Internet DRAFT - draft-tissa-trill-oam-fm
draft-tissa-trill-oam-fm
TRILL Working group Tissa Senevirathne
Internet Draft Norman Finn
Intended status: Standard Track Samer Salam
Deepak Kumar
CISCO
Donald Eastlake
Sam Aldrin
Yizhou Li
Huawei
May 28, 2013
Expires: November 2013
TRILL Fault Management
draft-tissa-trill-oam-fm-02.txt
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Abstract
TRILL OAM Fault Management specification is presented in this
document. Methods in this document follow the IEEE 802.1 CFM
framework and reuse OAM tools where possible. Additional messages and
TLVs are defined for TRILL specific applications or where a different
set of information is required other than IEEE 802.1 CFM.
Table of Contents
1. Introduction...................................................4
2. Conventions used in this document..............................4
3. General Format of TRILL OAM frames.............................5
3.1. Identification of TRILL OAM frames........................7
3.2. Use of TRILL OAM Flag.....................................7
3.2.1. Handling of TRILL frames with the "A" Flag...........8
3.3. Backwards Compatibility Method............................8
3.4. OAM Capability Announcement..............................10
4. TRILL OAM Layering vs. IEEE Layering..........................11
4.1. Processing at ISS Layer..................................12
4.1.1. Receive Processing..................................12
4.1.2. Transmit Processing.................................12
4.2. End Station VLAN and Priority Processing.................12
4.2.1. Receive Processing..................................12
4.2.2. Transmit Procession.................................12
4.3. TRILL Encapsulation and De-capsulation Layer.............13
4.3.1. Receive Processing for Unicast packets..............13
4.3.2. Transmit Processing for unicast packets.............13
4.3.3. Receive Processing for Multicast packets............14
4.3.4. Transmit Processing of Multicast packets............15
4.4. TRILL OAM Layer Processing...............................16
5. Maintenance Associations (MA) in TRILL........................17
6. MEP Addressing................................................18
6.1. Use of MIP in TRILL......................................21
7. Approach for Backwards Compatibility..........................23
8. Continuity Check Message (CCM)................................24
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9. TRILL OAM Message Channel.....................................26
9.1. TRILL OAM Message header.................................26
9.2. TRILL OAM Opcodes........................................27
9.3. Format of TRILL OAM TLV..................................27
9.4. TRILL OAM TLVs...........................................28
9.4.1. Common TLVs between 802.1ag and TRILL...............28
9.4.2. TRILL OAM Specific TLVs.............................29
9.4.3. TRILL OAM Application Identifier TLV................29
9.4.4. Out Of Band Reply Address TLV.......................31
9.4.5. Diagnostics Label TLV...............................31
9.4.6. Original Data Payload TLV...........................32
9.4.7. RBridge scope TLV...................................33
9.4.8. Previous RBridge nickname TLV.......................33
9.4.9. Next Hop RBridge List TLV...........................34
9.4.10. Multicast Receiver Port count TLV..................35
9.4.11. Flow Identifier (flow-id) TLV......................35
10. Loopback Message.............................................37
10.1. Loopback OAM Message format.............................37
10.2. Theory of Operation.....................................37
10.2.1. Originator RBridge.................................37
10.2.2. Intermediate RBridge...............................38
10.2.3. Destination RBridge................................38
11. Path Trace Message...........................................39
11.1. Theory of Operation.....................................39
11.1.1. Originator RBridge.................................39
11.1.2. Intermediate RBridge...............................40
11.1.3. Destination RBridge................................41
12. Multi-Destination Tree Verification (MTV) Message............41
12.1. Multi-Destination Tree Verification (MTV) OAM Message Format
..............................................................42
12.2. Theory of Operation.....................................42
12.2.1. Originator RBridge.................................42
12.2.2. Receiving RBridge..................................44
12.2.3. In scope RBridges..................................44
13. Application of Continuity Check Message (CCM) in TRILL.......45
13.1. CCM Error Notification..................................45
13.2. Theory of Operation.....................................47
13.2.1. Originator RBridge.................................47
13.2.2. Intermediate RBridge...............................47
13.2.3. Destination RBridge................................47
14. Fragmented Reply.............................................48
15. Security Considerations......................................48
16. IEEE Allocation Considerations...............................48
17. IANA Considerations..........................................49
18. References...................................................49
18.1. Normative References....................................49
18.2. Informative References..................................49
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19. Acknowledgments..............................................50
Appendix A. Unicast MAC Request..................................51
1. Introduction
The general structure of TRILL OAM messages is presented in
[TRLOAMFRM]. According to [TRLOAMFRM], TRILL OAM messages consist of
five parts: link header, TRILL header, flow entropy, OAM message
channel, and link trailer.
The OAM message channel allows defining various control information
and carrying OAM related data between TRILL switches, also known as
RBridges or Routing Bridges.
A common OAM message channel representation can be shared between
different technologies. This enables consistency between different
OAM technologies and promotes nested fault monitoring and isolation
between technologies that share the same OAM framework.
This document uses the message format defined in IEEE 802.1ag
Connectivity Fault Management (CFM) [8021Q] as the basis for the
TRILL OAM message channel.
The ITU-T Y.1731 [Y1731] standard utilizes the same messaging format
as [8021Q] and OAM messages where applicable. This documenttake a
similar stance and propose reusing [8021Q] in TRILL OAM. It is
assumed readers are familiar with [8021Q] and [Y1731]. Readers who
are not familiar with these documents are encouraged to review them.
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].
Acronyms used in the document include the following:
MP - Maintenance Point [TRLOAMFRM]
MEP - Maintenance End Point [TRLOAMFRM] [8021Q]
MIP - Maintenance Intermediate Point [TRLOAMFRM] [8021Q]
MA - Maintenance Association [8021Q] [TRLOAMFRM]
MD - Maintenance Domain [8021Q]
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CCM - Continuity Check Message [8021Q]
LBM - Loop Back Message [8021Q]
PTM - Path Trace Message
MTV - Multi-destination Tree Verification Message
OAM - Operations, Administration, and Maintenance [RFC6291]
TRILL - Transparent Interconnection of Lots of Links [RFC6325]
FGL - Fine Grained Label [RFCfgl]
ECMP - Equal Cost Multipath
ISS - Internal Sub Layer Service [8021Q]
3. General Format of TRILL OAM frames
The TRILL forwarding paradigm allows an implementation to select a
path from a set of equal cost paths to forward a unicast TRILL Data
packet. For multi-destination TRILL Data packets, a distribution tree
is chosen by the TRILL switch that ingresses or creates the packet.
Selection of the path of choice is implementation dependent at each
hop for unicast and at the ingress for multi-destination. However, it
is a common practice to utilize Layer 2 through Layer 4 information
in the frame payload for path selection.
For accurate monitoring and/or diagnostics, OAM Messages are required
to follow the same path as corresponding data packets. [TRLOAMFRM]
proposes a high-level format of the OAM messages. The details of the
TRILL OAM frame format are defined in this document.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Link Header . (variable)
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ TRILL Header + 8 or more bytes
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Flow Entropy . 96 bytes
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OAM Ether Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. OAM Message Channel . Variable
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Trailer | Variable
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 Format of TRILL OAM Messages
Link Header: Media-dependent header. For Ethernet, this includes
Destination MAC, Source MAC, VLAN (optional) and EtherType fields.
TRILL Header: Minimum of 8 bytes when the Extended Header is not
included [RFC6325]
Flow Entropy: This is a 96-byte fixed size field. The least
significant bits of the field MUST be padded with zeros, up to 96
bytes, when the flow entropy is less than 96 bytes. Flow entropy
enables emulation of the forwarding behavior of the desired data
packets. The Flow Entropy field starts with the Inner.MacDA. The
offset of the Inner.MacDA depends on whether extensions are included
or not as specified in [TRILLEXT] and [RFC6325].
OAM Ether Type: OAM Ether Type is 16-bit EtherType that identifies
the OAM Message channel that follows. This document specifies using
the EtherType allocated for 802.1ag for this purpose. Identifying the
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OAM Message Channel with a dedicated EtherType allows the easy
identification of the beginning of the OAM message channel across
multiple standards.
OAM Message Channel: This is a variable size section that carries OAM
related information. Message format defined in [8021Q] will be reused
for TRILL OAM.
Link Trailer: Media-dependent trailer. For Ethernet, this is the FCS
(Frame Check Sequence).
3.1. Identification of TRILL OAM frames
TRILL, as originally specified in [RFC6325], did not have a specific
flag or a method to identify OAM frames. This document updates
[RFC6325] to include specific methods to identify TRILL OAM frames.
