Re: Fwd: [Mter] Need to decide on potential next steps for MTER
"Diego Caviglia" <Diego.Caviglia@marconi.com> Tue, 16 May 2006 13:16 UTC
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Subject: Re: Fwd: [Mter] Need to decide on potential next steps for MTER
To: "JP Vasseur <jvasseur" <jvasseur@cisco.com>, mter@ietf.org
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From: Diego Caviglia <Diego.Caviglia@marconi.com>
Date: Tue, 16 May 2006 13:58:38 +0200
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Hi JP,
the ID expired in April this year so is no longer on the ID
database.
Here is the ID, comments are very welcome.
Regards
Diego
CCAMP
Internet Draft Diego Caviglia
(Marconi)
Dino Bramanti
(Marconi)
Huub van
Helvoort(Huawei
Technologies
Ltd)
Document: draft-caviglia-ccamp-gmpls-msspring-
req-00
Expires: April 2006 October
2005
GMPLS Requirements for MS-SPRing support
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of 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 ôwork in progressö.
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
Abstract
GMPLS [1] provides ideally a robust and flexible control plane
protocols set designed for application over generalized transport
network. A typical application of GMPLS is, among others, the control
of transport networks based on SDH/SONET [2] technology. In this
scenario, the introduction of GMPLS based control plane should ensure
support of and/or compatibility with the most important and widely
exploited SDH/SONET features, making possible a seamless interworking
with inherent data plane requirements. In this document we focus on
one of the most attractive SDH/SONET protection mechanism,
implemented through MS-SPRing (G.841 [3]), a widely deployed ITU
standard for ring-shared protection.
Caviglia Expires - April 2006 [Page 1]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
In general, when setting up and configuring a data plane circuit
traversing a MS-SPRing ring (or segments of it) via traditional
management plane control, special constraints, which are specific to
this kind of technology, have to be considered in order to ensure its
correct operation. The same constraints have to be carefully taken
into account when the data plane circuit is no more set up in a
traditional way, but through a GMPLS based control plane.
The specific constraints imposed by MS-SPRing are related to:
. Time Slot Interchange (TSI)
. Ring Map filling in case of squelching
In this document a brief overview of MS-SPRing operation is
introduced and its specific requirements are explained, putting in
evidence the way they may impact when GMPLS is used as control plane.
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 [4].
Table of Contents
1. MS-SPRing Bird Eye Overview...................................3
1.1 Information needed by MS-SPRing..............................5
1.2 MS-SPRing Example............................................6
1.3 Time Slot Interchange (TSI).................................11
1.4 Squelching..................................................11
2. GMPLS requirements imposed by MS-SPRing......................13
2.1 LSP Set-Up..................................................13
2.2 Data Plane and Control Plane misalignment...................13
2.3 Interworking between GMPLS restoration and MS-SPRing Protection14
3. Security Considerations......................................14
References......................................................14
Acknowledgments.................................................15
Author's Addresses..............................................15
Caviglia Expires - April 2006 [Page 2]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
1. MS-SPRing Bird Eye Overview
The main reference for this Section is ITU-T G.841. G.841 defines
two different kinds of MS-SPRing namely two fibers and four fibers.
Two-fiber MS switched rings require only two fibers for each span of
the ring. Each fiber carries both working channels and protection
channels. On each fiber, up to half the channels are defined as
working channels and up to half are defined as protection channels.
It is possible that some channels are not protected at all, being
defined as Non-pre-emptible Unprotected Traffic (NUT) channels.
The traffic carried on working channels inside one fiber is protected
by channels going in the opposite direction around the ring. This
allows for a bi-directional transport of normal traffic and makes
possible a sharing of the protection resources when needed.
The following picture illustrates the two fibers case, no NUT in this
example.
WPx links are 50% for worker traffic and 50% for protection traffic,
e.g. and STM-16 links have 8 AU-4 timeslot for worker traffic and 8
AU-4 timeslot for protection.
