Clarify that there are two SSL I/O buffers
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 376de6f..17271c1 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2399,7 +2399,7 @@
 //#define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50 /**< Maximum entries in cache */
 
 /* SSL options */
-//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384 /**< Size of the input / output buffer */
+//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384 /**< Maxium fragment length in bytes, determines the size of each of the two internal I/O buffers */
 //#define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME     86400 /**< Lifetime of session tickets (if enabled) */
 //#define MBEDTLS_PSK_MAX_LEN               32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
 //#define MBEDTLS_SSL_COOKIE_TIMEOUT        60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */