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Re: Draft draft-vasseur-ccamp-loose-path-reopt-01.txt
Hi JP,
Please find attached a version of your draft with a bunch of comments, nits
and questions.
Cheers,
Adrian
PS Please see RFC3667 for new copyright and IPR boilerplate (or use one of
the IETF
editing tools)
----- Original Message -----
From: "Jean Philippe Vasseur" <jvasseur@cisco.com>
To: <ccamp@ops.ietf.org>
Sent: Tuesday, April 20, 2004 4:08 AM
Subject: Draft draft-vasseur-ccamp-loose-path-reopt-01.txt
Hi,
Just to mention that we posted a new revision of
draft-vasseur-ccamp-loose-path-reopt-01.txt that proposes some mechanisms
for the reoptimization of loosely routed TE LSP (intra-area, inter-area and
Inter-AS). Thanks for the various comments and support that we got on this
ID, this new revision incorporates the comments that we received + various
edits and clarifications.
JP.
## please don't have header on first page
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
IETF Internet Draft Jean-Philippe Vasseur (Editor)
Proposed Status : Standard Cisco Systems, Inc
Expires: October 2004 Yuichi Ikejiri
NTT Communications Corporation
April 2004
draft-vasseur-ccamp-loose-path-reopt-01.txt
Reoptimization of MPLS Traffic Engineering loosely routed LSP paths
## I really don't like "LSP path"
## "Label Switched Path path"
## How long before we write "LSPP"?
## Then we can introduce "LSPP path"! :-)
## Applies throughout the document.
##
## Can we mainly delete "path". I.e. "Loosely routed LSPs" or
## "LSP loose route" or "loose LSP route"
Status of this Memo
## Please indent text correctly throughout document
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026. 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.
Vasseur and Ikejiri 1
## please use page throws
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
## Please place abstract before contents
Table of content
1. Introduction
2. Establishment of a loosely routed TE LSP
3. Reoptimization of a loosely routed TE LSP path
4. Signalling extensions
4.1 ERO expansion signaling request
4.2 New Path Error sub-codes
5. Mode of operation
5.1 Head-end reoptimization control
5.2 Reoptimization triggers
5.3 Head-end request versus mid-point explicit notification modes
5.3.1 Head-end request mode
5.3.2 Mid-point explicit notification mode
5.3.3 ERO cashing
6. Interoperability
7. Security considerations
8. Acknowledgments
9. Intellectual property
Abstract
## This abstract is a little long. Normally aim for about 10 lines.
## Probably OK, however.
<The aim of this document is to propose a mechanism for the
>This document defines a mechanism for the
reoptimization of MPLS Traffic Engineering loosely routed LSP paths. A
loosely routed LSP path is a path specified as a combination of strict
and loose hop(s) that contains at least one loose hop and zero or more
strict hop(s). The path calculation (which implies an ERO expansion) to
reach a loose hop is performed by the previous hop defined in the TE
LSP path. This document proposes a mechanism that allows:
## Why is this draft limited to "loose" hops
## Surely strict hops that are non-specific abstract nodes are also
## important. For example, if I have an AS number in my ERO I might not
## use a loose hop, but reoptimization would still be important.
- The TE LSP head-end LSR to trigger a new ERO expansion on every
hop having a next hop defined as a loose hop,
- A mid-point LSR to signal to the head-end LSR that either a better
path exists to reach a loose hop (compared to the current path in
use) or that the TE LSP must be reoptimized because of some
maintenance required on the TE LSP path. A better path is defined as
a lower cost path, where the cost is determined by the metric used
to compute the path.
The proposed mechanism applies to intra-domain and inter-domain packet
and non-packet TE LSPs when the path is defined as a list of loose
hops. Examples of domains are IGP areas and Autonomous Systems.
1. Introduction
The Traffic Engineering Work Group has specified a set of requirements
for inter-area [INTER-AREA-TE-REQ] and inter-AS [INTER-AS-TE-REQ] MPLS
Traffic Engineering. Both requirements documents specify the need for
## well they say "SHOULD", not "MUST"
some mechanism providing an option for the head-end to control the
Vasseur and Ikejiri 2
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
reoptimization process, should a more optimal path exist in a
downstream domain (IGP area or Autonomous System).
