Internet DRAFT - draft-fedyk-ccamp-l1vpn-extnd-overlay
draft-fedyk-ccamp-l1vpn-extnd-overlay
Network Working Group D. Fedyk
Internet Draft D. Beller
Intended status: Standards Track Lieven Levrau
Alcatel-Lucent
D. Ceccarelli
Ericsson
F. Zhang
Huawei Technologies
Y. Tochio
Fujitsu
Expires: April 2013 October 22, 2012
Overlay Extension Service Model
draft-fedyk-ccamp-l1vpn-extnd-overlay-01.txt
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
This Internet-Draft will expire on April 25, 2013.
Fedyk et al. Expires December 2012 [Page 1]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
Copyright Notice
Copyright (c) 2012 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Abstract
This document builds on the GMPLS overlay model [RFC4208] and defines
extensions to the GMPLS User-Network Interface (UNI) to support route
diversity within the core network for sets of LSPs initiated by edge
nodes. A particular example where route diversity within the core
network is desired, are dual-homed edge nodes. The document also
defines GMPLS UNI extensions to deal with latency requirements for
edge node initiated LSPs.
This document is also applicable to the L1VPN framework [RFC4847] to
extend the L1VPN from the basic mode to the enhanced mode by
including additional constraints, focusing upon the overlay extension
service model. Route Diversity for customer LSPs are common
requirement applicable to L1VPNs. This document describes L1VPN
compatible mechanisms to achieve diversity for sets of customer LSPs.
The extended overlay service model can support other extensions for
L1VPN signaling, for example, those related to latency requirements.
Table of Contents
1. Introduction...................................................3
2. Conventions used in this document..............................3
3. Contributors...................................................3
4. LSP Diversity in the Overlay Extension Service Model...........4
4.1. LSP diversity for dual-homed customer edge (CE) devices...5
4.1.1. Exchanging SRLG information between the PEs via the CE
device......................................................7
4.1.1.1. Operational Procedures..........................8
4.1.1.2. Error handling procedures.......................8
4.1.2. Using Path Affinity Set extension....................9
4.1.2.1. Operational Procedures.........................12
Fedyk et al. Expires December 2012 [Page 2]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
4.1.2.2. Error handling procedures......................13
4.1.2.3. Distribution of the Path Affinity Set information
........................................................13
5. Latency signaling.............................................14
6. Security Considerations.......................................14
7. IANA Considerations...........................................15
8. References....................................................15
8.1. Normative References.....................................15
8.2. Informative References...................................15
9. Acknowledgments...............................................16
Fedyk et al. Expires December 2012 [Page 3]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
1. Introduction
This document builds on the GMPLS overlay model [RFC4208] and defines
extensions to the GMPLS User-Network Interface (UNI) to support route
diversity within the core network for sets of LSPs initiated by edge
nodes. In the following, the term customer edge (CE) device node is
used synonymously for the term edge node (EN) as in [RFC4208].
Moreover, the L1VPN terminology is used below when the core network
as in [RFC4208] is described.
The document is also applicable to the L1VPN framework [RFC4847] to
extend the L1VPN from the basic mode to the enhanced mode by
including additional constraints, focusing upon the overlay extension
service model.
The overlay model assumes a UNI interface between the edge nodes of
the respective transport domains. Route diversity for LSPs from
single homed CE and dual-home CEs is a common requirement in optical
transport networks. This document describes two signaling variations
that may be used for supporting LSP diversity within the overlay
extension service model considering dual-homing. Dual-homing is
typically used to avoid a single point of failure (UNI link, PE) or
if two disjoint connections are forming a protection group. While
both methods are similar in that they utilize common mechanisms in
the PE network to achieve diversity, they are distinguished according
to whether the CE is permitted to retrieve provider SRLG diversity
information for an LSP from a PE1 and pass it on to a PE2 (SRLG
information is shared with the CE), or whether a new attribute is
used that allows the PE2 that receives this attribute to derive the
SRLG information for an LSP based on this attribute value.
The extended overlay service model can support other extensions for
L1VPN signaling, for example, those related to latency. When
requesting diverse LSPs latency may also be an additional
requirement.
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].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lower case uses of these words are not to be
interpreted as carrying RFC-2119 significance.
Fedyk et al. Expires December 2012 [Page 4]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
3. Contributors
The Authors would like to thank Eve Varma and Sergio Belotti for
their review and contributions to this document.
4. LSP Diversity in the Overlay Extension Service Model
The L1VPN Framework [RFC4847] (Enhanced Mode) describes the overlay
extension service model, which builds upon the UNI Overlay [RFC4208]
serving as the interface between the CE edge node and the PE edge
node. In this service model, a CE receives a list of CE-PE TE link
addresses to which it can request a L1VPN connection (i.e.,
membership information) and may include additional information
concerning these TE links. This document further builds on the
overlay extension service model by adding shared constraint
information for path diversity in the optical transport network.
This document describes two signaling variations that may be used for
supporting LSP diversity within the overlay extension service model
considering dual-homing. While both methods are similar in that they
utilize common mechanisms in the PE network to achieve diversity,
they are distinguished according to whether the CE is permitted to
retrieve provider SRLG diversity information for an LSP from a PE1
and pass it on to a PE2 (SRLG information is shared with the CE or
whether a new attribute is used that allows the PE2 that receives
this attribute to derive the SRLG information for an LSP based on
this attribute value. The selection between these methods is governed
by both PE-network specific policies and approaches taken (i.e., in
terms of how the provider chooses to perform routing internal to
their network).
The first method (see 3.1.1) assumes that provider Shared Resource
Link Group (SRLG) Identifier information is both available and
shareable (policy decision) with the CE. Since SRLG IDs can then be
used (passed transparently between PEs via the dual-homed CE) as
signaled information on a UNI message, a mechanism supporting LSP
diversity for the overlay extension service model can be provided via
straightforward signaling extensions.
The second method (see 3.1.2) assumes that provider SRLG IDs are
either not available or not shareable (based on provider network
operator policy) with the CE. For this case, a mechanism is provided
where information signaled to the PE on UNI messages does not require
shared knowledge of provider SRLG IDs to support LSP diversity for
the overlay extension model.
Both approaches follow the L1VPN framework.
Fedyk et al. Expires December 2012 [Page 5]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
While both methods could be implemented in the same PE network, it is
likely that an L1VPN CE network would use only one mechanism at a
time.
4.1. LSP diversity for dual-homed customer edge (CE) devices
Single-homed CE devices are connected to a single PE device via a
single UNI link (could be a bundle of parallel links which are
typically using the same fiber cable). This single UNI link may
constitute a single point of failure. Such a single point of failure
can be avoided when the CE device is connected to two PE devices via
two UNI interfaces as depicted for CE1 in Figure 1 below.
For the dual-homing case, it is possible to establish two connections
from the source CE device to the same destination CE device where one
connection is using one UNI link to, for example, PE1 and the other
connection is using the UNI link to PE2. In order to avoid single
points of failure within the provider network, it is necessary to
also ensure path (LSP) diversity within the provider network in order
to achieve end-to-end diversity for the two LSPs between the two CE
devices. This document describes how it is possible to enable such
path diversity to be achieved within the provider network (which is
subject to additional routing constraints). [RFC4202] defines SRLG
information that can be used to allow GMPLS to provide path diversity
in a GMPLS controlled transport network. As the two connections are
entering the provider network at different PE devices, the PE device
that receives the connection request for the second connection needs
to be capable of determining the additional path computation
constraints such that the path of the second LSP is disjoint with
respect to the already established first connection entering the
network at a different PE device. The methods described in this
document allow a PE device to determine the SRLG information for a
connection in the provider network that is entering the network on a
different PE device.
PE SRLG information can be used directly by a CE if the CE
understands the context, and the CE view is limited to its L1VPN
context. In this case, there is a dependency on the provider
information and there is a need to be able to query the SRLG in the
provider network.
