TRILL Transparent Transport over MPLS
draft-muks-trill-transport-over-mpls-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|---|---|---|---|
| Authors | Mohammed Umair , Kingston Smiler , Donald E. Eastlake 3rd , Lucy Yong | ||
| Last updated | 2015-07-06 | ||
| Replaced by | draft-ietf-trill-transport-over-mpls, draft-ietf-trill-transport-over-mpls | ||
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| Stream | Stream state | (No stream defined) | |
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draft-muks-trill-transport-over-mpls-00
INTERNET-DRAFT Mohammed Umair
Intended Status: Proposed Standard Kingston Smiler
IP Infusion
Donald Eastlake 3rd
Lucy Yong
Huawei Technologies
Expires: January 7, 2016 July 6, 2015
TRILL Transparent Transport over MPLS
draft-muks-trill-transport-over-mpls-00
Abstract
This document specifies how to interconnect Transparent
Interconnection of Lots of links (TRILL) sites belonging to a tenant
that are separated geographically over an MPLS domain. This draft
addresses two problems 1) Providing connection between more than two
TRILL sites that are separated by an MPLS provider network using
[RFC7173] 2) Providing connection between TRILL sites belonging to a
tenant over a MPLS provider network
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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Copyright and License Notice
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Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
2. TRILL Over MPLS Model . . . . . . . . . . . . . . . . . . . . 4
3. VPLS Model . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Entities in the VPLS Model . . . . . . . . . . . . . . . . 6
3.3. TRILL Adjacency for VPLS model . . . . . . . . . . . . . . 7
3.4. MPLS encapsulation for VPLS model . . . . . . . . . . . . . 7
3.5 Loop Free provider PSN/MPLS. . . . . . . . . . . . . . . . 7
3.6. Frame processing. . . . . . . . . . . . . . . . . . . . . 7
4. VPTS Model . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Entities in the VPTS Model . . . . . . . . . . . . . . . . 9
4.1.1 TRILL Intermediate Routers [TIR] . . . . . . . . . . . . 9
4.1.2 Virtual TRILL Switch Domain (VTSD) . . . . . . . . . . . 10
4.2. TRILL Adjacency for VPLS model . . . . . . . . . . . . . . 10
4.3. MPLS encapsulation for VPLS model . . . . . . . . . . . . . 10
4.4 Loop Free provider PSN/MPLS. . . . . . . . . . . . . . . . 10
4.5. Frame processing. . . . . . . . . . . . . . . . . . . . . 10
4.5.1 Multi-Destination Frame processing . . . . . . . . . . . 10
4.5.2 Unicast Frame processing . . . . . . . . . . . . . . . . 11
5. Extensions to TRILL Over Pseudowires [RFC7173] . . . . . . . . 11
6. VPTS Model Versus VPLS Model . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1 Normative References . . . . . . . . . . . . . . . . . . . 12
9.2 Informative References . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1 Introduction
The IETF Transparent Interconnection of Lots of Links (TRILL)
protocol [RFC6325] [RFC7177] [RFC7180bis] provides transparent
forwarding in multi-hop networks with arbitrary topology and link
technologies using a header with a hop count and link-state routing.
TRILL provides optimal pair-wise forwarding without configuration,
safe forwarding even during periods of temporary loops, and support
for multipathing of both unicast and multicast traffic. Intermediate
Systems (ISs) implementing TRILL are called Routing Bridges(RBridges)
or TRILL Switches
This draft, in conjunction with [RFC7173], address two problems
1) Providing connection between more than two TRILL sites of a single
TRILL network that are separated by an MPLS provider network using
[RFC7173]. (Herein also called as problem statement 1.)
2) Providing connection between TRILL sites belongs to a
tenant/tenants over a MPLS provider network. (Herein also called as
problem statement 2.)
A tenant is the administrative entity on whose behalf one or more
customers and their associated services are managed. Here Customer
refers to TRILL campus not Data Label.
A key multi-tenancy requirement is traffic isolation so that one
tenant's traffic is not visible to any other tenant. This draft also
addresses the problem of multi-tenancy by isolating one tenant's
traffic from the other.
