diff --git a/notes/计算机网络.md b/notes/计算机网络.md
index 2411f8cc..dfc31711 100644
--- a/notes/计算机网络.md
+++ b/notes/计算机网络.md
@@ -33,10 +33,8 @@
         * [3. ²î´í¼ì²â](#3-²î´í¼ì²â)
     * [µã¶ÔµãÐŵÀ - PPP ЭÒé](#µã¶ÔµãÐŵÀ---ppp-ЭÒé)
     * [¾ÖÓòÍøµÄÍØÆË](#¾ÖÓòÍøµÄÍØÆË)
-    * [Media Access Control](#media-access-control)
     * [¹ã²¥ÐŵÀ - CSMA/CD ЭÒé*](#¹ã²¥ÐŵÀ---csmacd-ЭÒé)
     * [¼¯ÏßÆ÷](#¼¯ÏßÆ÷)
-    * [·ÓÉÆ÷½»»»»úºÍ¼¯ÏßÆ÷µÄ¶Ô±È](#·ÓÉÆ÷½»»»»úºÍ¼¯ÏßÆ÷µÄ¶Ô±È)
     * [MAC ²ã](#mac-²ã)
     * [ÐéÄâ¾ÖÓòÍø](#ÐéÄâ¾ÖÓòÍø)
 * [µÚËÄÕ ÍøÂç²ã*](#µÚËÄÕÂ-ÍøÂç²ã)
@@ -300,12 +298,10 @@ TCP/IP Э
 
 Ä¿Ç°Êý¾ÝÁ´Â·²ã¹ã·ºÊ¹ÓÃÁËÑ­»·ÈßÓà¼ìÑ飨CRC£©À´¼ì²é±ÈÌزî´í¡£
 
-×¢Òâ²î´í¼ìÑé²»ÊÇ 100% ¿É¿¿¡£
-
 ³ýÁË CRC£¬»¹ÓеļìÑé·½·¨±ÈÈ磺
 
 - ÆæżУÑ飺Ìí¼Ó 1 λʹ 1 µÄλÊýΪÆæÊý»òżÊý£¬¸ü½øÒ»²½µÄ¶þάÆæżУÑé·½·¨£¬²»µ«¿ÉÒÔ¼ì´í»¹¿ÉÒÔ¾À´í²¿·Ö´íÎó¡£
-- ¼ìÑéºÍ·½·¨£º¾ßÌå²Î¿¼ UDP ¼ìÑéºÍ¼ÆËã·½·¨ÅжÏ
+- ¼ìÑéºÍ·½·¨£º¾ßÌå²Î¿¼ UDP ¼ìÑéºÍ¼ÆËã·½·¨£»
 
 ## µã¶ÔµãÐŵÀ - PPP ЭÒé
 
@@ -321,10 +317,6 @@ TCP/IP Э
 
 ![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/8b15e36f-69b4-46b6-a07c-7234ac7c7927.jpg)
 
-## Media Access Control
-
-ýÌå·ÃÎÊ¿ØÖÆ Ö÷Òª´¦Àí¶ÔÓÚ 1 ¸öÁ´Â·É϶à¸ö½ÚµãµÄ·ÃÎÊ
-
 ## ¹ã²¥ÐŵÀ - CSMA/CD ЭÒé*
 
 Ôڹ㲥ÐŵÀÉÏ£¬Í¬Ò»Ê±¼äÖ»ÄÜÔÊÐíһ̨¼ÆËã»ú·¢ËÍÊý¾Ý¡£
@@ -349,15 +341,6 @@ CSMA/CD 
 
 ![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/40c3f8e5-3a20-45b6-a60c-77b9b952e104.jpg)
 
-## ·ÓÉÆ÷½»»»»úºÍ¼¯ÏßÆ÷µÄ¶Ô±È
-
-| \ | ¼¯ÏßÆ÷ | ·ÓÉÆ÷ | ½»»»»ú |
-| --- | --- | --- | --- |
-| traffic isolation | No | Yes | Yes |
-| ¼´²å¼´Óà | Yes | No | Yes |
-
-·ÓÉÆ÷Ìṩ·À»ðǽ±£»¤Õë¶Ô¹ã²¥·ç±©£¬½»»»»ú²»ÏÞÖÆ
-
 ## MAC ²ã
 
 MAC µØÖ·ÊÇ 6 ×Ö½Ú£¨48 룩µÄµØÖ·£¬ÓÃÓÚΨһ±íʾÍøÂçÊÊÅäÆ÷£¨Íø¿¨£©£¬Ò»Ì¨Ö÷»úÓµÓжàÉÙ¸öÊÊÅäÆ÷¾ÍÓжàÉÙ¸ö MAC µØÖ·£¬ÀýÈç±Ê¼Ç±¾µçÄÔÆÕ±é´æÔÚÎÞÏßÍøÂçÊÊÅäÆ÷ºÍÓÐÏßÍøÂçÊÊÅäÆ÷¡£