Section 3.2. below explains the details of the method. However, it is
important, for backwards compatibility reasons, to define methods of
identifying TRILL OAM frames without using these extensions. Section
3.3. presents a set of possible methods for identifying OAM frames
without using the proposed extensions of section 3.2. The methods
defined in section 3.3. impose limitations on the construction of the
flow entropy field of the OAM frames but MUST be used when backward
compatibility is required with TRILL switches not supporting the
method specified in Section 3.2.
3.2. Use of TRILL OAM Flag
The TRILL Header, as defined in [RFC6325], has two reserved bits that
are currently unused. RBridges are currently required to ignore these
fields. This document specifies use of the reserved bit next to
Version field in the TRILL header as the Alert flag. Alert flag will
be denoted by "A".
Implementations that support the extension of using the "A" flag to
identify frames MUST use that flag and the methods specified in
section 3.2.1. The "A" flag MUST NOT be utilized for forwarding
decisions such as the selection of which ECMP path or multi-
destination tree to use.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| V |A|R|M|Op-Length| Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Egress RBridge Nickname | Ingress RBridge Nickname |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options...
+-+-+-+-+-+-+-+-+-+-+-+-
Figure 2 TRILL Header
A (1 bit) - Indicates this is a possible OAM frame and is subject to
specific handling as specified in this document.
All other fields carry the same meaning as defined in RFC6325.
3.2.1. Handling of TRILL frames with the "A" Flag
Value "1" in the A flag indicates TRILL frames that may qualify as
OAM frames. Implementations are further required to validate such
frames by comparing the value at the OAM Ether Type (Figure 1)
location with the CFM EtherType "0x8902" [8021Q]. If the value
matches, such frames are identified as TRILL OAM frames and SHOULD be
processed as discussed in Section 4.
3.3. Backwards Compatibility Method
Backward compatibility method presented in this section defines
methods to identify OAM frames when implementations do not have
capabilities to utilize TRILL OAM Alert flag presented earlier. It is
assumed ECMP path selection of non-IP flows utilize MAC DA, MAC SA
and VLAN, IP Flows utilize IP DA, IP SA and TCP/UDP port numbers and
other Layer 3 and Layer 4 information. The well-known fields to
identify OAM flows are chosen such that, they mimic the ECMP
selection of the actual data along the path. However, it is important
to note that, there may be implementations that would utilize these
well-known fields for ECMP selections. Hence, implementations that
support OAM SHOULD move to utilizing TRILL OAM Flag, as soon as
possible and methods presented here SHOULD be used only as an interim
solution.
Identification methods are divided in to 4 broader groups.
Identification of Unicast non-IP OAM Flows,
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Identification of Multicast non-IP OAM Flows,
Identification of Unicast IP OAM Flows and
Identification of Multicast IP OAM Flows
As presented in the table below, based on the flow type (as defined
above), implementations are required to use a well-known value in
either the source MAC field or Ethertype field to identify OAM flows.
Receiving RBridges identifies OAM flows based on the presence of the
well-known values in the specified fields, AND additionally, for
unicast flows, egress RBRdige nickname of the packet MUST match that
of the local RBRidge or for multicast flows, TRILL header mutlicast
flag MUST be set.
Unicast OAM flows that qualify for local processing MUST be
redirected to the OAM process and MUST NOT be forward along (that to
prevent leaking of the packet out of the TRILL campus).
A copy of Multicast OAM flows that qualify for local processing MUST
be sent to the OAM process and packet MUST be forwarded along the
normal path. Additionally, methods MUST be in place to prevent
multicast packets leaking out of the TRILL campus.
The following table summarizes the identification of different OAM
frames from data frames.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Flow Entropy |Inner |OAM Ether|Egress |
| |MacSA |Type |nickname |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|unicast no IP | N/A |Match |Match |
| | | | |
|Multicast no IP| N/A |Match |N/A |
| | | | |
|Unicast IP | Match |N/A |Match |
| | | | |
|Multicast IP | Match |N/A |N/A |
| | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3 Identification of TRILL OAM Frames
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3.4. OAM Capability Announcement
Any given TRILL RBridge can be (1) OAM incapable or (2) OAM capable
with new extensions or (3) OAM capable with backwards-compatible
method. The OAM request originator, prior to origination of the
request is required to identify the OAM capability of the target and
generate the appropriate OAM message.
Capability flags defined in TRILL version sub-TLV (TRILL-VER)
[rfc6326bis] will be utilized for announcing OAM capabilities. The
following OAM related Flags are defined:
O - OAM Capable
B - Backwards Compatible.
A capability announcement, with O Flag set to 1 and B flag set to 1,
indicates that the implementation is OAM capable but utilize
backwards compatible method defined in section 3.3. A capability
announcement, with O Flag set to 1 and B flag set to 0, indicates
that the implementation is OAM capable and utilizes the method
specified in section 3.2.
When O Flag is set to 0, the announcing implementation is considered
not capable of OAM and in this case the B flag is ignored.
+-+-+-+-+-+-+-+-+
| Type | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
| Max-version | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
|A|O|B|Other Capabilities and Header Flags| (4 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+
0 1 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 0 1
Figure 4 TRILL-VER sub-TLV [rfc6326bis] with O and B flags
NOTE: Bit position of O and B flags in the TRILL-VER sub-TLV are
presented above as an example. Actual positions of the flags will be
determined by TRILL WG and IANA and future revision of this document
will be updated to include the allocations.
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4. TRILL OAM Layering vs. IEEE Layering
This section presents the placement of the TRILL OAM shim within the
IEEE 802.1 layers. The processing of both the Transmit and Receive
directions is explained.
+-+-+-+-+-+-+-+-+-+-+
| RBridge Layer |
| Processing |
+-+-+-+-+-+-+-+-+-+-+
|
|
+-+-+-+-+-+-+
| TRILL OAM | UP MEP
| Layer | MIP
+-+-+-+-+-+-+ Down MEP
|
|
+-+-+-+-+-+-+
(3)--------> | TRILL |
| Encap/Decap
+-+-+-+-+-+-+
|
+-+-+-+-+-+-+
(2)--------> |End station|
| VLAN & priority Processing
+-+-+-+-+-+-+
|
+-+-+-+-+-+-+
(1)--------> |ISS |
|Processing |
+-+-+-+-+-+-+
|
|
|
Figure 5 Placement of TRILL MP within IEEE 802.1
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[RFC6325] Section 4.6 provides a detailed explanation of frame
processing. Please refer to [RFC6325] for processing scenarios not
covered herein.
Sections 4.1 and 4.2 below apply to links using a broadcast LAN
technology such as Ethernet.
On links using an inherently point-to-point technology, such as PPP
[RFC6361], there is no Outer.MacDA, Outer.MacSA, our Outer.VLAN
because these are part of the link for Ethernet. Point-to-point links
typically have link headers without these fields. These fields are
primarily significant for native frames from and/or to end stations.
4.1. Processing at ISS Layer
4.1.1. Receive Processing
The ISS Layer receives an indication from the port. It extracts DA,
SA and marks the remainder of the payload as M1. ISS Layer passes on
(DA,SA,M1) as an indication to the higher layer.
For TRILL Ethernet frames, this is Outer.MacDA and Outer.MacSA. M1 is
the remainder of the packet.
4.1.2. Transmit Processing
The ISS layer receives an indication from the higher layer that
contains (DA, SA, M1). It constructs an Ethernet frame and passes
down to the port.
4.2. End Station VLAN and Priority Processing
4.2.1. Receive Processing
Receives (DA, SA, M1) indication from ISS Layer. Extracts the VLAN ID
an priority from the M1 part of the received indication and
constructs (DA, SA, VLAN, PRI, M2). VLAN+PRI+M2 map to M1 in the
received indication. Pass (DA, SA, VLAN, PRI, M2) to the TRILL
encap/decap procession layer.
4.2.2. Transmit Procession
Receive (DA, SA, VLAN, PRI, M2) indication from TRILL encap/decap
processing layer. Merge VLAN, M2 to form M1. Pass down (DA, SA, M1)
to the ISS processing Layer.
