draft-ietf-idr-flowspec-interfaceset-00.txt   draft-ietf-idr-flowspec-interfaceset-01.txt 
Routing Area Working Group S. Litkowski Routing Area Working Group S. Litkowski
Internet-Draft Orange Internet-Draft Orange
Intended status: Standards Track A. Simpson Intended status: Standards Track A. Simpson
Expires: November 19, 2016 Alcatel Lucent Expires: December 10, 2016 Alcatel Lucent
K. Patel K. Patel
Cisco Cisco
J. Haas J. Haas
Juniper Networks Juniper Networks
May 18, 2016 June 8, 2016
Applying BGP flowspec rules on a specific interface set Applying BGP flowspec rules on a specific interface set
draft-ietf-idr-flowspec-interfaceset-00 draft-ietf-idr-flowspec-interfaceset-01
Abstract Abstract
BGP Flow-spec is an extension to BGP that allows for the BGP Flow-spec is an extension to BGP that allows for the
dissemination of traffic flow specification rules. The primary dissemination of traffic flow specification rules. The primary
application of this extension is DDoS mitigation where the flowspec application of this extension is DDoS mitigation where the flowspec
rules are applied in most cases to all peering routers of the rules are applied in most cases to all peering routers of the
network. network.
This document will present another use case of BGP Flow-spec where This document will present another use case of BGP Flow-spec where
flow specifications are used to maintain some access control lists at flow specifications are used to maintain some access control lists at
network boundary. BGP Flowspec is a very efficient distributing network boundary. BGP Flowspec is a very efficient distributing
machinery that can help in saving OPEX while deploying/updating ACLs. machinery that can help in saving OPEX while deploying/updating ACLs.
This new application requires flow specification rules to be applied This new application requires flow specification rules to be applied
only on a specific subset of interfaces and in a specific direction. only on a specific subset of interfaces and in a specific direction.
The current specification of BGP Flow-spec does not detail where the The current specification of BGP Flow-spec ([RFC5575]) introduces the
flow specification rules need to be applied. notion of flow specification (which describes the matching criterion)
and traffic filtering actions. The flow specification is encoded as
part of the NLRI while the traffic filtering actions are encoded as
extended communities. The combination of a flow specification and
one or more actions is known as a flow specification rule. [RFC5575]
does not detail where the flow specification rules need to be
applied.
This document presents a new interface-set flowspec action that will Besides the flow specification and traffic filtering actions, this
be used in complement of other actions (marking, rate-limiting ...). document introduces the notion of traffic filtering scope in order to
The purpose of this extension is to inform remote routers on where to drive where a particular rule must be applied. In particular, this
apply the flow specification. document introduces the "interface-set" traffic filtering scope that
could be used in parallel of traffic filtering actions (marking,
rate-limiting ...). The purpose of this extension is to inform
remote routers about groups of interfaces where the rule must be
applied.
This extension can also be used in a DDoS mitigation context where a This extension can also be used in a DDoS mitigation context where a
provider wants to apply the filtering only on specific peers. provider wants to apply the filtering only on specific peers.
Requirements Language Requirements Language
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].
