[Status] WG Action: Formed Source Packet Routing in Networking (spring)

[The IESG <[e-mail]>]

A new IETF working group has been formed in the Routing Area. For
additional information please contact the Area Directors or the WG
Chairs.

Source Packet Routing in Networking (spring)
------------------------------------------------
Current Status: Proposed WG

Chairs:
  Alvaro Retana <[e-mail]>
  John Scudder <[e-mail]>

Assigned Area Director:
  Stewart Bryant <[e-mail]>

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Charter:

The ability for a node to specify a forwarding path, other 
than the normal shortest path, that a particular packet 
will traverse, benefits a number of network functions, 
for example:

o    Some types of network virtualization, including multi-
     topology networks and the partitioning of network 
     resources for VPNs
o    Network path and node protection such as fast re-route
o    Network programmability
o    New OAM techniques
o    Simplification and reduction of network signalling 
     components
o    Load balancing and traffic engineering

Source-based routing mechanisms have previously been 
specified for network protocols, but have not seen 
widespread adoption other than in MPLS traffic engineering. 
These network functions may require greater flexibility and 
per packet source imposed routing than can be achieved 
through the use of the previously defined methods. In the 
context of this charter, 'source' means 'the point at 
which the explicit route is imposed'.

The SPRING working group will define procedures that 
will allow a node to steer a packet along an explicit 
route using information attached to the packet and
without the need for per-path state information to be
held at transit nodes. Full explicit control (through loose
or strict path specification) can be achieved in a network 
comprising only SPRING nodes, however SPRING must 
inter-operate through loose routing in existing networks
and may find it advantageous to use loose routing for
for other network applications. 

The initial data planes that will be considered are MPLS
and IPv6.

There is an assumed trust model such that any node 
imposing an explicit route on a packet is assumed to 
be allowed to do so, however administrative and trust 
boundaries may strip explicit routes from a packet.
For each data plane technology that SPRING specifies, 
a security analysis must be provided showing how protection 
is provided against an attacker disrupting the network by 
for example, maliciously injecting SPRING packets.
There are a number of serious security concerns with 
source routing at the IP layer [RFC 5095].  As a part 
of its work, the working group will define the new 
IPv6-based routing header in way that blind attacks 
are never possible, i.e., attackers will be unable to 
send source routed packets that get successfully 
processed, without being part of the negotiation for 
setting up the source routes or being able to eavesdrop 
legitimate source routed packets. In some networks 
this base level security may be complemented with 
other mechanisms, such as packet filtering, cryptographic 
security, etc.

Initial work will focus on SPRING within in a single AS, 
however design decisions must not preclude operation 
of SPRING across AS boundaries. In such multi-AS 
deployments, the previously-stated trust model would 
still apply. 

SPRING should support both centralised and distributed 
path computation.  

The SPRING WG should provide OAM and the 
management needed to manage SPRING enabled networks. 
The SPRING procedures may also be used as a tool for OAM
in SPRING enabled networks.

SPRING should avoid modification to existing data 
planes that would make them incompatible with 
existing deployments. Where possible, existing control
and management plane protocols must be used within existing 
architectures to implement the SPRING function. Any
modification of or extension to existing architectures,
data planes, or control or management plane protocols 
must be carried out in the working groups responsible 
for the architecture, data plane, or control or 
management plane protocol being modified and in 
co-ordination with this working group, but may be 
done in this working group after agreement with 
all the relevant WG chairs and responsible Area Directors.

The SPRING working group is chartered for the following 
list of items:

o Identification and evaluation of use cases for SPRING. 
   These use cases must include a definition of the 
   data plane for the environment in which they are to be 
   deployed.

o Definition of requirements for any new data plane 
   encodings and procedures, required to implement 
   the use cases. Such procedures must include the 
   necessary security considerations.

o Definition of requirements and if necessary any 
   new control plane mechanism needed to enable 
   the use cases.

o Definition of requirements and if necessary management  
   plane mechanisms needed to manage and operate a 
   SPRING enabled network.

The SPRING working group will not work on any 
mechanisms for use in networks that forward IPv4 packets.
 


Milestones:
  Jul 2014 - One or more documents describing SPRING use cases.
  Nov 2014 - Specification of a high-level abstract architecture for
SPRING.
  Dec 2014 - Requirements for modifications if any to MPLS architecture
to support SPRING use cases.
  Jan 2015 - Requirements for modifications if any to IPv6 architecture
to support SPRING use cases.
  Mar 2015 - Specification of any required new procedures to support
SPRING use cases.
  Jul 2015 - One or more data plane extension requirements documents,
including documenting the impact on existing deployments of the existing
data planes.
  Jul 2015 - One or more control protocol extensions requirements
documents. 
  Jul 2015 - Management requirements document.
  Nov 2015 - Specify the OAM mechanisms needed to support SPRING.
  Nov 2015 - Document inter-working and co-existence between the new
procedures and the existing signalling and routing protocols.
  Jan 2016 - Inter-operability reports pertaining to the implementation
of extensions supporting SPRING.
  Feb 2016 - Recharter or close WG.