Internet DRAFT - draft-liang-idr-flowspec-mpls-action
draft-liang-idr-flowspec-mpls-action
IDR Working Group Q. Liang
Internet-Draft S. Hares
Intended status: Standards Track J. You
Expires: September 22, 2016 Huawei
R. Raszuk
Bloomberg LP
D. Ma
Cisco
March 21, 2016
BGP Flow Specification MPLS action
draft-liang-idr-flowspec-mpls-action-00
Abstract
This document specifies a BGP Flow specification policy action to
push/pop/swap MPLS labels.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. MPLS Flow Specification Deployment . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Overview of Proposal . . . . . . . . . . . . . . . . . . . . 3
4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 4
5. Deployment Examples . . . . . . . . . . . . . . . . . . . . . 6
5.1. Exampel 1 - MPLS Filter + MPLS Action . . . . . . . . . . 6
5.2. Example 2 - IP filter + MPLS action . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References . . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
This section provides the background for proposing a new action for
BGP Flow specification [RFC5575] that push/pops MPLS labels or swaps
MPLS labels. For those familiar with BGP Flow specification
([RFC5575], [RFC7674] [I-D.ietf-idr-flow-spec-v6],
[I-D.ietf-idr-flowspec-l2vpn], and MPLS ([RFC3107]) can skip this
background section.
1.1. Background
[RFC5575] defines the flow specification (FlowSpec) that is an
n-tuple consisting of several matching criteria that can be applied
to IP traffic. The matching criteria can include elements such as
source and destination address prefixes, IP protocol, and transport
protocol port numbers. A given IP packet is said to match the
defined flow if it matches all the specified criteria. [RFC5575]
also defines a set of filtering actions, such as rate limit,
redirect, marking, associated with each flow specification. A new
Border Gateway Protocol ([RFC4271]) Network Layer Reachability
Information (BGP NLRI) (AFI/SAFI: 1/133 for IPv4, AFI/SAFI: 1/134 for
VPNv4) encoding format is used to distribute traffic flow
specifications.
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[RFC3107] specifies the way in which the label mapping information
for a particular route is piggybacked in the same Border Gateway
Protocol Update message that is used to distribute the route itself.
Label mapping information is carried as part of the Network Layer
Reachability Information (NLRI) in the Multiprotocol Extensions
attributes. The Network Layer Reachability Information is encoded as
one or more triples of the form <length, label, prefix>. The NLRI
contains a label is indicated by using Subsequent Address Family
Identifier (SAFI) value 4.
[RFC4364] describes a method in which each route within a Virtual
Private Network (VPN) is assigned a Multiprotocol Label Switching
(MPLS) label. If the Address Family Identifier (AFI) field is set to
1, and the SAFI field is set to 128, the NLRI is an MPLS-labeled VPN-
IPv4 address.
1.2. MPLS Flow Specification Deployment
In BGP VPN/MPLS networks when flow specification policy rules exist
on multiple forwarding devices in the network bound with labels from
one or more LSPs, only the ingress LSR (Label Switching Router) needs
to identify a particular traffic flow based on the matching criteria
for flow. Once the flow is match by the ingress LSR, the ingress LSR
steers the packet to a corresponding LSP (Label Switched Path).
Other LSRs of the LSP just need to forward the packet according to
the label carried in it.
2. Terminology
Flow Specification (FlowSpec): A flow specification is an n-tuple
consisting of several matching criteria that can be applied to IP
traffic, including filters and actions. Each FlowSpec consists of a
set of filters and a set of actions.
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Overview of Proposal
This document proposes adding a BGP-FS action in an extended
community alters the label switch path associated with a matched
flow. If the match does not have a label switch path, this action is
skipped.
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The BGP flow specification (BGP-FS) policy rule could match on the
destination prefix and then utilize a BGP-FS action to adjust the
label path associated with it (push/pop/swap tags.) Or a BGP-FS
policy rule could match on any set of BGP-FS match conditions
associated with a BGP-FS action that adjust the label switch path
(push/pop/swap).
draft-ietf-yong-flowspec-mpls-match provides a match BGP-FS that may
be used with this action to match and direct MPLS packets.
4. Protocol Extensions
A new label-action is defined as BGP extended community value based
on Section 7 of [RFC5575].
+--------+--------------------+--------------------------+
| type | extended community | encoding |
+--------+--------------------+--------------------------+
| TBD1 | label-action | MPLS tag |
+--------+--------------------+--------------------------+
Figure 1
Label-action is described below:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (TBD1 | OpCode|Reserve| order |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Label
| Label | Exp |S| TTL | Stack
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Entry
The use and the meaning of these fields are as follows:
Type: the same as defined in [RFC4360]
Figure 2
OpCode: Operation code
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+------+------------------------------------------------------------+
|OpCode| Function |
+------+------------------------------------------------------------+
| 0 | Push the MPLS tag |
+------+------------------------------------------------------------+
| 1 | Pop the outermost MPLS tag in the packet |
+------+------------------------------------------------------------+
| 2 | Swap the MPLS tag with the outermost MPLS tag in the packet|
+------+------------------------------------------------------------+
| 3~15 | Reserved |
+------+------------------------------------------------------------+
* where:
* When the Opcode field is set to 0, the label stack entry Should
be pushed on the MPLS label stack.
