Network Working Group Parag Jain, Ed.
Internet Draft Sami Boutros
Intended status: Standards Track Samer Salam
Expires: December 18, 2014 Cisco Systems
June 17, 2014
LSP-Ping Mechanisms for E-VPN and PBB-EVPN
draft-jain-l2vpn-evpn-lsp-ping-03.txt
Abstract
LSP-Ping is a widely deployed Operation, Administration, and
Maintenance (OAM) mechanism in MPLS networks. This document
describes mechanisms for detecting data-plane failures using LSP
Ping in MPLS based E-VPN and PBB-EVPN networks.
Status of this Memo
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Table of Contents
1. Introduction 2
2. Conventions used in this document 3
3. Terminology 3
4. Proposed Target FEC Stack Sub-TLVs 4
4.1. E-VPN MAC Sub-TLV 4
4.2. E-VPN Inclusive Multicast Sub-TLV 5
4.3. E-VPN Auto-Discovery Sub-TLV 6
5. Operations 6
5.1. Unicast Data-plane connectivity checks 6
5.2. Inclusive Multicast Data-plane Connectivity Checks 8
5.2.1. Ingress Replication 8
5.2.2. Using P2MP P-tree 9
5.2.3. Controlling Echo Responses when using P2MP P-tree 10
5.3. E-VPN Aliasing Data-plane connectivity check 10
6. Security Considerations 10
7. IANA Considerations 10
8. References 11
8.1. Normative References 11
8.2. Informative References 11
9. Acknowledgments 12
1. Introduction
[EVPN] describes MPLS based Ethernet VPN (E-VPN) technology. An E-
VPN comprises CE(s) connected to PE(s). The PEs provide layer 2 E-
VPN among the CE(s) over the MPLS core infrastructure. In E-VPN
networks, PEs advertise the MAC addresses learned from the locally
connected CE(s), along with MPLS Label, to remote PE(s) in the
control plane using multi-protocol BGP. E-VPN enables multi-homing
of CE(s) connected to multiple PEs and load balancing of traffic to
and from multi-homed CE(s).
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[PBBEVPN] describes the use of Provider Backbone Bridging [802.1ah]
with E-VPN. PBB-EVPN maintains the C-MAC learning in data plane and
only advertises Provider Backbone MAC (B-MAC) addresses in control
plane using BGP.
Procedures for simple and efficient mechanisms to detect data-plane
failures using LSP Ping in MPLS network are well defined in
[RFC4379][RFC6425]. This document defines procedures to detect data-
plane failures using LSP Ping in MPLS networks deploying E-VPN and
PBB-EVPN. This draft defines 3 new Sub-TLVs for Target FEC Stack TLV
with the purpose of identifying the FEC on the Peer PE.
2. Conventions used in this document
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].
The term FEC-Type is used to refer to a tuple consisting of <FEC
Element Type, Address Family>.
3. Terminology
B-MAC: Backbone MAC Address
CE: Customer Edge Device
C-MAC: Customer MAC Address
DF: Designated Forwarder
ESI: Ethernet Segment Identifier
EVI: E-VPN Instance
E-VPN: Ethernet Virtual Private Network
MPLS-OAM: MPLS Operations, Administration and Maintenance
P2MP: Point-to-Multipoint
PBB: Provider Backbone Bridge
PE: Provider Edge Device
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4. Proposed Target FEC Stack Sub-TLVs
This document introduces three new Target FEC Stack sub-TLVs that
are included in the LSP-Ping Echo Request packet sent for detecting
faults in data-plane connectivity in E-VPN and PBB-EVPN networks.
These Target FEC Stack sub-TLVs are described next.
4.1. E-VPN MAC Sub-TLV
The E-VPN MAC sub-TLV is used to identify the MAC for an EVI under
test at a peer PE.
The E-VPN MAC sub-TLV fields are derived from the MAC advertisement
route defined in [EVPN] and has the format as shown in Figure 1.
This TLV is included in the Echo Request sent to the Peer PE by the
PE that is the originator of the request.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Segment Identifier |
| (10 octets) |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | must be zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Tag ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address |
+ (6 Octets) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | MAC Addr Len | IP Addr Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (4 or 16 Octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EVI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: E-VPN MAC sub-TLV format
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The LSP Ping echo request is sent using the E-VPN MPLS label(s)
associated with the MAC route announced by a remote PE and the MPLS
transport label(s) to reach the remote PE.
4.2. E-VPN Inclusive Multicast Sub-TLV
The E-VPN Inclusive Multicast sub-TLV fields are based on the E-VPN
Inclusive Multicast route defined in [EVPN].