skipping to change at page 2, line 20 skipping to change at page 2, line 29
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 November 19, 2016. This Internet-Draft will expire on December 10, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 43 skipping to change at page 3, line 11
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. Use case . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Use case . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Specific filtering for DDoS . . . . . . . . . . . . . . . 3 1.1. Specific filtering for DDoS . . . . . . . . . . . . . . . 3
1.2. ACL maintenance . . . . . . . . . . . . . . . . . . . . . 4 1.2. ACL maintenance . . . . . . . . . . . . . . . . . . . . . 4
2. Collaborative filtering and managing filter direction . . . . 5 2. Collaborative filtering and managing filter direction . . . . 5
3. Interface specific filtering using BGP flowspec . . . . . . . 6 3. Traffic filtering scope . . . . . . . . . . . . . . . . . . . 6
4. Interface-set extended community . . . . . . . . . . . . . . 7 4. Interface specific filtering using BGP flowspec . . . . . . . 6
5. Interaction with permanent traffic actions . . . . . . . . . 8 5. Interface-set extended community . . . . . . . . . . . . . . 8
5.1. Interaction with interface ACLs . . . . . . . . . . . . . 9 6. Interaction with permanent traffic filtering rules . . . . . 9
5.2. Interaction with flow collection . . . . . . . . . . . . 10 6.1. Interaction with interface ACLs . . . . . . . . . . . . . 9
6. Scaling of per interface rules . . . . . . . . . . . . . . . 10 6.2. Interaction with flow collection . . . . . . . . . . . . 11
7. Deployment considerations . . . . . . . . . . . . . . . . . . 11 7. Scaling of per interface rules . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8. Deployment considerations . . . . . . . . . . . . . . . . . . 11
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
11.1. Normative References . . . . . . . . . . . . . . . . . . 12 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . 13 12.1. Normative References . . . . . . . . . . . . . . . . . . 13
12.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Use case 1. Use case
1.1. Specific filtering for DDoS 1.1. Specific filtering for DDoS
----------------- --- (ebgp) - Peer3 (BW 10G) ----------------- --- (ebgp) - Peer3 (BW 10G)
/ \/ / \/
| /| | /|
| PE --- (ebgp) - Transit1(BW 4x10G) | PE --- (ebgp) - Transit1(BW 4x10G)
skipping to change at page 4, line 5 skipping to change at page 4, line 21
The Flowspec infrastructure may be reused by the service provider to The Flowspec infrastructure may be reused by the service provider to
implement such rate-limiting in a very quick manner and being able to implement such rate-limiting in a very quick manner and being able to
adjust values in future quickly without having to configure each node adjust values in future quickly without having to configure each node
one by one. Using the current BGP flowspec specification, it would one by one. Using the current BGP flowspec specification, it would
not be possible to implement different rate limiter on different not be possible to implement different rate limiter on different
interfaces of a same router. The flowspec rule is applied to all interfaces of a same router. The flowspec rule is applied to all
interfaces in all directions or on some interfaces where flowspec is interfaces in all directions or on some interfaces where flowspec is
activated but flowspec rule set would be the same among all activated but flowspec rule set would be the same among all
interfaces. interfaces.
Section Section 3 will detail a solution to address this use case Section Section 4 will detail a solution to address this use case
using BGP Flowspec. using BGP Flowspec.
1.2. ACL maintenance 1.2. ACL maintenance
--------------- --- (ebgp) - Cust4_VPN --------------- --- (ebgp) - Cust4_VPN
/ \/ / \/
Cust1_INT -- (ebgp) --- PE /| Cust1_INT -- (ebgp) --- PE /|
| PE ------ (ebgp) - Transit1 | PE ------ (ebgp) - Transit1
Cust3_VPN -- (ebgp) --- PE | Cust3_VPN -- (ebgp) --- PE |
| PE ------ (ebgp) - Peer2 | PE ------ (ebgp) - Peer2
skipping to change at page 4, line 40 skipping to change at page 5, line 7
and deploying ACLs on hundreds/thousands of routers is really painful and deploying ACLs on hundreds/thousands of routers is really painful
and time consuming and a service provider would be interested to and time consuming and a service provider would be interested to
deploy/updates ACLs using BGP Flowspec. In this scenario, depending deploy/updates ACLs using BGP Flowspec. In this scenario, depending
on the interface type (Internet customer, VPN customer, Peer, Transit on the interface type (Internet customer, VPN customer, Peer, Transit
...) the content of the ACL may be different. ...) the content of the ACL may be different.
We foresee two main cases : We foresee two main cases :
o Maintaining complete ACLs using flowspec : in this case all the o Maintaining complete ACLs using flowspec : in this case all the
ingress ACL are maintained and deployed using BGPFlowspec. See ingress ACL are maintained and deployed using BGPFlowspec. See
section Section 8 for more details on security aspects. section Section 9 for more details on security aspects.
o Requirement of a quick deployment of a new filtering term due to a o Requirement of a quick deployment of a new filtering term due to a
security alert : new security alerts often requires a fast security alert : new security alerts often requires a fast
deployment of new ACL terms. Using traditional CLI and hop by hop deployment of new ACL terms. Using traditional CLI and hop by hop
provisioning, such deployment takes time and network is provisioning, such deployment takes time and network is
unprotected during this time window. Using BGP flowspec to deploy unprotected during this time window. Using BGP flowspec to deploy
such rule, a service provider can protect its network in few such rule, a service provider can protect its network in few
seconds. Then the SP can decide to keep the rule permanently in seconds. Then the SP can decide to keep the rule permanently in
BGP Flowspec or update its ACL or remove the entry (in case BGP Flowspec or update its ACL or remove the entry (in case
equipments are not vulnerable anymore). equipments are not vulnerable anymore).
