Upvote:0
The question is not about a geographical road.
The silk roads went through the country you mentionned in your North, central and South examples. They put in common trade a lot of actors, not only Persia and China or whoever. Southern Europe (Byzantine Empire, Italian harbours) Arab world and Persia were milestones as well as partners of the trade with China, India and even the Moluques Islands.
In this big commercial network, Khazars were partners and milestones as well. They opened an efficient road to Eastern and Central Europe, and they had a big piece of land under control which meant they had some resources for the silk roads such as furs.
Obviously from the map, the roads that connected Khazars were in Central Asia (Tashkent) and in Persia.