the labels must reflect the order of the payloads to concatenate (not
the physical order of time-slots). The above representation limits
virtual concatenation to remain within a single (component) link; it
imposes, as such, a restriction compared to the ANSI [T1.105]/ ITU-T
[G.707] recommendations. The standard definition for virtual
concatenation allows each virtual concatenation components to travel
over diverse paths. Within GMPLS, virtual concatenation components
must travel over the same (component) link if they are part of the
same LSP. This is due to the way that labels are bound to a
(component) link. Note, however, that the routing of components on
different paths is indeed equivalent to establishing different LSPs,
each one having its own route. Several LSPs can be initiated and
terminated between the same nodes, and their corresponding components
can then be associated together (i.e., virtually concatenated).
In case of multiplication (i.e., using the multiplier transform), the
explicit ordered list of all labels that take part in the Final
Signal is given. This ordered list of labels is encoded as a
sequence of 32-bit label values (as defined in this section) of the
Generalized Label object (Class-Num = 16, C-Type = 2)/TLV (0x0825).
In case of multiplication of virtually concatenated signals, the
explicit ordered list of the set of labels that take part in the
Final Signal is given. The first set of labels indicates the time-
slots occupied by the first virtually concatenated signal, the second
set of labels indicates the time-slots occupied by the second
virtually concatenated signal, and so on. The above representation
limits multiplication to remain within a single (component) link.
The format of the label for SONET and/or SDH TDM-LSR link is
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| S | U | K | L | M |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This is an extension of the numbering scheme defined in [G.707],
Sections 7.3.7 through 7.3.13; i.e., the (K, L, M) numbering. Note
that the higher order numbering scheme defined in [G.707], Sections
7.3.1 through 7.3.6, is not used here.
Each letter indicates a possible branch number starting at the parent
node in the multiplex structure. Branches are considered as being
numbered in increasing order, starting from the top of the
multiplexing structure. The numbering starts at 1; zero is used to
indicate a non-significant or ignored field.
When a field is not significant or ignored in a particular context,
it MUST be set to zero when transmitted and ignored when received.
When a hierarchy of SONET/SDH LSPs is used, a higher-order LSP with a
given bandwidth can be used to carry lower-order LSPs. Remember that
a higher-order LSP is established through a SONET/SDH higher-order
path layer network, and a lower-order LSP through a SONET/SDH lower-
order path layer network (see also ITU-T G.803, Section 3, for the
corresponding definitions). In this context, the higher-order
SONET/SDH LSP behaves as a "virtual link" with a given bandwidth
(e.g., VC-3); it may also be used as a Forwarding Adjacency. A
lower-order SONET/SDH LSP can be established through that higher-
order LSP. Since a label is local to a (virtual) link, the highest
part of that label (i.e., the S, U, and K fields) is non-significant
and is set to zero; i.e., the label is "0,0,0,L,M". Similarly, if
the structure of the lower-order LSP is unknown or not relevant, the
lowest part of that label (i.e., the L and M fields) is non-
significant and is set to zero; i.e., the label is "S,U,K,0,0".
For instance, a VC-3 LSP can be used to carry lower-order LSPs. In
that case, the labels allocated between the two ends of the VC-3 LSP
for the lower-order LSPs will have S, U, and K set to zero (i.e.,
non-significant) while L and M will be used to indicate the signal
allocated in that VC-3.
In case of tunneling, such as VC-4 containing VC-3 containing
VC-12/VC-11, where the SUKLM structure is not adequate to represent
the full signal structure, a hierarchical approach must be used;
i.e., per layer network signaling.
The possible values of S, U, K, L, and M are defined as follows:
1. S=1->N is the index of a particular STS-3/AUG-1 inside an
STS-N/STM-N multiplex. S is only significant for SONET STS-N
(N>1) and SDH STM-N (N>0). S must be 0 and ignored for STS-1 and
STM-0.
2. U=1->3 is the index of a particular STS-1_SPE/VC-3 within an
STS-3/AUG-1. U is only significant for SONET STS-N (N>1) and SDH
STM-N (N>0). U must be 0 and ignored for STS-1 and STM-0.