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4.3. TRILL Encapsulation and De-capsulation Layer
4.3.1. Receive Processing for Unicast packets
Receive indication (DA, SA, VLAN,PRI,M2) from End Station VLAN and
Priority Processing Layer.
o If DA matches port Local DA and Frame is of TRILL EtherType
. Discard DA, SA, VLAN, PRI. From M2, derive (TRILL-HDR, iDA,
iSA, i-VL, M3)
. If TRILL nickname is Local and TRILL-OAM Flag is set
Pass on to OAM processing
. Else pass on (TRILL-HDR, iDA, iSA, i-VL, M3) to RBridge
Layer
o If DA matches port Local DA and EtherType is RBridge-Channel
[Channel]
. Process as a possible unicast native RBridge Channel packet
o If DA matches port Local DA and EtherType is neither TRILL nor
RBridge-Channel
. Discard packet
o If DA does not match and port is Appointed Forwarder for VLAN and
EtherType is not TRILL or RBridge-Channel
. Insert TRILL-Hdr and send (TRILL-HDR, iDA, iSA,i-VL, M3)
indication to RBridge Layer <- This is the ingress function
4.3.2. Transmit Processing for unicast packets
o Receive indication (TRILL-HDR, iDA, iSA, iVL, M3) from RBridge
Layer
o If egress TRILL nickname is local
o If port is Appointed Forwarder for iVL and the port is not
configured as a trunk or p2p port and (TRILL Alert Flag set
and OAM EtherType present) then
. Strip TRILL-HDR and construct (DA, SA, VLAN, M2)
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o Else
. Discard packet
o If egress TRILL nickname is not local
o Insert Outer.MacDA, Outer.MacSA, Outer.VLAN, TRILL EtherType
and construct (DA,SA,VLAN,M2). Where M2 is (TRILL-HDR, iDA,
iSA, iVL, M)
o Forward (DA,SA,V,M2) to the VLAN End Station processing Layer.
4.3.3. Receive Processing for Multicast packets
o Receive (DA,SA,V,M2) from VLAN aware end station processing
layer
o If the DA is All-RBridges and the EtherType is TRILL
o Strip DA,SA and V. From M2, extract (TRILL-HDR, iDA, iSA,
iVL and M3).
o If TRILL OAM Flag is set and OAM EtherType is present at the
end of Flow entropy
. Perform OAM Processing
o Else extract the TRILL header, inner MAC addresses and inner
VLAN and pass indication (TRILL-HDR, iDA, iSA, iVL and M3)
to TRILL RBridge Layer
o If the DA is All-IS-IS-RBridges and the Ethertype is L2-IS-IS
then pass frame up to TRILL IS-IS processing
o If the DA is All-RBridges or All-IS-IS-RBridges but Ethertype
is not TRILL or L2-IS-IS respectively
o Discard the packet
o If the EtherType is TRILL but the multicast DA is not All-
RBridge or if the EtherType is L2-IS-IS but the multicast Da is
not All-IS-IS-RBridges
o Discard the packet
o If DA is All-Edge-RBridges and EtherType is RBridge-Channel
[Channel]
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o Process as a possible multicast native RBridge Channel
packet
o If the DA is in the initial bridging/link protocols block (01-
80-C2-00-00-00 to 01-80-C2-00-00-0F) or is in the TRILL block
and not assigned for Outer.MacDA use (01-80-C2-00-00-42 to 01-
80-C2-00-00-4F) then
o The frame is not propagated through an RBridge although some
special processing may be done at the port as specified in
[RFC6325] and the frame may be dispatched to Layer 2
processing at the port if certain protocols are supported
by that port (examples: Link Aggregation Protocol, Link
Layer Discovery Protocol).
o If the DA is some other multicast value
o Insert TRILL-HDR and construct (TRILL-HDR, iDA, iSA, IVL,
M3)
o Pass the (TRILL-HDR, iDA, iSA, IVL, M3) to RBridge Layer
4.3.4. Transmit Processing of Multicast packets
The following ignores the case of transmitting TRILL IS-IS packets.
o Receive indication (TRILL-HDR, iDA, iSA, iVL, M3) from RBridge
layer.
o If TRILL-HDR multicast flag set and TRILL-HDR Alert flag set
and OAM EtherType present then:
o (DA,SA,V,M2) by inserting TRILL Outer.MacDA of All-
RBridges, Outer.MacSA, Outer.VL and TRILL EtherType. M2
here is (Ethertype TRILL, TRILL-HDR, iDA, iSA, iVL, M)
NOTE: Second copy of native format is not made.
o Else If TRILL-HDR multicast flag set and Alert flag not set
o If the port is appointed Forwarder for iVL and the port is
not configured as a trunk port or a p2p port, Strip TRILL-
HDR, iSA, iDA, iVL and construct (DA,SA,V,M2) for native
format.
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o Make a second copy (DA,SA,V,M2) by inserting TRILL
Outer.MacDA, Outer.MacSA, Outer.VL and TRILL EtherType. M2
here is (EtherType TRILL, TRILL-HDR, iDA, iSA, iVL, M)
o Pass the indication (DA,SA,V,M2) to End Station VLAN processing
layer.
4.4. TRILL OAM Layer Processing
TRILL OAM Processing Layer is located between the TRILL Encapsulation
/ De-capsulation layer and RBridge Layer. It performs 1.
Identification of OAM frames that need local processing 2. Perform
OAM processing or redirect to the CPU for OAM processing.
o Receive indication (TRILL-HDR, iDA, iSA, iVL, M3) from RBridge
layer.
o If the TRILL Multicast Flag is set and TRILL Alert Flag is set
and TRILL OAM EtherType is present then
o If MEP or MIP is configured on the Inner.VLAN of the packet
then
. discard packets that have MD-LEVEL Less than that of
the MEP or packets that do not have MD-LEVEL present
(e.g due to packet truncation).
. If MD-LEVEL matches MD-LEVEL of the MEP then
. Re-direct to OAM Processing (Do not forward
further)
. If MD-LEVEL matches MD-LEVEL of MIP then
. Make a Copy for OAM processing and continue
o Else if TRILL Alert Flag is set and TRILL OAM EtherType is
present then
o If MEP or MIP is configured on the Inner.VLAN of the packet
then
. discard packets that have MD-LEVEL not present or MD-
LEVEL is Less than that of the MEP.
. If MD-LEVEL matches MD-LEVEL of the MEP then
. Re-direct to OAM Processing (Do not forward
further)
. If MD-LEVEL matches MD-LEVEL of MIP then
. Make a Copy for OAM processing and continue
o Else // Non OAM l Packet
o Continue
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o Pass the indication (DA,SA,V,M2) to End Station VLAN processing
layer.
NOTE: In the Received path, processing above compares against Down
MEP and MIP Half functions. In the transmit processing it compares
against Up MEP and MIP Half functions.
Appointed Forwarder is a Functionality that TRILL Encap/De-Cap layer
performs. The TRILL Encap/De-cap Layer is responsible for prevention
of leaking of OAM packets as native frames.
5. Maintenance Associations (MA) in TRILL
[8021Q] defines a maintenance association as a logical relationship
between a group of nodes. Each Maintenance Association (MA) is
identified with a unique MAID of 48 bytes [8021Q]. CCM and other
related OAM functions operate within the scope of an MA. The
definition of MA is technology independent. Similarly it is encoded
within the OAM message, not in the technology dependent portion of
the packet. Hence the MAID as defined in [8021Q] can be utilized for
TRILL OAM, without modifications. This also allows us to utilize CCM
and LBM messages defined in [8021Q], as is.
In TRILL, an MA may contain two or more RBridges (MEPs). For unicast,
it is likely that the MA contains exactly two MEPs that are the two
end-points of the flow. For multicast, the MA may contain two or more
MEPs.
For TRILL, in addition to all of the standard 802.ag MIB definitions,
each MEP's MIB contains one or more flow entropy definitions
corresponding to the set of flows that the MEP monitors.
[8021Q] MIB is augmented to add the TRILL specific information.
Figure 6, below depicts the augmentation of the CFM MIB to add the
TRILL specific Flow Entropy.
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MA---
|
--- MEP
|
. - Remote MEP List
.
|
--- MEP-A
|
--- MEP-B
.
|
. - Flow Entropy List { Augments IEEE8021-CFM-MIB}
|
--- (Flow Entropy-1)
|
--- (Flow-entropy-2)
|
. --- ( Flow Entropy n)
|
Other MIB entries
Figure 6 Correlation of TRILL augmented MIB
6. MEP Addressing
In IEEE 802.1ag [8021Q], OAM messages address the target MEP by
utilizing a unique MAC address. In TRILL MEP is addressed by
combination of the egress RBridge nickname and the Inner VLAN/FGL.
At the MEP, OAM packets go through a hierarchy of op-code de-
multiplexers. The op-code de-multiplexers channel the incoming OAM
packets to the appropriate message processor (e.g. LBM) The reader
may refer to Figure 7 below for a visual depiction of these different
de-multiplexers.
1. Identify the packets that need OAM processing at the Local RBridge
as specifies in Section 4.
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a. Identify the MEP that is associated with the Inner.VLAN.
