> <logical-tunnel> ::= <tunnel-type> <TUNNEL_NAME>
<tunnel-type> ::= <IP> | <MPLS> | <GRE> | <VxLAN> | <NVGRE> <tunnel-type> ::= <IP> | <MPLS> | <GRE> | <VxLAN> | <NVGRE>
<tunnel-encap> ::= (<IPV4> <ipv4-header>) | <tunnel-encap> ::= (<IPV4> <ipv4-header>) |
(<IPV6> <ipv6-header>) | (<IPV6> <ipv6-header>) |
(<MPLS> <mpls-header>) | (<MPLS> <mpls-header>) |
skipping to change at page 18, line 12 skipping to change at page 20, line 12
This section provides examples on using objects in the RIB grammar This section provides examples on using objects in the RIB grammar
and examples to program certain use cases. and examples to program certain use cases.
7.1. Using route preference and metric 7.1. Using route preference and metric
Using route preference one can pre-install protection paths in the Using route preference one can pre-install protection paths in the
network. For example, if OSPF has a route preference of 10, then one network. For example, if OSPF has a route preference of 10, then one
can install a route with route preference of 20 to the same can install a route with route preference of 20 to the same
destination. The OSPF route will get precedence and will get destination. The OSPF route will get precedence and will get
installed in the FIB. When the OSPF route goes away (for any installed in the FIB. When the OSPF route goes away (for any
reason), the protection path will get installed in the FIB. reason), the protection path will get installed in the FIB. If the
hardware supports it, then the RIB manager can choose to pre-install
both routes, with the OSPF nexthop getting preference.
Route preference can also be used to prevent denial of service Route preference can also be used to prevent denial of service
attacks by installing routes with the best preference, which either attacks by installing routes with the best preference, which either
drops the offending traffic or routes it to some monitoring/analysis drops the offending traffic or routes it to some monitoring/analysis
station. Since the routes are installed with the best preference, station. Since the routes are installed with the best preference,
they will supersede any route installed by any other protocol. they will supersede any route installed by any other protocol.
Route metric is used to disambiguate between 2 or more routes to the Route metric is used to disambiguate between 2 or more routes to the
same destination with the same preference and in the same route same destination with the same preference and in the same RIB. One
table. One usage of this is to install 2 routes, each with a usage of this is to install 2 routes, each with a different nexthop.
different nexthop. The preferred nexthop is given a better metric The preferred nexthop is given a better metric than the other one.
than the other one. This results in traffic being forwarded to the This results in traffic being forwarded to the preferred nexthop. If
preferred nexthop. If the preferred nexthop fails, then the RIB the preferred nexthop fails, then the RIB manager will automatically
manager will automatically install a route to the other nexthop. install a route to the other nexthop.
7.2. Using different nexthops types 7.2. Using different nexthops types
The RIB grammar allows one to create a variety of nexthops. This The RIB grammar allows one to create a variety of nexthops. This
section describes uses for certain types of nexthops. section describes uses for certain types of nexthops.
7.2.1. Tunnel nexthops 7.2.1. Tunnel nexthops
A tunnel nexthop points to a tunnel of some kind. Traffic that goes A tunnel nexthop points to a tunnel of some kind. Traffic that goes
over the tunnel gets encapsulated with the tunnel encap. Tunnel over the tunnel gets encapsulated with the tunnel encap. Tunnel
skipping to change at page 19, line 16 skipping to change at page 21, line 16
The above can be derived from the grammar as follows: The above can be derived from the grammar as follows:
<nexthop-list> ::= <nexthop-list-member> [<nexthop-list-member> ...] <nexthop-list> ::= <nexthop-list-member> [<nexthop-list-member> ...]
<nexthop-list> ::= <nexthop-chain> [<nexthop-chain> ...] <nexthop-list> ::= <nexthop-chain> [<nexthop-chain> ...]
<nexthop-list> ::= <nexthop> [ <nexthop> ... ] <nexthop-list> ::= <nexthop> [ <nexthop> ... ]
7.2.3. Weighted lists 7.2.3. Weighted lists
A weighted list is used to load-balance traffic among a set of A weighted list is used to load-balance traffic among a set of
nexthops. A weighted list is very similar to a replication list, nexthops. From a modeling perspective, a weighted list is very
with the difference that each member nexthop MUST have a similar to a replication list, with the difference that each member
LOAD_BALANCE_WEIGHT associated with it. nexthop MUST have a LOAD_BALANCE_WEIGHT associated with it.