3. K=1->3 is the index of a particular TUG-3 within a VC-4. K is
only significant for an SDH VC-4 structured in TUG-3s. K must be
0 and ignored in all other cases.
4. L=1->7 is the index of a particular VT_Group/TUG-2 within an
STS-1_SPE/TUG-3 or VC-3. L must be 0 and ignored in all other
cases.
5. M is the index of a particular VT1.5_SPE/VC-11, VT2_SPE/VC-12, or
VT3_SPE within a VT_Group/TUG-2. M=1->2 indicates a specific VT3
SPE inside the corresponding VT Group; these values MUST NOT be
used for SDH, since there is no equivalent of VT3 with SDH.
M=3->5 indicates a specific VT2_SPE/VC-12 inside the
corresponding VT_Group/TUG-2. M=6->9 indicates a specific
VT1.5_SPE/VC-11 inside the corresponding VT_Group/TUG-2.
Note that a label always has to be interpreted according the
SONET/SDH traffic parameters; i.e., a label by itself does not allow
knowing which signal is being requested (a label is context
sensitive).
The label format defined in this section, referred to as SUKLM, MUST
be used for any SONET/SDH signal requests that are not transparent;
i.e., when all Transparency (T) bits defined in Section 2.1 are set
to zero. Any transparent STS-1/STM-0/STS-3*N/STM-N (N=1, 4, 16, 64,
256) signal request MUST use a label format as defined in [RFC3471].
The S encoding is summarized in the following table:
S SDH SONET
------------------------------------------------
0 other other
1 1st AUG-1 1st STS-3
2 2nd AUG-1 2nd STS-3
3 3rd AUG-1 3rd STS-3
4 4rd AUG-1 4rd STS-3
: : :
N Nth AUG-1 Nth STS-3
The U encoding is summarized in the following table:
U SDH AUG-1 SONET STS-3
-------------------------------------------------
0 other other
1 1st VC-3 1st STS-1 SPE
2 2nd VC-3 2nd STS-1 SPE
3 3rd VC-3 3rd STS-1 SPE
The K encoding is summarized in the following table:
K SDH VC-4
---------------
0 other
1 1st TUG-3
2 2nd TUG-3
3 3rd TUG-3
The L encoding is summarized in the following table:
L SDH TUG-3 SDH VC-3 SONET STS-1 SPE
-------------------------------------------------
0 other other other
1 1st TUG-2 1st TUG-2 1st VTG
2 2nd TUG-2 2nd TUG-2 2nd VTG
3 3rd TUG-2 3rd TUG-2 3rd VTG
4 4th TUG-2 4th TUG-2 4th VTG
5 5th TUG-2 5th TUG-2 5th VTG
6 6th TUG-2 6th TUG-2 6th VTG
7 7th TUG-2 7th TUG-2 7th VTG
The M encoding is summarized in the following table:
M SDH TUG-2 SONET VTG
-------------------------------------------------
0 other other
1 - 1st VT3 SPE
2 - 2nd VT3 SPE
3 1st VC-12 1st VT2 SPE
4 2nd VC-12 2nd VT2 SPE
5 3rd VC-12 3rd VT2 SPE
6 1st VC-11 1st VT1.5 SPE
7 2nd VC-11 2nd VT1.5 SPE
8 3rd VC-11 3rd VT1.5 SPE
9 4th VC-11 4th VT1.5 SPE
Examples of Labels
Example 1: the label for the STS-3c_SPE/VC-4 in the Sth
STS-3/AUG-1 is: S>0, U=0, K=0, L=0, M=0.
Example 2: the label for the VC-3 within the Kth-1 TUG-3 within
the VC-4 in the Sth AUG-1 is: S>0, U=0, K>0, L=0, M=0.
Example 3: the label for the Uth-1 STS-1_SPE/VC-3 within the Sth
STS-3/AUG-1 is: S>0, U>0, K=0, L=0, M=0.