It may, on the other hand, be preferable to avoid this dependency and
to decouple the SRLG identifier space used in the provider network
from the SRLG space used in the client network. This is possible with
both methods detailed below. Even for the method where provider SRLG
information is passing through the CE device (note the CE device does
not need to process and decode this information) the two SRLG
Fedyk et al. Expires December 2012 [Page 6]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
identifier spaces can remain fully decoupled and the operator of the
client network is free to assign SRLG identifiers from the client
SRLG identifier space to the CE to CE connection that is passing
through the provider network.
Referring to Figure 1, the UNI signaling mechanism must support at
least one of the two mechanisms described in this document for CE
dual homing to achieve LSP diversity in the provider network.
The described mechanisms can also be applied to a scenario where two
CE devices are connected to two different PE devices. In this case,
the additional information that is exchanged across the UNI
interfaces also needs to be exchanged between the two CE devices in
order to achieve the desired diversity in the provider network.
This information may be configured or exchanged by some automated
mechanism not described in this document.
In the dual-homing example, CE1 can locally correlate the LSP
requests. For the slightly more complicated example involving CE2 and
CE3, both requiring a path that shall be diverse to a connection
initiated by the other CE device, CE2 and CE3 need to have a common
view of the SRLG information to be signaled. In this document, we
detail the required diversity information and the signaling of this
diversity information; however, the means for distributing this
information within the PE domain or the CE domain is out of scope.
+---+ +---+
| P |....| P |
+---+ +---+
/ \
+-----+ +-----+ +---+
+---+ | PE1 | | |----| |
|CE1|----| | | | |CE2|
+---+\ +-----+ | |----| |
\ | | PE3 | +---+
\ +-----+ | |
\| PE2 | | | +---+
| | | |----|CE3|
+-----+ +-----+ +---+
\ /
+---+ +---+
| P |....| P |
Fedyk et al. Expires December 2012 [Page 7]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
+---+ +---+
Figure 1: Generalized Layer 1 VPN Reference Model
Figure 1 Overlay Reference Diagram
In an overlay model, the information exchanged between the CE and the
PE is kept to a minimum.
How diversity is achieved, in terms of configuration, distribution
and usage in each part of the transport networks should be kept
independent and separate from how diversity is signaled at the UNI
between the two transport networks.
Signaling parameters discussed in this document are:
o SRLG information (see [RFC4202])
o Path Affinity Set
4.1.1. Exchanging SRLG information between the PEs via the CE device
SRLG information is defined in [RFC4202] and if the SRLG information
of an LSP is known, it can be used to calculate a path for another
LSP that is SRLG diverse with respect to an existing LSP. SRLG
information is an unordered list of SRLGs. SRLG information is
normally not shared between the transport network and the client
network; i.e., not shared with the CEs of a L1VPN in the L1VPN
context. However, this becomes more challenging when a CE is dual-
homed. For example, CE1 in Figure 1 may have requested an LSP1 from
CE1 to CE2 via PE1 and PE3. CE1 could subsequently request an LSP2
to CE2 via PE2 and PE3 with the requirement that it should be
maximally SRLG disjoint with respect to LSP1. Since PE2 does not have
any information about LSP1, PE2 would need to know the SRLG
information associated with LSP1. If CE1 could request the SRLG
information of LSP1 from PE1, it could then transparently pass this
information to PE2 as part of the LSP2 setup request, and PE2 would
now be capable of calculating a path for LSP2 that is SRLG disjoint
with respect to LSP1.
The exchange of SRLG information is achieved on a per L1VPN LSP basis
using the existing RSVP-TE signaling procedures. It can be exchanged
in the PATH (exclusion information) or RESV message in the original
request or it can be requested by the CE at any time the path is
active.
It shall be noted that SRLG information is an unordered list of SRLG
Fedyk et al. Expires December 2012 [Page 8]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
identifiers and the encoding of SRLG information for RSVP signaling
is already defined in [SRLG_info]. Even if SRLG information is known
for several LSPs it is not possible for the CEs to derive the
provider network topology from this information.
