March 2007 68th IETF - Prague 1

TRILL Working Group

From draft 03 to draft 04

Dinesh Dutt, CiscoSilvano Gai, NuovaRadia Perlman, Sun

March 2007 From draft 03 to draft 04 2

Agenda

• Bridge vs RBridge: Reuse/Specify– SVL vs IVL– ST compatibility: to which extent?– Other 802.1 protocols compatibility?

• IS-IS TLV formats

March 2007 From draft 03 to draft 04 3

Bridge vs RBridge: Reuse/Specify

• Data Plane– What is leveraged from .1Q and what is new

• Learning– Do we support IVL and SVL?

• Control Plane– What versions of STP will we support – What about non-STP protocols such as

GARP, GVRP etc.

March 2007 From draft 03 to draft 04 4

Data Plane (1)

802.n 802.n

LLC LLC

LAN LAN

ISS ISS

ForwardingProcess

FilteringDatabase

EISSEIS

S

PortState

IngressRules

Bridge Port TX/RX Bridge Port TX/RX

PortState

IngressRules

Reuse Specify Not Sure

March 2007 From draft 03 to draft 04 5

Data Plane (2)

• From IEEE 802.1Q, TRILL uses:– Bridge port transmit and receive– EISS

• It includes port-and-protocol-based VLAN classification

– Port States• no new states are defined

– Ingress Rule / Egress Rule

March 2007 From draft 03 to draft 04 6

EISS (Enhanced Internal Sublayer Service)

• API that provides a normalized frame (independent of tagging) to the forwarding process:– Shall we assume that the RBridge’s interface is the same ?– Assumes that TRILL header encap/decap is part of forwarding

processEM_UNITDATA.indication (destination_address,source_address,mac_service_data_unit,priority,vlan_identifier,frame_check_sequence,canonical_format_indicator,rif_information (optional))

EM_UNITDATA.request (destination_address,source_address,mac_service_data_unit,priority,vlan_identifier,frame_check_sequence,canonical_format_indicator,rif_information (optional))

March 2007 From draft 03 to draft 04 7

Data Plane (3)

• TRILL specifies:– Forwarding Process

• Includes Encap/Decap of shim header

– Filtering database extension to:• Support TRILL encap decision• Identify Egress RBridge• Identify distribution tree for multi-destination

frames• Identify encapsulation and address to reach Next

Hop Rbridge

March 2007 From draft 03 to draft 04 8

Learning (1)

802.n 802.n

LLC LLC

LAN LAN

ISS ISS

FilteringDatabase

EISSEIS

S

IngressRules

Bridge Port TX/RX Bridge Port TX/RX

IngressRules

Reuse Specify Not Sure

IS-IS

March 2007 From draft 03 to draft 04 9

Learning (2)

• IEEE 802.1Q distinguishes between – VID: VLAN ID– FID: Filtering ID

• This allows:– IVL (Independent VLAN learning): one VID equal one FID– SVL (Shared VLAN learning): multiple VIDs map to one FID

• TRILL assumes the IVL model– It announces through IS-IS {MAC Address, VID} pairs learnt

locally

• Does TRILL care about IVL and SVL issues or not ?– SVL has not been fully investigated – Should TRILL additionally announce FID to VID association ?

March 2007 From draft 03 to draft 04 10

Control Plane (1)

802.n 802.n

LLC LLC

LAN LAN

ISS ISS

FilteringDatabase

EISSEIS

S

PortState

IngressRules

Bridge Port TX/RX Bridge Port TX/RX

PortState

IngressRules

Reuse Specify Not Sure

IS-IS

+ +

ST (per port)

March 2007 From draft 03 to draft 04 11

Control Plane (2)

• TRILL adds IS-IS – Need to formally specify IS-IS TLVs

• The port state is controlled by:– Designated RBridge election– Spanning Tree

• We need a ST per port per VLAN• Different from classical ST that is common to all ports

• We need to add an algorithm to combine the ST state and the DR state into a port State

March 2007 From draft 03 to draft 04 12

Spanning Trees (1)

• Which styles does TRILL support:– STP – YES– RSTP – YES– MSTP - ???

Since the original Spanning Tree Protocol (STP) has been removed from the 2004 revision of IEEE Std 802.1D, an implementation of RSTP is required for any claim of conformance for an implementation ofIEEE Std 802.1Q-2003 that refers to the current revision of IEEE Std 802.1D unless that implementation includes the Multiple Spanning Tree Protocol (MSTP) specified in IEEE Std 802.1Q-2003. MSTP is basedon RSTP, extended to provide support for multiple spanning trees.

March 2007 From draft 03 to draft 04 13

Other Restrictions ofthe first version of TRILL

• No support for:– GARP and its derivatives such as GVRP,

GMRP– RIF (Routing Information)– CFI different from 0

March 2007 From draft 03 to draft 04 14

ARP/ND

• Is ARP/ND support mandatory for an RBridge ?• One suggestion :

– TRILL MUST provide mechanisms to carry this information in IS-IS, if known

– To avoid interoperability issues• TRILL SHOULD NOT specify how to learn it• TRILL SHOULD NOT specify proxy ARP/ND behavior

– TRILL implementation may decide to optimize ARP/ND

– ARP/ND optimization and such can be called out in a separate draft

March 2007 From draft 03 to draft 04 15

IS-IS TLV Formats

• draft-ward-l2isis-01.txt has expired

• Need to restart and finalize TLV formats