transport-target documentation

[jhaas-pfrc]

The -ct draft largely discusses the normative procedures vs. the "transport class" throughout much of the document. A few references in the document, not clearly defined until later, casually mention "transport-target". We get past section definition in 4.3 to section 5.1 before we realize that transport-target is intended to be an extended community implementing a transport class.

Ideally, one bit of wording should be picked and carried consistently throughout the document.

[jhaas-pfrc]

Note: Similar to the color community issue, the middle field of 0 should be discussed in the notation before first use.

[kalirajv]

Incorporated comment, replied on IDR list:

https://mailarchive.ietf.org/arch/msg/idr/I84ya1TAXicc8YcEYiI-fRGvmII/

Pls take a look.

Thanks Kaliraj