The E-VPN Inclusive Multicast sub-TLV has the format as shown in
Figure 2. This TLV is included in the echo request sent to the E-VPN
peer PE by the originator of request to verify the multicast
connectivity state on the peer PE(s) in E-VPN and PBB-EVPN.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Segment Identifier |
| (10 octets) |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | must be zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Tag ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EVI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: E-VPN Inclusive Multicast sub-TLV format
Broadcast, multicast and unknown unicast traffic can be sent using
ingress replication or P2MP P-tree in E-VPN and PBB-EVPN network. In
case of ingress replication, the Echo Request is sent using a label
stack of <Transport label, Inclusive Multicast label> to each remote
PE participating in E-VPN or PBB-EVPN. The inclusive multicast label
is the downstream assigned label announced by the remote PE to which
the Echo Request is being sent. The Inclusive Multicast label is the
inner label in the MPLS label stack.
When using P2MP P-tree in E-VPN or PBB-EVPN, the Echo Request is
sent using P2MP P-tree transport label for inclusive P-tree
arrangement or using a label stack of <P2MP P-tree transport label,
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upstream assigned EVPN Inclusive Multicast label> for aggregate
inclusive P2MP P-tree arrangement as described in Section 5.
In case of E-VPN, an additional, E-VPN Auto-Discovery sub-TLV and
ESI MPLS label as the bottom label, may also be included in the Echo
Request as is described in Section 5.
4.3. E-VPN Auto-Discovery Sub-TLV
The E-VPN Auto-Discovery (AD) sub-TLV fields are based on the
Ethernet AD route advertisement defined in [EVPN]. E-VPN AD sub-TLV
applies to only E-VPN.
The E-VPN AD sub-TLV has the format shown in Figure 3.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Segment Identifier |
| (10 octets) |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | must be zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ethernet Tag ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EVI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: E-VPN Auto-Discovery sub-TLV format
5. Operations
5.1. Unicast Data-plane connectivity checks
Figure 4 is an example of a PBB-EVPN network. CE1 is dual-homed to
PE1 and PE2. Assume, PE1 announced a MAC route with RD 1.1.1.1:00 and
B-MAC 00aa.00bb.00cc and with MPLS label 16001 for EVI 10. Similarly
PE2 announced a MAC route with RD 2.2.2.2:00 and B-MAC 00aa.00bb.00cc
and with MPLS label 16002.
On PE3, when a operator performs a connectivity check for the B-MAC
address 00aa.00bb.00cc on PE1, the operator initiates an LSP Ping
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request with the target FEC stack TLV containing E-VPN MAC sub-TLV in
the Echo Request packet. The Echo Request packet is sent with the
{Transport Label(s) to reach PE1 + E-VPN Label = 16001} MPLS label
stack. Once the echo request packet reaches PE1, it will process the
packet and perform checks for the E-VPN MAC sub-TLV present in the
Target FEC Stack TLV as described in Section 4.4 in [RFC4379] and
respond according to [RFC4379] processing rules.
BEB +-----------------+ BEB
|| | | ||
\/ | | \/
+----+ AC1 +-----+ +-----+ +----+
| CE1|------| | | PE 3|-----| CE2|
+----+\ | PE1 | IP/MPLS | | +----+
\ +-----+ Network +-----+
\ | |
AC2\ +-----+ |
\ | | |
\| PE2 | |
+-----+ |
/\ | |
|| +-----------------+
BEB
<-802.1Q-> <------PBB over MPLS------> <-802.1Q->
Figure 4: PBB EVPN network
Similarly, on PE3, when an operator performs a connectivity check for
the B-MAC address 00aa.00bb.00cc on PE2, the operator initiates an
LSP Ping request with the target FEC stack TLV containing E-VPN MAC
sub-TLV in the echo request packet. The echo request packet is sent
with the {MPLS transport Label(s) to reach PE2 + E-VPN Label = 16002}
MPLS label stack.
LSP Ping operation for unicast data-plane connectivity checks in E-
VPN, are similar to as described above for PBB-EVPN except that the
checks are for C-MACs and not for B-MACs.
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5.2. Inclusive Multicast Data-plane Connectivity Checks
5.2.1. Ingress Replication
Assume PE1 announced an Inclusive Multicast route for EVI 10, with
RD 1.1.1.1:00, Ethernet Tag (ISID 10), PMSI tunnel attribute Tunnel
type set to ingress replication and downstream assigned inclusive
multicast MPLS label 17001. Similarly PE2 announced an Inclusive
Multicast route for EVI 10, with RD 2.2.2.2:00, Ethernet Tag (ISID
10), PMSI tunnel attribute Tunnel type set to ingress replication
and downstream assigned inclusive multicast MPLS label 17002.
