Internet DRAFT - draft-ietf-idr-flowspec-l2vpn
draft-ietf-idr-flowspec-l2vpn
IDR Working Group W. Hao
Internet-Draft Huawei Technologies
Intended status: Standards Track D. Eastlake
Expires: 18 April 2024 Futurewei Technologies
S. Litkowski
Cisco Systems, Inc.
S. Zhuang
Huawei Technologies
16 October 2023
BGP Dissemination of L2 Flow Specification Rules
draft-ietf-idr-flowspec-l2vpn-22
Abstract
This document defines a Border Gateway Protocol (BGP) Flow
Specification (flowspec) extension to disseminate Ethernet Layer 2
(L2) and Layer 2 Virtual Private Network (L2VPN) traffic filtering
rules either by themselves or in conjunction with L3 flowspecs. AFI/
SAFI 6/133 and 25/134 are used for these purposes. New component
types and two extended communities are also 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
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This Internet-Draft will expire on 18 April 2024.
Copyright Notice
Copyright (c) 2023 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.
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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 Revised BSD License text as
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Layer 2 Flow Specification Encoding . . . . . . . . . . . . . 5
2.1. L2 Component Types . . . . . . . . . . . . . . . . . . . 6
2.1.1. Type 1 - Ethernet Type (EtherType) . . . . . . . . . 6
2.1.2. Type 2 - Source MAC . . . . . . . . . . . . . . . . . 7
2.1.3. Type 3 - Destination MAC . . . . . . . . . . . . . . 7
2.1.4. Type 4 - DSAP (Destination Service Access Point) . . 7
2.1.5. Type 5 - SSAP (Source Service Access Point) . . . . . 7
2.1.6. Type 6 - Control field in LLC . . . . . . . . . . . . 7
2.1.7. Type 7 - SNAP . . . . . . . . . . . . . . . . . . . . 8
2.1.8. Type 8 - VLAN ID . . . . . . . . . . . . . . . . . . 8
2.1.9. Type 9 - VLAN PCP . . . . . . . . . . . . . . . . . . 8
2.1.10. Type 10 - Inner VLAN ID . . . . . . . . . . . . . . . 8
2.1.11. Type 11 - Inner VLAN PCP . . . . . . . . . . . . . . 9
2.1.12. Type 12 - VLAN DEI . . . . . . . . . . . . . . . . . 9
2.1.13. Type 13 - Inner VLAN DEI . . . . . . . . . . . . . . 9
2.1.14. Type 14 - Source MAC Special Bits . . . . . . . . . . 10
2.1.15. Type 15 - Destination MAC Special Bits . . . . . . . 10
2.2. Order of Traffic Filtering Rules . . . . . . . . . . . . 10
3. L2VPN Flow Specification Encoding in BGP . . . . . . . . . . 11
3.1. Order of L2VPN Filtering Rules . . . . . . . . . . . . . 12
4. Ethernet Flow Specification Traffic Actions . . . . . . . . . 12
4.1. VLAN-action . . . . . . . . . . . . . . . . . . . . . . . 13
4.2. TPID-action . . . . . . . . . . . . . . . . . . . . . . . 15
5. Flow Spec Validation . . . . . . . . . . . . . . . . . . . . 15
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8. Normative References . . . . . . . . . . . . . . . . . . . . 18
9. Informative References . . . . . . . . . . . . . . . . . . . 19
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 19
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
Border Gateway Protocol (BGP) Flow Specification [RFC8955] (flowspec)
is an extension to BGP that supports the dissemination of traffic
flow specifications and resulting actions to be taken on packets in a
specified flow. It leverages the BGP Control Plane to simplify the
distribution of ACLs (Access Control Lists). Using the Flow
Specification extension new filter rules can be injected to all BGP
peers simultaneously without changing router configuration. A
typical application is to automate the distribution of traffic filter
lists to routers for DDoS (Distributed Denial of Service) mitigation,
access control, and similar applications.
BGP Flow Specification [RFC8955] defines a BGP Network Layer
Reachability Information (NLRI) format used to distribute traffic
flow specification rules. The NLRI for (AFI=1, SAFI=133) specifies
IPv4 unicast filtering. The NLRI for (AFI=1, SAFI=134) specifies
IPv4 BGP/MPLS VPN filtering [RFC7432]. The Flow Specification match
part defined in [RFC8955] only includes L3/L4 information like IPv4
source/destination prefix, protocol, ports, and the like, so traffic
flows can only be filtered based on L3/L4 information. This has been
extended by [RFC8956] to cover IPv6 (AFI=2) L3/L4.