Example 4: the label for the VT6/VC-2 in the Lth-1 VT Group/TUG-2
in the Uth-1 STS-1_SPE/VC-3 within the Sth STS-3/AUG-1
is: S>0, U>0, K=0, L>0, M=0.
Example 5: the label for the 3rd VT1.5_SPE/VC-11 in the Lth-1 VT
Group/TUG-2 within the Uth-1 STS-1_SPE/VC-3 within the
Sth STS-3/AUG-1 is: S>0, U>0, K=0, L>0, M=8.
Example 6: the label for the STS-12c SPE/VC-4-4c which uses the
9th STS-3/AUG-1 as its first timeslot is: S=9, U=0,
K=0, L=0, M=0.
In case of contiguous concatenation, the label that is used is the
lowest label (value) of the contiguously concatenated signal, as
explained before. The higher part of the label indicates where the
signal starts, and the lowest part is not significant.
In case of STM-0/STS-1, the values of S, U, and K must be equal to
zero, according to the field coding rules. For instance, when a VC-3
in an STM-0 is requested, the label is S=0, U=0, K=0, L=0, M=0. When
a VC-11 in a VC-3 in an STM-0 is requested, the label is S=0, U=0,
K=0, L>0, M=6..9.
Note: when a Section/RS or Line/MS transparent STS-1/STM-0/
STS-3*N/STM-N (N=1, 4, 16, 64, 256) signal is requested, the SUKLM
label format and encoding is not applicable, and the label encoding
MUST follow the rules defined in [RFC3471], Section 3.2.
4. Acknowledgements
Valuable comments and input were received from the CCAMP mailing
list, where outstanding discussions took place.
The authors would like to thank Richard Rabbat for his valuable
input, which lead to this revision.
5. Security Considerations
This document introduces no new security considerations to either
[RFC3473] or [RFC3472]. GMPLS security is described in Section 11 of
[RFC3471] and refers to [RFC3209] for RSVP-TE and to [RFC3212] for
CR-LDP.
6. IANA Considerations
Three values defined by IANA for RFC 3946 now apply to this document.
Two RSVP C-Types in registry:
http://www.iana.org/assignments/rsvp-parameters
- A SONET/SDH SENDER_TSPEC object: Class = 12, C-Type = 4 (see
Section 2.2).
- A SONET/SDH FLOWSPEC object: Class = 9, C-Type = 4 (see Section
2.2).
One LDP TLV Type in registry:
http://www.iana.org/assignments/ldp-namespaces
- A type field for the SONET/SDH Traffic Parameters TLV (see Section
2.3).
Contributors
Contributors are listed in alphabetical order:
Stefan Ansorge (Alcatel)
Lorenzstrasse 10
70435 Stuttgart, Germany
EMail: stefan.ansorge@alcatel.de
Peter Ashwood-Smith (Nortel)
PO. Box 3511 Station C,
Ottawa, ON K1Y 4H7, Canada
EMail:petera@nortelnetworks.com
Ayan Banerjee (Calient)
5853 Rue Ferrari
San Jose, CA 95138, USA
EMail: abanerjee@calient.net
Lou Berger (Movaz)
7926 Jones Branch Drive
McLean, VA 22102, USA
EMail: lberger@movaz.com
Greg Bernstein (Ciena)
10480 Ridgeview Court
Cupertino, CA 94014, USA
EMail: greg@ciena.com
Angela Chiu (Celion)
One Sheila Drive, Suite 2
Tinton Falls, NJ 07724-2658
EMail: angela.chiu@celion.com
John Drake (Calient)
5853 Rue Ferrari
San Jose, CA 95138, USA
EMail: jdrake@calient.net
Yanhe Fan (Axiowave)
100 Nickerson Road
Marlborough, MA 01752, USA
EMail: yfan@axiowave.com
Michele Fontana (Alcatel)
Via Trento 30,
I-20059 Vimercate, Italy
EMail: michele.fontana@alcatel.it
Gert Grammel (Alcatel)
Lorenzstrasse, 10
70435 Stuttgart, Germany
EMail: gert.grammel@alcatel.de
Juergen Heiles (Siemens)
Hofmannstr. 51
D-81379 Munich, Germany
EMail: juergen.heiles@siemens.com
Suresh Katukam (Cisco)
1450 N. McDowell Blvd,
Petaluma, CA 94954-6515, USA
EMail: suresh.katukam@cisco.com
Kireeti Kompella (Juniper)