2. The MEP first validates the MD-LEVEL and then
a. Redirect to MD-LEVEL De-multiplexer
3. MD-LEVEL de-multiplexer compares the MD-Level of the packet
against the MD level of the local MEPs of a given MD-Level on the
port (Note: there can be more than one MEP at the same MD-Level
but belonging to different MAs)
a. If the packet MD-LEVEL is equal to the configured MD-LEVEL
of the MEP, then pass to the Opcode de-multiplexer
b. If the packet MD-LEVEL is less than the configured MD-LEVEL
of the MEP, discard the packet
c. If the packer MD-LEVEL is greater than the configured MD-
LEVEL of the MEP, then pass on to the next higher MD-LEVEL
de-multiplexer, if available. Otherwise, if no such higher
MD-LEVEL de-multiplexer exists, then forward the packet as
normal data.
4. Opcode De-multiplexer compares the opcode in the packet with
supported opcodes
a. If Op-code is CCM, LBM, LBR, PTM, PTR, MTVM, MTVR, then pass
on to the correct Processor
b. If Op-code is Unknown, then discard.
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|
.CCM LBM PTM MTV
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+
| OP Code DE-Mux |--- Unknown
+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^
MD==Li | | |
+-+-+ +-+-+ +-+-+
| L |-->|L2 |-.- |Ln |---- >
+-+-+ +-+-+ +-+-+ |
| ^ | | |
MD<LI Drop | Drop Drop |
| |
MD not --- |TRILL OAM need local |
Present | Processing |
| |
TRILL Data ---- TRILL Data ----
------->| T |----------------- >| M |--- >
+ TRILL OAM ---- + pass through OAM ----
Figure 7 OAM De-Multiplexers at MEP for active SAP
T : Denotes Tap, that identifies OAM frames that need local
processing. These are the packets with OAM flag set AND OAM
Ether type is present after the flow entropy of the packet
M : Is the post processing merge, merges data and OAM messages
that are pass through. Additionally, Merge the component
ensures, as explained earlier, that OAM packets are not
forwarded out as native frames.
L : Denotes MD-Level processing. Packets with MD-Level less than
the Level will be dropped. Packets with equal MD-Level are
passed on to the opcode de-multiplexer. Others are passed on to
the next level MD processors or eventually to the merge point
(M).
NOTE: LBM, MTV and PT are not subject to MA de-multiplexers.
These packets do not have an MA encoded in the packet. Adequate
response can be generated to these packets, without loss of
functionality, by any of the MEPs present on that interface or
an entity within the RBridge.
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6.1. Use of MIP in TRILL
Maintenance Intermediate Points (MIP) are mainly used for fault
isolation. Link Trace Messages in [8021Q] utilize a well-known
multicast MAC address and MIPs generate responses to Link Trace
messages. Response to Link Trace messages or lack thereof can be used
for fault isolation in TRILL.
As explained in section 11. , hop-count expiry approach will be
utilized for fault isolation and path tracing. The approach is very
similar to the well-known IP trace-route approach. Hence, explicit
addressing of MIPs is not required for the purpose of fault
isolation.
Any given RBridge can have multiple MIPs located within an interface.
As such, a mechanism is required to identify which MIP should respond
to an incoming OAM message.
Similar approach as presented above for MEPs can be used for MIP
processing. It is important to note that "M", the merge block of a
MIP, does not prevent OAM packets leaking out as native frames. On
edge interfaces, MEPs MUST be configured to prevent the leaking of
TRILL OAM packets out of the TRILL Campus.
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PT MTV
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP Code De-Mux |-> Unknown
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^
MD==Li | | |
+-+-+ +-+-+ +-+-+
| L |- >|L2 |-.- |Ln |------+
+-+-+ +-+-+ +-+-+ |
^ |
| |
Drop | |
MD not --- |TRILL OAM |
Present | |
| v
TRILL Data ---- TRILL Data -----
------- >| T |------------------ >| M |---->
+ TRILL OAM ---- ----
Figure 8 OAM De-Multiplexers at MIP for active SAP
T: TAP processing for MIP. All packets with OAM flag set are
captured.
L : MD Level Processing, Packet with matching MD Level are "copied"
to the Opcode de-multiplexer and original packet is passed on to the
next MD level processor. Other packets are simply passed on to the
next MD level processor, without copying to the OP code de-
multiplexer.
M : Merge processor, merge OAM packets to be forwarded along with the
data flow.
Packets that carry Path Trace Message (PTM) or Multi-destination Tree
Verification (MTV) OpCode are passed on to the respective processors.
Packets with unknown OpCodes are counted and discarded.
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7. Approach for Backwards Compatibility
Methodology presented above in this document is in-line with the
[8021Q] framework for providing fault management coverage. However,
in practice, some platforms may not have the required capabilities to
support some of the proposed techniques. In this section, we present
a method that allows RBridges, which do not have the required
hardware capabilities, to participate in the proposed OAM solution.
For backwards compatibility, MEPs and MIPs are located in the CPU.
This will be referred to as the "central brain" model as opposed to
"port brain" model.
In the "central brain" model, an RBridge using either ACLs or some
other method, forwards qualifying OAM messages to the CPU. The CPU
then performs the required processing and multiplexing to the correct
MP (Maintenance Point).
Additionally, RBridges MUST have the capability to prevent the
leaking of OAM packets, as specified in [RFC6905] and in the
Transmission processing in Figure 9.
Receiver Processing:
If (M==1 && F==1) then
Copy to CPU and Forward normally as defined in [RFC6325]
Else if (M==0 && F==1 && egress nickname is the processing RBridge)
then
Forward to CPU BUT DO NOT forward along the data plane
Else
Forward as defined in [RFC6325]
End;
Transmit Processing:
If (F==1) then
Forward as defined in [RFC6325] BUT Do not de-capsulate and forward
as a native frame
Else
Forward as defined in [RFC6325]
Figure 9 Pseudo code for Backward compatible Processing
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[8021Q] requires that the MEP filters or pass through OAM messages
based on the MD-Level. The MD-Level is embedded deep in the OAM
message. Hence, conventional methods of frame filtering may not be
able to filter frames based on the MD-Level. As a result, OAM
messages that must be dropped due to MD level mismatch may leak in to
a TRILL domain with different MD-Level.
This leaking may not cause any functionality loss. The receiving
MEP/MIP is required to validate the MD-level prior to acting on the
message. Any frames received with an incorrect MD-Level will be
dropped.
Generally, TRILL campuses are managed by a single operator, hence
there is no risk of security exposure. However, in the event of multi
operator deployments, operators should be aware of possible exposure
of device specific information and appropriate measures must be
taken.
It is also important to note that the MPLS OAM [RFC4379] framework
does not include the concept of domains and OAM filtering based on
operators. It is our opinion that the lack of OAM frame filtering
based on domains does not introduce significant functional deficiency
or security risk.
8. Continuity Check Message (CCM)
CCMs are used to monitor connectivity and configuration errors.
[8021Q] monitors connectivity by listening to periodic CCM messages
received from its remote MEP partners in the MA. An [8021Q] MEP
identifies cross-connect errors by comparing the MAID in the received
CCM message with the MEP's local MAID. The MAID [8021Q] is a 48 byte
field that is technology independent. Similarly, the MEPID is a 2
byte field that is independent of the technology. Given this generic
definition of CCM fields, CCM as defined in [8021Q] can be utilized
in TRILL with no changes. TRILL specific information may be carried
in CCMs when encoded using TRILL specific TLVs or sub-TLVs. This is
possible since CCMs may carry optional TLVs.
Unlike classical Ethernet environments, TRILL contains multipath
forwarding. The path taken by a packet depends on the payload of the
packet. The Maintenance Association identifies the interested end-
points (MEPs) of a given monitored path. For unicast there are only
two MEPs per MA. For multicast there can be two or more MEPs in the
MA. The entropy values of the monitored flows is defined within the
MA. CCM transmit logic will utilize these flow entropy values when
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constructing the CCM packets. Please see section 13. below for the
theory of operation of CCM.
The MIB of [8021Q] is augmented with the definition of flow-entropy.
Please see [TRILLOAMMIB] for definition of these and other TRILL
related OAM MIB definitions. Below Figure depicts the correlation
between MA, CCM and proposed flow-entropy.
MA---
|
--- MEP
|
. - Remote MEP List
.
|
--- MEP-A
|
--- MEP-B
.
|
. - Flow Entropy List {Augments IEEE8021-CFM-MIB}
|
--- (Flow Entropy-1) {note we have to define
| destination nickname with
--- (Flow-entropy-2) the flow entropy discuss}
|
. ---(Flow Entropy n)
|
. - CCM
|
--- (standard 8021ag entries)
|
--- (hop-count) { Augments IEEE8021-CFM-MIB}
|
--- (Other TBD TRILL OAM specific entries)
{Augmented}
|
.
|
- Other MIB entries
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Figure 10Augmentation of CCM MIB in TRILL
In a multi-pathing environment, a Flow - by definition - is
unidirectional. A question may arise as to what flow entropy should
be used in the response. CCMs are unidirectional and have no explicit
reply; as such, the issue of the response flow entropy does not
arise. In the transmitted CCM, each MEP reports local status using
the Remote Defect Indication (RDI) flag. Additionally, a MEP may
raise SNMP TRAPs [TRILLOAMMIB] as Alarms when a connectivity failure
occurs.
