draft-ietf-idr-flow-spec-03.txt   draft-ietf-idr-flow-spec-04.txt 
IDR Working Group P. Marques IDR Working Group P. Marques
Internet-Draft N. Sheth Internet-Draft N. Sheth
Expires: May 24, 2009 R. Raszuk Intended status: Standards Track R. Raszuk
B. Greene Expires: July 22, 2009 B. Greene
Juniper Networks Juniper Networks
J. Mauch J. Mauch
NTT/Verio NTT/Verio
D. McPherson D. McPherson
Arbor Networks Arbor Networks
November 20, 2008 January 18, 2009
Dissemination of flow specification rules Dissemination of flow specification rules
draft-ietf-idr-flow-spec-03 draft-ietf-idr-flow-spec-04
Status of this Memo Status of this Memo
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Abstract Abstract
This document defines a new BGP NLRI encoding format that can be used This document defines a new BGP NLRI encoding format that can be used
to distribute traffic flow specifications. This allows the routing to distribute traffic flow specifications. This allows the routing
system to propagate information regarding more-specific components of system to propagate information regarding more-specific components of
the traffic aggregate defined by an IP destination prefix. the traffic aggregate defined by an IP destination prefix.
Additionally it defines two applications of that encoding format. Additionally it defines two applications of that encoding format.
One that can be used to automate inter-domain coordination of traffic One that can be used to automate inter-domain coordination of traffic
filtering, such as what is required in order to mitigate filtering, such as what is required in order to mitigate
(distributed) denial of service attacks. And a second application to (distributed) denial of service attacks. And a second application to
traffic filtering in the context of a BGP/MPLS VPN service. traffic filtering in the context of a BGP/MPLS VPN service.
The information is carried via the Border Gateway Protocol (BGP), The information is carried via the Border Gateway Protocol (BGP),
thereby reusing protocol algorithms, operational experience and thereby reusing protocol algorithms, operational experience and
administrative processes such as inter-provider peering agreements. administrative processes such as inter-provider peering agreements.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Definitions of Terms Used in this Memo . . . . . . . . . . . . 4
2. Flow specifications . . . . . . . . . . . . . . . . . . . . . 6 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Dissemination of Information . . . . . . . . . . . . . . . . . 7 3. Flow specifications . . . . . . . . . . . . . . . . . . . . . 6
4. Traffic filtering . . . . . . . . . . . . . . . . . . . . . . 13 4. Dissemination of Information . . . . . . . . . . . . . . . . . 6
4.1. Order of traffic filtering rules . . . . . . . . . . . . . 14 5. Traffic filtering . . . . . . . . . . . . . . . . . . . . . . 12
5. Validation procedure . . . . . . . . . . . . . . . . . . . . . 15 5.1. Order of traffic filtering rules . . . . . . . . . . . . . 13
6. Traffic Filtering Actions . . . . . . . . . . . . . . . . . . 17 6. Validation procedure . . . . . . . . . . . . . . . . . . . . . 13
7. Traffic filtering in RFC2547bis networks . . . . . . . . . . . 19 7. Traffic Filtering Actions . . . . . . . . . . . . . . . . . . 14
8. Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8. Traffic filtering in RFC2547bis networks . . . . . . . . . . . 16
9. Security considerations . . . . . . . . . . . . . . . . . . . 21 9. Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 10. Security considerations . . . . . . . . . . . . . . . . . . . 17
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
12. Normative References . . . . . . . . . . . . . . . . . . . . . 25 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26 13. Normative References . . . . . . . . . . . . . . . . . . . . . 20
Intellectual Property and Copyright Statements . . . . . . . . . . 28 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Definitions of Terms Used in this Memo
NLRI - Network Layer Reachability Information
RIB - Routing Information Base
Loc-RIB - Local RIB
AS - Autonomous System Number
VRF - Virtual Routing and Forwarding instance
PE - Provider Edge router
2. Introduction
Modern IP routers contain both the capability to forward traffic Modern IP routers contain both the capability to forward traffic
according to aggregate IP prefixes as well as to classify, shape, according to aggregate IP prefixes as well as to classify, shape,
limit filter or redirect packets based on administratively defined limit filter or redirect packets based on administratively defined
policies. policies.
While forwarding information is, typically, dynamically signaled While forwarding information is, typically, dynamically signaled
across the network via routing protocols, there is no agreed upon across the network via routing protocols, there is no agreed upon
mechanism to dynamically signal flows across autonomous-systems. mechanism to dynamically signal flows across autonomous-systems.
skipping to change at page 5, line 18 skipping to change at page 5, line 34
reuse both internal route distribution infrastructure (e.g.: route reuse both internal route distribution infrastructure (e.g.: route
reflector or confederation design) and existing external reflector or confederation design) and existing external
relationships (e.g.: inter-domain BGP sessions to a customer relationships (e.g.: inter-domain BGP sessions to a customer
network). network).
While it is certainly possible to address this problem using other While it is certainly possible to address this problem using other
mechanisms, the authors believe that this solution offers the mechanisms, the authors believe that this solution offers the
substantial advantage of being an incremental addition to deployed substantial advantage of being an incremental addition to deployed
mechanisms. mechanisms.
At the current deployments the information distributed by the flow-
spec extension is originated both manually as well as automatically
by systems which are able to detect malicious flows. When automated
systems are used care should be taken to their correctness and rate
of advertisement of flow routes.
This specification defines required protocol extensions to address
most common applications of IPv4 unicast and VPNv4 unicast filtering.
The same mechanism can be reused and new match criteria added to
address similar filtering needs for other BGP address families (for
example IPv6 unicast). Authors believe that those would be best to
be addressed in a separate document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Flow specifications 3. Flow specifications
A flow specification is an n-tuple consisting on several matching A flow specification is an n-tuple consisting on several matching
criteria that can be applied to IP traffic. A given IP packet is criteria that can be applied to IP traffic. A given IP packet is
said to match the defined flow if it matches all the specified said to match the defined flow if it matches all the specified
criteria. criteria.
A given flow may be associated with a set of attributes, depending on A given flow may be associated with a set of attributes, depending on
the particular application, such attributes may or may not include the particular application, such attributes may or may not include
reachability information (i.e. NEXT_HOP). Well-known or AS-specific reachability information (i.e. NEXT_HOP). Well-known or AS-specific
community attributes can be used to encode a set of predeterminate community attributes can be used to encode a set of predetermined
actions. actions.
A particular application is identified by a specific (AFI, SAFI) pair A particular application is identified by a specific (AFI, SAFI) pair
[RFC4760] and corresponds to a distinct set of RIBs. Those RIBs [RFC4760] and corresponds to a distinct set of RIBs. Those RIBs
should be treated independently from each other in order to assure should be treated independently from each other in order to assure
non-interference between distinct applications. non-interference between distinct applications.
BGP itself treats the NLRI as an opaque key to an entry in its BGP itself treats the NLRI as an opaque key to an entry in its
databases. Entries that are placed in the Loc-RIB are then databases. Entries that are placed in the Loc-RIB are then
associated with a given set of semantics which is application associated with a given set of semantics which is application
skipping to change at page 7, line 5 skipping to change at page 6, line 38
path information (AFI=1, SAFI=2) are handled by BGP without any path information (AFI=1, SAFI=2) are handled by BGP without any
particular semantics being associated with them until installed in particular semantics being associated with them until installed in
the Loc-RIB. the Loc-RIB.
Standard BGP policy mechanisms, such as UPDATE filtering by NLRI Standard BGP policy mechanisms, such as UPDATE filtering by NLRI
prefix and community matching, SHOULD apply to the newly defined prefix and community matching, SHOULD apply to the newly defined
NLRI-type. Network operators can also control propagation of such NLRI-type. Network operators can also control propagation of such
routing updates by enabling or disabling the exchange of a particular routing updates by enabling or disabling the exchange of a particular
(AFI, SAFI) pair on a given BGP peering session. (AFI, SAFI) pair on a given BGP peering session.
3. Dissemination of Information 4. Dissemination of Information
We define a "Flow Specification" NLRI type that may include several We define a "Flow Specification" NLRI type that may include several
components such as destination prefix, source prefix, protocol, components such as destination prefix, source prefix, protocol,
ports, etc. This NLRI is treated as an opaque bit string prefix by ports, etc. This NLRI is treated as an opaque bit string prefix by
BGP. Each bit string identifies a key to a database entry which a BGP. Each bit string identifies a key to a database entry which a
set of attributes can be associated with. set of attributes can be associated with.
