Network Working Group W. Hao
Internet-Draft D. Eastlake
Intended status: Standards Track Huawei
Expires: July 7, 2019 J. Uttaro
AT&T
S. Litkowski
Orange Business Service
S. Zhuang
Huawei
January 03, 2019
BGP Dissemination of L2VPN Flow Specification Rules
draft-ietf-idr-flowspec-l2vpn-09
Abstract
This document defines a BGP flow-spec extension to disseminate L2 VPN
Ethernet traffic filtering rules. SAFI=134 in [RFC5575] is redefined
for this purpose. A new subset of component types and extended
community also are defined. A new subset of component types and new
extended community also are defined.
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 RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 7, 2019.
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Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Layer 2 Flow Specification encoding in BGP . . . . . . . . . 3
3. Ethernet Flow Specification encoding in BGP . . . . . . . . . 4
3.1. Order of Traffic Filtering Rules . . . . . . . . . . . . 6
4. Ethernet Flow Specification Traffic Actions . . . . . . . . . 7
4.1. VLAN-action . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. TPID-action . . . . . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References . . . . . . . . . . . . . . . . . . 11
9.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
BGP Flow-spec is an extension to BGP that supports the dissemination
of traffic flow specification rules. It leverages the BGP Control
Plane to simplify the distribution of ACLs. Using this extension new
filter rules can be injected to all BGP peers simultaneously without
changing router configuration. The typical application of BGP Flow-
spec is to automate the distribution of traffic filter lists to
routers for DDOS mitigation, access control, etc.
[RFC5575] defines a new BGP Network Layer Reachability
Information(NLRI) format used to distribute traffic flow
specification rules. NLRI (AFI=1, SAFI=133) is for IPv4 unicast
filtering. NLRI (AFI=1, SAFI=134) is for BGP/MPLS VPN filtering.
The Flow specification match part only includes L3/L4 information
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like source/destination prefix, protocol, ports, and etc., so traffic
flows can only be selectively filtered based on L3/L4 information.
Layer 2 Virtual Private Networks (L2VPNs) have already been deployed
in an increasing number of networks today. In L2VPN network, we also
have requirement to deploy BGP Flow-spec to mitigate DDoS attack
traffic. Within L2VPN network, both IP and non-IP Ethernet traffic
maybe exist. For IP traffic filtering, the Flow specification rules
defined in [RFC5575] which include match criteria and actions can
still be used, flow specification rules received via new NLRI format
apply only to traffic that belongs to the VPN instance(s) in which it
is imported. For non-IP Ethernet traffic filtering, Layer 2 related
information like source/destination MAC and VLAN should be
considered. But the flow specification match criteria defined in
[RFC5575] only include layer 3 and layer 4 IP information, not layer
2 Ethernet information.
There are different kinds of L2VPN networks like EVPN [RFC7432], BGP
VPLS [RFC4761], LDP VPLS [RFC4762] and border gateway protocol (BGP)
auto discovery [RFC6074]. Because the flow-spec feature relies on
BGP protocol to distribute traffic filtering rules, it can only be
incrementally deployed in those L2VPN networks where BGP has already
been used for auto discovery and/or signaling purposes such as BGP-
based VPLS [RFC4761], EVPN and LDP-based VPLS [RFC4762] [4762] with
BGP auto-discovery [RFC6074].
This draft proposes a new subset of flow-spec component types and an
extended community to support L2VPN flow-spec application. The flow-
spec rules can be enforced on all border routers or on some interface
sets of the border routers. SAFI=134 in [RFC5575] is redefined for
dissemination of traffic filtering information in an L2VPN
environment.
2. Layer 2 Flow Specification encoding in BGP
The [RFC5575] defines SAFI 133 and SAFI 134 for "dissemination of
IPv4 flow specification rules" and "dissemination of VPNv4 flow
specification rules" respectively. [I-D.ietf-idr-flow-spec-v6]
redefines the [RFC5575] SAFIs in order to make them applicable to
both IPv4 and IPv6 applications. This document will further redefine
the SAFI 134 in order to make them applicable to L2VPN applications.
The following changes are defined:
"SAFI 134 for dissemination of L3VPN flow specification rules" to now
be defined as "SAFI 134 for dissemination of VPN flow specification
rules"
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For SAFI 134 the indication to which address family it is referring
to will be recognized by AFI value (AFI=1 for VPNv4, AFI=2 VPNv6 and
AFI=25 for L2VPN). Such modification is fully backwards compatible
with existing implementation and production deployments.
For SAFI 134 the indication to which address family it is referring
to will be recognized by AFI value (AFI=1 for VPNv4, AFI=2 VPNv6 and
AFI=25 for L2VPN). Such modification is fully backwards compatible
with existing implementation and production deployments.
3. Ethernet Flow Specification encoding in BGP
The NLRI format for this address family consists of a fixed-length
Route Distinguisher field (8 bytes) followed by a flow specification,
following the encoding defined in this document. The NLRI length
field includes both the 8 bytes of the Route Distinguisher as well as
the subsequent flow specification.
Flow specification rules received via this NLRI apply only to traffic
that belongs to the VPN instance(s) into which it is imported. Flow
rules are accepted by default when received from remote PE routers.
Besides the component types defined in [RFC5575] and
[I-D.ietf-idr-flow-spec-v6], this document specifies the following
additional component types for L2 VPN Ethernet traffic filtering:
Type 14 - Ethernet Type
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match two-octet
field. Values are encoded as 2-byte quantities. Ethernet II framing
defines the two-octet Ethernet Type (EtherType) field in an Ethernet
frame, preceded by destination and source MAC addresses, that
identifies an upper layer protocol encapsulating the frame data.
Type 15 - Source MAC
Encoding: <type (1 octet), MAC Address length (1 octet), MAC Address>
Defines the source MAC Address to match.
Type 16 - Destination MAC
Encoding: <type (1 octet), MAC Address length (1 octet), MAC Address>
Defines the destination MAC Address to match.
Type 17 - DSAP(Destination Service Access Point) in LLC
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Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the 1-octet
DSAP in the 802.2 LLC (Logical Link Control Header). Values are
encoded as 1-byte quantities. The operation field is encoded as a
'Numeric operator' defined in [RFC5575].
Type 18 - SSAP(Source Service Access Point) in LLC
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the 1-octet
SSAP in the 802.2 LLC. Values are encoded as 1-byte quantities.
Type 19 - Control field in LLC
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 1-octet
control field in the 802.2 LLC. Values are encoded as 1-byte
quantities.
Type 20 - SNAP
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 5-octet SNAP
(Sub-Network Access Protocol) field. Values are encoded as 5-byte
quantities.
Type 21 - VLAN ID
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match VLAN ID.
Values are encoded as 2-byte quantities, where the four most
significant bits are zero and the 12 least significant bits contain
the VLAN value.
In the virtual local-area network (VLAN) stacking case, the VLAN ID
is the outer VLAN ID.
Type 22 - VLAN COS
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 3-bit VLAN
COS fields [802.1Q]. Values are encoded using a single byte, where
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the five most significant bits are zero and the three least
significant bits contain the VLAN COS value.
In the virtual local-area network (VLAN) stacking case, the VLAN COS
is outer VLAN COS.
Type 23 - Inner VLAN ID
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the inner
VLAN ID using for virtual local-area network (VLAN) stacking or Q in
Q use. Values are encoded as 2-byte quantities, where the four most
significant bits are zero and the 12 least significant bits contain
the VLAN value.
In single VLAN case, this component type MUST NOT be used.
Type 24 - Inner VLAN COS
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 3-bit inner
VLAN COS fields [802.1Q] using for virtual local-area network (VLAN)
stacking or Q in Q use. Values are encoded using a single byte,
where the five most significant bits are zero and the three least
significant bits contain the VLAN COS value.
In single VLAN case, the component type MUST not be used.
3.1. Order of Traffic Filtering Rules
The original definition for the order of traffic filtering rules can
be reused with new consideration for the MAC Address offset. As long
as the offsets are equal, the comparison is the same, retaining
longest-prefix-match semantics. If the offsets are not equal, the
lowest offset has precedence, as this flow matches the most
significant bit.
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Pseudocode:
flow_rule_L2_cmp (a, b)
{
comp1 = next_component(a);
comp2 = next_component(b);
while (comp1 || comp2) {
// component_type returns infinity on end-of-list
if (component_type(comp1) < component_type(comp2)) {
return A_HAS_PRECEDENCE;
}
if (component_type(comp1) > component_type(comp2)) {
return B_HAS_PRECEDENCE;
}
if (component_type(comp1) == MAC_DESTINATION || MAC_SOURCE) {
common = MIN(MAC Address length (comp1),
MAC Address length (comp2));
cmp = MAC Address compare(comp1, comp2, common);
// not equal, lowest value has precedence
// equal, longest match has precedence
} else {
common =
MIN(component_length(comp1), component_length(comp2));
cmp = memcmp(data(comp1), data(comp2), common);
// not equal, lowest value has precedence
// equal, longest string has precedence
}
}
return EQUAL;
}
4. Ethernet Flow Specification Traffic Actions
The default action for a layer 2 traffic filtering flow specification
is to accept traffic that matches that particular rule. The
following extended community values per [RFC5575] can be used to
specify particular actions in an L2 VPN network:
+--------+--------------------+--------------------------+
| type | extended community | encoding |
+--------+--------------------+--------------------------+
| 0x8006 | traffic-rate | 2-byte as#, 4-byte float |
| 0x8007 | traffic-action | bitmask |
| 0x8008 | redirect | 6-byte Route Target |
| 0x8009 | traffic-marking | DSCP value |
+--------+--------------------+--------------------------+
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Redirect: The action should be redefined to allow the traffic to be
redirected to a MAC or IP VRF routing instance that lists the
specified route-target in its import policy.
Besides the above extended communities, this document also proposes
the following BGP extended communities specifications for Ethernet
flow to extend [RFC5575]:
+--------+------------------------+--------------------------+
| type | extended community | encoding |
+--------+------------------------+--------------------------+
| TBD1 | VLAN-action | bitmask |
| TBD2 | TPID-action | bitmask |
+--------+------------------------+--------------------------+
4.1. VLAN-action
The VLAN-action extended community, as shown in the diagram below,
consists of 6 bytes that include t action Flags, two VLAN IDs, and
the associating COS value. The action Flags fields are further
divided into two parts which correspond to the first action and the
second action respectively, bit 0 to bit 7 give the first action
while bit 8 to bit 15 give the second action. The bits of PO, PU,
SW, RI and RO in each part represent the action of Pop, Push, Swap,
Rewrite inner VLAN and Rewrite outer VLAN respectively. Through this
method, more complicated actions also can be represented in a single
VLAN-action extened community, such as SwapPop, PushSwap, etc. For
example, SwapPop action is the sequence of two actions, the first
action is Swap and the second action is Pop.
0 7 15
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|PO1|PU1|SW1|RI1|RO1|...|PO2|PU2|SW2|RI2|RO2|...|
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| VLAN ID1 |COS1 |R1|
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| VLAN ID2 |COS2 |R2|
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
PO1: Pop action. If the PO1 flag is one, it indicates the outmost
VLAN should be removed.
PU1: Push action. If PU1 is one, it indicates VLAN ID1 will be
added, the associated COS is COS1.
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SW1: Swap action. If the SW1 flag is one, it indicates the outer
VLAN and inner VLAN should be swapped.
PO2: Pop action. If the PO2 flag is one, it indicates the outmost
VLAN should be removed.
PU2: Push action. If PU2 is one, it indicates VLAN ID2 will be
added, the associated COS is COS2.
SW2: Swap action. If the SW2 flag is one, it indicates the outer
VLAN and inner VLAN should be swapped.
RI1 and RI2: Rewrite inner VLAN action. If the RI flag is one, it
indicates the inner VLAN should be replaced by a new VLAN, the new
VLAN is VLAN ID1, the associated COS is COS1. If the VLAN ID1 is 0,
the action is to only modify the COS value of inner VLAN.
RO1 and RO2: Rewrite outer VLAN action. If the RO flag is one, it
indicates the outer VLAN should be replaced by a new VLAN, the new
VLAN is VLAN ID2, the associated COS is COS2. If the VLAN ID2 is 0,
the action is to only modify the COS value of outer VLAN.
R1 and R2: Reserved for future use. MUST be sent as zero and ignored
on receipt.
Giving an example, if the action of PUSH Inner VLAN 10 with COS value
5 and Outer VLAN 20 with COS value 6 is needed, the format of the
VLAN-action extended community is as follows:
0 7 15
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|0 |1 |0 |0 |0 |0 |0 |0 |0 |1 |0 |0 |0 |0 |0 |0 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 10 |1 |0 |1 |0 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 20 |1 |1 |0 |0 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
4.2. TPID-action
The TPID-action extended community consists of 6 bytes which includes
the fields of action Flags, TPID1 and TPID2.
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0 15
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|TI|TO| Resv |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TP ID1 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TP ID2 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
TI: Mapping inner TP ID action. If the TI flag is one, it indicates
the inner TP ID should be replaced by a new TP ID, the new TP ID is
TP ID1.
TO: Mapping outer TP ID action. If the TO flag is one, it indicates
the outer TP ID should be replaced by a new TP ID, the new TP ID is
TP ID2.
Resv: Reserved for future use. MUST be sent as zero and ignored on
receipt.
5. IANA Considerations
IANA is requested to change the description for SAFI 134 [RFC5575]
[RFC5575] to read as follows more general description and to change
the reference for it to [this document]:
134 VPN dissemination of flow specification rules
IANA is requested to allocate 11 new values in the Flow-Spec
Component Type registry as follows:
+--------+-------------------------------+--------------------------+
| type | RFC or Draft | discription |
+--------+-------------------------------+--------------------------+
| 14 |This draft | Ethernet Type |
| 15 |This draft | Source MAC |
| 16 |This draft | Destination MAC |
| 17 |This draft | DSAP in LLC |
| 18 |This draft | SSAP in LLC |
| 19 |This draft | Control field in LLC |
| 20 |This draft | SNAP |
| 21 |This draft | VLAN ID |
| 22 |This draft | VLAN COS |
| 23 |This draft | Inner VLAN ID |
| 24 |This draft | Inner VLAN COS |
+--------+-------------------------------+--------------------------+
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IANA is requested to update the reference for the following
assignment in the "BGP Extended Communities Type - extended,
transitive" registry:
Type value Name Reference
---------- ---------------------------------------- ---------
0x080A Flow spec VLAN action [this document]
0x080B Flow spec TPID action [this document]
6. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification.
7. Acknowledgements
The authors wish to acknowledge the important contributions of Hannes
Gredler, Xiaohu Xu, Zhenbin Li, Lucy Yong and Feng Dong.
8. Contributors
Qiandeng Liang
Huawei Technologies
101 Software Avenue, Yuhuatai District
Nanjing 210012
China
Email: liangqiandeng@huawei.com
9. References
9.1. Normative References
[I-D.ietf-idr-flow-spec-v6]
McPherson, D., Raszuk, R., Pithawala, B.,
akarch@cisco.com, a., and S. Hares, "Dissemination of Flow
Specification Rules for IPv6", draft-ietf-idr-flow-spec-
v6-09 (work in progress), November 2017.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and
Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007,
<https://www.rfc-editor.org/info/rfc4761>.
[RFC4762] Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
<https://www.rfc-editor.org/info/rfc4762>.
[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,
<https://www.rfc-editor.org/info/rfc5575>.
[RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
"Provisioning, Auto-Discovery, and Signaling in Layer 2
Virtual Private Networks (L2VPNs)", RFC 6074,
DOI 10.17487/RFC6074, January 2011,
<https://www.rfc-editor.org/info/rfc6074>.
9.2. Informative References
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
2015, <https://www.rfc-editor.org/info/rfc7432>.
Authors' Addresses
Weiguo Hao
Huawei
101 Software Avenue,
Nanjing 210012
China
Email: haoweiguo@huawei.com
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Donald E. Eastlake, 3rd
Huawei
155 Beaver Street
Milford, MA 01757
USA
Email: d3e3e3@gmail.com
James Uttaro
AT&T
Email: uttaro@att.com
Stephane Litkowski
Orange Business Service
Email: stephane.litkowski@orange.com
Shunwan Zhuang
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
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