1194 N. Mathilda Ave.
Sunnyvale, CA 94089, USA
EMail: kireeti@juniper.net
Jonathan P. Lang (Calient)
25 Castilian
Goleta, CA 93117, USA
EMail: jplang@calient.net
Fong Liaw (Solas Research)
EMail: fongliaw@yahoo.com
Zhi-Wei Lin (Lucent)
101 Crawfords Corner Rd
Holmdel, NJ 07733-3030, USA
EMail: zwlin@lucent.com
Ben Mack-Crane (Tellabs)
EMail: ben.mack-crane@tellabs.com
Dimitrios Pendarakis (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA
EMail: dpendarakis@tellium.com
Mike Raftelis (White Rock)
18111 Preston Road
Dallas, TX 75252, USA
Bala Rajagopalan (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA
EMail: braja@tellium.com
Yakov Rekhter (Juniper)
1194 N. Mathilda Ave.
Sunnyvale, CA 94089, USA
EMail: yakov@juniper.net
Debanjan Saha (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA
EMail: dsaha@tellium.com
Vishal Sharma (Metanoia)
335 Elan Village Lane
San Jose, CA 95134, USA
EMail: vsharma87@yahoo.com
George Swallow (Cisco)
250 Apollo Drive
Chelmsford, MA 01824, USA
EMail: swallow@cisco.com
Z. Bo Tang (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA
EMail: btang@tellium.com
Eve Varma (Lucent)
101 Crawfords Corner Rd
Holmdel, NJ 07733-3030, USA
EMail: evarma@lucent.com
Yangguang Xu (Lucent)
21-2A41, 1600 Osgood Street
North Andover, MA 01845, USA
EMail: xuyg@lucent.com
Appendix 1. Signal Type Values Extension for VC-3
This appendix defines the following optional additional Signal
Type value for the Signal Type field of Section 2.1:
Value Type
----- ---------------------
20 "VC-3 via AU-3 at the end"
According to the ITU-T [G.707] recommendation, a VC-3 in the TU-
3/TUG-3/VC-4/AU-4 branch of the SDH multiplex cannot be structured in
TUG-2s; however, a VC-3 in the AU-3 branch can be. In addition, a
VC-3 could be switched between the two branches, if required.
A VC-3 circuit could be terminated on an ingress interface of an LSR
(e.g., forming a VC-3 forwarding adjacency). This LSR could then
want to demultiplex this VC-3 and switch internal low-order LSPs.
For implementation reasons, this could be only possible if the LSR
receives the VC-3 in the AU-3 branch. For example, for an LSR not
able to switch internally from a TU-3 branch to an AU-3 branch on its
incoming interface before demultiplexing and then switching the
content with its switch fabric.
In that case, it is useful to indicate that the VC-3 LSP must be
terminated at the end in the AU-3 branch instead of the TU-3 branch.
This is achieved by using the "VC-3 via AU-3 at the end" signal type.
This information can be used, for instance, by the penultimate LSR to
switch an incoming VC-3 received in any branch to the AU-3 branch on
the outgoing interface to the destination LSR.
The "VC-3 via AU-3 at the end" signal type does not imply that the
VC-3 must be switched via the AU-3 branch at some other places in the
network. The VC-3 signal type just indicates that a VC-3 in any
branch is suitable.
Annex 1. Examples
This annex defines examples of SONET and SDH signal coding. The
objective is to help the reader to understand how the traffic
parameter coding works and not to give examples of typical SONET or
SDH signals.
As stated above, signal types are Elementary Signals to which
successive concatenation, multiplication, and transparency transforms
can be applied to obtain Final Signals.