<This document proposed a solution to meet this requirement, in addition
<to some mechanism to discover the existence of such a more optimal path
>This document defines a solution to meet this requirement, in addition
>to a mechanism to discover the existence of such a more optimal path
## Is this true? Do you discover the existence of a more optimal path or
## do you inform the head-end the of the existence of a more optimal
## path?
## So you should say "a mechanism to communicate the existence of a
## more optimal path or a request to reoptimize..."
or the need to reoptimize due to some maintenance required in a
downstream domain.
## Do you need to describe what you mean by "reoptimize"?
## In particular, you mean "...re-signal the LSP using a new LSP Id
## so that the LSP can be re-routed onto a more optimal (or simply
## different) path with minimal disruption to traffic. In particular,
## re-optimaization SHOULD NOT use a simple change to the ERO of the
## existing LSP because this may adversely impact traffic. The reasons
## for not using a change to the ERO are explained further in section x"
2. Establishment of a loosely routed TE LSP
A loosely routed explicit path is a path specified as a combination of
strict and loose hop(s) that contains at least one loose hop and a set
of zero or more strict hop(s). Loose hops are listed in the ERO object
<of the RSVP Path message with the L flag of the Ipv4 or the IPv6 prefix
>of the RSVP Path message with the L flag of the IPv4 or the IPv6 prefix
sub-object set, as defined in [RSVP-TE]. In this case, each LSR along
<path whose next hop is specified as a loose hop triggers a path
>the path whose next hop is specified as a loose hop triggers a path
computation (also referred to as an ERO expansion), before forwarding
## You see, ERO expansion also refers to the expansion of abstract nodes
## Also what about when there are no loose hops, but the ERO does not go
## as far as the egress? Surely you want to include this, too.
<the RSVP Path message downstream. The path computation may be either be
>the RSVP Path message downstream. The path computation may either be
performed by means of CSPF or any Path Computation Element (PCE) and
can be partial (up to the next loose hop) and complete (up to the TE
LSP destination).
## Note that whil *I* agree with your point here, this directly goes
## against 3209 which says that expansion is (at most) only as far as
## the next specified hop (loose or strict).
## I think that you need to explain the fact that you are extending the
## definition of 3209.
Note that the examples in the rest of this document are provided in the
context of MPLS inter-area TE but the proposed mechanism equally
applies to loosely routed explicit paths within a single routing domain
and across multiple Autonomous Systems.
The examples below are provided with OSPF as the IGP but the described
set of mechanisms similarly apply to IS-IS.
## Make the following into section 2.1
An example of an explicit loosely routed TE LSP signaling.
<---area 1--><-area 0--><-area 2->
< R1---R2----R3---R6 R8-----R10
< | | | / |\ |
< | | | -- | --\ |
< | | |/ | \|
< R4---------R5---R7----R9-----R11
> R1---R2----R3---R6 R8----R10
> | | | / |\ |
> | | | / | \ |
> | | | / | \ |
> | | |/ | \|
> R4---------R5---R7----R9----R11
Assumptions
- R3, R5, R8 and R9 are ABRs
<- The path an inter-area TE LSP T1 from R1 (head-End LSR) to R11 (tail-
>- The path of an inter-area TE LSP T1 from R1 (head-End LSR) to R11 (tail-
end LSR) is defined on R1 as the following loosely routed path: R1-
R3(loose)-R8(loose)-R11(loose). R3, R8 and R11 are defined as loose
hops.
## In step 3 you say how R3 determines how to expand the ERO. Why do you
## not say how R1 determines the ERO in step 1?
Step 1: R1 builds the following ERO object: R1(S)-R2(S)-R3(S)-R8(L)-
R11(L) where:
S: Strict hop (L=0)
L: Loose hop (L=1)
Vasseur and Ikejiri 3
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
The R1-R2-R3 path obeys T1Æs set of constraints
## Bad character in text
Step 2: the RSVP Path message is then forwarded by R1 following the ERO
path and reaches R3 with the following content: R8(L)-R11(L)
Step 3: R3 determines that the next hop (R8) is a loose hop (not
directly connected to R3) and then performs an ERO expansion operation
## Actually, even if it was directly connected, if it is a loose hop
## we should do a CSPF computation. We don't necessarily want to go
## on the direct link.
to reach the next loose hops R8 either by means of CSPF or any other
PCE-based path computation method. The new ERO becomes: R6(S)-R7(S)-
R8(S)-R11(L)
Note: in this example, the assumption is made that the path is computed
on a per loose hop basis, also referred to a partial route computation.
Note that PCE-based mechanisms may also allow for full route
computation (up to the final destination).
## I suspect that people will complain about the strong use of PCE in
## the two previous paragraphs
Step 4: the same procedure applies at R8 to reach T1Æs destination:
R11.
## Bad character in text
3. Reoptimization of a loosely routed TE LSP path
Once a loosely routed explicit TE LSP is set up, it is maintained
through normal RSVP procedures. Then a more optimal path might appear
<between an LSR and its next loose hop(for the sake of illustration,
>between an LSR and its next loose hop (for the sake of illustration,
suppose in the example above that a link between R6 and R8 is added or
restored that provides a shorter path between R3 and R8 (R3-R6-R8) than
the existing R3-R6-R7-R8 path). Since the better path is not visible
from the head-end LSR by means of the IGP because it does not belong to
the head-end IGP area, the head-end cannot make use of this better path
<(and perform a make before break) when appropriate. Hence some
>(and re-route the LSP using make before break) when appropriate. Hence some
mechanism is required to detect the existence of such a better path and
<notifies the head-end accordingly.
>notify the head-end accordingly.
<This document proposes a mechanism that allows:
>This document defines a mechanism that allows:
- A head-end LSR to trigger on every LSR whose next hop is a
loose hop the re-evaluation of the current path in order to
detect a potential more optimal path,
- A mid-point LSR whose next hop is a loose-hop to signal
(using a new ERROR-SPEC sub-code carried in a Path Error Notify
## What do you mean "sub-code"?
## Do you mean Error Value?
##
## What do you mean "Path Error Notify message"?
## Do you mean PathErr and Notify messages
message) to the head-end that a better path exists (a path with
a lower cost, where the cost is defined by the metric used to
compute the path û see [SEC-METRIC], [METRIC]).
## Bad character in text
## Besides, I don't see that this is the time to start to describe
## what might be meant by a "better path" in terms of possible
## CSPF computations. This really is simply a statement that "if the
## path computation were to be applied for a second time it would
## produce a different result." This covers optimization, maintenance,
## and all forms of CSPF grooming.
Then once the existence of such a better path is notified to the head-
end, the head-end LSR can decide (depending on the TE LSP
characteristics) whether to perform a TE LSP graceful reoptimization.
There is another scenario whereby notifying the head-end of the
Vasseur and Ikejiri 4
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
existence of a better path is desirable: if the current path is about
the fail due to some (link or node) required maintenance.
This allows the head-end to reoptimize a TE LSP making use of the non
disruptive make before break procedure if and only if a better path
exists and if such a reoptimized is desired.
## There is a specific, more precise requirement here. What if the
## component link or label is about to go out of service? Do we
## also need to resignal using make-before break?
##
## I have been trying to formulate something for this in GMPLS.
## The specific concern here is that the maintenance decision may
## be taken at the network node (within the domain), not at the
## centralized management/routing controller (PCE) for the domain.
## Thus there is a need to signal this resource (i.e. not link)
## change back up the LSP to the point of computation, and possibly
## forward again in the new Path request as an explicit exclusion.
## For example, think of a 20 lambda link where the in-use lambda is
## about to be deprovisioned. The link and TE stays good, but the
## in-use label is about to go away.
## Hmmm, on reflection, it is fine simply to cause re-signaling the
## way you propose, and allow label re-negotiation on the make-before-
## break LSP.
## Perhaps it would be good to comment on this usage since it is a major
## requirement for GMPLS.
4. Signalling extensions
4.1. ERO expansion signaling request
The following new flag of the SESSION_ATTRIBUTE object (C-Type 1 and 7)
is defined:
ERO Expansion request: 0x20
## I think your IANA section should request that IANA manages this
## flags field and allocates you a new value.
This flag indicates that a new ERO expansion is requested.
