clarify what happens when consuming CIDs excessively

draft-ietf-quic-transport.md

@@ -961,12 +961,16 @@ cannot expect its peer to store and use all issued connection IDs.
 An endpoint SHOULD ensure that its peer has a sufficient number of available and
 unused connection IDs.  While each endpoint independently chooses how many
 connection IDs to issue, endpoints SHOULD provide and maintain at least eight
-connection IDs.  The endpoint SHOULD do this by always supplying a new
-connection ID when a connection ID is retired by its peer or when the endpoint
-receives a packet with a previously unused connection ID.  Endpoints that
-initiate migration and require non-zero-length connection IDs SHOULD provide
-their peers with new connection IDs before migration, or risk the peer closing
-the connection.
+connection IDs.  The endpoint SHOULD do this by supplying a new connection ID
+when a connection ID is retired by its peer or when the endpoint receives a
+packet with a previously unused connection ID.  However, it MAY limit the
+frequency or the total number of connection IDs issued for each connection to
+avoid the risk of running out of connection IDs (see {{reset-token}}).
+
+An endpoint that initiates migration and requires non-zero-length connection IDs
+SHOULD ensure that the pool of connection IDs available to its peer allows the
+peer to use a new connection ID on migration, as the peer will close the
+connection if the pool is exhausted.
 
 
 ### Consuming and Retiring Connection IDs {#retiring-cids}