1. A VC-4 signal is formed by the application of RCC with value 0,
NCC with value 0, NVC with value 0, MT with value 1, and T with
value 0 to a VC-4 Elementary Signal.
2. A VC-4-7v signal is formed by the application of RCC with value
0, NCC with value 0, NVC with value 7 (virtual concatenation of
7 components), MT with value 1, and T with value 0 to a VC-4
Elementary Signal.
3. A VC-4-16c signal is formed by the application of RCC with value
1 (standard contiguous concatenation), NCC with value 16, NVC
with value 0, MT with value 1, and T with value 0 to a VC-4
Elementary Signal.
4. An STM-16 signal with Multiplex Section layer transparency is
formed by the application of RCC with value 0, NCC with value 0,
NVC with value 0, MT with value 1, and T with flag 2 to an
STM-16 Elementary Signal.
5. An STM-4 signal with Multiplex Section layer transparency is
formed by the application of RCC with value 0, NCC with value 0,
NVC with value 0, MT with value 1, and T with flag 2 applied to
an STM-4 Elementary Signal.
6. An STM-256 signal with Multiplex Section layer transparency is
formed by the application of RCC with value 0, NCC with value 0,
NVC with value 0, MT with value 1, and T with flag 2 applied to
an STM-256 Elementary Signal.
7. An STS-1 SPE signal is formed by the application of RCC with
value 0, NCC with value 0, NVC with value 0, MT with value 1,
and T with value 0 to an STS-1 SPE Elementary Signal.
8. An STS-3c SPE signal is formed by the application of RCC with
value 1 (standard contiguous concatenation), NCC with value 1,
NVC with value 0, MT with value 1, and T with value 0 to an
STS-3c SPE Elementary Signal.
9. An STS-48c SPE signal is formed by the application of RCC with
value 1 (standard contiguous concatenation), NCC with value 16,
NVC with value 0, MT with value 1, and T with value 0 to an
STS-3c SPE Elementary Signal.
10. An STS-1-3v SPE signal is formed by the application of RCC with
value 0, NVC with value 3 (virtual concatenation of 3
components), MT with value 1, and T with value 0 to an STS-1 SPE
Elementary Signal.
11. An STS-3c-9v SPE signal is formed by the application of RCC with
value 1, NCC with value 1, NVC with value 9 (virtual
concatenation of 9 STS-3c), MT with value 1, and T with value 0
to an STS-3c SPE Elementary Signal.
12. An STS-12 signal with Section layer (full) transparency is
formed by the application of RCC with value 0, NCC with value 0,
NVC with value 0, MT with value 1, and T with flag 1 to an
STS-12 Elementary Signal.
13. A 3 x STS-768c SPE signal is formed by the application of RCC
with value 1, NCC with value 256, NVC with value 0, MT with
value 3, and T with value 0 to an STS-3c SPE Elementary Signal.
14. A 5 x VC-4-13v composed signal is formed by the application of
RCC with value 0, NVC with value 13, MT with value 5, and T with
value 0 to a VC-4 Elementary Signal.
The encoding of these examples is summarized in the following table:
Signal ST RCC NCC NVC MT T
--------------------------------------------------------
VC-4 6 0 0 0 1 0
VC-4-7v 6 0 0 7 1 0
VC-4-16c 6 1 16 0 1 0
STM-16 MS transparent 10 0 0 0 1 2
STM-4 MS transparent 9 0 0 0 1 2
STM-256 MS transparent 12 0 0 0 1 2
STS-1 SPE 5 0 0 0 1 0
STS-3c SPE 6 1 1 0 1 0
STS-48c SPE 6 1 16 0 1 0
STS-1-3v SPE 5 0 0 3 1 0
STS-3c-9v SPE 6 1 1 9 1 0
STS-12 Section transparent 9 0 0 0 1 1
3 x STS-768c SPE 6 1 256 0 3 0
5 x VC-4-13v 6 0 0 13 5 0
Normative References
[G.707] ITU-T Recommendation G.707, "Network Node Interface for
the Synchronous Digital Hierarchy", October 2000.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated