Subject: New BOF in Internet Area - TRILL

From: [email-masked]
Date: Fri, 04 Mar 2005 02:25:43 -0500

Transparent Interconnection of Lots of Links BOF (trill)

Thursday, March 10 at 1300-1500
===============================

CHAIR: Erik Nordmark <[email-masked]>

AGENDA:

 - Welcome and Administrivia 5 minutes Chair

- Charter review 10 minutes Chair

- Problem statement discussion 30 minutes Erik Nordmark
  Including the "service" that a cloud of hybrid devices will
  provide, whether it is equivalent to IEEE 802.1D devices, or
  handles IP packets differently
  When is it ok to reorder packets? MTU considerations?

- Threats and security considerations 10 minutes ???
  What should the goal be? What can we do better?

- Requirements on routing protocols 20 minutes ???
  For zero configuration
  Carrying MAC addresses
  Broadcast
  IS-IS vs. OSPF vs. something else

- Connecting different L2 types 30 minutes Radia Perlman

- Choices for ARP/ND 10 minutes Joe Touch
  Constraints from security discussion (intentionally duplicate L2
  addresses), mobility, SeND support, etc.

- Choices for broadcast/multicast 10 minutes Joe Touch??
  Worth doing any optimizations? Spanning tree between rbridges?

Reading list:
-------------

Participants are encouraged to read draft-perlman-rbridge-01.txt to
familiarize themselves with the problem space.
There are also some papers available at the web page.

DESCRIPTION:

While IEEE 802 bridges are attractive due to not needing explicit
configuration and allowing hosts to move within the bridged topology,
they are more limited than IP routers since bridges only support IEEE 802 
technologies, and the most common layer 2 interconnection method 
(dynamically created spanning tree formation using bridges) is not as 
flexible and robust as layer 3 routing.

The WG will design a hybrid solution that combines the simplicity of
configuration while taking full advantage of complex topologies.

The design should have the following properties:
- zero configuration of the hybrid devices
- ability for hosts to move without changing their IP address
- it should be possible to forward packets using pair-wise shortest paths,
  and exploit the redundant paths through the network for increased
  aggregate bandwidth
- possible optimizations for ARP and Neighbor Discovery packets
  (potentially avoid flooding all the time)
- support Secure Neighbor Discovery
- the packet header should have a hop count for robustness in the presence
  of temporary routing loops
- nodes should be able to have multiple attachments to the network
- no delay when a new node is attached to the network
- multicast should work (and after a re-charter it might make sense to
  look at optimizations for IP multicast)
- be no less secure than existing bridges (and explore whether the
  protocol can make "L2 address theft" harder or easier to detect)

A required piece of the solution is an IP routing protocol which is extended
to carry L2 address reachability, handle broadcast, and is friendly to
zero-configuration. Likely candidate are the link-state routing protocols
since they can easily be extended to provide for broadcast, which is
believed to be difficult for distance vector protocols.

This working group will define the requirements on such routing protocol(s),
and select the routing protocol(s) to be used. The intent is that the
actual extensions to the routing protocol(s) be performed in the WGs with
expertise in the routing protocol(s).

The working group will look into solutions that can interconnect different
layer 2 technologies, and also look at providing support for non-IP
protocols, even though one can not combine those two features together; the 
interconnection of different layer 2 technologies (with different layer 2
address formats) will most likely only work for the IP family of protocols.
Whether the same or different address formats are used, there might be a 
need to handle different MTUs.

The WG will design a protocol that combines the benefits of bridges
and routers in a way that will co-exist with existing hosts, IP routers
and bridges. The design must support both IPv4 and IPv6

The working group will not work any layer 3 aspects except to provide
- Possible optimizations for ARP and ND packets (not always
  flooded everywhere)
- Being able to carry IP broadcast and multicast packets (which might
  just fall out from supporting L2 multicast)
- Defining the L3 operations needed to interconnect different L2
  technologies

The work consists of several, separable pieces:
- Defining the requirement on the routing protocol(s), and select one or
  more routing protocols. The detailed specification of the extensions to
  a particular routing protocol will be left as an action item for the
  specific routing protocol WG.
- Defining what information must be carried in an encapsulation header for
  data packets, and how to map that information to various link types
  (e.g., IEEE LAN, Fibrechannel, MPLS)
- Defining how address resolution (ARP and Neighbor Discovery) is
  performed, taking into account the desire to be compatible with 
  Secure Neighbor Discovery.
- Defining how the solution extends to the case when multiple layer 2
  technologies, that have different address format/length, are
  interconnected.

Deliverables
- A short draft on the problem statement and goals
- A document defining what information needs to be carried in routing
  protocols to support the trill concept, and other requirements on
  the routing protocols.
- Encapsulation draft specifying what needs to be carried in general
  and the specific format to use on IEEE LANs
- ARP and ND draft
- Draft on interconnecting different types of layer 2 technologies
- Threat analysis document

Goals and Milestones

Jun 05 Problem statement and Goals submitted to IESG for Informational
Sep 05 Routing protocol support requirements to IESG for Informational
Dec 05 Encapsulation document to IESG for Proposed Standard
Sep 05 ARP & ND to IESG for Proposed Standard
Mar 06 Interconnecting Layer 2 Technologies document to IESG for
Proposed Standard
Dec 05 Threat analysis to IESG for Informational

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