Layer 2 Virtual Private Networks (L2VPNs) have been deployed in an
increasing number of networks. Such networks also have requirements
to deploy BGP Flow Specification to mitigate DDoS attack traffic.
Within an L2VPN network, both IP and non-IP Ethernet traffic may
exist. For IP traffic filtering, the VPN Flow Specification rules
defined in [RFC8955] and/or [RFC8956], which include match criteria
and actions, can still be used. For non-IP Ethernet traffic
filtering, Layer 2 related information like source/destination MAC
and VLAN must be considered.
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 Specification feature
relies on the 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]
with BGP auto-discovery [RFC6074].
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This document defines new flowspec component types and two new
extended communities to support L2 and L2VPN flowspec applications.
The flowspec rules can be enforced on all border routers or on some
interface sets of the border routers. SAFI=133 in [RFC8955] and
[RFC8956] is extended for AFI=6 as specified in Section 2 to cover L2
traffic filtering information and in Section 3 SAFI=134 is extended
for AFI=25 to cover the L2VPN environment.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following acronyms and terms are used in this document:
AFI - Address Family Identifier
ACL - Access Control List
DDoS - Distributed Denial of Service
DEI - Drop Eligible Indicator
EVPN - Ethernet VPN [RFC7432]
flowspec - BGP Flow Specification
L2 - Layer 2
L2VPN - Layer 2 VPN
L3 - Layer 3
L3VPN - Layer 3 VPN
NLRI - Network Layer Reachability Information
PCP - Priority Code Point [IEEE802.1Q]
SAFI - Subsequent Address Family Identifier
TPID - Tag Protocol ID, typically a VLAN ID
VLAN - Virtual Local Area Network
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VPLS - Virtual Private Line Service [RFC4762]
VPN - Virtual Private Network
2. Layer 2 Flow Specification Encoding
[RFC8955] defines SAFI 133 and SAFI 134, with AFI=1, for
"dissemination of IPv4 flow specification rules" and "dissemination
of VPNv4 flow specification rules", respectively. [RFC8956] extends
[RFC8955] to also allow AFI=2 thus making it applicable to both IPv4
and IPv6 applications. This document further extends SAFI=133 for
AFI=6 and SAFI=134 for AFI=25 to make them applicable to L2 and L2VPN
applications. This document also provides for the optional
combination of L3 flow specifications with these L2 flow
specifications.
This section specifies the L2 flowspec for AFI=6/SAFI=133. To
simplify assignments, a new registry is used for L2 flowspec. Since
it is frequently desirable to also filter on L3/L4 fields, provision
is made for their inclusion along with an indication of the L3
protocol involved (IPv4 or IPv6).
The NLRI part of the MP_REACH_NLRI and MP_UNREACH_NLRI is encoded as
a 1- or 2-octet total NLRI length field followed by several fields as
described below.
+-------------------------------+
| total-length (0xnn or 0xfnnn) | 2 or 3 octets
+-------------------------------+
| L3-AFI | 2 octets
+-------------------------------+
| L2-length (0xnn or 0xfnnn) | 2 or 3 octets
+-------------------------------+
| NLRI-value | variable
+-------------------------------+
Figure 1: Flow Specification NLRI for L2
The fields show in Figure 1 are further specified below:
total-length: The length of the subsequent fields (L3 AFI,
L2-length, and NRLI-value) encoded as provided in Section 4.1 of
[RFC8955]. If this field is less than 4, which is the minimum
valid value, then the NLRI is malformed in which case a
NOTIFICATION message is sent and the BGP connection closed as
provided in Section 6.3 of [RFC4271].
L3-AFI: If no L3/L4 filtering is desired, this two octet field MUST
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be zero which is a reserved AFI value. Otherwise L3-AFI indicates
the L3 protocol involved by giving its AFI (0x0001 for IPv4 or
0x0002 for IPv6). If the receiver does not understand the value
of the L3-AFI field, the MP_REACH or MP_UNREACH attribute is
ignored.
L2-length: The length of the L2 components at the beginning of the
NLRI-value field encoded as provided in Section 4.1 of [RFC8955].
If the value of this field indicates that the L2 components extend
beyond the total-length, the NLRI is malformed in which case a
NOTIFICATION message is sent and the BGP connection closed as
provided in Section 6.3 of [RFC4271]. N2-length MAY be zero
although, in that case, it would have been more efficient to
encode the attribute as an L3 Flow spec unless it is desired to
apply an L2 action (see Section 4). A null L2 flowspec always
matches.
