More stuff.

Mention no support for asymmetric link shaping.
Point out that conversion is not a source-to-source translation.

emulab-transition.scrbl

@@ -67,7 +67,7 @@ descriptions into geni-lib based profiles.
 In addition to the hardware and software resources required by an experiment,
 a profile also contains various metadata.
 The Description and Instructions fields permit you to provide additional
-information to the instantiator of an experiment.
+information to the user of a profile.
 These fields support @seclink["markdown"]{Markdown} formatting allowing more
 expressive text.
 Classic experiments allow only a short, ASCII-only description.
@@ -183,15 +183,41 @@ These include:
     current equivalent to starting an experiment when resources become
     available and then automatically terminating it when done.
 }
+@item{
+    @bold{Asymmetric Link Shaping.}
+    The classic interface supports the ability to shape a link with
+    different characteristic (BW, latency, loss) in each direction.
+    The portal interface only allows specification of one set of
+    characteristics that apply in both directions.
+}
 ]
 
 @section[#:tag "emulab-conversion"]{Converting an Emulab experiment to a Profile}
 
-@bold{Note:} if you have no classic Emulab experiments (swapped in or swapped out)
-then you can skip this section and return to the
-@seclink["getting-started"]{getting started} section.
-The following assumes you have an existing experiment created via the classic
-interface.
+As a convenience to users, we provide a mechanism to convert NS-based
+experiments into geni-lib profiles.
+@margin-note{
+    If you have no classic Emulab experiments (swapped in or swapped out)
+    then you can skip this section and return to the
+    @seclink["getting-started"]{getting started} section.
+}
+Before walking through an example conversion, there are a couple of
+things to be aware of:
+@itemlist[
+@item{
+    The converter does not support all Emulab NS extensions, only those
+    most commonly used by users.
+}
+@item{
+    The conversion process is @italic{not} a source-to-source translation,
+    rather it works by interpreting the NS script to generate state for
+    the Emulab DB and then generating the geni-lib script from that state.
+    From a practical standpoint, what this means is that if you use TCL
+    loops, conditionals or variables in your original description, those
+    will not appear in the resulting geni-lib script--loops will be unrolled,
+    conditionals evaluated, and variables bound to fix values.
+}
+]
 
 When you login to the new portal interface at @url[(apturl)], you will be
 taken to your @italic{dashboard} on which there are a number of tabs.