TNE A TNE B TNE C
+------------+ +------------+ +------------+
| | | | | |
| | | | | |
| | | | | |
| |----------->| |----------->| |
| | WP1 | | WP2 | |
| |<-----------| |<-----------| |
| | | | | |
| | | | | |
| | | | | |
+------------+ +------------+ +------------+
^ | ^ |
| | | |
| | | |
| WP3 | WP Links Resources are | WP4 |
| | 50% Worker | |
| | 50% Protection | |
| v | v
+------------+ +------------+ +------------+
| | | | | |
| | | | | |
| | | | | |
| |----------->| |----------->| |
Caviglia Expires - April 2006 [Page 3]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
| | WP5 | | WP6 | |
| |<-----------| |<-----------| |
| | | | | |
| | | | | |
| | | | | |
+------------+ +------------+ +------------+
TNE F TNE E TNE D
Figure 1-1: MS-SPRing two fibers reference circuit
Four-fiber MS shared protection rings require four fibers for each
span of the ring. As illustrated in Figure 1-2, working and
protection channels are carried over different fibers: two multiplex
sections transmitting in opposite directions carry the working
channels while two multiplex sections, also transmitting in opposite
directions, carry the protection channels. This enables the bi-
directional transport of normal traffic, sharing as well the
protection capability.
The following picture illustrates the reference circuit (four fiber
MS-SPRing) used in this Section.
TNE A TNE B TNE C
+------------+ +------------+ +------------+
| | | | | |
| |----------->| |----------->| |
| | W1 | | W2 | |
| |<-----------| |<-----------| |
| | | | | |
| |===========>| |===========>| |
| | P1 | | P2 | |
| |<===========| |<===========| |
| | | | | |
+------------+ +------------+ +------------+
^ | ^ l ^ l ^ |
| | l l l l | |
| | l l l l | |
|W3| lP3l ------------ Working Link lP4l |W4|
| | l l llll and === Protection Link l l | |
| | l l l l | |
| v l v l v | v
+------------+ +------------+ +------------+
| | | | | |
| |===========>| |===========>| |
| | P5 | | P6 | |
| |<===========| |<===========| |
| | | | | |
| |----------->| |----------->| |
| | W5 | | W6 | |
Caviglia Expires - April 2006 [Page 4]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
| |<-----------| |<-----------| |
| | | | | |
+------------+ +------------+ +------------+
TNE F TNE E TNE D
Figure 1-2: Reference circuit for MS-SPRing, four fibers variant
1.1 Information needed by MS-SPRing
The MS-SPRing protection mechanism is implemented via a SDH
signalling protocol known as Automatic Protection Switching (APS).
This protocol makes use of SDH overhead bytes (K1 and K2, MS overhead
bytes) as a means to transport its own information. APS is not
detailed here as it is outside the scope of this document.
Each node on the ring shall be assigned an ID that is a number from 0
to 15, allowing a maximum of 16 nodes on the ring. Such ID value is
not related to the position of corresponding node in the ring, i.e.
the order of the nodes is not tied to nodes ID assignment.
Each node has a ring topology map that associates a nodeÆs ID with
its address.
With respect to the Figures 1-1/2 the ring topology map is:
TNE-ID TNE-Address
1 B
2 F
3 A
4 E
5 C
6 D
Table 1-1 Ring Topology map
The following tables represent the traffic matrix of the ring and the
squelching (for definition of squelching please refer to Section 1.4)
tables of the TNEs.
+------------------------------------------------------------------+
| AU | <---- West Nodes East ---->|
| Number | A B C D E F A|
+--------+---------------------------------------------------------+
| 1 | <--------> <------------------> |
| 2 | <-----------------------------> |
| 3 | <--------------------><-------------------------> |
+------------------------------------------------------------------+
Caviglia Expires - April 2006 [Page 5]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
Table 1-2 Traffic Matrix
+---------------------------------+---------------------------------
TNE-A | TNE-B
AU West East | AU West East
Src Dst Src Dst | Src Dst Src Dst
1 A B | 1 B A B D
2 A D | 2 D A A D
3 A C | 3 C A C F
----------------------------------+----------------------------------
----------------------------------+---------------------------------
TNE-C | TNE-D
AU West East | AU West East
Src Dst Src Dst | Src Dst Src Dst
1 D B B D | 1 D B B D
2 D A A D | 2 D A A D
3 C A C F | 3 F C C F
----------------------------------+---------------------------------
----------------------------------+---------------------------------
TNE-E | TNE-F
AU West East | AU West East
Src Dst Src Dst | Src Dst Src Dst
1 | 1
2 | 2
3 F C C F | 3 F C C F
----------------------------------+---------------------------------
Table 1-3 Squelching Table
When a node determines that a protection switch is required, it
sources the appropriate bridge request using the APS protocol to the
node at the far end of the affected MS (for more details on how APS
carries that information please refer to G.841 [4]).