4.1.1.1. Operational Procedures
Retrieving SRLG information from a PE for an existing LSP:
When a dual-homed UNI-C intends to establish an LSP to the same
destination UNI-C via another PE node, it can request the SRLG
information for an already established LSP by setting the SRLG
information flag in the LSP attributes sub-object of the RSVP PATH
message (IANA to assign the new SRLG flag). As long as the SRLG
information flag is set in the PATH message, the PE node inserts the
SRLG sub-object as defined in [SRLG_info] into the RSVP RESV message
that contains the current SRLG information for the LSP. If the
provider network's policy has been configured so as not to share SRLG
information with the client network, the SRLG sub-object is not
inserted in the PATH message even if the SRLG information flag is
set. The PE passes on the SRLG information for the LSP. Note the
SRLG information is expected to be up-to-date.
Establishment of a new LSP with SRLG diversity constraints:
When a dual-homed CE device sends an LSP setup requests to a PE
device for a new LSP that is required to be SRLG diverse with respect
to an existing LSP that is entering the network via another PE
device, the UNI-C sets the SRLG diversity flag (note: IANA to assign
the new SRLG diversity flag) in the LSP attributes sub-object of the
PATH message that initiates the setup of this new LSP. When the PE
device receives this request it calculates a path to the given
destination and uses the received SRLG information as path
computation constraints.
4.1.1.2. Error handling procedures
To be added in the next version of the document.
Fedyk et al. Expires December 2012 [Page 9]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
4.1.2. Using Path Affinity Set extension
The Path Affinity Set (PAS) is used to signal diversity in a pure CE
context by abstracting SRLG information. There are two types of
diversity information in the PAS. The first type of information is a
single PAS identifier. Optionally, more detailed PATH information of
an exclude path or set of paths can be specified. The motive behind
the PAS information is to have as little exchange of diversity
information as possible between the L1VPN CE and PE elements.
Rather than a detailed CE or PE SRLG list, the Path Affinity Set
contains an abstract SRLG identifier that associates the given path
as diverse. Logically the identifier is in an L1VPN context and
therefore only unique with respect to a particular L1VPN.
How the CE determines the PAS identifier is a local matter for the CE
administrator. A CE may signal PAS as a diversity object in the PATH
message. This identifier is a suggested identifier and may be
overridden by a PE under some conditions.
For example, PAS can be used with no prior exchange of PAS
information between the CE and the PE. Upon reception of the PAS
information the PE can infer the CEs requirements. The actual PAS
identifier used will be returned in the RESV message. Optionally an
empty PAS identifier allows the PE to pick the PAS identifier.
Similar to the section 4.1.1 on SRLG information, a PE can return PAS
identifier as the response to a Query allowing flexibility.
A PE interprets the specific PAS identifier, for example, "123" as
meaning to exclude that identifier and by association any PE related
SRLG information, for any LSPs associated with the resources assigned
to the L1VPN. For example, if a Path exists for the LSP with the
identifier "123", the PE would use local knowledge of the PE SRLGs
associated with the "123" LSPs and exclude those SRLGs in the path
request. In other words, two LSPs that need to be diverse both
signal "123" and the PEs interpret this as meaning not to use shared
resources. Alternatively, a PE could use the PAS identifier to
select from already established LSPs. Once the path is established it
becomes associated with the "123" identifier or optionally another
PAS identifier for that L1VPN.
The PAS Source and Destination Address tuple represents one or more
source addresses and destination addresses associated with the CE
Path Affinity Set identifier. These associated address tuples
represent paths that use resources that should be excluded for the
establishment of the current LSP. The address tuple information
gives both finer grain details on the path diversity request and
serves as an alternative identifier in the case when the PAS
Fedyk et al. Expires December 2012 [Page 10]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
identifier is not known by the PE. The address tuples used in
signaling is within a CE context and its interpretation is local to a
PE that receives a Path request from a CE. The PE can use the address
information to relate to PE Addresses and PE SRLG information. When
a PE satisfies a connection setup for a (SRLG) diverse signaled path,
the PE may optionally record the PE SRLG information for that
connection in terms of PE based parameters and associate that with
the CE addresses in the Path message.