This NLRI information is encoded using MP_REACH_NLRI and This NLRI information is encoded using MP_REACH_NLRI and
MP_UNREACH_NLRI attributes as defined in RFC4760 [RFC4760]. Whenever MP_UNREACH_NLRI attributes as defined in RFC4760 [RFC4760]. Whenever
the corresponding application does not require Next Hop information, the corresponding application does not require Next Hop information,
skipping to change at page 8, line 27 skipping to change at page 8, line 12
The operator byte is encoded as: The operator byte is encoded as:
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| e | a | len | 0 |lt |gt |eq | | e | a | len | 0 |lt |gt |eq |
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
Numeric operator Numeric operator
+ End of List bit. Set in the last {op, value} pair in the * End of List bit. Set in the last {op, value} pair in the list.
list.
+ And bit. If unset the previous term is logically ORed with * And bit. If unset the previous term is logically ORed with the
the current one. If set the operation is a logical AND. It current one. If set the operation is a logical AND. It should
should be unset in the first operator byte of a sequence. be unset in the first operator byte of a sequence. The AND
The AND operator has higher priority than OR for the operator has higher priority than OR for the purposes of
purposes of evaluating logical expressions. evaluating logical expressions.
+ The length of value field for this operand is given as (1 << * The length of value field for this operand is given as (1 <<
len). len).
+ Lt - less than comparison between data and value. * Lt - less than comparison between data and value.
+ gt - greater than comparison between data and value. * gt - greater than comparison between data and value.
+ eq - equality between data and value. * eq - equality between data and value.
The bits lt, gt, and eq can be combined to produce "less or * The bits lt, gt, and eq can be combined to produce "less or
equal", "greater or equal" and inequality values. equal", "greater or equal" and inequality values.
Type 4 - Port Type 4 - Port
Encoding: <type (1 octet), [op, value]+> Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs that matches source Defines a list of {operation, value} pairs that matches source
OR destination TCP/UDP ports. This list is encoded using the OR destination TCP/UDP ports. This list is encoded using the
numeric operand format defined above. Values are encoded as 1 numeric operand format defined above. Values are encoded as 1
or 2 byte quantities. or 2 byte quantities.
Type 5 - Destination port Type 5 - Destination port
Encoding: <type (1 octet), [op, value]+> Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the Defines a list of {operation, value} pairs used to match the
skipping to change at page 10, line 10 skipping to change at page 9, line 39
definitions specified in the TCP header format [RFC0793]. definitions specified in the TCP header format [RFC0793].
This type uses the bitmask operand format, which differs from This type uses the bitmask operand format, which differs from
the numeric operator format in the lower nibble. the numeric operator format in the lower nibble.
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| e | a | len | 0 | 0 |not| m | | e | a | len | 0 | 0 |not| m |
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
+ Top nibble: (End of List bit, And bit and Length field), as * Top nibble: (End of List bit, And bit and Length field), as
defined for in the numeric operator format. defined for in the numeric operator format.
+ Not bit. If set, logical negation of operation. * Not bit. If set, logical negation of operation.
+ Match bit. If set this is a bitwise match operation defined * Match bit. If set this is a bitwise match operation defined as
as "(data & value) == value"; if unset (data & value) "(data & value) == value"; if unset (data & value) evaluates to
evaluates to true if and of the bits in the value mask are true if any of the bits in the value mask are set in the data.
set in the data.
Type 10 - Packet length Type 10 - Packet length
Encoding: <type (1 octet), [op, value]+> Encoding: <type (1 octet), [op, value]+>
Match on the total IP packet length (excluding L2 but including Match on the total IP packet length (excluding L2 but including
IP header). Values are encoded using as 1 or 2 byte IP header). Values are encoded using as 1 or 2 byte
quantities. quantities.
Type 11 - DSCP Type 11 - DSCP
Encoding: <type (1 octet), [op, value]+> Encoding: <type (1 octet), [op, value]+>
skipping to change at page 11, line 38 skipping to change at page 11, line 21
+------------------+----------+----------+ +------------------+----------+----------+
| 0x01 18 0a 00 01 | 03 81 06 | 04 81 19 | | 0x01 18 0a 00 01 | 03 81 06 | 04 81 19 |
+------------------+----------+----------+ +------------------+----------+----------+
Decode for protocol: Decode for protocol:
+-------+----------+------------------------------+ +-------+----------+------------------------------+
| Value | | | | Value | | |
+-------+----------+------------------------------+ +-------+----------+------------------------------+
| 0x03 | type | | | 0x03 | type | |
| | | |
| 0x81 | operator | end-of-list, value size=1, = | | 0x81 | operator | end-of-list, value size=1, = |
| | | |
| 0x06 | value | | | 0x06 | value | |
+-------+----------+------------------------------+ +-------+----------+------------------------------+
An example of a Flow Specification encoding for: "all packets to An example of a Flow Specification encoding for: "all packets to
10.0.1/24 from 192/8 and port {range [137, 139] or 8080}". 10.0.1/24 from 192/8 and port {range [137, 139] or 8080}".