WeÆll call Ring Map the sum of the information contained in all the
above Tables.
1.2 MS-SPRing Example
The worker circuit follows this path (4_fibers/2_fibers):
TNE-A <-Link W1/WP1-> TNE-B <-Link W2/WP2-> TNE-C <-Link W4/WP4->
TNE-D : AU Timeslot 1
Caviglia Expires - April 2006 [Page 6]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
In four fibers scenario failure of Links W2 and P2 triggers the MS-
SPRing protection.
Traffic is protected using this path:
TNE-A <-Link W1-> TNE-B [Internal Bridge] <-Link P1-> TNE-A <-Link
P3-> TNE F <-Link P5-> TNE-E <-Link P6-> TNE-D <-Link P4-> TNE-C
[Internal Bridge] <- Link W4 -> TNE-D: AU Timeslot 1.
The following picture illustrates the state of the network after the
recovery, by means of MS-SPRing, of the failure.
1
TNE A v TNE B TNE C
+----------|-+ +------------+ +------------+
| | | | | | |
| +------------->----->----+ |XXXXXXXXXXXX| +--------+ |
| | W1 | | | W2 | | | |
| |<-----------| | |XXXXXXXXXXXX| | | |
| | | v | | ^ v |
| |===========>| | |XXXXXXXXXXXX| | | |
| | P1 | | | P2 | | | |
| +--<===========-----<----+ |XXXXXXXXXXXX| | | |
| | | | | | | | |
+----------|-+ +------------+ +-|--------|-+
^ | ^ l ^ l ^ |
| | l l l l | |
| | l l l l | |
|W3| lP3l ------------ Working Link lP4l |W4|
| | l l llll and === Protection Link l l | |
| | l l l l | |
| v l v l v | v
+----------|-+ +------------+ +-|--------|-+
| | | | | | | | |
| +--===========>------->------===========>--+ | |
| | P5 | | P6 | | |
| |<===========| |<===========| | |
| | | | | v |
| |----------->| |----------->| | |
| | W5 | | W6 | | |
| |<-----------| |<-----------| | |
| | | | | | |
+------------+ +------------+ +----------|-+
TNE F TNE E TNE D v
1
Figure 1-3: MS-SPRing four fibers ring-switching
Caviglia Expires - April 2006 [Page 7]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
The extra traffic in spans P1, P3, P4, P5 and P6 is affected.
Note that in this case working traffic passes the same section two
times, i.e. link W1 and link P1, link P4 and link W4.
If these sections are very long, e.g. in trans-oceanic applications,
the propagation delay is affected considerably and will result in a
degradation of performance.
For trans-oceanic applications intermediate nodes, not adjacent to an
affected section, will switch bridges as well.
Traffic is now protected using this path:
TNE-A [Internal Bridge] TNE-A <-Link P3-> TNE F <-Link P5-> TNE-E <-
Link P6-> TNE-D [Internal Bridge] TNE-D: AU Timeslot 1.
The following picture illustrates the state of the network after the
recovery, by means of trans-oceanic MS-SPRing, of the failure.
1
TNE A v TNE B TNE C
+----------|-+ +------------+ +------------+
| | | | | | |
| | |----------->| |XXXXXXXXXXXX| |
| | | W1 | | W2 | |
| | |<-----------| |XXXXXXXXXXXX| |
| v | | | | |
| | |===========>| |XXXXXXXXXXXX| |
| | | P1 | | P2 | |
| | |<===========| |XXXXXXXXXXXX| |
| | | | | | |
+----------|-+ +------------+ +------------+
^ | ^ l ^ l ^ |
| | l l l l | |
| | l l l l | |
|W3| lP3l ------------ Working Link lP4l |W4|
| | l l llll and === Protection Link l l | |
| | l l l l | |
| v l v l v | v
+----------|-+ +------------+ +------------+
| | | | | | |
| +--===========>------->------===========>------>----+ |
| | P5 | | P6 | | |
| |<===========| |<===========| | |
| | | | | v |
| |----------->| |----------->| | |
| | W5 | | W6 | | |
| |<-----------| |<-----------| | |
| | | | | | |
+------------+ +------------+ +----------|-+
Caviglia Expires - April 2006 [Page 8]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
TNE F TNE E TNE D v
1
Figure 1-4: MS-SPRing four fibers trans-oceanic ring-switching
Only the extra traffic in spans P3, P5 and P6 is affected.
Instead of bridging all working traffic to the protections channels
in the nodes adjacent to the failure in trans-oceanic ring-switching
the individual AU tributaries are switched in their ingress and
egress nodes using ring maps and APS information. Due to the transfer
and evaluation of the information more time is required for the
protection switch to complete, the objective is 300 ms or less.
Because tributaries are switched in their ingress and egress nodes no
squelching is required and protection channels not required for
protection may carry pre-empted extra traffic.
A mechanism is required to auto-provision the ring maps and maintain
their consistency.
In two fibers scenario failure of Links W2 and P2 triggers the MS-
SPRing protection.
Traffic is protected using this path:
TNE-A <-Link WP1-> TNE-B [Internal Bridge] <-Link WP1-> TNE-A <-Link
WP3-> TNE F <-Link WP5-> TNE-E <-Link WP6-> TNE-D <-Link WP4-> TNE-C
[Internal Bridge] <- Link WP4 -> TNE-D: AU Timeslot 1 is used on all
the links.
The following picture illustrates the state of the network after the
recovery from the failure done by means of MS-SPRing mechanism.
|
TNE A v TNE B TNE C
+------------+ +------------+ +------------+
| | | | | | |
| | | | | | |
| | | | | | |
| +-|----------->|------+ |xxxxxxxxxxx>| +-----+ |
| | WP1 | | | WP2 | | | |
| +----|<-----------|------+ |<-----------| ^ v |
| | | | | | | | |
| | | | | | | | |
| | | | | | | | |
+------------+ +------------+ +------------+
^ | ^ |
| | | |
| | | |
| WP3 | WP Links Resources are | WP4 |
Caviglia Expires - April 2006 [Page 9]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
| | 50% Worker | |
| | 50% Protection | |
| v | v
+------------+ +------------+ +------------+
| | | | | | | | |
| | | | | | | | |
| | | | | | | | |
| +----|----------->|------------|----------->|---+ | |
| | WP5 | | WP6 | | |
| |<-----------| |<-----------| | |
| | | | | | |
| | | | | | |
| | | | | | |
+------------+ +------------+ +------------+
TNE F TNE E TNE D v
Figure 1-5: MS-SPRing two fibers ring-switching
Figure 1-3 and 1-5 illustrates the so-called ôring-switchingö
protection.
In four-fiber MS-SPRing there exists also ôspan-switchingö and in
this case only the working fibers are cut while the protection fibers
remain intact. See figure 1-6. The protection switch affects the
extra traffic in span P2.