The L1VPN Port Information table (PIT) [RFC5251] can be leveraged to
translate between CE based addresses and PE based addresses. The Path
Affinity Set and associated PE addresses with PE SRLG information can
be distributed via the IGP in the provider transport network (or by
other means such as configuration); they can be utilized by other PEs
when other CE Paths are setup that would require path/connection
diversity. This information is distributed on a L1VPN basis and
contains a PAS identifier, PE addresses and SRLG information.
The CE Path Affinity Set may be used to signal paths without CE
Source and Destination addresses; however, the PE will always
associate the CE SRLG Group with a list of PE SRLG plus the PE
addresses associated with this LSP.
If diversity is not signaled, the assumption is that no diversity is
required and the Provider network is free to route the LSP to
optimize traffic. No Path affinity set information needs to be
recorded for these LSPs. If a diversity object is included in the
connection request, the PE in the Provider Network should be able to
look-up the existing Provider SRLG information from the provider
network and choose an LSP that is maximally diverse from other LSPs.
The mechanisms to achieve this are outside the scope of this
document.
Fedyk et al. Expires December 2012 [Page 11]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
A new L1VPN Diverse LSP LABEL object is specified:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type (TBA) |0| C-type (TBA)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ADDR Length |Number of PAS |D| reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Affinity Set identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Address (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 Diverse LSP information
1. The Address Length field (8 bits) is the number of bytes for both
the source address and destination address. The address may be in
any format from 1 to 32 bytes but the key point is the customers
can maintain their existing addresses. A value of zero indicates
there are no addresses included.
2. The Number of Path Affinity (8 bits)sets is included in the
object. This is typically 1. Addition of other sets is for further
study.
3. The Path affinity Set identifier (4 bytes) is a single number that
represents a summarized SRLG for this path. Paths with that same
Path Affinity set should be set up with diverse paths and
associated with the path affinity set. A value of all zeros
allows the PE to pick a PAS identifier to return. A PAS
identifier of an established path may be different than the
requested path identifier.
4. The diversity Bit (D) (one Bit) indicates if the diversity must be
satisfied when set as a one. If a PE finds an established path
with a Path Affinity set matching the signaled Path Affinity Set
or the signaled Address tuple it should attempt find a diverse
path.
Fedyk et al. Expires December 2012 [Page 12]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
5. The Diverse Path Source address/destination address tuple is that
of an established LSP in the PE network that belongs to the same
Path Affinity Set identifier. If the path for these addresses is
not setup or cannot be determined by the PE edge processing the
UNI then the path is only with the Path Affinity set constraint.
If the path(s) for these address tuples are known by the PE the PE
uses the SRLG information associated with these addresses. If in
any case a diverse path cannot be setup then the Diverse bit
controls whether a path is established anyway. The PE must use a
mechanism to translate CE Addresses into provider addresses when
correlating with provider SRLG information. How SRLG information
and network address tuples are distributed is for future study.
Fedyk et al. Expires December 2012 [Page 13]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
4.1.2.1. Operational Procedures
When a UNI-C constructs a PATH message it may optionally specify and
insert a Path Affinity Set in the PATH message. This Path Affinity
Set may optionally include the address of an LSP that that could
belong to the same Path Affinity Set. The Path Affinity Set
identifier is a value (0 through 2**32-255) that is independent of
the mechanism the CE or the PE use for diversity. The Path Affinity
Set is a single identifier that can be used to request diversity and
associate diversity.
When processing a CE PATH message in a L1VPN Overlay, the PE first
looks up the PE based addresses in the Provider Index Table (PIT). If
the Path Affinity Set is included in the PATH message, the PE must
look up the SRLG information (or equivalent) in the PE network that
has been allocated by LSPs associated with a Path Affinity Set and
exclude those resources from the path computation for this LSP if it
is a new path. The PE may alternatively choose from an existing path
with a disjoint set of resources. If a path that is disjoint cannot
be found, the value of the PAS diversity bit determines whether a
path should be setup anyway. If the PAS diversity bit is clear, one
can still attempt to setup the LSP. A PE should still attempt to
minimize shared resources but that is an implementation issue, and is
outside the scope of this document.