NLRI-value: This consists of the L2 flowspec, of length L2-length,
followed by an optionally present L3 flowspec. The result can be
treated in most ways as a single flowspec, matching the
intersection (AND) of all the components except that the
components in the initial L2 region are interpreted as L2
components and the remainder as L3 components per the L3-AFI
field. This is necessary because there are different registries
for the L2, L3 IPv4, and L3 IPv6 component types. If the L3
flowspec is null (length zero), it always matches.
2.1. L2 Component Types
The L2 flowspec portion of the NLRI-value consists of flowspec
components as in [RFC8955] but using L2 components and types as
specified below. All components start with a type octet followed by
a length octet followed by any additional information needed. The
length octet gives the length, in octets, of the information after
the length octet. This structure applies to all new components to be
defined in the L2 Flow-spec Component Registry (see Section 6) and to
all existing components except Types 2 and 3 where the length is in
bits.
2.1.1. Type 1 - Ethernet Type (EtherType)
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the two-
octet EtherType field. op is encoded as specified in Section 4.2.1.1
of [RFC8955]. Values are encoded as 2-octet quantities. Ethernet II
framing defines the two-octet Ethernet Type (EtherType) field in an
Ethernet frame, preceded by destination and source MAC addresses,
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that identifies an upper layer protocol encapsulating the frame data.
The match fails if LLC encoding is being used rather than EtherType
encoding.
2.1.2. Type 2 - Source MAC
Encoding: <type (1 octet), MAC Prefix length (1 octet), MAC Prefix>
Defines the source MAC Address prefix to match encoded as in BGP
UPDATE messages [RFC4271]. Prefix length is in bits and the MAC
Prefix is fill out with from 1 to 7 padding bits so that it is an
integer number of octets. These padding bits are ignored for
matching purposes.
2.1.3. Type 3 - Destination MAC
Encoding: <type (1 octet), MAC Prefix length (1 octet), MAC Prefix>
Defines the destination MAC Address to match encoded as in BGP UPDATE
messages [RFC4271]. Prefix length is in bits and the MAC Prefix is
fill out with from 1 to 7 padding bits so that it is an integer
number of octets. These padding bits are ignored for matching
purposes.
2.1.4. Type 4 - DSAP (Destination Service Access Point)
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the 1-octet
DSAP in the IEEE 802.2 LLC (Logical Link Control Header). Values are
encoded as 1-octet quantities. op is encoded as specified in
Section 4.2.1.1 of [RFC8955]. The match fails if EtherType L2 header
encoding is being used rather than LLC encoding.
2.1.5. Type 5 - SSAP (Source Service Access Point)
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the 1-octet
SSAP in the IEEE 802.2 LLC. Values are encoded as 1-octet
quantities. op is encoded as specified in Section 4.2.1.1 of
[RFC8955]. The match fails if EtherType L2 header encoding is being
used rather than LLC encoding.
2.1.6. Type 6 - Control field in LLC
Encoding: <type (1 octet), length (1 octet), [op, value]+>
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Defines a list of {operation, value} pairs used to match the 1-octet
control field in the IEEE 802.2 LLC. Values are encoded as 1-octet
quantities. op is encoded as specified in Section 4.2.1.1 of
[RFC8955]. The match fails if EtherType L2 header encoding is being
used rather than LLC encoding.
2.1.7. Type 7 - SNAP
Encoding: <type (1 octet), length (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 8-octet
quantities with the zero padded SNAP left justified. op is encoded as
specified in Section 4.2.1.1 of [RFC8955]. The match fails if
EtherType L2 header encoding is being used rather than LLC encoding.
2.1.8. Type 8 - VLAN ID
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match VLAN ID.
Values are encoded as 2-octet quantities, where the four most
significant bits are set to zero and ignored for matching and the 12
least significant bits contain the VLAN value. op is encoded as
specified in Section 4.2.1.1 of [RFC8955].
In the virtual local-area network (VLAN) stacking case, the VLAN ID
is the outer VLAN ID.
2.1.9. Type 9 - VLAN PCP
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 3-bit VLAN
PCP (priority code point) fields [IEEE802.1Q]. Values are encoded
using a single octet, where the five most significant bits are set to
zero and ignored for matching and the three least significant bits
contain the VLAN PCP value. op is encoded as specified in
Section 4.2.1.1 of [RFC8955].