1
TNE A v TNE B TNE C
+----------|-+ +------------+ +------------+
| | | | | | |
| +------------->----->----+ |XXXXXXXXXXXX| +--------+ |
| | W1 | | | W2 | | | |
| |<-----------| v |XXXXXXXXXXXX| ^ | |
| | | | | | | | |
| |===========>| +---===========>--+ v |
| | P1 | | P2 | | |
| |<===========| |<===========| | |
| | | | | | |
+------------+ +------------+ +----------|-+
^ | ^ l ^ l ^ |
| | l l l l | |
| | l l l l | |
|W3| lP3l ------------ Working Link lP4l |W4|
| | l l llll and === Protection Link l l | |
| | l l l l | |
| v l v l v | v
+------------+ +------------+ +----------|-+
| | | | | | |
| |===========>| |===========>| | |
Caviglia Expires - April 2006 [Page 10]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
| | P5 | | P6 | | |
| |<===========| |<===========| | |
| | | | | v |
| |----------->| |----------->| | |
| | W5 | | W6 | | |
| |<-----------| |<-----------| | |
| | | | | | |
+------------+ +------------+ +----------|-+
TNE F TNE E TNE D v
1
Figure 1-6: MS-SPRing span-switch
1.3 Time Slot Interchange (TSI)
TSI is the connection function capability of changing the time slot
position of through-connected traffic (i.e. traffic that is not added
or dropped from the node). At present there is no TSI capability
specified in nodes belonging to a MS-SPRing sub network. Channels at
MS-SPRing nodeÆs egress are nailed to the same timeslot used by the
same channels at nodeÆs ingress. This is a currently required
condition to ensure MS-SPRing correct operation.
1.4 Squelching
Squelching is defined as the process of inserting AU-AIS in order to
prevent misconnections. The squelching process application over
traffic results in an ôall 1Æsö signal.
1.4.1 Squelching to avoid misconnected traffic
To perform a ring switch, the protection channels are essentially
shared among each span of the ring. Also, extra traffic may reside in
the protection channels when the protection channels are not
currently being used to restore normal traffic transported on the
working channels. Thus, each protection channel time slot is subject
to use by multiple services (services from the same time slot but on
different spans, and service from extra traffic). With no extra
traffic on the ring, under certain multiple point failures, such as
those that cause node(s) isolation, services (from the same time slot
but on different spans) may contend for access to the same protection
channel time slot. This yields a potential for misconnected traffic.
With extra traffic on the ring, even under single point failures,
normal traffic on the working channels may contend for access to the
same protection channel time slot that carries the extra traffic.
This also yields a potential for misconnected traffic.
Without a mechanism to prevent misconnection, the following failure
scenario would yield misconnections.
Caviglia Expires - April 2006 [Page 11]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
Referring to Figure 1-1, two circuits traverse the MS-SPRing namely
circuit Q and R the path that they traverse is:
Circuit R: TNE-A <-Link WP3 AU 1-> TNE-F
Circuit Q: TNE-A <-Link WP1 AU 1-> TNE-B <-Link WP2 AU 1-> TNE-C
Suppose a cut in both the spans between nodes A and F and between
nodes A and B (isolating node A, that is the same as a TNE A failure)
causes circuits Q and R to attempt to access time slot #1P on the
protection channels. The mechanism for the MS-SPRing protection is
as depicted in previous sub-section.
A potential misconnection is determined by identifying the nodes that
will act as the switching nodes for a bridge request, and by
examining the traffic that will be affected by the switch. The
switching nodes can be determined from the node addresses in the K1
and K2 bytes. The switching nodes determine the traffic affected by
the protection switch from the information contained in their ring
maps and from the identifications of the switching nodes. Potential
misconnections shall be squelched by inserting the appropriate AU-AIS
in those time slots where misconnected traffic could occur.
Specifically, the traffic that is sourced or dropped at the node(s)
isolated from the ring by the failure shall be squelched. For rings
operating at an AU-4 level, this squelching occurs at the switching
nodes. AU level squelching occurs for the normal or extra traffic
into or out of the protection channels (i.e. normal traffic into or
out of working channels is never squelched).
For example, consider a segment of a ring consisting of three nodes,
A, B, and C where B has failed. In a typical scenario, both A and C
will send bridge requests destined for B. When A sees the bridge
request from C, and sees that B is between A and C (from the node
map) it can deduce that B is isolated from the ring. A and C will use
their respective maps to find out which channels are added or dropped
by B. A and C will squelch these channels before the ring switch is
performed by inserting AU-AIS. Thus, any node on the ring that was
connected to B will now receive AIS on those channels.
Each of the ring maps, then, shall contain at minimum:
1. a ring map that contains information regarding the order in which
the nodes appear on the ring;
2. a cross-connect map that contains the AU-4 time-slot assignments
for traffic that is both terminated at that node and passed-
through that node;
3. a squelch table that contains, for each of these AU-4 time slots,
the node addresses at which the traffic enters and exits the ring;
and
Caviglia Expires - April 2006 [Page 12]
draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
4. an optional indication of whether the AU is being accessed at the
lower order VC level somewhere on the ring (not covered by this
Document)
An example of such ring maps and squelching table is given in Section
1.1.
2. GMPLS requirements imposed by MS-SPRing
When setting up (either via traditional management plane actions or
via GMPLS control plane protocols) a data plane circuit going across
parts of the network that include MS-SPRing based protection
mechanism, it MUST be done according to MS-SPRing specific needs as
explained in previous sections.
2.1 LSP Set-Up
When GMPLS is used for circuit setup, the presence of MS-SPRing rings
in the network results in a set of requirements that have to be
handled at control plane level.
Basically when setting up an LSP over a data plane that includes TNEs
connected in MS-SPRing scheme, the control plane taking care of
routing and signaling of such LSP has to behave in a way that
1. the label(corresponding to a SDH/SONET timeslot) must not be
changed within the MS-SPRing ring traversed;
2. involved TNE MUST have all the information necessary to fill the
Ring Map.
From the NMS point of view it is important to be able to univocally
identify a ring in the network, this leads to the Ring Identifier
(RingId) concept. Even if the RingId is not needed for the MS-SPRing
operation it is needed for management issues.
Given the above there is the requirement to add the RingId
information to the information stored when an LSP traverses a node
that is part of a MS-SPRing.
The above requirements can be satisfied either via signaling only or
signaling plus routing.
2.2 Data Plane and Control Plane misalignment
When a failure affects an LSP that traverse an MS-SPRing protected
ring the data plane scenario is the same as in Figure 1-3.
Data Traffic is flowing through:
Node-A<-->Node-B<-->Node-A<-->Node-F<-->Node-E<-->Node-D<-->Node-C<--
>Node-D while from a control plane perspective traffic is still
flowing through Node-A<-->Node-B<-->Node-C<-->Node-D.
It may be noted that the loop Node-A<-->Node-B<-->Node-A can be
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draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
bridged and releases the protection channels for use by extra traffic
thus increasing the availability of extra traffic, however this
requires an update to the Ring map.
The misalignment between control and data plane arises because the
control plane is un-aware of the failure.
In this case there is the need for a control plane data plane re-
alignment.
When, without the intervention of the control plane, inherent
protection scheme changes some characteristic of an LSP there should
be a communication mechanism that re-aligns control plane and data
plane information.
2.3 Interworking between GMPLS restoration and MS-SPRing Protection
A hold-off timer e.g. 50 ms should be provided in order to allow MS-
SPRing protection to react firstly to a failure.
In case of failures unrecoverable by MS-SPRing the hold-off elapse
triggering the control plane recovery mechanism, of course in order
to recover the traffic control plane and data plane must be aligned,
see above Section about control plane and data plane misalignment.
3. Security Considerations
This document does not introduce any additional Security issues.
References
[1] Mannie, E. öGeneralized Multi-Protocol Label Switching (GMPLS)
Architectureö Standard Track, RFC 3945, October 2004
[2] ITU-T G.707 ôNetwork node interface for the synchronous digital
hierarchy (SDH)ö, December 2003
[3] ITU-T G.841 "Types and characteristics of SDH network protection
architectures", October 1998.
[4] Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996
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draft-caviglia-ccamp-GMPLS-MSSPRing-Req-00 October 2005
Acknowledgments
Greg Bernstein
Grotto Networking
Email: gregb@grotto-networking.com
Author's Addresses
Diego Caviglia
Marconi
V. A. Negrone 16/A
16153 Cornigliano (GE)
Italy
Phone: +390106003736
Email: diego.caviglia@Marconi.com
Huub van Helvoort
Huawei Technologies Ltd.
Kolkgriend 38
NL-1356 BC Almere
the Netherlands
Phone: +31365315076
Email: hhelvoort@chello.nl
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