Optionally the CE may use a value of all zeros in the PAS identifier
allowing the PE to select an appropriate PAS identifier. Also the PE
may to override the PAS identifier allowing the PE to re-assign the
identifier if required. A CE should not assume that the PAS
identifier used for setup is the actual PAS identifier.
4.1.2.2. Error handling procedures
The PAS object must be understood by the PE device. Otherwise, the CE
should not use the PAS object. Path Message processing of the PAS
object SHOULD follow CTYPE 0. An Error code of IANA (TBD) indicates
that the PAS object is not understood.
When a PAS identifier is not recognized by a PE it must assume this
LSP defines that PAS identifier however the PE may override PAS
identifier under certain conditions.
If the identifier is recognized but the Source Address-Destination
address pair(s) are not recognized, this LSP must be set up using the
PAS identifier only.
If the identifier is recognized and the Source Address-Destination
Fedyk et al. Expires December 2012 [Page 14]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
address pair(s) are also recognized, then the PE SHOULD use the PE
SRLG information associated with the LSPs identified by the address
pairs to select a disjoint path.
The Following are the additional error codes:
1) Route Blocked by Exclude Route Value IANA (TBA).
4.1.2.3. Distribution of the Path Affinity Set information
Information about SRLG is already available in the IGP TE database. A
PE network can be designed to have additional opaque records for
Provider paths that distribute PE paths and SRLG on a L1VPN basis.
When a PE path is setup, the following information allows a PE to
lookup the PE diversity information:
- L1 VPN Identifier 8 bytes
- Path Affinity Set Identifier
- Source PE Address
- Destination PE Address
- List of PE SRLG (variable)
The source PE address and destination PE address are the same
addresses in the L1VPN PIT and correspond to the respective CE
address identifiers.
Note that all of the information is local to the PE context and is
not shared with the CE. The L1VPN Identifier is associated with a CE.
The only value that is signaled from the CE is the Path Affinity Set
and optionally the addresses of an existing LSP. The PE stores source
and destination PE addresses of the LSP in their native format along
with the SRLG information. This information is internal to the PE
network and is always known.
PE paths may be setup on demand or they may be pre-established. When
paths are pre-established, the Path Affinity Set is set to unassigned
0x0000 and is ignored. When a CE uses a pre-established path the PE
may set the Path SRLG Path Affinity Set value if the CE signals one
otherwise the Path Affinity Set remains unassigned 0x0000.
5. Latency signaling
A latency requirement can be added to signaling in the form of a
constraint [DRAFT OBJECTIVE FUNCTION]. The constraint can take the
form of:
Fedyk et al. Expires December 2012 [Page 15]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
- Minimize latency
- Maximum acceptable
While some systems may be able to compute routes based on delay
metrics it is usual that minimizing hops subject to bandwidth
reservation are satisfied as the object function and delay is not
considered. When considering diversity latency falls after diversity
constraints have been satisfied.
Recording the latency of existing paths [DRAFT_TE_METRIC RECORD] to
ensure they meet a maximum acceptable latency can be utilized to
ensure latency constraint is met.
When a low latency path is required, the minimize latency subject to
other constraints criteria should be signaled. A CE device can use
the record latency to ensure that the maximum acceptable latency has
been met.
More detail to be added in a future revision.
6. Security Considerations
Security for L1VPNs is covered in [RFC4847], [RFC5251] and [RFC5253].
In this document, the model follows the L1VPN control plane model
where CE addresses are completely distinct from the PE addresses.
The use of a private network assumes that entities outside the
network cannot spoof or modify control plane communications between
CE and PE. Furthermore, all entities in the private network are
assumed to be trusted. Thus, no security mechanisms are required by
the protocol exchanges described in this document.
However, an operator that is concerned about the security of their
private control plane network may use the authentication and
integrity functions available in RSVP-TE [RFC3473] or utilize IPsec
([RFC4301], [RFC4302], [RFC4835], [RFC5996], and [RFC6071]) for the
point-to-point signaling between PE and CE. See [RFC5920] for a full
discussion of the security options available for the GMPLS control
plane.