In the virtual local-area network (VLAN) stacking case, the VLAN PCP
is part of the outer VLAN tag.
2.1.10. Type 10 - Inner VLAN ID
Encoding: <type (1 octet), length (1 octet), [op, value]+>
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Defines a list of {operation, value} pairs used to match the inner
VLAN ID for virtual local-area network (VLAN) stacking or Q-in-Q use.
Values are encoded as 2-octet quantities, where the four most
significant bits are set to zero and ignored for matching and the 12
least significant bits contain the VLAN value. op is encoded as
specified in Section 4.2.1.1 of [RFC8955].
In the single VLAN case, this component type MUST NOT be used. If it
appears the match will fail.
2.1.11. Type 11 - Inner VLAN PCP
Encoding: <type (1 octet), length (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 3-bit inner
VLAN PCP fields [IEEE802.1Q] for virtual local-area network (VLAN)
stacking or Q-in-Q use. Values are encoded using a single octet,
where the five most significant bits are set to zero and ignored for
matching and the three least significant bits contain the VLAN PCP
value. op is encoded as specified in Section 4.2.1.1 of [RFC8955].
In the single VLAN case, this component type MUST NOT be used. If it
appears the match will fail.
2.1.12. Type 12 - VLAN DEI
Encoding: <type (1 octet), length (1 octet), op (1 octet)>
This type tests the DEI (Drop Eligible Indicator) bit in the VLAN
tag. If op is zero, it matches if and only if the DEI bit is zero.
If op is non-zero, it matches if and only if the DEI bit is one.
In the virtual local-area network (VLAN) stacking case, the VLAN DEI
is part of the outer VLAN tag.
2.1.13. Type 13 - Inner VLAN DEI
Encoding: <type (1 octet), length (1 octet), op (1 octet)>
This type tests the DEI bit in the inner VLAN tag. If op is zero, it
matches if and only if the DEI bit is zero. If op is non-zero, it
matches if and only if the DEI bit is one.
In the single VLAN case, this component type MUST NOT be used. If it
appears the match will fail.
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2.1.14. Type 14 - Source MAC Special Bits
Encoding: <type (1 octet), length (1 octet), op (1 octet)>
This type tests the bottom nibble of the top octet of the Source MAC
address. The two low order bits of that nibble have long been the
local bit (0x2) and the group addressed bit (0x1). However, recent
changes in IEEE 802 have divided the local address space into 4
quadrants specified by the next two bits (0x4 and 0x8) [RFC7042bis].
This flowspec component permits testing, for example, that a MAC is
group addressed or is a local address in a particular quadrant. The
encoding is as given in Section 4.2.1.2 of [RFC8955].
2.1.15. Type 15 - Destination MAC Special Bits
Encoding: <type (1 octet), length (1 octet), op (1 octet)>
As discussed in Section 2.1.14 but for the Destination MAC Address
special bits.
2.2. Order of Traffic Filtering Rules
The existing rules in Section 5.1 of [RFC8955] and in [RFC8956] for
the ordering of traffic filtering are extended as follows:
L2 flowspecs (AFI = 6, 25) take precedence over L3 flowspecs (AFI =
1, 2). Between two L2 flowspecs, precedence of the L2 portion is
determined as specified in this section after this paragraph. If the
L2 flowspec L2 portions are the same and the L3-AFI is nonzero, then
the L3 portions are compared as specified in [RFC8955] or [RFC8956]
as appropriate. Note: if the L3-AFI fields are different between two
L2 flowspecs, they will never match the same packet so it will not be
necessary to prioritize two flowspecs with different L3-AFI values.
The original definition for the order of traffic filtering rules can
be reused for L2 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.
Pseudocode:
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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;
}
3. L2VPN Flow Specification Encoding in BGP
The NLRI format for AFI=25/SAFI=134 (L2VPN), as with the other VPN
flowspec AFI/SAFI pairs, is the same as the non-VPN Flow-Spec but
with the addition of a Route Distinguisher to identify the VPN to
which the flowspec is to be applied.
In addition, the IANA entry for SAFI 134 is slightly generalized as
specified at the beginning of Section 6.
The L2VPN NLRI format is as follows:
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+-------------------------------+
| total-length (0xnn or 0xfnnn) | 2 or 3 octets
+-------------------------------+
| Route Distinguisher | 8 octets
+-------------------------------+
| L3-AFI | 2 octets
+-------------------------------+
| L2-length (0xnn or 0xfnnn) | 2 or 3 octets
+-------------------------------+
| NLRI-value | variable
+-------------------------------+
Figure 2: Flow Specification NLRI for L2VPN
The fields in Figure 2, other than the Route Distinguisher, are
encoded as specified in Section 2 except that the minimum value for
total-length is 12.
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 as specified in Section 5.
3.1. Order of L2VPN Filtering Rules
The order between L2VPN filtering rules is determined as specified in
Section 2.2. Note that if the Route Distinguisher is different
between two L2VPN filtering rules, they will never both match the
same packet so they need not be prioritized.
4. Ethernet Flow Specification Traffic Actions
The default action for an L2 traffic filtering flowspec is to accept
traffic that matches that particular rule. The following extended
community values per [RFC8955] can be used to specify particular
actions in an L2 VPN network:
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+========+====================+============================+
| type | extended community | encoding |
+========+====================+============================+
| 0x8006 | traffic-rate | 2-octet as#, 4-octet float |
+--------+--------------------+----------------------------+
| 0x8007 | traffic-action | bitmask |
+--------+--------------------+----------------------------+
| 0x8008 | redirect | 6-octet Route Target |
+--------+--------------------+----------------------------+
| 0x8009 | traffic-marking | DSCP value |
+--------+--------------------+----------------------------+
Table 1
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 specifies
the following BGP extended communities for Ethernet flows to extend
[RFC8955]:
+======+====================+==========+
| type | extended community | encoding |
+======+====================+==========+
| TBD1 | VLAN-action | bitmask |
+------+--------------------+----------+
| TBD2 | TPID-action | bitmask |
+------+--------------------+----------+
Table 2
4.1. VLAN-action
The VLAN-action extended community, as shown in the diagram below,
consists of 6 octets that include action Flags, two VLAN IDs, and the
associated PCP and DEI values. 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 extended 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.
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|PO1|PU1|SW1|RI1|RO1| Resv |PO2|PU2|SW2|RI2|RO2| Resv |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| VLAN ID1 | PCP1 |DE1|
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| VLAN ID2 | PCP2 |DE2|
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
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 PCP and DEI are PCP1 and DE1.
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 PCP and DEI are PCP2 and DE2.
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 RIx flag is one
(where "x" is "1" or "2"), it indicates the inner VLAN should be
replaced by a new VLAN where the new VLAN is VLAN IDx and the
associated PCP and DEI are PCPx and DEx. If the VLAN IDx is 0,
the action is to only modify the PCP and DEI value of the inner
VLAN.
RO1 and RO2: Rewrite outer VLAN action. If the ROx flag is one
(where "x" is "1" or "2"), it indicates the outer VLAN should be
replaced by a new VLAN where the new VLAN is VLAN IDx and the
associated PCP and DEI are PCPx and DEx. If the VLAN IDx is 0,
the action is to only modify the PCP and DEI value of the outer
VLAN.
Resv: Reserved for future use. MUST be sent as zero and ignored on
receipt.
Giving an example below: if the action of PUSH Inner VLAN 10 with PCP
value 5 and DEI value 0 and PUSH Outer VLAN 20 with PCP value 6 and
DEI value 0 is needed, the format of the VLAN-action extended
community is as follows:
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 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 octets which
includes the fields of action Flags, TP ID1 and TP ID2.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 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. Flow Spec Validation
Flow Specifications received over AFI=25/SAFI=134 are validated
against routing reachability received over AFI=25/SAFI=128 as
modified to conform to [RFC9117].