+------------------+----------+-------------------------+ +------------------+----------+-------------------------+
| destination | source | port | | destination | source | port |
+------------------+----------+-------------------------+ +------------------+----------+-------------------------+
| 0x01 18 0a 01 01 | 02 08 c0 | 04 03 89 45 8b 91 1f 90 | | 0x01 18 0a 01 01 | 02 08 c0 | 04 03 89 45 8b 91 1f 90 |
skipping to change at page 12, line 4 skipping to change at page 11, line 33
+-------+----------+------------------------------+ +-------+----------+------------------------------+
An example of a Flow Specification encoding for: "all packets to An example of a Flow Specification encoding for: "all packets to
10.0.1/24 from 192/8 and port {range [137, 139] or 8080}". 10.0.1/24 from 192/8 and port {range [137, 139] or 8080}".
+------------------+----------+-------------------------+ +------------------+----------+-------------------------+
| destination | source | port | | destination | source | port |
+------------------+----------+-------------------------+ +------------------+----------+-------------------------+
| 0x01 18 0a 01 01 | 02 08 c0 | 04 03 89 45 8b 91 1f 90 | | 0x01 18 0a 01 01 | 02 08 c0 | 04 03 89 45 8b 91 1f 90 |
+------------------+----------+-------------------------+ +------------------+----------+-------------------------+
Decode for port: Decode for port:
+--------+----------+------------------------------+ +--------+----------+------------------------------+
| Value | | | | Value | | |
+--------+----------+------------------------------+ +--------+----------+------------------------------+
| 0x04 | type | | | 0x04 | type | |
| | | |
| 0x03 | operator | size=1, >= | | 0x03 | operator | size=1, >= |
| | | |
| 0x89 | value | 137 | | 0x89 | value | 137 |
| | | |
| 0x45 | operator | &, value size=1, <= | | 0x45 | operator | &, value size=1, <= |
| | | |
| 0x8b | value | 139 | | 0x8b | value | 139 |
| | | |
| 0x91 | operator | end-of-list, value-size=2, = | | 0x91 | operator | end-of-list, value-size=2, = |
| | | |
| 0x1f90 | value | 8080 | | 0x1f90 | value | 8080 |
+--------+----------+------------------------------+ +--------+----------+------------------------------+
This constitutes a NLRI with an NLRI length of 16 octets. This constitutes a NLRI with an NLRI length of 16 octets.
Implementations wishing to exchange flow specification rules MUST use Implementations wishing to exchange flow specification rules MUST use
BGP's Capability Advertisement facility to exchange the Multiprotocol BGP's Capability Advertisement facility to exchange the Multiprotocol
Extension Capability Code (Code 1) as defined in RFC4760 [RFC4760]. Extension Capability Code (Code 1) as defined in RFC4760 [RFC4760].
The (AFI, SAFI) pair carried in the Multiprotocol Extension The (AFI, SAFI) pair carried in the Multiprotocol Extension
capability MUST be the same as the one used to identify a particular capability MUST be the same as the one used to identify a particular
application that uses this NLRI-type. application that uses this NLRI-type.
4. Traffic filtering 5. Traffic filtering
Traffic filtering policies have been traditionally considered to be Traffic filtering policies have been traditionally considered to be
relatively static. relatively static.
The popularity of traffic-based denial of service (DoS) attacks, The popularity of traffic-based denial of service (DoS) attacks,
which often requires the network operator to be able to use traffic which often requires the network operator to be able to use traffic
filters for detection and mitigation, brings with it requirements filters for detection and mitigation, brings with it requirements
that are not fully satisfied by existing tools. that are not fully satisfied by existing tools.