9. TRILL OAM Message Channel
The TRILL OAM Message Channel can be divided into two parts: TRILL
OAM Message header and TRILL OAM Message TLVs. Every OAM Message MUST
contain a single TRILL OAM message header and a set of one or more
specified OAM Message TLVs.
9.1. TRILL OAM Message header
As discussed earlier, a common messaging framework between [8021Q],
TRILL, and other similar standards such as Y.1731 can be accomplished
by re-using the OAM message header defined in [8021Q].
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MD-L | Version | OpCode | Flags |FirstTLVOffset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Opcode Specific Information .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. TLVs .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11OAM Message Format
o MD-L: Maintenance Domain Level (3 bits). Identifies the
maintenance domain level. For TRILL, in general, this field is
set to zero. However, extension of TRILL, for example to support
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multilevel, may create different MD-LEVELs and MD-L field must
be appropriately set in those scenarios. (Please refer to
[8021Q] for the definition of MD-Level)
o Version: Indicates the version (5 bits). As specified in
[8021Q]. This document does not propose to change the Version
defined in [8021Q].
o Flags: Includes operational flags (1 byte). The definition of
flags is Opcode-specific and is covered in the applicable
sections.
o FirstTLVOffset: Defines the location of the first TLV, in
bytes, starting from the end of the FirstTLVOffset field (1
byte). (Refer to [8021Q] for the definition of the
FirstTLVOffset.)
MD-L, Version, Opcode, Flags and FirstTLVOffset fields collectively
are referred to as the OAM Message Header.
The Opcode specific information section of the OAM Message may
contain Session Identification number, time-stamp, etc.
9.2. TRILL OAM Opcodes
The following Opcodes are defined for TRILL. Each of the Opcodes
indicates a separate type of TRILL OAM message. Details of the
messages are presented in the related sections.
TRILL OAM Message Opcodes:
TBD-64 : Path Trace Reply
TBD-65 : Path Trace Message
TBD-66 : Multicast Tree Verification Reply
TBD-67 : Multicast Tree Verification Message
9.3. Format of TRILL OAM TLV
The same TLV format as defined in section 21.5.1 of [8021Q] is used
for TRILL OAM. The following figure depicts the general format of a
TRILL OAM TLV:
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0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Value(variable) .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12 TRILL OAM TLV
Type (1 octet) : Specifies the Type of the TLV (see sections 9.4.
for TLV types).
Length (2 octets) : Specifies the length of the 'Value' field in
octets. Length of the 'Value' field can be either zero or more
octets.
Value (variable): The length and the content of this field depend on
the type of the TLV. Please refer to applicable TLV definitions for
the details.
Semantics and usage of Type values allocated for TRILL OAM purpose
are defined by this document and other future related documents.
9.4. TRILL OAM TLVs
TRILL related TLVs are defined in this section. [8021Q] defined TLVs
are reused, where applicable. Types 32-63 are reserved for ITU-T
Y.1731. We propose to reserve Types 64-95 for TRILL OAM TLVs.
9.4.1. Common TLVs between 802.1ag and TRILL
The following TLVs are defined in [8021Q]. We propose to re-use them
where applicable. The format and semantics of the TLVs are as defined
in [8021Q].
Type Name of TLV in [8021Q]
---- -------------
0 End TLV
1 Sender ID TLV
2 Port Status TLV
3 Data TLV
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4 Interface Status TLV
5 Reply Ingress TLV
6 Reply Egress TLV
7 LTM Egress Identifier TLV
8 LTR Egress Identifier TLV
9-30 Reserved
31 Organization Specific TLV
9.4.2. TRILL OAM Specific TLVs
As indicated above, Types 64-95 will be requested to be reserved for
TRILL OAM purposes. Listed below is a summary of TRILL OAM TLVs and
their corresponding codes. Format and semantics of TRILL OAM TLVs are
defined in subsequent sections.
Type TLV Name
----------- ----------------------
TBD-TLV-64 TRILL OAM Application Identifier
TBD-TLV-65 Out of Band IP Address
TBD-TLV-66 Diagnostic VLAN
TBD-TLV-67 RBridge Scope
TBD-TLV-68 Original Payload
TBD-TLV-69 Previous RBridge Nickname
TBD-TLV-70 RILL Next Hop RBridge List (ECMP)
TBD-TLV-71 Multicast Receiver Availability
TBD-TLV-72 Flow Identifier
TBD-TLV-73 to TBD-TLV-95 Reserved
9.4.3. TRILL OAM Application Identifier TLV
TRILL OAM Application Identifier TLV carries TRILL OAM application
specific information. The TRILL OAM Application Identifier TLV MUST
always be present and MUST be the first TLV in TRILL OAM messages.
Messages that do not include the TRILL OAM Application Identifier TLV
as the first TLV MUST be discarded by an RBridge, unless that RBridge
is also running Ethernet CFM.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Return Code |Return sub-code| Reserved |F|C|O|I|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13TRILL OAM Message TLV
Type (1 octet) = 64 indicate that this is the TRILL OAM Version
Length (2 octets) = 6
TRILL OAM Version (1 Octet), currently set to zero. Indicates the
TRILL OAM version. TRILL OAM version can be different than the
[8021Q] version.
Return Code (1 Octet): Set to zero on requests. Set to an appropriate
value in response messages.
Return sub-code (1 Octet): Return sub-code is set to zero on
transmission of request message. Return sub-code identifies
categories within a specific Return code. Return sub-code MUST be
interpreted within a Return code.
Reserved: set to zero on transmission and ignored on reception.
F (1 bit) : Final flag, when set, indicates this is the last
response.
C (1 bit ): Label error (VLAN/Label mapping error), if set indicates
that the label (VLAN/FGL) in the flow entropy is different than the
label included in the diagnostic TLV. This field is ignored in
request messages and MUST only be interpreted in response messages.
O (1 bit) : If set, indicates, OAM out-of-band response requested.
I (1 bit) : If set, indicates, OAM in-band response requested.
NOTE: When both O and I bits are set to zero, indicates that no
response is required (silent mode). User MAY specify both O and I or
one of them or none. When both O and I bits are set response is sent
both in-band and out-of-band.
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9.4.4. Out Of Band Reply Address TLV
Out of Band Reply Address TLV specifies the address to which an out
of band OAM reply message MUST be sent. When O bit in the TRILL
Version TLV is not set, Out of Band Reply Address TLV is ignored.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Address Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Addr Length | |
+-+-+-+-+-+-+-+-+ |
| |
. Reply Address .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14Out of Band IP Address TLV
Type (1 octet) = 64
Length (2 octets) = Variable. Minimum length is 2.
Address Type (1 Octet): 0 - IPv4. 1 - IPv6. 2 - TRILL RBridge
nickname. All other values reserved.
Addr Length (1 Octet). 4 - IPv4. 16 - IPv6, 2 - TRILL RBRidge
nickname.
Reply Address (variable): Address where the reply needed to be sent.
Length depends on the address specification.
9.4.5. Diagnostics Label TLV
Diagnostic label specifies the data label (VLAN or FGL) in which the
OAM messages are generated. Receiving RBridge MUST compare the data
label of the Flow entropy to the data label specified in the
Diagnostic Label TLV. Label Error Flag in the response (TRILL OAM
Message Version TLV) MUST be set when the two VLANs do not match.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | L-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Label(VLAN) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 15Diagnostic VLAN TLV
Type (1 octet) = 65 indicates that this is the TRILL Diagnostic VLAN
TLV
Length (2 octets) = 5
L-Type (Label type, 1 octet)
0- indicate 802.1Q 12 bit VLAN.
1 - indicate TRILL 24 bit fine grain label
Label (24 bits): Either 12 bit VLAN or 24 bit fine grain label.
RBridges do not perform Label error checking when Label TLV is not
included in the OAM message. In certain deployments intermediate
devices may perform label (VLAN) translation. In such scenarios,
originator should not include the diagnostic Label TLV in OAM
messages. Inclusion of diagnostic TLV will generate unwanted label
error notifications.
9.4.6. Original Data Payload TLV
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
. Original Payload .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16Original Data Payload TLV
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Length (2 octets) = variable
9.4.7. RBridge scope TLV
RBridge scope TLV identifies nicknames of RBridges from which a
response is required. The RBridge scope TLV is only applicable to
Multicast Tree Verification messages. This TLV SHOULD NOT be included
in other messages. Receiving RBridges MUST ignore this TLV on
messages other than Multicast Verification Message.
