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
+---------------------------------------+-----------------------+
|         FlexE Group Number            |        Reserved       |
+---------------------------------------+-----------------------+
| Client (being added or removed) |  Flags                      |
+----------------+--------------------------------+-------------+
|  PHY Number    |     Rate       | Granularity   | Unav. Slots |
+----------------+----------------+-------------+-+-------------+
|  Slot Map (0 to 19 slot for 100G PHY)         |   Reserved    |
+-----------------------------------------------+---------------+
|                           ......                              |
+----------------+----------------+---------------+-------------+
|   PHY Number   |     Rate       |  Granularity  | Unav.  Slots|
+----------------+----------------+-------------+-+-------------+
|  Slot Map (0 to 19 slot for 100G PHY)         |   Reserved    |
+-----------------------------------------------+---------------+
|                           ......                              |
+---------------------------------------------------------------+
		 
                    
                    

Figure 1: FlexE Generalized Label

• FlexE Group Number (20 bits) fields allows to check that the correct PHY is being received from the correct group number [OIFFLEXE1].
• Client (16 bits) field indicates which of the FlexE clients is mapped into a given calendar slot in the A and B calendar configurations for the sub-calendar carried over that PHY [OIFFLEXE1].
• Flags (8 bits) field is reserved for future use. [OIFFLEXE1].
• PHY Number (8 bits) field is used to identify PHY by a number in the 1-254 range [OIFFLEXE1].
• Rate (8 bits) field is used to specify rate of the given PHY number. Currently [OIFFLEXE1] has defined a 100G PHY rate. In the future, this field may be used to indicate other PHY rates (e.g., 400G).
• Granularity (8 bits) field is used to indicate granularity of the FlexE calendar. Currently [OIFFLEXE1] has defined 5G granularity. In future, this field can have additional values, as further granularity are defined.
• Slot Map (20 bits) field is used to indicate which calendar slots of the associated PHY number is assigned to a given FlexE client. For a PHY with a rate of 100G and granularity of 5G, the slot map consists of 20 slots (0-19 range). In the future, when other PHY rates and/or calender granularities are defined, the slot map size for a PHY can be derived based on the Rate and Granularity fields values.
• Unavailable Slots (8 bits) field is used to indicate the number of unavailable calendar slots (0-19 range) for example due to transport network constraints (i.e., no FlexE client should be assigned to the unused slots). Unavailable slots are placed at the end of each relevant sub-calendar (i.e., the highest numbered slots) [OIFFLEXE1].

3.2. FlexE Group Initial Setup

Suppose it is desired to establish a FlexE group containing two 100G PHYs between node A and B. This can be accomplished by having node A send a RSVP-TE message containing a FlexE generalized label to node B with the following field values:

1. FlexE Group Number = 100 (say), Client = 0x0000 (i.e., no client)
2. First PHY Number = 5 (say), Rate= 100G, Granularity=5G, Unavailable Slots=0, Slot Map = 0-19 bit set to 0 (i.e., all slots available)
3. Second PHY Number = 7 (say), Rate-100G, Granularity=5G, Unavailable Slots=0, Slot Map = 0-19 bit set to 0 (i.e., all slots available)

Thus both ends will have the same FlexE group configuration and the FlexE group can be brought in service.

3.3. FlexE Client Setup

Suppose it is desired to establish a FlexE client of rate 50G node A and B to the FlexE group created in the Section 3.2. This can be accomplished by having node A send a RSVP-TE message containing a FlexE generalized label to node B with the following field values:

1. FlexE Group Number = 100, Client = 0x0001 (i.e., client id = 1)
2. First PHY Number = 5 , Rate= 100G, Granularity=5G, Unavailable Slots=0, Slot Map = 0 to 4 bit set to 1 (i.e., 25G on this PHY)
3. Second PHY Number = 7, Rate-100G, Granularity=5G, Unavailable Slots=0, Slot Map = 0 to 4 bit set to 1 (i.e., 25G on this PHY)

3.4. Related Work

The generalized label described in [FLEXESIGNAL] is limited to 100G PHY only. In contrast, the generalized label proposed in this document is extendible to PHY rates beyond 100G. Specifically, the label proposed in this document introduces additional per PHY fields, namely, Rate and Granularity. This enables to drive per PHY calendar size information in the face of calendar granularity and/or calendar size changes that might be required for PHY rates beyond 100G (such as 400G).

4. Acknowledgements

5. IANA Considerations

This memo includes no request to IANA.

6. Security Considerations

None.

7. References

7.1. Normative References

[FLEXEROUTING]	IETF, "FlexE GMPLS Routing Extension, draft-pithewan-ccamp-flexe-routing-extensions", June 2016.
[FLEXESIGNAL]	IETF, "RSVP-TE Signaling Extensions in support of Flexible Ethernet networks, draft-wang-ccamp-flexe-signaling-00", March 2016.
[FLEXEUSECASES]	IETF, "FlexE Usecases, draft-hussain-ccamp-flexe-usecases", June 2016.
[OIFFLEXE1]	OIF, "FLex Ethernet Implementation Agreement Version 1.0 (OIF-FLEXE-01.0)", March 2016.
[RFC2119]	Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3471]	IETF, "G Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description, RFC3471", January 2003.
[RFC3473]	IETF, "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions, RFC3473", January 2003.

7.2. Informative References

[OIFMLG3]

OIF, "Multi-Lane Gearbox Implementation Agreement Version 3.0 (OIF-MLG-3.0)", April 2016.

Appendix A. Additional Stuff

This becomes an Appendix.

Authors' Addresses