Section Section 3 will detail a solution to address this use case Section Section 4 will detail a solution to address this use case
using BGP Flowspec. using BGP Flowspec.
2. Collaborative filtering and managing filter direction 2. Collaborative filtering and managing filter direction
[RFC5575] states in Section 5. : "This mechanism is primarily [RFC5575] states in Section 5. : "This mechanism is primarily
designed to allow an upstream autonomous system to perform inbound designed to allow an upstream autonomous system to perform inbound
filtering in their ingress routers of traffic that a given downstream filtering in their ingress routers of traffic that a given downstream
AS wishes to drop.". AS wishes to drop.".
In case of networks collaborating in filtering, there is a use case In case of networks collaborating in filtering, there is a use case
skipping to change at page 6, line 5 skipping to change at page 6, line 17
Using collaborative filtering, the upstream provider may propose to Using collaborative filtering, the upstream provider may propose to
MyAS to filter malicious traffic sent to it. We propose to enhance MyAS to filter malicious traffic sent to it. We propose to enhance
[RFC5575] to make myAS able to send BGP FlowSpec updates (on eBGP [RFC5575] to make myAS able to send BGP FlowSpec updates (on eBGP
sessions) to the upstream provider to request outbound filtering on sessions) to the upstream provider to request outbound filtering on
peering interfaces towards MyAS. When the upstream provider will peering interfaces towards MyAS. When the upstream provider will
receive the BGP Flowspec update from MyAS, the BGP flowspec update receive the BGP Flowspec update from MyAS, the BGP flowspec update
will contain request for outbound filtering on a specific set of will contain request for outbound filtering on a specific set of
interfaces. The upstream provider will apply automatically the interfaces. The upstream provider will apply automatically the
requested filter and congestion will be prevented. requested filter and congestion will be prevented.
3. Interface specific filtering using BGP flowspec 3. Traffic filtering scope
We see with the use case described above that some BGP flowspec rules
may need to be applied only on specific elements of the network
(interfaces, nodes ...). The basic specification detailed in
[RFC5575] does not address this and does not give any detail on where
the traffic filtering rule need to be applied.
In addition to the flow specification (flow matching criterion) and
traffic filtering actions described in [RFC5575], this document
introduces the notion of traffic filtering scope. The traffic
filtering scope will describe where a particular flow specification
rule must be applied.
Using a traffic filtering scope in a BGP Flow spec rule is optional.
When a rule does not contain any traffic filtering scope parameter,
[RFC5575] applies.
4. Interface specific filtering using BGP flowspec
The use case detailed above requires application of different BGP The use case detailed above requires application of different BGP
Flowspec rules on different set of interfaces. The basic Flowspec rules on different set of interfaces.
specification detailed in [RFC5575] does not address this and does
not give any detail on where the FlowSpec filter need to be applied.
We propose to introduce, within BGP Flowspec, an identification of We propose to introduce, within BGP Flowspec, a traffic filtering
interfaces where a particular filter should apply on. Identification scope that identifies a group of interfaces where a particular filter
of interfaces within BGP Flowspec will be done through group should apply on. Identification of interfaces within BGP Flowspec
identifiers. A group identifier marks a set of interfaces sharing a will be done through group identifiers. A group identifier marks a
common administrative property. Like a BGP community, the group set of interfaces sharing a common administrative property. Like a
identifier itself does not have any significance. It is up to the BGP community, the group identifier itself does not have any
network administrator to associate a particular meaning to a group significance. It is up to the network administrator to associate a
identifier value (e.g. group ID#1 associated to Internet customer particular meaning to a group identifier value (e.g. group ID#1
interfaces). The group identifier is a local interface property. associated to Internet customer interfaces). The group identifier is
Any interface may be associated with one or more group identifiers a local interface property. Any interface may be associated with one
using manual configuration. or more group identifiers using manual configuration.