Each TLV can contain up to 255 nicknames of in scope RBridges. A
Multicast Verification Message may contain multiple "RBridge scope
TLVs", in the event that more than 255 in scope RBridges need to be
specified.
Absence of the "RBridge scope TLV" indicates that a response is
needed from all the RBridges. Please see section 12. for details.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | nOfnicknames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| nickname-1 | nickname-2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | nickname-n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 17RBridge Scope TLV
Type (1 octet) = 67 indicates that this is the "RBridge scope TLV"
Length (2 octets) = variable. Minimum value is 2.
Nickname (2 octets) = 16 bit RBridge nickname.
9.4.8. Previous RBridge nickname TLV
"Previous RBridge nickname TLV" identifies the nickname or nicknames
of the upstream RBridge. [RFC6325] allows a given RBridge to hold
multiple nicknames.
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"Upstream RBridge nickname TLV" is an optional TLV. Multiple
instances of this TLV MAY be included when an upstream RBridge is
represented by more than 255 nicknames (highly unlikely).
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | nickname |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18Upstream RBridge nickname TLV
Type (1 octet) = 69 indicates that this is the "Upstream RBridge
nickname"
Length (2 octets) = 4.
Nickname (2 octets) = 16 bit RBridge nickname.
9.4.9. Next Hop RBridge List TLV
"Next Hop RBridge List TLV" identifies the nickname or nicknames of
the downstream next hop RBridges. [RFC6325] allows a given RBridge to
have multiple Equal Cost Paths to a specified destination. Each next
hop RBridge is represented by one of its nicknames.
"Next Hop RBridge List TLV" is an optional TLV. Multiple instances of
this TLV MAY be included when there are more than 255 Equal Cost
Paths to the destination.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | nOfnicknames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| nickname-1 | nickname-2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | nickname-n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19Next Hop RBridge List TLV
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Type (1 octet) = 70 indicates that this is the "Next nickname"
Length (2 octets) = variable. Minimum value is 2.
Nickname (2 octets) = 16 bit RBridge nickname.
9.4.10. Multicast Receiver Port count TLV
"Multicast Receiver Port Count TLV" identifies the number of ports
interested in receiving the specified multicast stream within the
responding RBridge on the VLAN specified by the Diagnostic VLAN TLV.
Multicast Receiver Port count is an Optional TLV.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| number of Receivers |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20Multicast Receiver Availability TLV
Type (1 octet) = 71 indicates that this is the "Multicast
Availability TLV"
Length (2 octets) = 5.
Number of Receivers (4 octets) = Indicates the number of Multicast
receivers available on the responding RBridge on the VLAN specified
by the diagnostic VLAN.
9.4.11. Flow Identifier (flow-id) TLV
Flow Identifier (flow-id) uniquely identifies a specific flow. The
flow-id value is unique per MEP and needs to be interpreted as such.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MEP-ID | flow-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21Out of Band IP Address TLV
Type (1 octet) = 72
Length (2 octets) = 5.
Reserved (1 octet) set to 0 on transmission and ignored on reception.
MEP-ID (2 octets) = MEP-ID of the originator [8021Q].
Flow-id (2 octets) = uniquely identifies the flow per MEP. Different
MEPs may allocate the same flow-id value. The {MEP-ID, flow-id} pair
is globally unique.
Inclusion of the MEP-ID in the flow-id TLV allows inclusion of MEP-ID
for messages that do not contain MEP-ID in OAM header. Applications
may use MEP-ID information for different types of troubleshooting.
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10. Loopback Message
10.1. Loopback OAM Message format
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MD-L | Version | OpCode | Flags |FirstTLVOffset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loopback Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. TLVs .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 22Loopback OAM Message Format
The above figure depicts the format of the Loopback Request and
response messages as defined in [8021Q]. The Opcode for Loopback
Message is set to 65 and the Opcode for the Reply Message is set to
64. The Session Identification Number is a 32-bit integer that allows
the requesting RBridge to uniquely identify the corresponding
session. Responding RBridges, without modification, MUST echo the
received "Loopback Transaction Identifier" number..
10.2. Theory of Operation
10.2.1. Originator RBridge
Identifies the destination RBridge nickname based on user
specification or based on the specified destination MAC or IP
address.
Constructs the flow entropy based on user specified parameters or
implementation specific default parameters.
Constructs the TRILL OAM header: sets the opcode to Loopback message
type (3). Assign applicable Loopback Transaction Identifier number
for the request.
The TRILL OAM Version TLV MUST be included and with the flags set to
applicable values.
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Include following OAM TLVs, where applicable
o Out-of-band Reply address TLV
o Diagnostic Label TLV
o Sender ID TLV
Specify the Hop count of the TRILL data frame per user specification
or utilize an applicable Hop count value.
Dispatch the OAM frame for transmission.
RBridge may continue to retransmit the request at periodic intervals,
until a response is received or the re-transmission count expires. At
each transmission Session Identification number MUST be incremented.
10.2.2. Intermediate RBridge
Intermediate RBridges forward the frame as a normal data frame and no
special handling is required.
10.2.3. Destination RBridge
If the Loopback message is addressed to the local RBridge and
satisfies the OAM identification criteria specified in section 3.1.
then, the RBridge data plane forwards the message to the CPU for
further processing.
The TRILL OAM application layer further validates the received OAM
frame by checking for the presence of OAM-Ethertype at the end of the
flow entropy and the MD Level. Frames that do not contain OAM-
Ethertype at the end of the flow entropy MUST be discarded.
Construction of the TRILL OAM response:
TRILL OAM application encodes the received TRILL header and flow
entropy in the Original payload TLV and includes it in the OAM
message.
Set the Return Code and Return sub code to applicable values. Update
the TRILL OAM opcode to 2 (Loopback Message Reply)
Optionally, if the VLAN/FGL identifier value of the received flow
entropy differs from the value specified in the diagnostic Label, set
the Label Error Flag on TRILL OAM Application Identifier TLV.
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Include the sender ID TLV (1)
If in-band response was requested, dispatch the frame to the TRILL
data plane with request-originator RBridge nickname as the egress
RBridge nickname.
If out-of-band response was requested, dispatch the frame to the IP
forwarding process.
11. Path Trace Message
The primary use of the Path Trace Message is for fault isolation. It
may also be used for plotting the path taken from a given RBridge to
another RBridge.
[8021Q] accomplishes the objectives of the TRILL Path Trace Message
using Link Trace Messages. Link Trace Messages utilize a well-known
multicast MAC address. This works for [8021Q], because for 802.1 both
the unicast and multicast paths are congruent. However, TRILL is
multicast and unicast incongruent. Hence, TRILL OAM is required to
utilize a new message format: the Path Trace message.
The Path Trace Message has the same format as Loopback Message.
Opcode for Path Trace Reply Message is 65 and Request 64
Operation of the Path Trace message is identical to the Loopback
message except that it is first transmitted with a TRILL Hop count
field value of 1. The sending RBridge expects a Time Expiry Return-
Code from the next hop or a successful response. If a Time Expiry
Return-code is received as the response, the originator RBridge
records the information received from intermediate node that
generated the Time Expiry message and resends the message by
incrementing the previous Hop count value by 1. This process is
continued until, a response is received from the destination RBridge
or Path Trace process timeout occur or Hop count reaches a configured
maximum value.
11.1. Theory of Operation
11.1.1. Originator RBridge
Identify the destination RBridge based on user specification or based
on location of the specified MAC address.
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Construct the flow entropy based on user specified parameters or
implementation specific default parameters.
Construct the TRILL OAM header: Set the opcode to Path Trace Request
message type (65). Assign an applicable Session Identification number
for the request. Return-code and sub-code MUST be set to zero.
The TRILL OAM Application Identifier TLV MUST be included and set the
flags to applicable values.
Include following OAM TLVs, where applicable
o Out-of-band IP address TLV
o Diagnostic Label TLV
o Include the Sender ID TLV
Specify the Hop count of the TRILL data frame as 1 for the first
request.
Dispatch the OAM frame to the TRILL data plane for transmission.
An RBridge may continue to retransmit the request at periodic
intervals, until a response is received or the re-transmission count
expires. At each new re-transmission, the Session Identification
number MUST be incremented. Additionally, for responses received from
intermediate RBridges, the RBridge nickname and interface information
MUST be recorded.
11.1.2. Intermediate RBridge
Path Trace Messages transit through Intermediate RBridges
transparently, unless Hop-count has expired.
TRILL OAM application layer further validates the received OAM frame
by examining the presence of TRILL OAM Flag and OAM-Ethertype at the
end of the flow entropy and by examining the MD Level. Frames that do
not contain OAM-Ethertype at the end of the flow entropy MUST be
discarded.