A weighted list (at the simplest level) can be represented as: A weighted list (at the simplest level) can be represented as:
<nexthop-list> ::= (<nexthop> <LOAD_BALANCE_WEIGHT>) <nexthop-list> ::= (<nexthop> <LOAD_BALANCE_WEIGHT>)
[(<nexthop> <LOAD_BALANCE_WEIGHT>)... ] [(<nexthop> <LOAD_BALANCE_WEIGHT>)... ]
The above can be derived from the grammar as follows: The above can be derived from the grammar as follows:
<nexthop-list> ::= <nexthop-list-member> [<nexthop-list-member> ...] <nexthop-list> ::= <nexthop-list-member> [<nexthop-list-member> ...]
<nexthop-list> ::= (<nexthop-chain> <nexthop-list-member-attributes>) <nexthop-list> ::= (<nexthop-chain> <nexthop-list-member-attributes>)
skipping to change at page 20, line 39 skipping to change at page 22, line 39
<nexthop-list> ::= <tunnel-encap> (<nexthop> [ <nexthop> ...]) <nexthop-list> ::= <tunnel-encap> (<nexthop> [ <nexthop> ...])
<nexthop-list> ::= <tunnel-encap> (<tunnel-encap>) <nexthop-list> ::= <tunnel-encap> (<tunnel-encap>)
<nexthop-list> ::= (<MPLS> <mpls-header>) (<GRE> <gre-header>) <nexthop-list> ::= (<MPLS> <mpls-header>) (<GRE> <gre-header>)
7.2.6. Lists of lists 7.2.6. Lists of lists
Lists of lists is a complex construct. One example of usage of such Lists of lists is a complex construct. One example of usage of such
a construct is to replicate traffic to multiple destinations, with a construct is to replicate traffic to multiple destinations, with
high availability. In other words, for each destination you have a high availability. In other words, for each destination you have a
primary and backup nexthop (replication list) to ensure there is no 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 traffic drop in case of a failure. So the outer list is a protection
destinations and the inner lists are replication lists of primary/ list and the inner lists are replication lists of primary/backup
backup nexthops. nexthops.
7.3. Performing multicast 7.3. Performing multicast
IP multicast involves matching a packet on (S, G) or (*, G), where IP multicast involves matching a packet on (S, G) or (*, G), where
both S (source) and G (group) are IP prefixes. Following the match, both S (source) and G (group) are IP prefixes. Following the match,
the packet is replicated to one or more recipients. How the the packet is replicated to one or more recipients. How the
recipients subscribe to the multicast group is outside the scope of recipients subscribe to the multicast group is outside the scope of
this document. this document.
In PIM-based multicast, the packets are IP forwarded on an IP In PIM-based multicast, the packets are IP forwarded on an IP
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7.4. Solving optimized exit control 7.4. Solving optimized exit control
In case of optimized exit control, a controller wants to control the In case of optimized exit control, a controller wants to control the
edge device (and optionally control the outgoing interface on that edge device (and optionally control the outgoing interface on that
edge device) that is used by a server to send traffic out. This can 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 be easily achieved by having the controller program the edge router
(Eg. 192.0.2.10) and the server along the following lines: (Eg. 192.0.2.10) and the server along the following lines:
Server: Server:
<route> ::= <routing-table-name> <match> (<edge-router> <route> ::= <rib-name> <match> (<edge-router>
<edge-router-interface>) <edge-router-interface>)
<route> ::= <routing-table-name> <198.51.100.1/16> <route> ::= <rib-name> <198.51.100.1/16>
(<MPLS> <mpls-header>) (<MPLS> <mpls-header>)
(<GRE> <gre-header>) (<GRE> <gre-header>)
<route> ::- <routing-table-name> <198.51.100.1/16> <route> ::- <rib-name> <198.51.100.1/16>
(<MPLS_PUSH> <100>) (<MPLS_PUSH> <100>)
(<GRE> <192.0.2.10> <GRE_PROTOCOL_MPLS>) (<GRE> <192.0.2.10> <GRE_PROTOCOL_MPLS>)
Edge Router: Edge Router:
<route> ::= <mpls-routing-table> <mpls-route> <nexthop> <route> ::= <mpls-rib> <mpls-route> <nexthop>
<route> ::= <mpls-routing-table> (<MPLS> <100>) <interface-10> <route> ::= <mpls-rib> (<MPLS> <100>) <interface-10>
In the above case, the label 100 identifies the egress interface In the above case, the label 100 identifies the egress interface
on the edge router. on the edge router.
8. RIB operations at scale 8. RIB operations at scale
This section discusses the scale requirements for a RIB data-model. This section discusses the scale requirements for a RIB data-model.
The RIB data-model should be able to handle large scale of The RIB data-model should be able to handle large scale of
operations, to enable deployment of RIB applications in large operations, to enable deployment of RIB applications in large
networks. networks.