* When the OpCode field is set to 1, the label stack entry is
invalid, and the router SHOULD pop the existing outermost MPLS
tag in the packet.
* When the OpCode field is set to 2, the router SHOULD swap the
label stack entry with the existing outermost MPLS tag in the
packet. If the packet has no MPLS tag, it just pushes the
label stack entry.
* Note-1: The OpCode 0 or 1 may be used in some SDN networks,
such as the scenario described in
[I-D.filsfils-spring-segment-routing-central-epe].
* The OpCode 2 can be used in traditional BGP MPLS/VPN networks.
Reserved: all zeros
Order: within multiple label actions A FlowSpec rule MAY be
associated with one or more ordering label-action each in an
extended community. If multiple label-actions occur, this field
gives the order of this action within that group. If two MPLs
actions arrive with the same order the last mpls action received
for an order will be used.
Label: the same as defined in [RFC3032]
Bottom of Stack (S): the same as defined in [RFC3032]. It SHOULD
be invalid, and set to zero by default. It MAY be modified by the
forwarding router locally.
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Time to Live (TTL): the same as defined in [RFC3032]. It MAY be
modified by the forwarding router locally.
Experimental Use (Exp): the same as defined in [RFC3032]. It MAY
be modified by the forwarding router according to the local
routing policy.
5. Deployment Examples
5.1. Exampel 1 - MPLS Filter + MPLS Action
Forwarding information for the traffic
for source: IP2, Destination: IP1
Purpose of BGP-FS filters: send DDoS traffic to IDS/IPS server
PE1: in(<IP2,IP1>) --> out(Label1)
ASBR1: in(Label1) --> out(Label1)
ASBR2: in(Label1) --> out(Label2)
PE2: in(Label2) --> out(--)
|<------AS1----->| |<------AS2----->|
+-----+ +------+ +------+ +-----+
VPN 1,IP1..| PE1 |====|ASBR-1|----|ASBR-2|====| PE2 |..IDS/IPS
IP2 +-----+ +------+ +------+ +-----+
|-----label 1---------||-label 2---------|
|---------BGP VPN Flowspec LSP--------->|
Figure 1 - Forwarding Diagram
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locally configured filters
Filters:
destination ip prefix:IP2/32
source ip prefix:IP1/32
Action:
put on LSP with Label 1
PE-2 Installs:
BGP-FS Filter:
MPLS filter for Label 1 and label 2
BGP-FS Actions:
Traffic-Rate limit
MPLS POP
PE-2 Sends to ASBR-2
BGP-FS Filter
MPLS filter for label 1 and Label 2
BGP-FS Actions:
Traffic-Rate limit
Label SWAP 1 to 2
PE-1 Sends to ASBR 1
BGP-FS filter
MPLS filter for label 1
BGP-FS Actions
Traffic-Rate limit
5.2. Example 2 - IP filter + MPLS action
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Forwarding information for the traffic from IP1 to IP2 in the Routers:
PE1: in(<IP2,IP1>) --> out(Label2)
ASBR1: in(Label2) --> out(Label3)
ASBR2: in(Label3) --> out(Label4)
PE2: in(Label4) --> out(--)
Labels allocated by Flow policy process
Label4 allocated by PE2
Label3 allocated by ASBR2
Label2 allocated by ASBR1
|<------AS1----->| |<------AS2----->|
+-----+ +-----+ +-----+ +-----+
VPN 1,IP1..| PE1 |====|ASBR1|----|ASBR2|====| PE2 |..
IP2 +-----+ +-----+ +-----+ +-----+
| LDP LSP1 | | LDP LSP2 |
| -------> | | -------> |
|-------BGP VPN Flowspec LSP---->|
(Label2) (Label3) (Label4)
Figure 1 - Forwarding Diagram
BGP-FS rule1 (locally configured)
Filters:
destination ip prefix:IP2/32
source ip prefix:IP1/32
Actions:
traffic-marking: 1
MPLS POP
Note:
The following Extended Communities are added/deleted
[rule-1a] BGP-FS action MPLS POP [used on PE2]
[rule-1b] BGP-FS action SWAP 4 [used on ASBR-2]
[rule-1c] BGP-FS action SWAP 3 [used on ASBR-1]
[rule-1d] BGP-FS action push 2 [used on PE1]
BGP Filter rules
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PE-2 Changes BGP-FS rule-1a to rule-1b prior to sending
Clears Extended Community: BGP-FS action MPLS POP
Adds Extended Community: BGP-FS action MPLS SWAP 4
ASBR-2 receives BGP-FS rule-1b (NRLI + 2 Extended Community)
Installs the BGP-FS rule-1b (MPLS SWAP 4, traffic-marking)
Changes BGP-FS rule-1b to rule-1c prior to sending to ASBR1
Clear Extended Community: BGP-FS action MPLS SWAP 4
Adds Extended Community: BGP-FS action MPLS SWAP 3
ASBR-1 Receives BGP-FS rule-1c (NLRI + 2 Extended Community)
Installs the BGP-FS rule-1c (MPLS SWAP 3, traffic-marking
Changes BGP-FS rule-1c to rule-1d prior to sending to PE-2
Clear Extended Community: BGP-FS action MPLS SWAP 3
Adds Extended Community: BGP-FS action MPLS SWAP 2
PE-1 Receives BGP-FS rule-1d (NLRI + 2 Extended Communities)
Installs BGP-FS rule-1d action [MPLS SWAP 2, traffic-marking]
6. Security Considerations
The validation of BGP Flow Specification policy in NLRI is considered
in [I-D.hares-idr-flowspec-combo] for option 1, and for option 2.
Additional security has been proposed in
[I-D.ietf-idr-bgp-flowspec-oid]. A BGP5575bis document will consider
the revised security.
For Option 1, the MPLS Match can be one of the match filters, and and
the final match is an "AND" of all the filters. Match filters are
tested in the order specified in [I-D.hares-idr-flowspec-combo] and/
or an RFC5575bis document.
[I-D.hares-idr-flowspec-combo] suggests a default order for filters
and for the BGP-FS action proposed after [RFC5575], and this document
discusses how conflicts between action are handled.
7. IANA Considerations
This section complies with [RFC7153]
IANA is requested to a new entry in "Flow Spec action types registry"
with the following values:
Value Name: Value Reference
=========== ===== =========
Lable Action TBD [this document]
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8. Acknowledgement
The authors would like to thank Shunwan Zhuang, Zhenbin Li, Peng Zhou
and Jeff Haas for their comments.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<http://www.rfc-editor.org/info/rfc3031>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<http://www.rfc-editor.org/info/rfc3032>.
[RFC3107] Rekhter, Y. and E. Rosen, "Carrying Label Information in
BGP-4", RFC 3107, DOI 10.17487/RFC3107, May 2001,
<http://www.rfc-editor.org/info/rfc3107>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <http://www.rfc-editor.org/info/rfc4360>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <http://www.rfc-editor.org/info/rfc4364>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>.
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[RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP
Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
March 2014, <http://www.rfc-editor.org/info/rfc7153>.
[RFC7674] Haas, J., Ed., "Clarification of the Flowspec Redirect
Extended Community", RFC 7674, DOI 10.17487/RFC7674,
October 2015, <http://www.rfc-editor.org/info/rfc7674>.
9.2. Informative References
[I-D.filsfils-spring-segment-routing-central-epe]
Filsfils, C., Previdi, S., Patel, K., Shaw, S., Ginsburg,
D., and D. Afanasiev, "Segment Routing Centralized Egress
Peer Engineering", draft-filsfils-spring-segment-routing-
central-epe-05 (work in progress), August 2015.
[I-D.hares-idr-flowspec-combo]
Hares, S., "An Information Model for Basic Network Policy
and Filter Rules", draft-hares-idr-flowspec-combo-01 (work
in progress), March 2016.
[I-D.ietf-idr-bgp-flowspec-oid]
Uttaro, J., Filsfils, C., Smith, D., Alcaide, J., and P.
Mohapatra, "Revised Validation Procedure for BGP Flow
Specifications", draft-ietf-idr-bgp-flowspec-oid-02 (work
in progress), January 2014.
[I-D.ietf-idr-flow-spec-v6]
McPherson, D., Raszuk, R., Pithawala, B., Andy, A., and S.
Hares, "Dissemination of Flow Specification Rules for
IPv6", draft-ietf-idr-flow-spec-v6-07 (work in progress),
March 2016.
[I-D.ietf-idr-flowspec-l2vpn]
Weiguo, H., Litkowski, S., and S. Zhuang, "Dissemination
of Flow Specification Rules for L2 VPN", draft-ietf-idr-
flowspec-l2vpn-03 (work in progress), November 2015.
[I-D.yong-idr-flowspec-mpls-match]
Yong , L., Hares , S., Liang , Q., and J. You , "BGP Flow
Specification Filter for MPLS Label", March 2016.
Authors' Addresses
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Qiandeng Liang
Huawei
101 Software Avenue, Yuhuatai District
Nanjing 210012
China
Email: liangqiandeng@huawei.com
Susan Hares
Huawei
7453 Hickory Hill
Saline, MI 48176
USA
Email: shares@ndzh.com
Jianjie You
Huawei
101 Software Avenue, Yuhuatai District
Nanjing 210012
China
Email: youjianjie@huawei.com
Robert Raszuk
Bloomberg LP
731 Lexington Ave
New York City, NY 10022
USA
Email: robert@raszuk.net
Dan Ma
Cisco
Email: danma@cisco.com
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