Construction of the TRILL OAM response:
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TRILL OAM application encodes the received TRILL header and flow
entropy in the Original payload TLV and include it in the OAM
message.
Set the Return Code to (2) "Time Expired" and Return sub code to zero
(0). Update the TRILL OAM opcode to 64 (Path Trace Message Reply).
If the VLAN/FGL identifier value of the received flow entropy differs
from the value specified in the diagnostic Label, set the Label Error
Flag on TRILL OAM Application Identifier TLV.
Include following TLVs
Upstream RBridge nickname TLV (69)
Reply Ingress TLV (5)
Reply Egress TLV (6)
Interface Status TLV (4)
TRILL Next Hop RBridge (Repeat for each ECMP) (70)
Sender ID TLV (1)
If Label error detected, set C flag (Label error detected) in the
version.
If in-band response was requested, dispatch the frame to the TRILL
data plane with request-originator RBRidge nickname as the egress
RBridge nickname.
If out-of-band response was requested, dispatch the frame to the
standard IP forwarding process.
11.1.3. Destination RBridge
Processing is identical to section 11.1.2. With the exception that
TRILL OAM Opcode is set to Path Trace Reply (64).
12. Multi-Destination Tree Verification (MTV) Message
Multi-Destination Tree Verification messages allow verifying TRILL
distribution tree integrity and pruning. TRILL VLAN/FGL and multicast
pruning are described in [RFC6325] [RFCclcorrect] and [RFCfgl].
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Multi-destination tree verification and Multicast group verification
messages are designed to detect pruning defects. Additionally, these
tools can be used for plotting a given multicast tree within the
TRILL campus.
Multi-Destination tree verification OAM frames are copied to the CPU
of every intermediate RBridge that is part of the distribution tree
being verified. The originator of the Multi-destination Tree
verification message specifies the scope of RBridges from which a
response is required. Only the RBridges listed in the scope field
respond to the request. Other RBridges silently discard the request.
Inclusion of the scope parameter is required to prevent receiving an
excessive number of responses. The typical scenario of distribution
tree verification or group verification, involves verifying multicast
connectivity to a selected set of end-nodes as opposed to the entire
network. Availability of the scope facilitates narrowing down the
focus to only the RBridges of interest.
Implementations MAY choose to rate-limit CPU bound multicast traffic.
As a result of rate-limiting or due to other congestion conditions,
MTV messages may be discarded from time to time by the intermediate
RBRidges and the requester may be required to retransmit the request.
Implementations SHOULD narrow the embedded scope of retransmission
request only to RBRidges that have failed to respond.
12.1. Multi-Destination Tree Verification (MTV) OAM Message Format
Format of MTV OAM Message format is identical to that of Loopback
Message format defined in section 10. with the exception that the
Loopback Transaction Identifier, in section 10.1. , is replaced with
the Session Identifier.
12.2. Theory of Operation
12.2.1. Originator RBridge
The user is required at a minimum to specify either the distribution
trees that need to be verified, or the Multicast MAC address and
VLAN/FGL, or VLAN/FGL and Multicast destination IP address.
Alternatively, for more specific multicast flow verification, the
user MAY specify more information e.g. source MAC address, VLAN/FGL,
Destination and Source IP addresses. Implementations, at a minimum,
must allow the user to specify a choice of distribution trees,
Destination Multicast MAC address and VLAN/FGL that needed to be
verified. Although, it is not mandatory, it is highly desired to
provide an option to specify the scope. It should be noted that the
source MAC address and some other parameters may not be specified if
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the Backwards Compatibility Method of section 3.2 is used to identify
the OAM frames.
Default parameters MUST be used for unspecified parameters. Flow
entropy is constructed based on user specified parameters and/or
default parameters.
Based on user specified parameters, the originating RBridge
identifies the nickname that represents the multicast tree.
Obtain the applicable Hop count value for the selected multicast
tree.
Construct TRILL OAM message header and include Session Identification
number. Session Identification number facilitate the originator to
map the response to the correct request.
TRILL OAM Application Identifier TLV MUST be included.
Op-Code MUST be specified as Multicast Tree Verification Message (70)
Include RBridge scope TLV (67)
Optionally, include following TLV, where applicable
o Out-of-band IP address
o Diagnostic Label
o Sender ID TLV (1)
Specify the Hop count of the TRILL data frame per user specification
or alternatively utilize the applicable Hop count value if TRILL Hop
count is not being specified by the user.
Dispatch the OAM frame to the TRILL data plane to be ingressed for
transmission.
The RBridge may continue to retransmit the request at a periodic
interval until either a response is received or the re-transmission
count expires. At each new re-transmission, the Session
Identification number MUST be incremented. At each re-transmission,
the RBridge may further reduce the scope to the RBridges that it has
not received a response from.
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12.2.2. Receiving RBridge
Receiving RBridges identify multicast verification frames per the
procedure explained in sections 3.2.
CPU of the RBridge validates the frame and analyzes the scope RBridge
list. If the RBridge scope TLV is present and the local RBridge
nickname is not specified in the scope list, it will silently discard
the frame. If the local RBridge is specified in the scope list OR
RBridge scope TLV is absent, the receiving RBridge proceeds with
further processing as defined in section 12.2.3.
12.2.3. In scope RBridges
Construction of the TRILL OAM response:
TRILL OAM application encodes the received TRILL header and flow
entropy in the Original payload TLV and includes them in the OAM
message.
Set the Return Code to (0) and Return sub code to zero (0). Update
the TRILL OAM opcode to 66 (Multicast Tree Verification Reply).
Include following TLVs:
Upstream RBridge nickname TLV (69)
Reply Ingress TLV (5)
Interface Status TLV (4)
TRILL Next Hop RBridge (Repeat for each downstream RBridge) (70)
Sender ID TLV (1)
Multicast Receiver Availability TLV (71)
If VLAN cross connect error detected, set C flag (Cross connect error
detected) in the version.
If in-band response was requested, dispatch the frame to the TRILL
data plane with request-originator RBridge nickname as the egress
RBridge nickname.
If out-of-band response was requested, dispatch the frame to the
standard IP forwarding process.
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13. Application of Continuity Check Message (CCM) in TRILL
Section 8. provides an overview of CCM Messages defined in [8021Q]
and how they can be used within the TRILL OAM. This section,
presents the application and Theory of Operations of CCM within the
TRILL OAM framework. Readers are referred to [8021Q] for CCM message
format and applicable TLV definitions and usages. Only the TRILL
specific aspects are explained below.
In TRILL, between any two given MEPs there can be multiple potential
paths. Whereas in [8021Q], there is always a single path between any
two MEPs at any given time. [RFC6905] requires solutions to have the
ability to monitor continuity over one or more paths.
CCM Messages are uni-directional, such that there is no explicit
response to a received CCM message. Connectivity status is indicated
by setting the applicable flags (e.g. RDI) of the CCM messages
transmitted by an MEP.
It is important that the proposed solution accomplishes the
requirements specified in [RFC6905] within the framework of [8021Q]
in a straightforward manner and with minimum changes. Section 8,
above proposed to define multiple flows within the CCM object, each
corresponding to a flow that a given MEP wishes to monitor.
Receiving MEPs do not cross check whether a received CCM belongs to a
specific flow from the originating RBridge. Any attempt to track
status of individual flows may explode the amount of state
information that any given RBridge has to maintain.
The obvious question arises: How does the originating RBridge know
which flow or flows are at fault?
13.1. CCM Error Notification
This is accomplished with a combination of the RDI flag in the CCM
header, flow-id TLV, and SNMP Notifications (Traps).
Each MEP transmits 4 CCM messages per each flow. ([8021Q] detects CCM
fault when 3 consecutive CCM messages are lost). Each CCM Message has
a unique sequence number and unique flow-identifier. The flow
identifier is included in the OAM message via flow-id TLV.
When an MEP notices a CCM timeout from a remote MEP ( MEP-A), it sets
the RDI flag on the next CCM message it generates. Additionally, it
logs and sends SNMP notification that contain the remote MEP
Identification, flow-id and the Sequence Number of the last CCM
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message it received and if available, the flow-id and the Sequence
Number of the first CCM message it received after the failure. Each
MEP maintains a unique flow-id per each flow, hence the operator can
easily identify flows that correspond to the specific flow-id.
The following example illustrates the above.
Assume there are two MEPs, MEP-A and MEP-B.
Assume there are 3 flows between MEP-A and MEP-B.
Let,s assume MEP-A allocates sequence numbers as follows
Flow-1 Sequence={1,2,3,4,13,14,15,16,.. } flow-id=(1)
Flow-2 Sequence={5,6,7,8,17,18,19,20,.. } flow-id=(2)
Flow-3 Sequence={9,10,12,11,21,22,23,24,.. } flow-id=(3)
Let's Assume Flow-2 is at fault.