6. IANA Considerations
IANA is requested to change the description for SAFI 134 [RFC8955] to
read as follows and to change the reference for it to [this
document]:
134 VPN dissemination of flow specification rules
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IANA is requested to create an L2 Flow Specification Component Type
registry on the Flow Spec Component Types registries web page as
follows:
Name: L2 Flow Specification Component Types
Reference: [this document]
Registration Procedures:
0 Reserved
1-127 Specification Required
128-255 First Come First Served
Initial contents:
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+========+=================+==============================+
| type | Reference | description |
+========+=================+==============================+
| 0 | [this document] | Reserved |
+--------+-----------------+------------------------------+
| 1 | [this document] | Ethernet Type |
+--------+-----------------+------------------------------+
| 2 | [this document] | Source MAC |
+--------+-----------------+------------------------------+
| 3 | [this document] | Destination MAC |
+--------+-----------------+------------------------------+
| 4 | [this document] | DSAP in LLC |
+--------+-----------------+------------------------------+
| 5 | [this document] | SSAP in LLC |
+--------+-----------------+------------------------------+
| 6 | [this document] | Control field in LLC |
+--------+-----------------+------------------------------+
| 7 | [this document] | SNAP |
+--------+-----------------+------------------------------+
| 8 | [this document] | VLAN ID |
+--------+-----------------+------------------------------+
| 9 | [this document] | VLAN PCP |
+--------+-----------------+------------------------------+
| 10 | [this document] | Inner VLAN ID |
+--------+-----------------+------------------------------+
| 11 | [this document] | Inner VLAN PCP |
+--------+-----------------+------------------------------+
| 12 | [this document] | VLAN DEI |
+--------+-----------------+------------------------------+
| 13 | [this document] | Inner VLAN DEI |
+--------+-----------------+------------------------------+
| 14 | [this document] | Source MAC Special Bits |
+--------+-----------------+------------------------------+
| 15 | [this document] | Destination MAC Special Bits |
+--------+-----------------+------------------------------+
| 16-254 | [this document] | unassigned |
+--------+-----------------+------------------------------+
| 255 | [this document] | Reserved |
+--------+-----------------+------------------------------+
Table 3
IANA is requested to assign two values from the "BGP Extended
Communities Type - extended, transitive" registry [suggested value
provided in square brackets]:
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+==============+=======================+=================+
| Type value | Name | Reference |
+==============+=======================+=================+
| TBD1[0x080A] | Flow spec VLAN action | [this document] |
+--------------+-----------------------+-----------------+
| TBD2[0x080B] | Flow spec TPID action | [this document] |
+--------------+-----------------------+-----------------+
Table 4
7. Security Considerations
For General BGP Flow Specification Security Considerations, see
[RFC8955].
VLAN tagging identifies Layer 2 communities which are commonly
expected to be isolated except when higher layer connection is
provided, such as Layer 3 routing. Thus, the ability of the flowspec
VLAN action to change the VLAN ID in a frame might compromise
security.
8. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[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,
<https://www.rfc-editor.org/info/rfc4271>.
[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>.
[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>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8955] Loibl, C., Hares, S., Raszuk, R., McPherson, D., and M.
Bacher, "Dissemination of Flow Specification Rules",
RFC 8955, DOI 10.17487/RFC8955, December 2020,
<https://www.rfc-editor.org/info/rfc8955>.
[RFC8956] Loibl, C., Ed., Raszuk, R., Ed., and S. Hares, Ed.,
"Dissemination of Flow Specification Rules for IPv6",
RFC 8956, DOI 10.17487/RFC8956, December 2020,
<https://www.rfc-editor.org/info/rfc8956>.
[RFC9117] Uttaro, J., Alcaide, J., Filsfils, C., Smith, D., and P.
Mohapatra, "Revised Validation Procedure for BGP Flow
Specifications", RFC 9117, DOI 10.17487/RFC9117, August
2021, <https://www.rfc-editor.org/info/rfc9117>.
9. Informative References
[IEEE802.1Q]
IEEE 802, "IEEE Standard for Local and metropolitan area
networks - Media Access Control (MAC) Bridges and Virtual
Bridge Local Area Networks", IEE Std 802.1Q-2014, 3
November 2014.
[RFC7042bis]
Eastlake, D., Abley, J., and Y. Li, "OUI Registry
Restructuring", work in Progress, 14 April 2023,
<https://www.ietf.org/archive/id/draft-intarea-rfc7042bis-
02.txt>.
[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>.
Acknowledgements
The authors wish to acknowledge the important contributions and
suggestions of the following:
Hannes Gredler, Xiaohu Xu, Zhenbin Li, Lucy Yong, and Feng Dong.
Contributors
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Qiandeng Liang
Huawei Technologies
101 Software Avenue, Yuhuatai District
Nanjing
Jiangsu, 210012
China
Email: liangqiandeng@huawei.com
Authors' Addresses
Weiguo Hao
Huawei Technologies
101 Software Avenue
Nanjing
Jiangsu, 210012
China
Email: haoweiguo@huawei.com
Donald E. Eastlake, 3rd
Futurewei Technologies
2386 Panoramic Circle
Apopka, Florida 32703
United States of America
Phone: +1-508-333-2270
Email: d3e3e3@gmail.com
Stephane Litkowski
Cisco Systems, Inc.
Email: slitkows.ietf@gmail.com
Shunwan Zhuang
Huawei Technologies
Huawei Building, No.156 Beiqing Road
Beijing
100095
China
Email: zhuangshunwan@huawei.com
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