8.1. RIB reads 8.1. RIB reads
Bulking (grouping of multiple objects in a single message) MUST be Bulking (grouping of multiple objects in a single message) MUST be
supported when a network device sends RIB data to an external entity. supported when a network device sends RIB data to an external entity.
Similarly the data model MUST enable a RIB client to request data in
bulk from a network device.
8.2. RIB writes 8.2. RIB writes
Bulking (grouping of multiple write operations in a single message) Bulking (grouping of multiple write operations in a single message)
MUST be supported when an external entity wants to write to the RIB. MUST be supported when an external entity wants to write to the RIB.
The response from the network device MUST include a return-code for The response from the network device MUST include a return-code for
each write operation in the bulk message. each write operation in the bulk message.
8.3. RIB events and notifications 8.3. RIB events and notifications
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events and/or notifications from the network device to an external events and/or notifications from the network device to an external
entity. On the other hand, due to timing of multiple things entity. On the other hand, due to timing of multiple things
happening at the same time, a network device might have to send happening at the same time, a network device might have to send
multiple events and/or notifications to an external entity. The multiple events and/or notifications to an external entity. The
network device originated event/notification message MUST support network device originated event/notification message MUST support
bulking of multiple events and notifications in a single message. bulking of multiple events and notifications in a single message.
9. Security Considerations 9. Security Considerations
All interactions between a RIB manager and an external entity MUST be All interactions between a RIB manager and an external entity MUST be
authenticated. The RIB manager MUST protect itself against a denial authenticated and authorized. The RIB manager MUST protect itself
of service attack by a rouge external entity, by throttling request against a denial of service attack by a rogue external entity, by
processing. A RIB manager MUST enforce limits on how much data can throttling request processing. A RIB manager MUST enforce limits on
be programmed by an external entity and return error when such a how much data can be programmed by an external entity and return
limit is reached. error when such a limit is reached.
The RIB manager MUST expose a data-model that it implements. An The RIB manager MUST expose a data-model that it implements. An
external agent MUST send requests to the RIB manager that comply with external agent MUST send requests to the RIB manager that comply with
the supported data-model. The data-model MUST specify the behavior the supported data-model. The data-model MUST specify the behavior
of the RIB manager on handling of unsupported data requests. of the RIB manager on handling of unsupported data requests.
10. IANA Considerations 10. IANA Considerations
This document does not generate any considerations for IANA. This document does not generate any considerations for IANA.
11. Acknowledgements 11. Acknowledgements
The authors would like to thank Alia Atlas, Edward Crabbe, Hariharan The authors would like to thank the working group co-chairs and
Ananthakrishnan, Jeff Haas and Ina Minei on their comments and reviewers on their comments and suggestions on this draft. The
suggestions on this draft. The following people contributed to the following people contributed to the design of the RIB model as part
design of the RIB model as part of the I2RS Interim meeting in April of the I2RS Interim meeting in April 2013 - Wes George, Chris
2013 - Wes George, Chris Liljenstolpe, Jeff Tantsura, Sriganesh Kini, Liljenstolpe, Jeff Tantsura, Sriganesh Kini, Susan Hares, Fabian
Susan Hares, Fabian Schneider and Nitin Bahadur. Schneider and Nitin Bahadur.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
12.2. Informative References 12.2. Informative References
[I-D.atlas-i2rs-problem-statement] [I-D.atlas-i2rs-problem-statement]
Atlas, A., Nadeau, T., and D. Ward, "Interface to the Atlas, A., Nadeau, T., and D. Ward, "Interface to the
Routing System Problem Statement", Routing System Problem Statement",
draft-atlas-i2rs-problem-statement-01 (work in progress), draft-atlas-i2rs-problem-statement-02 (work in progress),
July 2013. August 2013.
[I-D.hares-i2rs-use-case-vn-vc] [I-D.hares-i2rs-use-case-vn-vc]
Hares, S., "Use Cases for Virtual Connections on Demand Hares, S., "Use Cases for Virtual Connections on Demand
(VCoD) and Virtual Network on Demand using Interface to (VCoD) and Virtual Network on Demand using Interface to
Routing System", draft-hares-i2rs-use-case-vn-vc-00 (work Routing System", draft-hares-i2rs-use-case-vn-vc-00 (work
in progress), February 2013. in progress), February 2013.
[I-D.white-i2rs-use-case] [I-D.white-i2rs-use-case]
White, R., Hares, S., and R. Fernando, "Use Cases for an White, R., Hares, S., and R. Fernando, "Use Cases for an
Interface to the Routing System", Interface to the Routing System",
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