1.1 Terminology
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 this document include the following:
AC - Attachment Circuit [RFC4664]
Data Label - VLAN or FGL
ECMP - Equal Cost Multi Path
FGL - Fine-Grained Labeling [RFC7172]
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IS-IS - Intermediate System to Intermediate System [IS-IS]
LDP - Label Distribution Protocol
LAN - Local Area Network
MPLS - Multi-Protocol Label Switching
PE - Provider Edge Device
PPP - Point-to-Point Protocol [RFC1661]
PSN - Packet Switched Network
PW - Pseudowire [RFC4664]
TIR - TRILL Intermediate Router
[Devices where Pseudowire starts and Terminates]
TRILL - Transparent Interconnection of Lots of Links
OR Tunneled Routing in the Link Layer
TRILL Site - A part of a TRILL campus that contains at
least one RBridge.
VLAN - Virtual Local Area Network
VPLS - Virtual Private LAN Service
VPTS - Virtual Private TRILL Service
VSI - Virtual Service Instance [RFC4664]
VTSD - Virtual TRILL Switch Domain
A Virtual RBridge which segregates one tenant's
TRILL database as well as traffic from the other.
WAN - Wide Area Network
2. TRILL Over MPLS Model
TRILL Over MPLS can be achieved by two different ways.
a) VPLS Model for TRILL
b) VPTS Model/TIR Model
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Both these models can be used to solve the problem statement 1 and 2.
Herein the VPLS Model for TRILL is also called Model 1 and the VPTS
Model/TIR Model is also called Model 2.
3. VPLS Model
Figure 1 shows the topological model of TRILL over MPLS using VPLS
model. The PE routers in the below topology model should support all
the functional Components mentioned in [RFC4664].
+-----+ +-----+
| RBa +---+ ........................... +---| RBb |
+-----+ | . . | +-----+
Site 1 | +----+ +----+ | Site 2
+----|PE1 | |PE2 |----+
+----+ MPLS Cloud +----+
. .
. +----+ .
..........|PE3 |...........
+----+ ^
| |
| +-- Emulated LAN
+-----+
| RBc |
+-----+
Site 3
Figure 1: Topological Model of TRILL over MPLS
connecting three TRILL Sites
Figure 2 below shows the topological model of TRILL over MPLS to
connect multiple TRILL sites belonging to a tenant (tenant here is a
campus, not a Data label). VSI1 and VSI2 are two Virtual Service
Instances which segregates Tenant1's traffic from Tenant2's. VSI1 will
maintain its own database for Tenant1, similarly VSI2 will maintain its
own database for Tenant2.
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+-----+ ............................ +-----+
|RBat1+---+ . ++++++++++++++++++++++++ . +---|RBbt1|
+-----+ | . + + . | +-----+
Tenant1 Site 1 | +----+ +----+ | Tenant1 Site2
+----|VSI1| |VSI1|----+
+----|VSI2| MPLS Cloud |VSI2|----+
| +----+ +----+ |
+-----+ | . + + . | +-----+
|RBat2+---+ . +++++++++ +----+ ++++++++ . +---|RBbt2|
+-----+ ............|VSI1|........... +-----+
Tenant2 Site 2 +----|VSI2|----+ ^ Tenant2 Site2
| +----+ | |
| | |
+-----+ +-----+ +-----Emulated
|RBct2| |RBct1| LAN
+-----+ +-----+
Tenant2 Site 3 Tenant1 Site 3
.... VSI1 Path
++++ VSI2 Path
Figure 2: Topological Model for VPLS Model
connecting 2 Tenants with 3 sites each
In this model TRILL sites are connected using VPLS-capable PE devices
that provide a logical interconnect, such that TRILL RBridges belonging
to a specific tenant connected via an single bridged Ethernet. These
devices are same as PE devices specified in [RFC4026]. The Attachment
Circuit ports of PE Routers are layer 2 switch ports that are connected
to the RBridges in a TRILL site. Here each VPLS instance looks like an
emulated LAN. This model is similar to connecting different RBridges
(TRILL sites) by a layer 2 bridge domain (multi access links) as
specified in [RFC6325]. This model doesn't requires any changes in PE
routers to carry TRILL frames, as TRILL frame will be transferred
transparently.