When a filtering rule advertised through BGP Flowspec must be applied When a filtering rule advertised through BGP Flowspec must be applied
only to particular sets of interfaces, the BGP Flowspec BGP update only to particular sets of interfaces, the BGP Flowspec BGP update
will contain the identifiers associated with the relevant sets of will contain the identifiers associated with the relevant sets of
interfaces. In addition to the group identifiers, it will also interfaces. In addition to the group identifiers, it will also
contain the direction the filtering rule must be applied in (see contain the direction the filtering rule must be applied in (see
Section 4). Section 5).
Configuration of group identifiers associated to interfaces may Configuration of group identifiers associated to interfaces may
change over time. An implementation MUST ensure that the filtering change over time. An implementation MUST ensure that the filtering
rules (learned from BGP Flowspec) applied to a particular interface rules (learned from BGP Flowspec) applied to a particular interface
are always updated when the group identifier mapping is changing. are always updated when the group identifier mapping is changing.
Considering figure 2, we can imagine the following design : Considering figure 2, we can imagine the following design :
o Internet customer interfaces are associated with group-identifier o Internet customer interfaces are associated with group-identifier
1. 1.
skipping to change at page 7, line 19 skipping to change at page 8, line 5
There are some cases where nodes are dedicated to specific functions There are some cases where nodes are dedicated to specific functions
(Internet peering, Internet Edge, VPN Edge, Service Edge ...), in (Internet peering, Internet Edge, VPN Edge, Service Edge ...), in
this kind of scenario, there is an interest for a constrained this kind of scenario, there is an interest for a constrained
distribution of filtering rules that are using the interface specific distribution of filtering rules that are using the interface specific
filtering. Without the constrained route distribution, all nodes filtering. Without the constrained route distribution, all nodes
will received all the filters even if they are not interested in will received all the filters even if they are not interested in
those filters. Constrained route distribution of flowspec filters those filters. Constrained route distribution of flowspec filters
would allow for a more optimized distribution. would allow for a more optimized distribution.
4. Interface-set extended community 5. Interface-set extended community
This document proposes a new BGP Route Target extended community This document proposes a new BGP Route Target extended community
called "flowspec interface-set". This document so expands the called "flowspec interface-set". This document so expands the
definition of the Route Target extended community to allow a new definition of the Route Target extended community to allow a new
value of high order octet (Type field) to be TBD (in addition to the value of high order octet (Type field) to be TBD (in addition to the
values specified in [RFC4360]). values specified in [RFC4360]).
In order to ease intra-AS and inter-AS use cases, this document In order to ease intra-AS and inter-AS use cases, this document
proposes to have a transitive as well as a non transitive version of proposes to have a transitive as well as a non transitive version of
this extended community. this extended community.
skipping to change at page 8, line 9 skipping to change at page 8, line 41
following group-identifier. following group-identifier.
o I : if set, the flow specification rule MUST be applied in input o I : if set, the flow specification rule MUST be applied in input
direction to the interface set referenced by the following group- direction to the interface set referenced by the following group-
identifier. identifier.
Both flags can be set at the same time in the interface-set extended Both flags can be set at the same time in the interface-set extended
community leading to flow rule to be applied in both directions. An community leading to flow rule to be applied in both directions. An
interface-set extended community with both flags set to zero MUST be interface-set extended community with both flags set to zero MUST be
treated as an error and as consequence, the FlowSpec update MUST be treated as an error and as consequence, the FlowSpec update MUST be
discarded. discarded. As having no direction indicated as no sense, there is no
need to propagate the filter informations in the network.
The Group Identifier is coded as a 14-bit number (values goes from 0 The Group Identifier is coded as a 14-bit number (values goes from 0
to 16383). to 16383).
Multiple instances of the interface-set community may be present in a Multiple instances of the interface-set community may be present in a
BGP update. This may appear if the flow rule need to be applied to BGP update. This may appear if the flow rule need to be applied to
multiple set of interfaces. multiple set of interfaces.
Multiple instances of the community in a BGP update MUST be Multiple instances of the community in a BGP update MUST be
interpreted as a "OR" operation : if a BGP update contains two interpreted as a "OR" operation : if a BGP update contains two
interface-set communities with group ID 1 and group ID 2, the filter interface-set communities with group ID 1 and group ID 2, the filter
would need to be installed on interfaces belonging to Group ID 1 or would need to be installed on interfaces belonging to Group ID 1 or
Group ID 2. Group ID 2.