MEP-B, receives CCM from MEP-A with sequence numbers 1,2,3,4, but did
not receive 5,6,7,8. CCM timeout is set to 3 CCM intervals in
[8021Q]. Hence MEP-B detects the error at the 8'th CCM message. At
this time the sequence number of the last good CCM message MEP-B has
received from MEP-A is 4 and flow-id of the last good CCM Message is
(1). Hence MEP-B will generate a CCM error SNMP notification with
MEP-A and Last good flow-id (1) and sequence number 4.
When MEP-A switches to flow-3 after transmitting flow-2, MEP-B will
start receiving CCM messages. In the foregoing example it will be CCM
message with Sequence Numbers 9,10,11,12,21 and so on. When in
receipt of a new CCM message from a specific MEP, after a CCM
timeout, the TRILL OAM will generate an SNMP Notification of CCM
resume with remote MEP-ID and the first valid flow-id and the
Sequence number after the CCM timeout. In the foregoing example, it
is MEP-A, flow-id (1) and Sequence Number 9.
The remote MEP list under the CCM MIB Object is augmented to contain
"Last Sequence Number", flow-id and "CCM Timeout" variables. Last
Sequence Number and flow-id are updated every time a CCM is received
from a remote MEP. CCM Timeout variable is set when the CCM timeout
occurs and is cleared when a CCM is received.
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13.2. Theory of Operation
13.2.1. Originator RBridge
Derive the flow entropy based on flow entropy specified in the CCM
Management object.
Construct the TRILL CCM OAM header as specified in [8021Q].
TRILL OAM Version TLV MUST be included as the first TLV and set the
flags to applicable values.
Include other TLVs specified in [8021Q]
Include the following optional TRILL OAM TLVs, where applicable
o Sender ID TLV
Specify the Hop count of the TRILL data frame per user specification
or utilize an applicable Hop count value.
Dispatch the OAM frame to the TRILL data plane for transmission.
An RBridge transmits a total of 4 requests, each at CCM
retransmission interval. At each transmission the Session
Identification number MUST be incremented by one.
At the 5'th retransmission interval, flow entropy of the CCM packet
is updated to the next flow entropy specified in the CCM Management
Object. If current flow entropy is the last flow entropy specified,
move to the first flow entropy specified and continue the process.
13.2.2. Intermediate RBridge
Intermediate RBridges forward the frame as a normal data frame and no
special handling is required.
13.2.3. Destination RBridge
If the CCM Message is addressed to the local RBridge or multicast and
satisfies OAM identification methods specified in sections 3.2. then
the RBridge data plane forwards the message to the CPU for further
processing.
The TRILL OAM application layer further validates the received OAM
frame by examining the presence of OAM-Ethertype at the end of the
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flow entropy. Frames that do not contain OAM-Ethertype at the end of
the flow entropy MUST be discarded.
Validate the MD-LEVEL and pass the packet to the Opcode de-
multiplexer. The Opcode de-multiplexer delivers CCM packets to the
CCM process.
The CCM Process performs processing specified in [8021Q].
Additionally the CCM process updates the CCM Management Object with
the sequence number of the received CCM packet. Note: The last
received CCM sequence number and CCM timeout are tracked per each
remote MEP.
If the CCM timeout is true for the sending remote MEP, then clear the
CCM timeout in the CCM Management object and generate the SNMP
notification as specified above.
14. Fragmented Reply
The response Message allow Fragmented Replies.. In case of Fragmented
Replies, all messages MUST follow the procedure defined in this
section.
All Reply Messages MUST be encoded as described in this document.
The same session Identification Number MUST be included in all
related fragments of the same message.
The TRILL OAM Application Identifier TLV MUST be included with the
appropriate Final Flag field. The Final Flag, MUST, only be set on
the final fragment of the reply.
15. Security Considerations
For general TRILL related security considerations, please refer to
[RFC6325]. Specific security considerations related methods presented
in this document are currently under investigation.
16. IEEE Allocation Considerations
The IEEE 802.1 Working Group is requested to allocate a separate
opcode and TLV space within 802.1QCFM messages for TRILL purpose.
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17. IANA Considerations
- IANA is requested to allocate a multicast MAC address from the
block assigned to TRILL [RFC6325].
- Set up sub-registry within the TRILL Parameters registry for block
of TRILL "OAM OpCodes" (Section 9.2. )-
- Set up sub-registry within the TRILL Parameters registry for TRILL
"OAM TLV Types" (Section 9.4. )-
- Request a unicast MAC addressed, reserved for identification of
OAM packets discussed in backward compatibility method (Section 3.3.
) See Appendix A.
18. References
18.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6325] Perlman, R., et.al., "Routing Bridges (RBridges): Base
Protocol Specification", RFC 6325, July 2011.
[RFCfgl] D. Eastlake, M. Zhang, P. Agarwal, R. Perlman, D. Dutt,
"TRILL: Fine-Grained Labeling", draft-ietf-trill-fine-
labeling, work in progress.
[8021Q] IEEE, "Media Access Control (MAC) Bridges and Virtual Bridged
Local Area Networks", IEEE Std 802.1Q-2011, August, 2011.
18.2. Informative References
[RFC4379] Kompella, K. et.al, "Detecting Multi-Protocol Label
Switched (MPLS) Data Plane Failures", RFC 4379, February
2006.
[RFC6291] Andersson, L., et.al., "Guidelines f<or the use of the
"OAM" Acronym in the IETF" RFC 6291, June 2011.
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[RFC6361] Carlson, J. and Eastlake, D. "PPP Transparent
Interconnection of Lots of Links (TRILL) Protocol Control
Protocol", RFC 6361, August 201.
[RFC6905] Senevirathne, T. et.al"Requirements for Operations,
Administration, and Maintenance (OAM) in Transparent
Interconnection of Lots of Links (TRILL)", RFC 6905, March
2013.
[TRLOAMFRM] Salam, S., et.al., "TRILL OAM Framework", draft-ietf-
trill-oam-framework, Work in Progress, November, 2012.
[RFCclcorrect] Eastlake, Donald, et.al. "TRILL: Clarifications,
Corrections, and Updates, draft-ietf-trill-clear-correct,
July 2012.
[TRILLEXT] Eastlake, Donald, et.al. "TRILL: Header Extension", draft-
ietf-trill-rbridge-extension, June, 2012.
[Y1731] ITU, "OAM functions and mechanisms for Ethernet based
networks", ITU-T G.8013/Y.1731, July, 2011.
[Channel] D. Eastlake, et.al. , "TRILL: RBridge Channel Support",
draft-ietf-trill-rbridge-channel-08.txt, in RFC Edtior's
queue.
[TRILLOAMMIB] Deepak Kumar et.al, "TRILL OAM MIB", draft-deepak-
trill-oam-mib, May 2013.
19. Acknowledgments
Work in this document was largely inspired by the directions provided
by Stewart Bryant in finding a common OAM solution between SDOs.
Acknowledgments are due for many who volunteered to review this
document, notably, Dan Romascanu and Gayle Nobel.
This document was prepared using 2-Word-v2.0.template.dot.
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Appendix A. Unicast MAC Request
Applicant Name: IETF TRILL Working Group
Applicant Email: tsenevir@cisco.com
Applicant Telephone: 408-853-2291
Use Name: TRILL OAM
Document: draft-tissa-trill-oam-fm
Specify whether this is an application for EUI-48 or EUI-64
identifiers: EUI-48
Size of Block requested: 1
Specify multicast, unicast, or both: Unicast
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Authors' Addresses
Tissa Senevirathne
CISCO Systems
375 East Tasman Drive.
San Jose, CA 95134
USA.
Phone: +1 408-853-2291
Email: tsenevir@cisco.com
Norman Finn
CISCO Systems
510 McCarthy Blvd
Milpitas, CA 95035
USA
Email: nfinn@cisco.com
Samer Salam
CISCO Systems
595 Burrard St. Suite 2123
Vancouver, BC V7X 1J1, Canada
Email: ssalam@cisco.com
Deepak Kumar
CISCO Systems
510 McCarthy Blvd,
Milpitas, CA 95035, USA
Phone : +1 408-853-9760
Email: dekumar@cisco.com
Donald Eastlake
Huawei Technologies
155 Beaver Street
Milford, MA 01757
Phone: +1-508-333-2270
Email: d3e3e3@gmail.com
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Sam Aldrin
Huawei Technologies
2330 Central Express Way
Santa Clara, CA 95951
USA
Email: aldrin.ietf@gmail.com
Yizhou Li
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Phone: +86-25-56625375
Email: liyizhou@huawei.com
Senevirathne Expires November 28, 2013 [Page 53]