3.1. Entities in the VPLS Model
The PE (VPLS-PE) and CE devices are defined in [RFC4026].
The Generic L2VPN Transport Functional Components like Attachment
Circuits, Pseudowires, VSI etc. are defined in [RFC4664].
The RB (RBridge) and TRILL Sites are defined in [RFC6325]
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3.3. TRILL Adjacency for VPLS model
As specified in section 3 of this document, the MPLS cloud looks like an
emulated LAN (also called multi-access link or broadcast link). This
results in RBridge of different sites looking like that they are
connected to a multi-access link. With such interconnection, the TRILL
adjacency over the link is automatically discovered and established
through TRILL IS-IS control messages [RFC7177] which is transparently
forwarded by the VPLS domain, after doing MPLS encapsulation specified
in the section 3.4.
3.4. MPLS encapsulation for VPLS model
MPLS encapsulation over Ethernet pseudowire is specified in [RFC7173]
Appendix A, and requires no changes in the frame format.
3.5 Loop Free provider PSN/MPLS.
No explicit handling is required to avoid loop free topology as, Split
Horizon technique mentioned in [RFC4664] in the provider PSN network
takes care of loop-free topology in the PSN.
3.6. Frame processing.
The PE device transparently process the TRILL control and data frames
and procedure to forward the frames are defined in [RFC4664]
4. VPTS Model
The [Virtual Private TRILL Service] VPTS is an L2 TRILL service that
emulates TRILL service across a Wide Area Network (WAN). VPTS is similar
to what VPLS does for bridge domain. VPLS provides virtual private LAN
service for different customers. VPTS provide Virtual Private TRILL
service (VPTS) for different TRILL tenants.
Figure 3 shows the topological model of TRILL over MPLS using VPTS. In
this model the PE routers are replaced with TIR [TRILL Intermediate
Router] and VSI is replaced with VTSD [Virtual TRILL Switch Domain]. The
TIR [TRILL Intermediate Router] devices are interconnected via PWs
appear as a single emulated TRILL Site with each VTSD inside a TIR
equivalent to a RBridge. The TIR devices must be capable of supporting
both MPLS and TRILL.
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+-----+ +-----+
| RBa +---+ ........................... +---| RBb |
+-----+ | . . | +-----+
Site 1 | +----+ +----+ | Site 2
+----|TIR1| |TIR2|----+
+----+ MPLS Cloud +----+
. .
. +----+ .
..........|TIR3|...........
+----+ ^
| |
| +-- Emulated TRILL
+-----+
| RBc |
+-----+
Site 3
Figure 3: Topological Model of VPTS/TIR
connecting three TRILL Sites
In the above figure (Figure 3) Site1, Site2 and Site3 (running TRILL
protocol) are connected to TIR Devices. These TIR devices along with
the MPLS cloud looks like an emulated TRILL Site with all the TRILL
Sites connecting to MPLS cloud forming a single TRILL campus. Only the
PE devices in the MPLS network should be replaced with TIRs that make
the intermediate P routers agnostic to the TRILL protocol.
Figure 4 below shows the topological model of TRILL over MPLS to
connect multiple TRILL sites belonging to a tenant (tenant here is a
campus, not a Data label) using VPTS model. VTSD1 and VTSD2 are two
Virtual TRILL Switch Domains (Virtual RBridges) that segregates
Tenant1's traffic from Tenant2's. VTSD1 will maintain its own TRILL
database for Tenant1, similarly VTSD2 will maintain its own TRILL
database for Tenant2.
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+-----+ ............................ +-----+
|RBat1+---+ . ######################## . +---|RBbt1|
+-----+ | . # # . | +-----+
Tenant1 Site 1| +-----+ +-----+ | Tenant1 Site 2
+----|VTSD1| |VTSD1|----+
+----|VTSD2| MPLS Cloud |VTSD2|----+
| +-----+ +-----+ |
+-----+ | . # # . | +-----+
|RBat2+---+ . #########+-----+######### . +---|RBbt2|
+-----+ ...........|VTSD1|........... +-----+
Tenant2 Site2 +---|VTSD2|----+ ^ Tenant2 Site 2
| +-----+ | |
| | |
+-----+ +-----+ +-----Emulated
|RBct2| |RBct1| TRILL
+-----+ +-----+
Tenant2 Site 3 Tenant1 Site 3
.... VTSD1 Connectivity
#### VTSD2 Connectivity
Figure 4: Topological Model of VPTS/TIR
connecting 2 tenants with three TRILL Sites
4.1. Entities in the VPTS Model
The CE devices are defined in [RFC4026].