Given CE1 is dual homed to PE1 and PE2, assume that PE1 is the DF
for ISID 10 for the port corresponding to the ESI 11aa.22bb.33cc.
44dd.5500.
When an operator at PE3 initiates a connectivity check for the
inclusive multicast on PE1, the operator initiates an LSP Ping
request with the target FEC stack TLV containing E-VPN Inclusive
Multicast sub-TLV in the Echo Request packet. The Echo Request
packet is sent with the {Transport Label(s) to reach PE1 + E-VPN
Incl. Multicast Label = 17001} MPLS label stack. Once the packet
reaches PE1, the packet will have E-VPN Inclusive multicast label.
PE1 will process the packet and perform checks for the E-VPN
Inclusive Multicast sub-TLV present in the Target FEC Stack TLV as
described in Section 4.4 in [RFC4379] and respond according to
[RFC4379] processing rules.
Operator at PE3, may similarly also initiate an LSP Ping to PE2 with
the target FEC stack TLV containing E-VPN Inclusive Multicast sub-
TLV in the echo request packet. The echo request packet is sent with
the {transport Label(s) to reach PE2 + E-VPN Incl. Multicast Label =
17002} MPLS label stack. Since PE2 is not the DF for ISID 10 for the
port corresponding to the ESI value in the Inclusive Multicast sub-
TLV in the Echo Request, PE2 will reply with special code indicating
that FEC exists on the router and the behavior is to drop the packet
because of not DF as described in Section 7.
In case of E-VPN, in the Echo Request packet, an Ethernet AD sub-TLV
and the associated MPLS Split Horizon Label at the bottom of the
MPLS label stack, may be added to emulate traffic coming from a MH
site, this label is used by leaf PE(s) attached to the same MH site
not to forward packets back to the MH site. If the behavior on a
leaf PE is to drop the packet because of Split Horizon filtering,
the PE2 will reply with special code indicating that FEC exists on
the router and the behavior is to drop the packet because of Split
Horizon Filtering as described in Section 7.
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5.2.2. Using P2MP P-tree
Both inclusive P-Tree and aggregate inclusive P-tree can be used in
E-VPN or PBB-EVPN networks.
When using an inclusive P-tree arrangement, p2mp p-tree transport
label itself is used to identify the L2 service associated with the
Inclusive Multicast Route, this L2 service could be a customer
Bridge, or a Provider Backbone Bridge.
For an Inclusive P-tree arrangement, when an operator performs a
connectivity check for the multicast L2 service, the operator
initiates an LSP Ping request with the target FEC stack TLV
containing E-VPN Inclusive Multicast sub-TLV in the echo request
packet. The echo request packet is sent with the {P2MP P-tree label}
MPLS label stack.
When using Aggregate Inclusive P-tree, a PE announces an upstream
assigned MPLS label along with the P-tree ID, in that case both the
p2mp p-tree MPLS transport label and the upstream MPLS label can be
used to identify the L2 service.
For an Aggregate Inclusive P-tree arrangement, when an operator
performs a connectivity check for the multicast L2 service, the
operator initiates an LSP Ping request with the target FEC stack TLV
containing E-VPN Inclusive Multicast sub-TLV in the echo request
packet. The echo request packet is sent with the {P2MP P-tree label +
E-VPN Upstream assigned Multicast Label} MPLS label stack.
The Leaf PE(s) of the p2mp tree will process the packet and perform
checks for the E-VPN Inclusive Multicast sub-TLV present in the
Target FEC Stack TLV as described in Section 4.4 in [RFC4379] and
respond according to [RFC4379] processing rules. A PE that is not
the DF for the EVI on the ESI in the Inclusive Multicast sub-TLV,
will reply with a special code indicating that FEC exists on the
router and the behavior is to drop the packet because of not DF as
described in Section 7.
In case of E-VPN, in the Echo Request packet, an Ethernet AD sub-TLV
and the associated MPLS Split Horizon Label at the bottom of the
MPLS label stack, may be added to emulate traffic coming from a MH
site, this label is used by leaf PE(s) attached to the same MH site
not to forward packets back to the MH site. If the behavior on a
leaf PE is to drop the packet because of Split Horizon filtering,
the PE2 will reply with special code indicating that FEC exists on
the router and the behavior is to drop the packet because of Split
Horizon Filtering as described in Section 7.