7. IANA Considerations
TBD
Fedyk et al. Expires December 2012 [Page 16]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
8. References
Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4202] Kompella, K., Rekhter, Y., "Routing Extensions in Support
of Generalized Multi-Protocol Label Switching (GMPLS)", RFC
4202, October 2005.
[RFC4208] G. Swallow, J. Drake, H. Ishimatsu, Y. Rekhter,
"Generalized Multiprotocol Label Switching (GMPLS) User-
Network Interface (UNI): Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Support for the Overlay
Model", RFC 4208, October 2005.
[RFC5251] Fedyk, D., Rekhter, Y., Editors "Layer 1 VPN Basic Mode",
RFC 5251, July 2008.
[SRLG_info] Zhang, F., Li, D., Gonzalez de Dios, O., Margaria, C.,
"RSVP-TE Extensions for Collecting SRLG Information",
draft-ietf-ccamp-rsvp-te-srlg-collect-00.txt, June 2012.
8.2. Informative References
[RFC6071] S. Frankel, S. Krishnan, " IP Security (IPsec) and Internet
Key Exchange (IKE) Document Roadmap", RFC 6071, February
2011.
[RFC3473] Berger, L. (editor), "Generalized MPLS Signaling - RSVP-TE
Extensions", RFC 3473, January 2003.
[RFC4301] S. Kent, K. Seo, "Security Architecture for the Internet
Protocol," December 2005.
[RFC4302] S. Kent, "IP Authentication Header," December 2005.
[RFC5996] C. Kaufman, P. Hoffman, Y. Nir, P. Eronen " Internet Key
Exchange Protocol Version 2 (IKEv2)", September 2010.
[RFC4835] V. Manral, "Cryptographic Algorithm Implementation
Requirements for Encapsulating Security Payload (ESP) and
Authentication Header (AH)", April 2007.
[RFC4847] Takeda, T., Editor "Framework and Requirements for Layer 1
Virtual Private Networks", RFC 4847, April 2007.
Fedyk et al. Expires December 2012 [Page 17]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
[RFC5253] Takeda, T., Editor "Applicability Statement for Layer 1
Virtual Private Network (L1VPN) Basic Mode", RFC 5253, July
2008.
[RFC5920] L. Fang, Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[DRAFT OBJECTIVE FUNCTION] Ali, Z., Swallow, G., Filsfils, C., Fang,
L., Kumaki, K., Kunze, R.,"Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) extension for signaling
Objective Function and Metric Bound", draft-ali-ccamp-rc-
objective-function-metric-bound-02.txt, July 2012.
[DRAFT_TE_METRIC RECORD] Ali, Z., Swallow, G., Filsfils, C., Kumaki,
K., Kunze, R., "Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) extension for recording TE Metric of
a Label Switched Path", draft-ali-ccamp-te-metric-
recording-02.txt, July 2012.
9. Acknowledgments
Copyright (c) 2012 IETF Trust and the persons identified as authors
of the code. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, is permitted pursuant to, and subject to the license
terms contained in, the Simplified BSD License set forth in Section
4.c of the IETF Trust's Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
Fedyk et al. Expires December 2012 [Page 18]
Internet-Draft draft-fedyk-ccamp-l1vpn-extnd-overlayy-00.txt July 2012
Authors' Addresses
Don Fedyk
Alcatel-Lucent
Groton, MA, 01450
Email: donald.fedyk@alcatel-lucent.com
Dieter Beller
Alcatel-Lucent
Email: Dieter.Beller@alcatel-lucent.com
Lieven Levrau
Alcatel-Lucent
Email: Lieven.Levrau@alcatel-lucent.com
Daniele Ceccarelli
Ericsson
Email: Daniele.Ceccarelli@ericsson.com
Fatai Zhang
Huawei Technologies
Email: zhangfatai@huawei.com
Yuji Tochio
Fujitsu
Email: tochio@jp.fujitsu.com
Fedyk et al. Expires December 2012 [Page 19]
