1. TRILL Header Extension Improvements
Donald Eastlake 3rd
Huawei Technologies
28 March 2011

2. TRILL Header Extensions
Updates from Beijing Meeting
Replace single (4-byte) first word of “bit encoded options” with two words:
First word now has a Flow ID and fewer flag bits
Optional second word has more flag bits
Tweak TLV encoding to provide more Types
Update ECN (Explicit Congestion Notification) option to correspond with RFC 6040
Update from mailing list
“Bit encoded options” -> “Extended Header Flags”
28 March 2011

3. TRILL Data Frame Format
Link Specific Header
TRILL Header
Header Extensions
Inner Ethernet DA
Inner Ethernet SA
Inner Frame
VLAN Tag
Payload
Link Specific Trailer
28 March 2011

4. Improvements
Multiple extension fields at a fixed offset from the start of the TRILL Header have been discussed.
Additional priority / QoS information
Fine grained data label
More extended flags
Saved VLAN tag
Other…
28 March 2011

5. Improvements
One solution is to provide for additional optional TRILL Header Extension words whose presence is indicated by the value of Op-Length.
28 March 2011

6. Improvements
The closer a field is to being a fixed size at a fixed offset, the easier it is to use it in the fast path.
These factors are more important for something referenced at each hop that something set at ingress and used only at egress.
TLV options, while very flexible, are hard for fast path hardware to use.
28 March 2011

7. TRILL Header, Base Protocol Draft
28 March 2011
TRILL Header, Base Protocol Draft
Flags OpLen Hops
Nicknames
| | Reserved
TLV Options
Critical Summary bits indicate if it is safe for a transit or egress RBridge that does not implement any extensions to process the frame.
28 March 2011

8. TRILL Header, After Beijing
28 March 2011
TRILL Header, After Beijing
Flags OpLen Hops
Nicknames
| |
Flow ID
More Flags
TLV Options
Critical Summary bits indicate if it is safe for a transit or egress RBridge that does not implement any extensions to process the frame.
Current: draft-ietf-trill-rbridge-options-04.txt
28 March 2011

9. TRILL Header, Improved • • • Flags OpLen Hops Nicknames | | . Flow ID
28 March 2011
TRILL Header, Improved
Flags OpLen Hops
Nicknames
| |
Flow ID
Fixed Extension Fields
Fixed Extension Fields
• • •
TLV Options
Critical Summary bits indicate if it is safe for a transit or egress RBridge that does not implement any extensions to process the frame.
28 March 2011

10. Improved Header Extensions Example
28 March 2011
Improved Header Extensions Example
(1)
Extended Flags | Flow ID
More Extended Flags | Other
(2)
Priority | Data Label
Saved VLAN Tag
TLV Options
First word present if OpLength is non-zero.
Presence of additional words independently indicated by Extended Flags info in the first word.
28 March 2011

11. Proposed WG Actions Rename “options” draft as “extensions” draft.
Update draft along the lines indicated in this presentation
Current draft: draft-ietf-trill-rbridge-options-04.txt
Issue Working Group Last Call on revised draft
28 March 2011

12. Donald Eastlake 3rd Huawei Technologies d3e3e3@gmail.com
28 March 2011
END
Donald Eastlake 3rd
Huawei Technologies
28 March 2011

13. Donald Eastlake 3rd Huawei Technologies d3e3e3@gmail.com
28 March 2011
Back Up Slides
Donald Eastlake 3rd
Huawei Technologies
28 March 2011

14. Nomenclature Change Approved on mailing list, from To TRILL Header
Bit Encoded Options + Flow ID
TLV Options To
TRILL Header
Extended Header Flags / Flow ID
TLV Options
28 March 2011

15. Current Header Extensions First 32 Bits
Present if OpLng in TRILL Header > 0
Flow ID, Non-zero if valid
C. I-t-E Bits
NC. I-t-E Bit
C. H-b-H Bits
NC. H-b-H Bits
Non-Critical Ingress-to-Egress TLV Option Present
Critical Ingress-to-Egress TLV Option Present
Non-Critical Hop-by-Hop TLV Option Present
More Extended Flags
Critical Ingress-to-Egress Summary Bit
Critical Hop-by-Hop Summary Bit
28 March 2011

16. Current Header Extensions Second 32 Bits
If “More Extended Flags” bit is a one, there are 4 bytes of additional extended header flags as follows:
Critical
Hop-by-Hop
Non-Critical
Hop-by-Hop
Critical
Ingress-to-Egress
Non-Critical
Ingress-to-Egress
28 March 2011