The Generic L2VPN Transport Functional Components like Attachment
Circuits, Pseudowires etc. are defined in [RFC4664].
The RB (RBridge) and TRILL Campus are defined in [RFC6325]
This model introduces two new entities called TIR and VTSD.
4.1.1 TRILL Intermediate Routers [TIR]
The TIRs [TRILL Intermediate Routers] must be capable of running both
VPLS and TRILL protocols. TIR devices are superset of VPLS-PE devices
which is defined in [RFC4026]. The VSI instance that provides
transparent bridging functionality in the PE device is replaced with
VTSD in TIR.
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4.1.2 Virtual TRILL Switch Domain (VTSD)
The VTSD [Virtual Trill Switch Domain] is similar to VSI (layer 2
bridge) in VPLS model, but this acts as TRILL RBridge. The VTSD is a
superset of VSI and must support all the functionality provided by the
VSI as defined in [RFC4026]. Along with VSI functionality, the VTSD must
be capable of supporting TRILL protocols and form TRILL adjacency. The
VTSD must be capable of performing all the operations that a standard
TRILL Switch can do.
One VTSD instance per tenant must be maintained, when multiple tenants
are connected to the TIR. The VTSD must maintain all the information
maintained by the RBridge on a per tenant basis. The VTSD must also take
care of segregating one tenant traffic from other.
4.2. TRILL Adjacency for VPLS model
The VTSD must be capable of forming TRILL adjacency with other VTSDs
present in its peer VPTS neighbor, and also the RBridges present in the
TRILL sites. The procedure to form TRILL Adjacency is specified in
[RFC7173] and [RFC7177].
4.3. MPLS encapsulation for VPLS model
MPLS encapsulation over pseudowire is specified in [RFC7173], and
requires no changes in the frame format.
4.4 Loop Free provider PSN/MPLS.
This model isn't required to employ Split Horizon mechanism in the
provider PSN network, as TRILL takes care of Loop free topology using
Distribution Trees. Any multi-destination frame will traverse a
distribution tree path. All distribution trees are calculated based on
TRILL base protocol standard [RFC6325] as updated by [RFC7180bis].
4.5. Frame processing.
This section specifies multi-destination and unicast frame processing in
VPTS/TIR model.
4.5.1 Multi-Destination Frame processing
Any unknown unicast, multicast or broadcast frames inside VTSD should be
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processed or forwarded through any one of the distribution tree's path.
If any multi-destination frame is received from the wrong pseudowire at
a VTSD, the TRILL protocol running in VTSD should perform a RPF check as
specified in [RFC7180bis] and drops the packet.
Pruning mechanism of Distribution Tree as specified in [RFC6325] and
[RFC7180bis] can also be used for forwarding of multi-destination data
frames on the branches that are not pruned.
4.5.2 Unicast Frame processing
Unicast frames must be forwarded in same way they get forwarded in a
standard TRILL Campus as specified in [RFC6325]. If multiple equal cost
paths are available over pseudowires to reach destination, then VTSD
should be capable of doing ECMP for them.
5. Extensions to TRILL Over Pseudowires [RFC7173]
The [RFC7173] mentions how to interconnect a pair of Transparent
Interconnection of Lots of Links (TRILL) switch ports using pseudowires.
This document explains, how to connect multiple TRILL sites (not limited
to only two sites) using the mechanisms and encapsulations defined in
[RFC7173].
6. VPTS Model Versus VPLS Model
VPLS Model uses a simpler loop breaking rule: the "split horizon" rule,
where a PE must not forward traffic from one PW to another in the same
VPLS mesh.
An issue with the above rule is that if a pseudowire between PEs fails,
frames will not get forwarded between the PEs where pseudowire went
down.