Increasingly, DoS mitigation, requires coordination among several Increasingly, DoS mitigation, requires coordination among several
skipping to change at page 14, line 9 skipping to change at page 13, line 15
In order to achieve that goal, we define an application specific NLRI In order to achieve that goal, we define an application specific NLRI
identifier (AFI=1, SAFI=133) along with specific semantic rules. identifier (AFI=1, SAFI=133) along with specific semantic rules.
BGP routing updates containing this identifier use the flow BGP routing updates containing this identifier use the flow
specification NLRI encoding to convey particular aggregated flows specification NLRI encoding to convey particular aggregated flows
that require special treatment. that require special treatment.
Flow routing information received via this (afi, safi) pair is Flow routing information received via this (afi, safi) pair is
subject to the validation procedure detailed bellow. subject to the validation procedure detailed bellow.
4.1. Order of traffic filtering rules 5.1. Order of traffic filtering rules
With traffic filtering rules, more than one rule may match a With traffic filtering rules, more than one rule may match a
particular traffic flow. Thus it is necessary to define the order at particular traffic flow. Thus it is necessary to define the order at
which rules get matched and applied to a particular traffic flow. which rules get matched and applied to a particular traffic flow.
This ordering function must be such that it must not depend on the This ordering function must be such that it must not depend on the
arrival order of the flow specifications rules and must be constant arrival order of the flow specifications rules and must be constant
in the network. in the network.
We choose to order traffic filtering rules such that the order of two We choose to order traffic filtering rules such that the order of two
flow specifications is given by the comparison of NLRI key byte flow specifications is given by the comparison of NLRI key byte
skipping to change at page 15, line 5 skipping to change at page 13, line 41
specific destination IP prefix. specific destination IP prefix.
This matches an application model where the user may want to define a This matches an application model where the user may want to define a
restriction that affects an aggregate of traffic and a subsequent restriction that affects an aggregate of traffic and a subsequent
rule that applies only to a subset of that. rule that applies only to a subset of that.
A flow-specification without a destination IP prefix is considered to A flow-specification without a destination IP prefix is considered to
match after all flow-specifications that contain an IP destination match after all flow-specifications that contain an IP destination
prefix. prefix.
5. Validation procedure 6. Validation procedure
Flow specifications received from a BGP peer and which are accepted Flow specifications received from a BGP peer and which are accepted
in the respective Adj-RIB-In are used as input to the route selection in the respective Adj-RIB-In are used as input to the route selection
process. Although the forwarding attributes of two routes for the process. Although the forwarding attributes of two routes for the
same Flow Specification prefix may be the same, BGP is still required same Flow Specification prefix may be the same, BGP is still required
to perform its path selection algorithm in order to select the to perform its path selection algorithm in order to select the
correct set of attributes to advertise. correct set of attributes to advertise.
The first step of the BGP Route Selection procedure (section 9.1.2) The first step of the BGP Route Selection procedure (section 9.1.2 of
is to exclude from the selection procedure routes that are considered [RFC4271]) is to exclude from the selection procedure routes that are
non-feasible. In the context of IP routing information this step is considered non-feasible. In the context of IP routing information
used to validate that the NEXT_HOP attribute of a given route is this step is used to validate that the NEXT_HOP attribute of a given
resolvable. route is resolvable.
The concept can be extended, in the case of Flow Specification NLRI, The concept can be extended, in the case of Flow Specification NLRI,
to allow other validation procedures. to allow other validation procedures.
A flow specification NLRI must be validated such that it is A flow specification NLRI must be validated such that it is
considered feasible if and only if: considered feasible if and only if:
a) The originator of the flow specification matches the originator of a) The originator of the flow specification matches the originator of
the best-match unicast route for the destination prefix embedded the best-match unicast route for the destination prefix embedded
in the flow specification. in the flow specification.
skipping to change at page 17, line 5 skipping to change at page 14, line 47
represents a denial of service in itself. Supposedly, the traffic is represents a denial of service in itself. Supposedly, the traffic is
being dropped by the downstream autonomous-system and there is no being dropped by the downstream autonomous-system and there is no
added value in carrying the traffic to it. added value in carrying the traffic to it.
BGP implementations MUST also enforce that the AS_PATH attribute of a BGP implementations MUST also enforce that the AS_PATH attribute of a
route received via eBGP contains the neighboring AS in the left-most route received via eBGP contains the neighboring AS in the left-most
position of the AS_PATH attribute. While this rule is optional in position of the AS_PATH attribute. While this rule is optional in
the BGP specification, it becomes necessary to enforce it for the BGP specification, it becomes necessary to enforce it for
security reasons. security reasons.