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5.2.3. Controlling Echo Responses when using P2MP P-tree
The procedures described in [RFC6425] for preventing congestion of
Echo Responses (Echo Jitter TLV) and limiting the echo reply to a
single egress node (Node Address P2MP Responder Identifier TLV) can
be applied to LSP Ping in PBB EVPN and E-VPN when using P2MP P-
trees for broadcast, multicast and unknown unicast traffic.
5.3. E-VPN Aliasing Data-plane connectivity check
Assume PE1 announced an Ethernet Auto discovery Route with the ESI
set to CE1 system ID and MPLS label 19001, and PE2 an Ethernet Auto
discovery Route with the ESI set to CE1 system ID and MPLS label
19002.
When an operator performs at PE3 a connectivity check for the
aliasing aspect of the Ethernet AD route to PE1, the operator
initiates an LSP Ping request with the target FEC stack TLV
containing E-VPN Ethernet AD sub-TLV in the echo request packet. The
echo request packet is sent with the {Transport label(s) to reach
PE1 + E-VPN Ethernet AD Label 19001} MPLS label stack.
When PE1 receives the packet it will process the packet and perform
checks for the E-VPN Ethernet AD sub-TLV present in the Target FEC
Stack TLV as described in Section 4.4 in [RFC4379] and respond
according to [RFC4379] processing rules.
6. Security Considerations
The proposal introduced in this document does not introduce any new
security considerations beyond that already apply to [EVPN], [PBBE
VPN] and [RFC6425].
7. IANA Considerations
This document defines 3 new sub-TLV type to be included in Target
FEC Stack TLV (TLV Type 1) [RFC4379] in LSP Ping.
IANA is requested to assign a sub-TLV type value to the following
sub-TLV from the "Multiprotocol Label Switching (MPLS) Label
Switched Paths (LSPs) Parameters - TLVs" registry, "TLVs and sub-
TLVs" sub-registry:
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o E-VPN MAC route sub-TLV.
o E-VPN Inclusive Multicast route sub-TLV
o E-VPN Auto-Discovery Route sub-TLV
Proposed new Return Codes
[RFC4379] defines values for the Return Code field of Echo Reply.
This document proposes two new Return Codes, which SHOULD be
included in the Echo Reply message by a PE in response to LSP Ping
Echo Request message:
1. The FEC exists on the PE and the behavior is to drop the packet
because of not DF.
2. The FEC exists on the PE and the behavior is to drop the packet
because of Split Horizon Filtering.
8. References
8.1. Normative References
[EVPN] Aggarwal et al., "BGP MPLS Based Ethernet VPN", draft-
ietf-l2vpn-evpn-07.txt, work in progress, May 7, 2014.
[PBBEVPN] Sajassi et al., "PBB E-VPN", draft-ietf-l2vpn-pbb-evpn-
06.txt, work in progress, October 2013.
[RFC4379] K. Kompella, G. Swallow, "Detecting Multi-Protocol Label
Switched (MPLS) Data Plane Failures", RFC 4379, February
2006.
[RFC6425] Saxena, S et al, Detecting Data Plane Failures in Point-
to-Multipoint Multiprotocol Label Switching (MPLS) -
Extensions to LSP. RFC 6425, November 2011.
8.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC2119, March 1997.
[RFC5085] T. Nadeau, et. al, "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel for
Pseudowires ", RFC 5085, December 2007.
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[RFC6388] Minei, I., Kompella, K., Wijnands, I., and Thomas, B.,
"LDP Extensions for Point-to-Multipoint and Multipoint-to-
Multipoint Label Switched Paths, RFC 6388, November 2011.
[RFC4875] Aggarwal, R., Papadimitriou, D., and Yasukawa, S.,
"Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007.
9. Acknowledgments
The authors would like to thank Patrice Brissette for his valuable
input and comments.
This document was prepared using 2-Word-v2.0.template.dot.
Authors' Addresses
Parag Jain
Cisco Systems, Inc.,
2000 Innovation Drive,
Kanata, ON K2K3E8, Canada.
E-mail: paragj@cisco.com
Sami Boutros
Cisco Systems, Inc.
3750 Cisco Way,
San Jose, CA 95134, USA.
E-mail: sboutros@cisco.com
Samer Salam
Cisco Systems, Inc.
595 Burrard Street, Suite 2123,
Vancouver, BC V7X 1J1, Canada.
E-mail: ssalam@cisco.com
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