As using a Route Target, route distribution of flowspec NLRI with As using a Route Target, route distribution of flowspec NLRI with
interface-set may be subject to constrained distribution as defined interface-set may be subject to constrained distribution as defined
in [RFC4684]. Constrained route distribution for flowspec routes in [RFC4684]. Constrained route distribution for flowspec routes
using interface-set requires discussion and will be addressed in a using interface-set requires discussion and will be addressed in a
future revision of the document. future revision of the document.
5. Interaction with permanent traffic actions 6. Interaction with permanent traffic filtering rules
[RFC5575] states that BGP Flowspec is primarily designed to allow [RFC5575] states that BGP Flowspec is primarily designed to allow
upstream AS to perform inbound filtering in their ingress routers. upstream AS to perform inbound filtering in their ingress routers.
This specification does not precise where this ingress filtering This specification does not precise where this ingress filtering
should happen in the packet processing pipe. should happen in the packet processing pipe.
This proposal enhances [RFC5575] in order to add action on traffic This proposal enhances [RFC5575] in order to add rules for traffic
coming from or going to specific interfaces. Based on this coming from or going to specific interfaces. Based on this
enhancement, some new requirements come to implementations. enhancement, some new requirements come to implementations.
An implementation SHOULD apply input actions (I bit set) within the An implementation SHOULD apply input actions (I bit set) within the
input packet processing pipe. An implementation SHOULD apply output input packet processing pipe. An implementation SHOULD apply output
actions (O bit set) within the output packet processing pipe. actions (O bit set) within the output packet processing pipe.
As input and output processing pipes may also involve already present As input and output processing pipes may also involve already present
static/permanent features that will manipulate the packet, the next static/permanent features that will manipulate the packet, the next
sections will try to clarify how the static behaviors should interact sections will try to clarify how the static behaviors should interact
will BGP flowspec actions. will BGP flowspec actions.
5.1. Interaction with interface ACLs 6.1. Interaction with interface ACLs
Deploying interface specific filters using BGP FlowSpec (dynamic Deploying interface specific filters using BGP FlowSpec (dynamic
entries) may interfere with existing permanent interface ACL (static entries) may interfere with existing permanent interface ACL (static
entries). The content of the existing permanent ACL MUST NOT be entries). The content of the existing permanent ACL MUST NOT be
altered by dynamic entries coming from BGP FlowSpec. Permanent ACLs altered by dynamic entries coming from BGP FlowSpec. Permanent ACLs
are using a specific ordering which is not compatible with the are using a specific ordering which is not compatible with the
ordering of FS rules and misordering of ACL may lead to undesirable ordering of FS rules and misordering of ACL may lead to undesirable
behaviour. In order, to keep a deterministic and well known behaviour. In order, to keep a deterministic and well known
behaviour, an implementation SHOULD process the BGP FlowSpec ACL as behaviour, an implementation SHOULD process the BGP FlowSpec ACL as
follows : follows :
o In inbound direction, the permanent ACL action is applied first o In inbound direction, the permanent ACL action is applied first
followed by FlowSpec action. This gives the primary action to the followed by FlowSpec action. This gives the primary action to the
permanent ACL as it is done today. permanent ACL as it is done today.
o In outbound direction, FlowSpec action action is applied first o In outbound direction, FlowSpec action is applied first followed
followed by permanent ACL. This gives the final action to the by permanent ACL. This gives the final action to the permanent
permanent ACL as it is done today. ACL as it is done today.
Inbound filters Outbound filters Inbound filters Outbound filters
--------- ------- ---------- ------- --------- --------- ------- ---------- ------- ---------
|Permanent| -> |Dynamic| -> |Forwarding| -> |Dynamic| -> |Permanent| |Permanent| -> |Dynamic| -> |Forwarding| -> |Dynamic| -> |Permanent|
In order for a flow to be accepted, the flow must be accepted by the In order for a flow to be accepted, the flow must be accepted by the
two ACLs and a flow is rejected when one of the ACL rejects it as two ACLs and a flow is rejected when one of the ACL rejects it as
described in the table below : described in the table below :
+-------------------------+--------------------------+--------------+ +-------------------------+--------------------------+--------------+
skipping to change at page 10, line 23 skipping to change at page 11, line 8
o a UDP flow from 10.0.0.1 to 11.0.0.2 on port 53 will be rejected o a UDP flow from 10.0.0.1 to 11.0.0.2 on port 53 will be rejected
because the dynamic ACL rejects it. because the dynamic ACL rejects it.