6. Traffic Filtering Actions 7. Traffic Filtering Actions
This specification defines a minimum set of filtering actions that it This specification defines a minimum set of filtering actions that it
standardizes as BGP extended community values [RFC4360]. This is not standardizes as BGP extended community values [RFC4360]. This is not
ment to be an inclusive list of all the possible actions but only a meant to be an inclusive list of all the possible actions but only a
subset that can be interpreted consistently across the network. subset that can be interpreted consistently across the network.
Implementations should provide mechanisms that map an arbitrary bgp Implementations should provide mechanisms that map an arbitrary bgp
community value (normal or extended) to filtering actions that community value (normal or extended) to filtering actions that
require different mappings in different systems in the network. For require different mappings in different systems in the network. For
instance, providing packets with a worse than best-effort per-hop instance, providing packets with a worse than best-effort per-hop
behavior is a functionality that is likely to be implemented behavior is a functionality that is likely to be implemented
differently in different systems and for which no standard behavior differently in different systems and for which no standard behavior
is currently known. Rather than attempting to define it here, this is currently known. Rather than attempting to define it here, this
can be accomplished by mapping a user defined community value to can be accomplished by mapping a user defined community value to
skipping to change at page 17, line 32 skipping to change at page 15, line 27
The default action for a traffic filtering flow specification is to The default action for a traffic filtering flow specification is to
accept IP traffic that matches that particular rule. accept IP traffic that matches that particular rule.
The following extended community values can be used to specify The following extended community values can be used to specify
particular actions. particular actions.
+--------+--------------------+--------------------------+ +--------+--------------------+--------------------------+
| type | extended community | encoding | | type | extended community | encoding |
+--------+--------------------+--------------------------+ +--------+--------------------+--------------------------+
| 0x8006 | traffic-rate | 2-byte as#, 4-byte float | | 0x8006 | traffic-rate | 2-byte as#, 4-byte float |
| | | |
| 0x8007 | traffic-action | bitmask | | 0x8007 | traffic-action | bitmask |
| | | |
| 0x8008 | redirect | 6-byte Route Target | | 0x8008 | redirect | 6-byte Route Target |
+--------+--------------------+--------------------------+ +--------+--------------------+--------------------------+
Traffic-rate The traffic-rate extended community is a non-transitive Traffic-rate The traffic-rate extended community is a non-transitive
extended community across the Autonomous system boundary and uses extended community across the Autonomous system boundary and uses
following extended community encoding: following extended community encoding:
The first two octets carry the 2 octet id which can be assigned The first two octets carry the 2 octet id which can be assigned
from a 2 byte AS number from a 2 byte AS number. When 4 byte AS number is locally
present 2 least significant bytes of such AS number can be
used.
The remaining 4 octets carry the rate information in IEEE The remaining 4 octets carry the rate information in IEEE
floating point format, units being bytes per second. A floating point format, units being bytes per second. A
traffic-rate of 0 should result on all traffic for the traffic-rate of 0 should result on all traffic for the
particular flow to be discarded. particular flow to be discarded.
Traffic-action The traffic-action extended community consists of 6 Traffic-action The traffic-action extended community consists of 6
bytes of which only the 2 least significant bits of the 6th byte bytes of which only the 2 least significant bits of the 6th byte
(from left to right) are currently defined. (from left to right) are currently defined.
skipping to change at page 19, line 5 skipping to change at page 16, line 19
Redirect The redirect extended community allows the traffic to be Redirect The redirect extended community allows the traffic to be
redirected to a VRF routing instance that list the specified redirected to a VRF routing instance that list the specified
route-target in its import policy. If several local instances route-target in its import policy. If several local instances
match this criteria, the choice between them is a local matter match this criteria, the choice between them is a local matter
(for example, the instance with the lowest Route Distinguisher (for example, the instance with the lowest Route Distinguisher
value can be elected). The traffic marking extended community value can be elected). The traffic marking extended community
instruct a system to modify the DSCP bits of a transiting IP instruct a system to modify the DSCP bits of a transiting IP
packet to the corresponding value. This extended community is packet to the corresponding value. This extended community is
encoded as a sequence of 5 zero bytes followed by the DSCP value. encoded as a sequence of 5 zero bytes followed by the DSCP value.
