diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 307b90b..667177a 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2896,7 +2896,51 @@
 //#define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50 /**< Maximum entries in cache */
 
 /* SSL options */
-//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384 /**< Maxium fragment length in bytes, determines the size of each of the two internal I/O buffers */
+
+/** \def MBEDTLS_SSL_MAX_CONTENT_LEN
+ *
+ * Maximum fragment length in bytes.
+ *
+ * Determines the size of both the incoming and outgoing TLS I/O buffers.
+ *
+ * Uncommenting MBEDTLS_SSL_IN_CONTENT_LEN and/or MBEDTLS_SSL_OUT_CONTENT_LEN
+ * will override this length by setting maximum incoming and/or outgoing
+ * fragment length, respectively.
+ */
+//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384
+
+/** \def MBEDTLS_SSL_IN_CONTENT_LEN
+ *
+ * Maximum incoming fragment length in bytes.
+ *
+ * Uncomment to set the size of the inward TLS buffer independently of the
+ * outward buffer.
+ */
+//#define MBEDTLS_SSL_IN_CONTENT_LEN              16384
+
+/** \def MBEDTLS_SSL_OUT_CONTENT_LEN
+ *
+ * Maximum outgoing fragment length in bytes.
+ *
+ * Uncomment to set the size of the outward TLS buffer independently of the
+ * inward buffer.
+ *
+ * It is possible to save RAM by setting a smaller outward buffer, while keeping
+ * the default inward 16384 byte buffer to conform to the TLS specification.
+ *
+ * The minimum required outward buffer size is determined by the handshake
+ * protocol's usage. Handshaking will fail if the outward buffer is too small.
+ * The specific size requirement depends on the configured ciphers and any
+ * certificate data which is sent during the handshake.
+ *
+ * For absolute minimum RAM usage, it's best to enable
+ * MBEDTLS_SSL_MAX_FRAGMENT_LENGTH and reduce MBEDTLS_SSL_MAX_CONTENT_LEN. This
+ * reduces both incoming and outgoing buffer sizes. However this is only
+ * guaranteed if the other end of the connection also supports the TLS
+ * max_fragment_len extension. Otherwise the connection may fail.
+ */
+//#define MBEDTLS_SSL_OUT_CONTENT_LEN             16384
+
 //#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 */