Shepherd writeup

1. Summary

   The document shepherd is Behcet Sarikaya. The responsible Area Director is Alia Atlas.

   Instead of considering a single SFC control plane that can manage 
   complete service paths from one end of the network
   to the other, the document adopts an approach that decomposes 
   large networks into smaller domains operated
   by as many SFC sub-domains (under the same administrative entity). 

   This approach is called: Hierarchical Service Function Chaining (hSFC)

   hSFC is a network architecture allowing an organization to decompose a large-scale
   network into multiple domains of administration.

   The goals of hSFC are to make a large-scale network easier to reason
   about, simpler to control and to support independent functional
   groups within large network operators.

   Another goal of the hierarchical approach is to simplify the
   mechanisms of scaling in and scaling out service functions (SFs).  All of the
   complexities of load-balancing among multiple SFs can be handled
   within a sub-domain, under control of the classifier, allowing the
   higher-level domain to be oblivious to the existence of multiple SF

   The document is informational. It formulates the problem and identifies
   viable options to achieve hSFC. For example, this document describes how
   nesting NSH headers, i.e. NSH-in-NSH functionality hinted in RFC8300 is used. 

2. Review and Consensus

   Two WGLCs were made for this document. The second one was mainly to confirm that the comments
   raised during the first call are well addressed. 
   There seems to be consensus in the working group that the document is ready for publication.

3. Intellectual Property

   There are no known IPR disclosures on the document. 

   Each of the authors has confirmed that they are not familiar with any IPR that applies
   to this document, in conformance with BCPs 78 and 79.

4. Other Points

   No IANA action is requested by the document.