7. Traffic filtering in RFC2547bis networks 8. Traffic filtering in RFC2547bis networks
Provider-based layer 3 VPN networks, such as the ones using an BGP/ Provider-based layer 3 VPN networks, such as the ones using an BGP/
MPLS IP VPN [RFC4364] control plane, have different traffic filtering MPLS IP VPN [RFC4364] control plane, have different traffic filtering
requirements than internet service providers. requirements than internet service providers.
In these environments, the VPN customer network often has traffic In these environments, the VPN customer network often has traffic
filtering capabilities towards their external network connections filtering capabilities towards their external network connections
(e.g. firewall facing public network connection). Less common is the (e.g. firewall facing public network connection). Less common is the
presence of traffic filtering capabilities between different VPN presence of traffic filtering capabilities between different VPN
attachment sites. In an any-to-any connectivity model, which is the attachment sites. In an any-to-any connectivity model, which is the
skipping to change at page 20, line 5 skipping to change at page 17, line 13
MPLS IP VPNs" [RFC4364] . MPLS IP VPNs" [RFC4364] .
Flow specification rules received via this NLRI apply only to traffic Flow specification rules received via this NLRI apply only to traffic
that belongs to the VRF(s) in which it is imported. By default, that belongs to the VRF(s) in which it is imported. By default,
traffic received from a remote PE is switched via an mpls forwarding traffic received from a remote PE is switched via an mpls forwarding
decision and is not subject to filtering. decision and is not subject to filtering.
Contrary to the behavior specified for the non-VPN NLRI, flow rules Contrary to the behavior specified for the non-VPN NLRI, flow rules
are accepted by default, when received from remote PE routers. are accepted by default, when received from remote PE routers.
8. Monitoring 9. Monitoring
Traffic filtering applications require monitoring and traffic Traffic filtering applications require monitoring and traffic
statistics facilities. While this is an implementation specific statistics facilities. While this is an implementation specific
choice, implementations SHOULD provide: choice, implementations SHOULD provide:
o A mechanism to log the packet header of filtered traffic, o A mechanism to log the packet header of filtered traffic,
o A mechanism to count the number of matches for a given Flow o A mechanism to count the number of matches for a given Flow
Specification rule. Specification rule.
9. Security considerations 10. Security considerations
Inter-provider routing is based on a web of trust. Neighboring Inter-provider routing is based on a web of trust. Neighboring
autonomous-systems are trusted to advertise valid reachability autonomous-systems are trusted to advertise valid reachability
information. If this trust model is violated, a neighboring information. If this trust model is violated, a neighboring
autonomous system may cause a denial of service attack by advertising autonomous system may cause a denial of service attack by advertising
reachability information for a given prefix for which it does not reachability information for a given prefix for which it does not
provide service. provide service.
As long as traffic filtering rules are restricted to match the As long as traffic filtering rules are restricted to match the
corresponding unicast routing paths for the relevant prefixes, the corresponding unicast routing paths for the relevant prefixes, the
security characteristics of this proposal are equivalent to the security characteristics of this proposal are equivalent to the
existing security properties of BGP unicast routing. existing security properties of BGP unicast routing.
Where it not the case, this would open the door to further denial of Where it not the case, this would open the door to further denial of
service attacks. service attacks.
10. IANA Considerations Enabling firewall like capabilities in routers without centralized
management could make certain failures harder to diagnose. For
example, with the extensions it is possible to allow TCP packets to
pass between a pair of addresses but not ICMP packets. It would also
be possible to permit packets smaller than 900 or greater than 1000
bytes to pass between a pair of addresses, but not packets whose
length is in the range 900 &mdash 1000. The Internet has become
sufficiently aware of firewalls that such behavior is less likely to
be confusing than it was a few years ago and there are no new
capabilities introduced by these extensions, just an increased
likelihood that such capabilities will be used.
11. IANA Considerations
A flow specification consists of a sequence of flow components, which A flow specification consists of a sequence of flow components, which
are identified by a an 8-bit component type. Types must be assigned are identified by a an 8-bit component type. Types must be assigned
and interpreted uniquely. The current specification defines types 1 and interpreted uniquely. The current specification defines types 1
though 12, with the value 0 being reserved. though 12, with the value 0 being reserved.