o a UDP flow from 10.0.0.2 to 11.0.0.2 on port 53 will be accepted o a UDP flow from 10.0.0.2 to 11.0.0.2 on port 53 will be accepted
because both ACLs accept it. because both ACLs accept it.
o a TCP flow from 10.0.0.2 to 11.0.0.2 on port 80 will be rejected o a TCP flow from 10.0.0.2 to 11.0.0.2 on port 80 will be rejected
because permanent ACL rejects it. because permanent ACL rejects it.
5.2. Interaction with flow collection 6.2. Interaction with flow collection
A router may activate flow collection features (used in collaboration A router may activate flow collection features (used in collaboration
with Netflow export). Flow collection can be done at input side or with Netflow export). Flow collection can be done at input side or
output side. As for ACL, an implementation SHOULD process : output side. As for ACL, an implementation SHOULD process :
o BGP FS rules after the inbound flow collection : in case of DDoS o BGP FS rules after the inbound flow collection : in case of DDoS
protection, it is important to keep monitoring of attack flows and protection, it is important to keep monitoring of attack flows and
so performing action, after collection. so performing action, after collection.
o BGP FS rules before the outbound flow collection : purpose of o BGP FS rules before the outbound flow collection : purpose of
outbound flow collection is really to track flows that are exiting outbound flow collection is really to track flows that are exiting
the interface. BGP FS rules should not interfere in this. the interface. BGP FS rules should not interfere in this.
Inbound Outbound Inbound Outbound
Flow BGP BGP Flow Flow BGP BGP Flow
collection FS FS collection collection FS FS collection
--------- ------- ---------- ------- --------- --------- ------- ---------- ------- ---------
|Permanent| -> |Dynamic| -> |Forwarding| -> |Dynamic| -> |Permanent| |Permanent| -> |Dynamic| -> |Forwarding| -> |Dynamic| -> |Permanent|
6. Scaling of per interface rules 7. Scaling of per interface rules
Creating rules that are applied on specific interfaces may create Creating rules that are applied on specific interfaces may create
forwarding rules that may be harder to share. forwarding rules that may be harder to share.
An implementation SHOULD take care about trying to keep sharing An implementation SHOULD take care about trying to keep sharing
forwarding structures as much as possible in order to limit the forwarding structures as much as possible in order to limit the
scaling impact. How the implementation would do so is out of scope scaling impact. How the implementation would do so is out of scope
of the document. of the document.
7. Deployment considerations 8. Deployment considerations
There are some cases where a particular BGP Flowspec NLRI may be There are some cases where a particular BGP Flowspec NLRI may be
advertised to different interface groups with a different action. advertised to different interface groups with a different action.
For example, a service provider may want to discard all ICMP traffic For example, a service provider may want to discard all ICMP traffic
from customer interfaces to infrastructure addresses and want to from customer interfaces to infrastructure addresses and want to
rate-limit the same traffic when it comes from some internal rate-limit the same traffic when it comes from some internal
platforms. These particular cases require ADD-PATH to be deployed in platforms. These particular cases require ADD-PATH to be deployed in
order to ensure that all paths (NLRI+interface group+actions) are order to ensure that all paths (NLRI+interface-set group-id+actions)
propagated within the BGP control plane. Without ADD-PATH, only a are propagated within the BGP control plane. Without ADD-PATH, only
single "NLRI+interface group+actions" will be propagated, so some a single "NLRI+interface-set group-id+actions" will be propagated, so
filtering rules will never be applied. some filtering rules will never be applied.
8. Security Considerations 9. Security Considerations
Managing permanent Access Control List by using BGP Flowspec as Managing permanent Access Control List by using BGP Flowspec as
described in Section 1.2 helps in saving roll out time of such ACL. described in Section 1.2 helps in saving roll out time of such ACL.
However some ACL especially at network boundary are critical for the However some ACL especially at network boundary are critical for the
network security and loosing the ACL configuration may lead to network security and loosing the ACL configuration may lead to
network open for attackers. network open for attackers.