VPTS solves this problem, since the VPTS Model uses distribution Trees
for loop free topology, so frames reach all TIRs even when any one of
the pseudowires fails in a mesh topology.
If equal cost paths are available to reach a site over pseudowires, VPTS
Model can use ECMP for processing of frames over pseudowires.
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7. Security Considerations
For general TRILL security considerations, see [RFC6325]
For transport of TRILL by Pseudowires security consideration, see
[RFC7173].
Since VPTS Model uses Distribution tree for processing of multi-
destination data frames, it is always advisable to run at least one
Distribution tree in a TRILL site per tenant, this will avoid data
frames getting received on TRILL sites where end-station service is not
enabled for that data frame.
8. IANA Considerations
This document requires no IANA actions. RFC Editor: Please delete this
section before publication
9. References
9.1 Normative References
[RFC6325] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and
A.Ghanwani, "Routing Bridges (RBridges): Base
Protocol Specification", RFC 6325, July 2011.
[RF7180bis] Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee,
A., A.Ghanwani, and Gupta, S, "Routing Bridges
(RBridges): TRILL: Clarifications, Corrections, and
Updates", work in progress.
"https://tools.ietf.org/html/draft-ietf-trill-
rfc7180bis-05"
[RFC7173] Yong, L., Eastlake 3rd, D., Aldrin, S., and
Hudson, J, "Transparent Interconnection of Lots of
Links (TRILL) Transport Using Pseudowires",
RFC 7173, May 2014.
[RFC4762] Lasserre, M., and Kompella, V., Virtual Private LAN
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Service (VPLS) Using Label Distribution Protocol
(LDP) Signaling, RFC 4762, January 2007
[RFC4026] Andersson, L., and Madsen, T., Provider Provisioned
Virtual Private Network (VPN) Terminology, RFC 4026,
March 2005
[RFC4664] Andersson, L., and Rosen, E., Framework for Layer 2
Virtual Private Networks (L2VPNs), RFC 4664,
September 2006
9.2 Informative References
[IS-IS] ISO/IEC 10589:2002, Second Edition,
"Information technology -- Telecommunications
and information exchange between systems --
Intermediate System to Intermediate System
intra-domain routeing information exchange
protocol for use in conjunction with the
protocol for providing the connectionless-mode
network service (ISO 8473)", 2002.
[RFC3985] Bryant, S., Ed., and P. Pate, Ed., "Pseudo
Wire Emulation Edge-to-Edge (PWE3)
Architecture", RFC 3985, March 2005.
[RFC4023] Worster, T., Rekhter, Y., and E. Rosen, Ed.,
"Encapsulating MPLS in IP or Generic Routing
Encapsulation (GRE)", RFC 4023, March 2005.
[RFC4448] Martini, L., Ed., Rosen, E., El-Aawar, N., and
G. Heron, "Encapsulation Methods for Transport
of Ethernet over MPLS Networks", RFC 4448,
April 2006.
[RFC7177] Eastlake 3rd, D., Perlman, R., Ghanwani, A.,
Yang, H., and V. Manral, "Transparent
Interconnection of Lots of Links (TRILL):
Adjacency", RFC 7177, May 2014.
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[RFC7172] Eastlake 3rd, D., Zhang, R., Agarwal, P.,
Perlman, R., and Dutt, D, "Transparent
Interconnection of Lots of Links (TRILL):
Fine-Grained Labeling", RFC 7172, May 2014.
Authors' Addresses
Mohammed Umair
IP Infusion
RMZ Centennial
Mahadevapura Post
Bangalore - 560048 India
EMail: mohammed.umair2@gmail.com
Kingston Smiler
IP Infusion
RMZ Centennial
Mahadevapura Post
Bangalore - 560048 India
EMail: kingstonsmiler@gmail.com
Donald E. Eastlake 3rd
Huawei Technologies
155 Beaver Street
Milford, MA 01757
USA
Phone: +1-508-333-2270
EMail: d3e3e3@gmail.com
Lucy Yong
Huawei Technologies
5340 Legacy Drive
Plano, TX 75024
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USA
Phone: +1-469-227-5837
EMail: lucy.yong@huawei.com
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