[hiaps] Description of work

[Behcet Sarikaya <[e-mail]>]

 Hi all,

We have been receiving offline queries about hiaps work, especially
from the new members. We worked out the work description and will
include it here for your comments:

Host Identification, Address and Prefix Sharing in Service Function
Chaining (hiaps)

In order to deliver  services to end users, network operators utilize
service functions. Service functions can be packet filtering at
firewalls, load balancers, port quota enforcers, traffic offloaders,
network address translation (NAT) functions, etc. For a given service
such as optimizing TCP parameters, a service function chain (SFC) is
the abstract view of the required functions and the order in which
they are applied.  An SFC is instantiated through selection of
specific service function instances on specific network nodes to form
a service graph: this is called a Service Function Path (SFP).

Hiaps is interested in the service function chains that involve NATs,
tunneling environments in IPv4 or when prefix sharing is used in IPv6.
In those chains, not only the subscriber but also the host needs to be
identified and host address needs to be known by the specific service
function. Such cases frequently occur in virtualized home networks and
in mobile networks.

In hiaps work, the architecture defined by Service Function Chaining
Working Group will be used.

The work in hiaps is expected to involve some new meta data/context
information in SFC encapsulation for the host id/address and a new out
of band protocol to transport host id/address to the service function
forwarder.

The protocols for chained execution of service functions may involve
in band approaches such as new IP options,  the use of VLANs or
tunneling, among other techniques. Such protocols to be used in
transporting the meta data/context information in SFC encapsulation to
be defined in hiaps are out of scope.

The protocols for transporting host id/address to the service function
forwarder may involve in band approaches such as new TCP/IP options
are out of scope due to the security and privacy issues in carrying
such sensitive information as the host id/address. Only out of band
protocols will be considered.

Specifically, hiaps will work on the following:
1) Use Cases: This is a document describing the use cases from home,
mobile, fixed networks where host identification, address and prefix
sharing issues occur in certain service function chains in delivering
services. This documents should clearly define the problem.
2) Requirements: This document will analyse and eventually enhance
requirements that need to be fulfilled  by the different entities such
as service function forwarder arising from the use cases document.

3) Solutions:
A document describing an out of band approach to provide host
identification to an external server in service function chaining
scenarios.
A document describing host id/address meta data/context.

Regards,

Behcet & Dirk