IDR W. Hao
Q. Liang
Internet Draft Huawei
Intended status: Standards Track Jim Uttaro
AT&T
S. Litkowski
Orange Business Service
S. Zhuang
Huawei
Expires: November 2016 May 17, 2016
Dissemination of Flow Specification Rules for L2 VPN
draft-ietf-idr-flowspec-l2vpn-04.txt
Abstract
This document defines BGP flow-spec extension for Ethernet traffic
filtering in L2 VPN network. SAFI=134 in [RFC5575] is redefined for
dissemination traffic filtering information in an L2VPN environment.
A new subset of component types and extended community also are
defined.
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), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
Hao & Liang,et,al Expires November 17, 2016 [Page 1]
Internet-Draft EVPN Flow Spec May 2016
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://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
5. Security Considerations..................................... 10
6. IANA Considerations ........................................ 10
6.1. Normative References................................... 12
6.2. Informative References................................. 12
7. Acknowledgments ............................................ 12
1. Introduction
BGP Flow-spec is an extension to BGP that allows for the
dissemination of traffic flow specification rules. It leverages the
BGP Control Plane to simplify the distribution of ACLs, 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 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
Hao & Liang,et,al Expires November 17, 2016 [Page 2]
Internet-Draft EVPN Flow Spec May 2016
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, layer 2
Ethernet information haven't been included.
There are different kinds of L2VPN networks like EVPN [EVPN], BGP
VPLS [RFC4761], LDP VPLS [RFC4762] and border gateway protocol (BGP)
auto discovery [RFC 6074]. Because the flow-spec feature relies on
BGP protocol to distribute traffic filtering rules, so 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 [4761], EVPN and LDP-based VPLS [4762] with BGP
auto-discovery [6074].
This draft proposes a new subset of component types and 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 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. [draft-ietf-idr-flow-spec-v6-06]
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''
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.
Hao & Liang,et,al Expires November 17, 2016 [Page 3]
Internet-Draft EVPN Flow Spec May 2016
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 shall include 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) in which it is imported.
Flow rules are accepted by default, when received from remote PE
routers.
Besides the component types defined in [RFC5575] and [draft-ietf-
idr-flow-spec-v6-06], this document proposes the following
additional component types for L2VPN 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 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
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 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
'Numeric operator' defined in [RFC5575].
Hao & Liang,et,al Expires November 17, 2016 [Page 4]
Internet-Draft EVPN Flow Spec May 2016
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 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 virtual local-area network (VLAN) stacking case, the VLAN ID is
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 [802.1p]. 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.
Hao & Liang,et,al Expires November 17, 2016 [Page 5]
Internet-Draft EVPN Flow Spec May 2016
In 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 inner VLAN
ID using for virtual local-area network (VLAN) stacking or Q in Q
case. 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, the 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 [802.1p] using for virtual local-area network (VLAN)
stacking or Q in Q case. 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.
Hao & Liang,et,al Expires November 17, 2016 [Page 6]
Internet-Draft EVPN Flow Spec May 2016
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 L2VPN network:
Hao & Liang,et,al Expires November 17, 2016 [Page 7]
Internet-Draft EVPN Flow Spec May 2016
+--------+--------------------+--------------------------+
| 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 |
+--------+--------------------+--------------------------+
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 |
+--------+------------------------+--------------------------+
VLAN-action: The VLAN-action extended community consists of 6 bytes
which include the fields of 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 belong to the first action part
while bit 8 to bit 15 belong to the second part. 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 extend community, such as SwapPop, PushSwap, etc. For
example, SwapPop action is the concatenation of two actions, the
first action is Swap and the second action is Pop.
Hao & Liang,et,al Expires November 17, 2016 [Page 8]
Internet-Draft EVPN Flow Spec May 2016
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.
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.
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:
Hao & Liang,et,al Expires November 17, 2016 [Page 9]
Internet-Draft EVPN Flow Spec May 2016
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 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
TPID-action: The TPID-action extended community consists of 6 bytes
which includes the fields of action Flags, TPID1 and TPID2.
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.
5. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification.
6. IANA Considerations
IANA is requested to rename currently defined SAFI 134 per [RFC5575]
to read:
134 VPN dissemination of flow specification rules
Hao & Liang,et,al Expires November 17, 2016 [Page 10]
Internet-Draft EVPN Flow Spec May 2016
IANA is requested to create and maintain a new registry for "Flow
spec L2VPN Component Types". For completeness, the types defined in
[RFC5575] and [draft-ietf-idr-flow-spec-v6-06] also are listed here.
+--------+-------------------------------+--------------------------+
| type | RFC or Draft | discription |
+--------+-------------------------------+--------------------------+
| 1 |RFC5575 | Destination Prefix |
| 1 |draft-ietf-idr-flow-spec-v6-06 | Destination IPv6 Prefix |
| 2 |RFC5575 | Source Prefix |
| 2 |draft-ietf-idr-flow-spec-v6-06 | Source IPv6 Prefix |
| 3 |RFC5575 | IP Protocol |
| 3 |draft-ietf-idr-flow-spec-v6-06 | Next Header |
| 4 |RFC5575 | Port |
| 5 |RFC5575 | Destination port |
| 6 |RFC5575 | Source port |
| 7 |RFC5575 | ICMP type |
| 8 |RFC5575 | ICMP code |
| 9 |RFC5575 | TCP flags |
| 10 |RFC5575 | Packet length |
| 11 |RFC5575 | DSCP |
| 12 |RFC5575 | Fragment |
| 13 |draft-ietf-idr-flow-spec-v6-06 | Flow Label |
| 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 |
+--------+-------------------------------+--------------------------+
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]
Hao & Liang,et,al Expires November 17, 2016 [Page 11]
Internet-Draft EVPN Flow Spec May 2016
6.1. Normative References
[1] [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[2] [RFC5575] P. Marques, N. Sheth, R. Raszuk, B. Greene, J.Mauch,
D. McPherson, "Dissemination of Flow Specification Rules", RFC
5575, August 2009.
[3] [RFC4761] K. Kompella, Ed., Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling",
RFC4761, January 2007.
[4] [RFC4762] M. Lasserre, Ed., V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC4762, January 2007.
[5] [RFC6074] E. Rosen, B. Davie, V. Radoaca, "Provisioning, Auto-
Discovery, and Signaling in Layer 2 Virtual Private Networks
(L2VPNs)", RFC6074, January 2011.
6.2. Informative References
[1] [EVPN] Sajassi et al., "BGP MPLS Based Ethernet VPN", draft-
ietf-l2vpn-evpn-07.txt, work in progress, May, 2014.
[2] [IEEE 802.1p] Javin, et.al. "IEEE 802.1p: LAN Layer 2 QoS/CoS
Protocol for Traffic Prioritization", 2012-02-15
7. Acknowledgments
The authors wish to acknowledge the important contributions of
Hannes Gredler, Xiaohu Xu, Zhenbin Li and Lucy Yong.
Hao & Liang,et,al Expires November 17, 2016 [Page 12]
Internet-Draft EVPN Flow Spec May 2016
Authors' Addresses
Weiguo Hao
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Email: haoweiguo@huawei.com
Qiandeng Liang
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Email: liangqiandeng@huawei.com
James Uttaro
AT&T
Email: uttaro@att.com
Stephane Litkowski
Orange
Email: stephane.litkowski@orange.com
Shunwan Zhuang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
Hao & Liang,et,al Expires November 17, 2016 [Page 13]