By design, BGP flowspec rules are ephemeral : the flow rule exists in By design, BGP flowspec rules are ephemeral : the flow rule exists in
the router while the BGP session is UP and the BGP path for the rule the router while the BGP session is UP and the BGP path for the rule
is valid. We can imagine a scenario where a Service Provider is is valid. We can imagine a scenario where a Service Provider is
skipping to change at page 12, line 5 skipping to change at page 12, line 33
ACLs should protect the BGP session from being attacked. ACLs should protect the BGP session from being attacked.
In order to complement the BGP flowspec solution is such deployment In order to complement the BGP flowspec solution is such deployment
scenario and provides security against such attack, a service scenario and provides security against such attack, a service
provider may activate Long lived Graceful Restart provider may activate Long lived Graceful Restart
[I-D.uttaro-idr-bgp-persistence] on the BGP session owning Flowspec [I-D.uttaro-idr-bgp-persistence] on the BGP session owning Flowspec
address family. So in case of BGP session to be down, the BGP paths address family. So in case of BGP session to be down, the BGP paths
of Flowspec rules would be retained and the flowspec action will be of Flowspec rules would be retained and the flowspec action will be
retained. retained.
9. Acknowledgements 10. Acknowledgements
Authors would like to thanks Wim Hendrickx for his valuable comments. Authors would like to thanks Wim Hendrickx and Robert Raszuk for
their valuable comments.
10. IANA Considerations 11. IANA Considerations
This document requests a new type from the "BGP Transitive Extended This document requests a new type from the "BGP Transitive Extended
Community Types" extended community registry. This type name shall Community Types" extended community registry. This type name shall
be 'FlowSpec'. be 'FlowSpec'.
This document requests a new type from the "BGP Non-Transitive This document requests a new type from the "BGP Non-Transitive
Extended Community Types" extended community registry. This type Extended Community Types" extended community registry. This type
name shall be 'FlowSpec'. name shall be 'FlowSpec'.
This document requests creation of a new registry called "FlowSpec This document requests creation of a new registry called "FlowSpec
Extended Community Sub-Types". This registry contains values of the Extended Community Sub-Types". This registry contains values of the
second octet (the "Sub-Type" field) of an extended community when the second octet (the "Sub-Type" field) of an extended community when the
value of the first octet (the "Type" field) is to one of those value of the first octet (the "Type" field) is to one of those
allocated in this document. allocated in this document.
Within this new registry, this document requests a new subtype Within this new registry, this document requests a new subtype
(suggested value 0x02), this sub-type shall be named "interface-set". (suggested value 0x02), this sub-type shall be named "interface-set".
11. References 12. References
11.1. Normative References 12.1. Normative References
[I-D.ietf-idr-rtc-no-rt] [I-D.ietf-idr-rtc-no-rt]
Rosen, E., Patel, K., Haas, J., and R. Raszuk, "Route Rosen, E., Patel, K., Haas, J., and R. Raszuk, "Route
Target Constrained Distribution of Routes with no Route Target Constrained Distribution of Routes with no Route
Targets", draft-ietf-idr-rtc-no-rt-05 (work in progress), Targets", draft-ietf-idr-rtc-no-rt-05 (work in progress),
May 2016. May 2016.
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
skipping to change at page 13, line 10 skipping to change at page 13, line 39
Distribution for Border Gateway Protocol/MultiProtocol Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684, Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <http://www.rfc-editor.org/info/rfc4684>. November 2006, <http://www.rfc-editor.org/info/rfc4684>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., [RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009, Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>. <http://www.rfc-editor.org/info/rfc5575>.
11.2. Informative References 12.2. Informative References
[I-D.uttaro-idr-bgp-persistence] [I-D.uttaro-idr-bgp-persistence]
Uttaro, J., Chen, E., Decraene, B., and J. Scudder, Uttaro, J., Chen, E., Decraene, B., and J. Scudder,
"Support for Long-lived BGP Graceful Restart", draft- "Support for Long-lived BGP Graceful Restart", draft-
uttaro-idr-bgp-persistence-03 (work in progress), November uttaro-idr-bgp-persistence-03 (work in progress), November
2013. 2013.
Authors' Addresses Authors' Addresses
Stephane Litkowski Stephane Litkowski
 End of changes. 31 change blocks. 
64 lines changed or deleted 93 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/