anchor.diff:  
   Upstream, the Gorouter subscribes to the NATS updates to keep its route information current. But network partitions can cause the Gorouter's routing tables to fall out of sync.
   
  -You can configure the Gorouter to direct traffic to app instances and preserve routing integrity in two modes, by validating app instances over TLS, or by pruning stale routes:
  +You can configure the Gorouter to direct traffic to app instances in two modes, with and without TLS enabled to containers:
   
   <table border="1" id="gorouter-modes" class="nice">
     <tr><th>Gorouter mode:</th>
     	<th>How Gorouter sends traffic to Diego cells:</th>
     	<th>How Gorouter updates its routing table:</th>
     </tr><tr>
  -  	<td><a href="#app-valid-tls"><strong>Validate App Instances over TLS</strong></a></td>
  +  	<td><a href="#with-tls"><strong>With TLS Enabled</strong></a></td>
     	<td>Secured, over TLS</td>
     	<td>Prunes routes with instance identity mismatch; see <a href="#when-tls-prune">Gorouter TLS pruning behavior</a></td>
     </tr><tr>
  -  	<td><a href="#stale"><strong>Prune Stale Routes</strong></a></td>
  +  	<td><a href="#without-tls"><strong>Without TLS Enabled</strong></a></td>
     	<td>Unsecured</td>
     	<td>Prunes routes that do not update for time-to-live (TTL), which defaults to 120 seconds.</td>
     </tr>
  
positive.code: 
  The first mode is newer, and it improves route availability and security. Both modes are described below.
  
  ### <a id="app-valid-tls"></a>Validate App Instances over TLS
  
  In this mode, each app instance has its own GUID and identity credentials for TLS verification. The Gorouter's routing table includes a GUID for each app instance, along with its address and port.
  
  
negative.code: 
  
  <table border="1" id="when-tls-prune" class="nice">
    <tr><th>Gorouter pruning behavior with TLS enabled</th>
    	<th>TLS handshake succeeds and app instance matches routing table</th>
    	<th>TLS handshake fails; app instance mismatch</th>
    </tr><tr>
    	<th>Time to Live (TTL) has expired</th>
    	<td>Do not prune the route</td>
    	<td>Prune the route and re-try with another instance of the app</td>
    </tr><tr>
    	<th>TTL has not expired</th>
    	<td>Do not prune the route</td>
    	<td>Do not prune the route, but mark container ineligible for requests for next 30 seconds and re-try with another instance of the app</td>
    </tr>
  </table>
  
  