Future TRILL Work 2

November 2010 Future TRILL Work 1

Future TRILL Work 2

Donald Eastlake 3rd

155 Beaver Street

Milford, MA 01757 USA

[email protected]

mailto:[email protected]


Future TRILL Work 2

• Future TRILL Work corresponding to specific points in the New Charter:1. ARP/ND Optimization and ESADI

2. Multi-Level RBridge Routing

3. Data Center Bridging

4. Fine Grained Labeling

ARP/ND

Opti

mization

and

ESADI

• ARP/ND Optimization has been part of the idea for RBridges and TRILL since the initial paper by Radia Perlman in 2004.

• ESADI (End Station Address Distribution Information) is an optional highly reliable VLAN scoped method for sharing data between RBridges, such as connected end station MAC addresses.

• By using ESADI to distribute Layer 2 <-> Layer 3 address pairs, the resulting data can be used to respond locally to ARP/ND queries reducing multi-destination frame traffic.


ARP/ND

Opti

mization

and

ESADI

• If all the RBridges in a VLAN within an RBridge campus have ESADI enabled, gratuitous ARPs in that VLAN can be terminated at the ingress RBridge, the information they are providing can be distributed via ESADI and, where appropriate, regenerated at what would have been egress RBridges.

• For VLANs with many end stations, gratuitous ARP should not update fast path MAC tables except for addresses actually in use.



Future TRILL Work 2





Data Center Bridging

• draft-eastlake-trill-rbridge-dcb-00.txt• Three standards being specified in 802.1 to

allocate bandwidth and eliminate frame loss due to queue overflow.– 802.1Qbb – per priority PAUSE

• 802.3bd – new PAUSE frame format

– 802.1Qaz – allocation of link bandwidth to traffic classes

– 802.1Qau – Congestion Notification. Facilities to limit flows at their originating end station




• The first two, 802.1Qbb and 802.1Qaz, can be implemented entirely within the ports of an RBridge. No TRILL processing changes but support should be announced in the LSP.

• 802.1Qau requires a minor extension to TRILL, which has been discussed in the TRILL WG since at least 2007, and support should be announce in the LSP.



• TRILL extension required because of the case where a TRILL-ignorant bridge between RBridges generates a Congestion Notification Message.

• The previous-hop RBRidge must adjust the CNM so it is returned to the true origin in the campus.

RBridgeRBridge RBridgeRBridgeOriginOrigin Bridge(s)Bridge(s)

CNMAdjusted CNM


Future TRILL Work 2






Fine Grained Labeling

• Requirements, in approximate order by importance with the most important first:1. Many cloud computing applications and data centers

require more than 4K labels of configurable isolation.

2. There should be provision for frame priority within the cloud / data center while preserving the original priority.

3. Due to the difficulty of all nodes optimally routing multi-destination frames by the many values of a fine grained label, some easier to route aggregate label should be available.


Fine Grained Labeling

• (Requirements, continued…)4. RBridges ignorant of file grained labeling should

usefully and safely route and handle frames that have fine grained labeling.

5. It would be desirable to use existing standardized field types rather than to create a new flavor of label.

Solution

• Use the 24-bit IEEE 802.1 Service Instance identifier as the fine grained label and

• Use a VLAN ID as the aggregated routing label.

• The can be done in at least two ways:A. Insert an 802.1ah tag in the encapsulated frame; or

B. Insert the 802.1ah tag body camouflaged by a TRILL Header Option.


Solution A


OuterMACAddrs

12

InnerCust.VLAN

4

TRILLEthertype& Header

8

Payload

InnerMACAddrs

12

OuterMACAddrs

12

Cust.VLAN

.4


8

InnerMACAddrs

12

DataCenterVLAN

4

802.1ahEthertype

.2

PriorityService

ID4

InnerMAC

Addrs12

Payload

802.1ah body

Solution B


OuterMACAddrs

12

InnerCust.VLAN

4


8

Payload

InnerMACAddrs

12

OuterMACAddrs

12

DataCenterVLAN

4


8

TLV &

Cust.VLAN2 + 2

PriorityService

ID4

Payload

Options Size = 3

BitOpt.Area

4

InnerMACAddrs

12

802.1ah body

Solution B• From view of a fine grained labels ignorant RBridge

• From the view of a fine grained aware RBridge


Payload

OuterMACAddrs

12

DataCenterVLAN

4


8

TLV &

Cust.VLAN2 + 2

PriorityService

ID4

BitOpt.Area

4

InnerMACAddrs

12

optionsoptions

Payload

OuterMACAddrs

12

DataCenterVLAN

4


8

TLV &

Cust.VLAN2 + 2

PriorityService

ID4

BitOpt.Area

4

InnerMACAddrs

12

802.1ah Body802.1ah Body

A versus B Comparison

• Solution A– Adds 20 bytes– Fine grained label ignorant RBridges cannot

parse the 802.1ah tag or anything past it.

• Solution B– Adds 12 bytes– Fine grained label ignorant RBridges

automatically skip the option and can properly parse the rest of the frame.


More Details on B

• Solution B

– Must be the last TLV option for parsing by fine grained labeling ignorant RBridge to work.

– But, to be sure that the frame is not decapsulated and delivered outside its fine grained label, the option needs to be handled as critical.


Future TRILL Work 2

Documents

Transcript of Future TRILL Work 2