## If you do make-before-break, it is a new LSP. How would you use the
## "old" ERO in this case? Of course, the old LSP's resource attributes
## must be available for sharing during the computation, but still, you
## compute a new route every time you get a Path message for a new LSP.
Note: in case of link bundling for instance, although the resulting ERO
might be identical, this might give the opportunity for a mid-point LSR
to locally select another link within a bundle, although strictly
speaking, the ERO has not changed.
## Aha! But the change in ERO doesn't matter in this case because it is
## a new LSP so the LSRs are free to make a new choice in any case.
##
## I *think* the destinction you are trying to signal is that the new
## LSP is NOT simply another LSP in the session that should attempt to
## maximally share resources with the existing LSP, but is actually a
## replacement LSP (using make-before-break) and the other LSP in this
## session will be torn down later so resource sharing is not required
## except where it occurs fortuitously.
##
## Further (oh gods, he goes on!) don't you actually need to know which
## LSP is being replaced? Consider that you have two load sharing LSPs
## within one session. It is possible that these LSPs share links or
## nodes within some parts of the network (full path diversity is not a
## requirement ofr load sharing). In this case, when you do make before
## break to establish an LSP on a better path, it is important to
## indicate which LSP is being replaced.
<4.2. New Path Error sub-code
>4.2. New Error Spec Error Values
As defined in [RSVP-TE], the ERROR-CODE 25 an ERROR SPEC object
<corresponds to a Path Error - Notify Error.
>corresponds to a Notify Error.
<This document proposes to add three new sub-codes:
>This document adds three new Error Values:
6 Better path exists
7 Local link maintenance required
8 Local node maintenance required
## Please add an IANA section for the allocation of these values.
## You may *suggest* these values.
The details about the local maintenance required modes are detailed in
section 5.3.2
5. Mode of operation
5.1. Head-end reoptimization control
The notification process of a better path (shorter path or new path due
to some maintenance required on the current path) is by nature de-
correlated from the reoptimization operation. In other words, the
location where a potentially more optimal path is discovered does not
have to be where the TE LSP is actually reoptimized. This document
applies to the context of a head-end reoptimization.
5.2. Reoptimization triggers
<There are two possible reoptimization triggers:
>There are three possible reoptimization triggers:
Vasseur and Ikejiri 5
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
- Timer-based: a reoptimization is triggered (process
evaluating whether a more optimal path can be found) when a
configurable timer expires,
- Event-driven: a reoptimization is triggered when a
particular network event occurs (such as a ôLink-UPö event),
## Bad characters in text
##
## Do you want to add "Deferred Event-driven" as a fourth class?
- Operator-driven: a reoptimization is manually triggered by
the Operator.
It is RECOMMENDED for an implementation supporting the extensions
proposed in this document to support both modes.
## Given that there are three modes, what do you want to recommend?
5.3. Head-end request versus mid-point explicit notification modes
This document defines two modes:
- ôHead-end requesting modeö: the request for a new path
## Bad characters in text
evaluation of a loosely routed TE LSP is requested by the head-
end LSR.
## I seriously misread this (and actually the draft up to this point).
## It was not previously clear that this mode is used by the head end
## to ask the network whether any better paths exist. This is done
## to determine whether there is value in make before break signaling.
## Could you make this clearer here and in earlier sections?
- ôMid-point explicit notificationö: a mid-point LSR having
## Bad characters in text
determined that a better path (than the current path is use)
exists or having the desire to perform a link/node local
maintenance explicitly notifies the head-end LSR which will in
turn decide whether to perform a reoptimization.
## It is unclear from this text whether the reporting LSR/domain is
## requesting or requiring a re-optimization (you use "desire"). Perhaps
## you need different quality actions according to the Error Values.
5.3.1.
Head-end request mode
## Format
In this mode, when a timer-based reoptimization is triggered on the
head-end LSR or the operator manually requests a reoptimization, the
head-end LSR immediately sends an RSVP Path message with the ôERO
Expansion requestö bit of the SESSION-ATTRIBUTE object set. This bit is
## bad characters in text
then cleared in subsequent RSVP path messages sent downstream.
## Ouch!
## See the pain that is required for similar behavior in the GMPLS
## ADMIN_STATUS Object. Your problem here is that you need to be sure
## that this flag has properly propagated and been acted on before you
## send a new Path message with the bit cleared.
##
## Perhaps you need a sequence number. Perhpas you need a toggle bit
## so you only act when the bit toggles.
Upon receiving a Path message with the ôERO expansion requestö bit set,
## bad characters in text
every LSR for which the next abstract node contained in the ERO is
defined as a loose hop, performs the following set of actions:
## ditto loose hop/abstract node
## Oh. Now you say what is going on!!!
## See my comment in 5.3 bullet one.
1) A new ERO expansion is triggered and the newly computed path is
compared to the existing path:
- If a better path can be found, the LSR MUST immediately send
< a Path Error to the head-end LSR (Error code 25 (Notify), sub-
< code=6 (better path exists)). At this point, the LSR MAY decide
> a Path Error to the head-end LSR (Error code 25 (Notify), Error
> Value=6 (better path exists)). At this point, the LSR MAY decide
to clear the ERO expansion request bit of the SESSION-ATTRIBUTE
object in subsequent RSVP Path messages sent downstream: this
< mode is the RECOMMENDED mode.
> mode is the RECOMMENDED mode for the reasons described below.
The sending of a Path Error Notify message ôBetter path existsö
## bad characters in text
## Say: Path Error message with the error "Notify"/"Better path exists"
to the head-end LSR will notify the head-end LSR of the
Vasseur and Ikejiri 6
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
existence of a better path (e.g in a downstream area/AS or in
another location within a single domain).
## How does the head end distinguish between solicited and unsolicited
## information? Does it care?
Hence, triggering
additional ERO expansions on downstream nodes is unnecessary.
The only motivation to forward subsequent RSVP Path messages
with the ôExpansion request bitö of the SESSION-ATTRIBUTE
## bad characters in text
object set would be to trigger path re-evaluation on downstream
nodes that could in turn cache some potentially better paths
downstream with the objective to reduce the signaling setup
delay, should a reoptimization be performed by the head-end
LSR.
- If no better path can be found, the recommended mode is for
an LSR to relay the request (by setting the ERO expansion bit
of the SESSION-ATTRIBUTE object in RSVP path message sent
downstream) only if no better path has been found on this mid-
point LSR.
## When the bit reaches the egress, should there be some response so that
## the head-end is notified that nothing could be done and everyone has
## correctly processed the request.
By better path, we mean a path having a lower cost. By default, an LSR
uses the TE metric to compute the shortest path that obeys a set of
constraints. Note that the head-end LSR might use the METRIC-TYPE
object (defined in [PATH-COMP]) in its path message to request the LSR
having a next hop defined as a loose hop in the ERO to use another
metric to determine the best path.
## Same issue as above. "Better" really means "different". That is,
## it is a local matter what better/different would mean and what is
## reported is that a different path would be preferred.
If the RSVP Path message with the ôERO expansion requestö bit set is
## bad characters in text
lost, then the next request will be sent when the reoptimization event
will trigger on the head-end LSR. The solution to handle RSVP reliable
messaging has been defined in [REFRESH-REDUCTION].
## It is unclear what you mean by "will trigger". If the operator has
## made a request, you must obey it or tell him that it has failed.
## How would he otherwise know to re-issue the request?
##
## Note that in MPLS the use of the refresh reduction mechanisms for
## guaranteed delivery can only be applied if refresh reduction is
## enabled. But not all nodes support refresh reduction (it is optional).
## GMPLS gets around this by specifically allowing Message ID without
## the use of Refresh Reduction. Is this what you are proposing here? If
## so, this is a significant change in RSVP-TE processing.
##
## In any case, reliable delivery is not enough since the subsequent
## Path message may catch up (and therefore overtake) the first message.
## This is actually highly likely since re-computation in many domains
## may take some considerable time. So your issue is that you may
## prematurely clear the computation required bit.
## Reliable delivery will not help here.
The network administrator may decide to establish some local policy
specifying to ignore such request or to consider those requests not
more frequently than a certain rate.
The proposed mechanism does not make any assumption of the path
computation method performed by the ERO expansion process: it can
either be CSPF or PCE based.
## Is PCE not also CSPF? :-)
5.3.2.
Mid-point explicit notification mode
## Format
In this mode, a mid-point LSR whose next abstract node is a loose hop
can locally trigger an ERO expansion (when a configurable timer expires
## trigger or request?
or on event-driven basis (link-up event for example) or the user
explicitly requests it). If a better path is found compared to the
existing one, the LSR sends a Path Error to the head-end LSR (Error
code 25 (Notify), sub-code=6 (better path exists)).
## Error Value
There are other circumstances in which a mid-point LSR MAY send an RSVP
Path Error Notify message with the objective for the TE LSP to be
## PathError message
rerouted by its head-end LSR: when a link or a node will go down for
local maintenance reasons. In this case, the mid-point LSR where the
local maintenance must be performed is responsible for sending an RSVP
Vasseur and Ikejiri 7
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
Path Error Notify message with the sub-code=7 or 8 depending on the
## PathError message with error code "Notify" and Error Value...
##
## By the way, it is better to always refer to the error value as a
## name string. That way there is only one editorial point for IANA
## to change.
affected network element (link or node). Then the first upstream node
having performed the ERO expansion MUST perform the following set of
actions:
- The link (sub-code=7) or the node (sub-code=8) MUST be
locally registered for further reference (the TE database must
be updated)
- The RSVP Path Error message MUST be immediately forwarded
unchanged upstream to the head-end LSR.
## But this crosses a domain boundary so there is a confidentiality
## issue. The domain boundary must be allowed to "aggregate" this
## information. Perhaps it would replace the link/node information
## with its own address.
Upon, receiving a Path Error Notify message with sub-code 7 or 8, the
## PathError message with error code "Notify" and Error Value...
Head-end LSR MUST perform a TE LSP reoptimization.
<Note that those modes are not exclusive: both the timer and even-driven
>Note that those modes are not exclusive: both the timer and event-driven
reoptimization triggers can be implemented on the head-end and/or any
mid-point LSR with potentially different timer values for the timer
driven reoptimization case.
A head-end LSR MAY decide upon receiving an explicit mid-point
notification to delay its next ERO expansion request.
## If you talk about delays, you MUST specify a default timer value.
## I believe this is an editorial requirement.
## You need to be careful that this delay is not in contradiction of
## "Upon, receiving a Path Error Notify message with sub-code 7 or 8,
## the Head-end LSR MUST perform a TE LSP reoptimization."
5.3.3.
ERO caching
## Format
Once a mid-point LSR has determined that a better path exists (after a
reoptimization request has been received by the head-end LSR or the
reoptimization timer on the mid-point has fired), the more optimal path
MAY be cached on the mid-point LSR for a limited amount of time to
avoid having to recompute a route once the head-LSR performs a make
before break. This mode is optional.
Comment
:
## Spurious text
6. Interoperability
Comment
:
## Spurious text
An LSR not supporting the ôERO expansion requestö bit of the SESSION-
## Bad characters in text
ATTRIBUTE object SHOULD just ignore it.
## 3209 says SHALL forward unmodified. I think you should say MUST and
## give reference to 3209.
Any head-end LSR not supporting a Path Error Notify message with sub-
code = 6, 7 or 8 MUST just silently ignore such Path Error messages.
## Erm, if it doesn't support them, you can't expect the code to be
## changed specially to ignore!
## It is interesting that there is a mistake in 3209 since it does not
## say that a Notify error code means anything special.
## Fortunately, it is well established that no PathErr message ever
## causes any change in the Path state at any transit LSR. Also, that
## the ingress that receives an error code/value that it does not
## understand. You can simply refer to 2205 for the correct processing
## at all legacy nodes.
7. Security Considerations
The practice described in this document does not raise specific
security issues beyond those of existing TE.
## Well, I have raised confidentiality for "maintenance required".
##
## What do you mean "existing TE"?
8. Acknowledgments
The authors would like to thank Carol Iturralde, Miya Kohno, Francois
Le Faucheur, Philip Matthews, Jim Gibson, Raymond Zhang, Jean-Louis Le
Roux and Kenji Kumaki for their useful and valuable comments.
Vasseur and Ikejiri 8
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
9. Intellectual Property
## Ooooh!
## We have to use the new boiler plate. This includes personal IPR
## declarations.
## BTW, could you tell us what elements have been claimed? As you
## may be aware, there is debate about when drafts should not be
## moved forward by WGs if there is IPR claimed. This applies even
## if appropriate reasonable terms are in place.
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to pertain
to the implementation or use of the technology described in this
document or the extent to which any license under such rights might or
might not be available; neither does it represent that it has made any
effort to identify any such rights. Information on the IETF's
procedures with respect to rights in standards-track and standards-
related documentation can be found in BCP-11. Copies of claims of
rights made available for publication and any assurances of licenses to
be made available, or the result of an attempt made to obtain a general
license or permission for the use of such proprietary rights by
implementors or users of this specification can be obtained from the
IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary rights
which may cover technology that may be required to practice this
standard. Please address the information to the IETF Executive
Director.
The IETF has been notified of intellectual property rights claimed in
regard to some or all of the specification contained in this document.
For more information consult the online list of claimed rights.
Normative References
## Format and bad characters throughout references.
[RFC] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels," RFC 2119.
[RSVP-TE] Awduche et al, "RSVP-TE: Extensions to RSVP for LSP Tunnels",
RFC3209, December 2001.
Informative references
[TE-REQ] Awduche et al, Requirements for Traffic Engineering over MPLS,
RFC2702, September 1999.
[METRICS] Fedyk et al, ôMultiple Metrics for Traffic Engineering with
IS-IS and OSPFö, draft-fedyk-isis-ospf-te-metrics-01.txt, November
2000.
[DS-TE] Le Faucheur et al, ôRequirements for support of Diff-Serv-aware
MPLS Traffic Engineeringö, draft-ietf-tewg-diff-te-reqts-01.txt, June
2001.
## Not really relevant? Not referenced.
Vasseur and Ikejiri 9
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
[MULTI-AREA-TE] Kompella et al, ôMulti-area MPLS Traffic Engineeringö,
draft-kompella-mpls-multiarea-te-03.txt, June 2002.
[SEC-METRIC] Le Faucheur et all,ô Use of Interior Gateway Protocol
(IGP) Metric as a second MPLS Traffic Engineering Metricö, draft-ietf-
tewg-te-metric-igp-02.txt, September, 2002.
[INTER-AREA-TE-REQ], Le Roux, Vasseur, Boyle et al. ½ Requirements for
Inter-area MPLS Traffic Engineering ©, draft-ietf-tewg-interarea-mpls-
te-req-01, April 2004 (Work in progress).
[INTER-AS-TE-REQ] Zhang et al, ôMPLS Inter-AS Traffic Engineering
requirementsö, draft-ietf-tewg-interas-mpls-te-req-06.txt, February
2004, Work in progress.
[INTER-AREA-AS] Vasseur and Ayyangar, ôInter-area and Inter-AS Traffic
Engineeringö, draft-vasseur-inter-area-AS-TE-00.txt, February 2004,
work in progress.
[REFRESH-REDUCTION] Berger et al, ôRSVP Refresh Overhead Reduction
Extensionsö, April 2001
## Spurious text below
Authors' addresses: Formatted:
Jean-Philippe Vasseur
Cisco Systems, Inc.
300 Beaver Brook Road
Boxborough , MA - 01719
USA
Email: jpv@cisco.com Formatted:
Formatted:
Yuichi Ikejiri Formatted:
NTT Communications Corporation Field Code
1-1-6, Uchisaiwai-cho, Chiyoda-ku
Tokyo 100-8019
JAPAN
Email: y.ikejiri@ntt.com Formatted:
Formatted:
Full Copyright Statement Formatted:
Field Code
Copyright (C) The Internet Society (2004). All Rights
Reserved.
## please use new boilerplate for copyright.
This document and translations of it may be copied and
furnished to others, and derivative works that comment on
or otherwise explain it or assist in its implementation may
be prepared, copied, published and distributed, in whole or
in part, without restriction of any kind, provided that the
above copyright notice and this paragraph are included on
all such copies and derivative works. However, this
document itself may not be modified in any way, such as by
Vasseur and Ikejiri 10
draft-vasseur-ccamp-loose-path-reopt-01.txt April 2004
removing the copyright notice or references to the Internet
Society or other Internet organizations, except as needed
for the purpose of developing Internet standards in which
case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to
translate it into languages other than English.
The limited permissions granted above are perpetual and
will not be revoked by the Internet Society or its
successors or assigns. This document and the information
contained herein is provided on an "AS IS" basis and THE
INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE
DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE.
Vasseur and Ikejiri 11