For the purpose of this work IANA has allocated values for two SAFIs: For the purpose of this work IANA has allocated values for two SAFIs:
SAFI 133 for IPv4 and SAFI 134 for VPNv4 dissemination of flow SAFI 133 for IPv4 and SAFI 134 for VPNv4 dissemination of flow
specification rules. specification rules.
skipping to change at page 22, line 49 skipping to change at page 19, line 4
Type 6 - Source port Type 6 - Source port
Type 7 - ICMP type Type 7 - ICMP type
Type 8 - ICMP code Type 8 - ICMP code
Type 9 - TCP flags Type 9 - TCP flags
Type 10 - Packet length Type 10 - Packet length
Type 11 - DSCP Type 11 - DSCP
Type 12 - Fragment Type 12 - Fragment
In order to manage the limited number space and accommodate several In order to manage the limited number space and accommodate several
usages the following policies defined by RFC 5226 [RFC5226] are used: usages the following policies defined by RFC 5226 [RFC5226] are used:
+--------------+-------------------------------+ +--------------+-------------------------------+
| Range | Policy | | Range | Policy |
+--------------+-------------------------------+ +--------------+-------------------------------+
| 0 | Invalid value | | 0 | Invalid value |
| | |
| [1 .. 12] | Defined by this specification | | [1 .. 12] | Defined by this specification |
| | |
| [13 .. 127] | Specification Required | | [13 .. 127] | Specification Required |
| | |
| [128 .. 255] | Private Use | | [128 .. 255] | Private Use |
+--------------+-------------------------------+ +--------------+-------------------------------+
The specification of a particular "flow component type" must clearly The specification of a particular "flow component type" must clearly
identify what is the criteria used to match packets forwarded by the identify what is the criteria used to match packets forwarded by the
router. This criteria should be meaningful across router hops and router. This criteria should be meaningful across router hops and
not depend on values that change hop-by-hop such as ttl or layer-2 not depend on values that change hop-by-hop such as ttl or layer-2
encapsulation. encapsulation.
The "Traffic-action" extended community defined in this document has The "Traffic-action" extended community defined in this document has
6 unused bits which can be used to convey additional meaning. These 6 unused bits which can be used to convey additional meaning.
values should be assigned via IETF Consensus rules only. Authors would like to ask IANA to create and maintain a new registry
entitled: "Traffic Action Fields". These values should be assigned
via IETF Consensus rules only. Authors recommend to allocate the
following traffic action fields:
Future assignment are to be made using either the Standards Action 0 Terminal Action
process defined in [RFC2434], the Early IANA Allocation process
defined in [RFC4020], or the "First Come First Served" policy defined
in [RFC2434].
11. Acknowledgments 1 Sample
The authors would like to thank Yakov Rekhter, Dennis Ferguson and 2-47 Unassigned
Chris Morrow for their comments.
12. Acknowledgments
The authors would like to thank Yakov Rekhter, Dennis Ferguson, Chris
Morrow and Charlie Kaufman for their comments.
Chaitanya Kodeboyina helped design the flow validation procedure. Chaitanya Kodeboyina helped design the flow validation procedure.
Steven Lin and Jim Washburn ironed out all the details necessary to Steven Lin and Jim Washburn ironed out all the details necessary to
produce a working implementation. produce a working implementation.
12. Normative References 13. Normative References
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981. RFC 793, September 1981.
[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.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006. Communities Attribute", RFC 4360, February 2006.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, February 2006. Networks (VPNs)", RFC 4364, February 2006.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
Authors' Addresses Authors' Addresses
Pedro Marques Pedro Marques
Juniper Networks Juniper Networks
1194 N. Mathilda Ave. 1194 N. Mathilda Ave.
Sunnyvale, CA 94089 Sunnyvale, CA 94089
skipping to change at page 27, line 4 skipping to change at page 21, line 25
Sunnyvale, CA 94089 Sunnyvale, CA 94089
US US
Email: bgreene@juniper.net Email: bgreene@juniper.net
Jared Mauch Jared Mauch
NTT/Verio NTT/Verio
8285 Reese Lane 8285 Reese Lane
Ann Arbor, MI 48103-9753 Ann Arbor, MI 48103-9753
US US
Email: jared@puck.nether.net
Danny McPherson Danny McPherson
Arbor Networks Arbor Networks
Email: danny@arbor.net Email: danny@arbor.net
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