Update 'Test_Cases/Test_Case1/readme'

Test_Cases/Test_Case1/readme

@@ -46,10 +46,12 @@ header[12] = 0xc8, Source IP,
 header[13] = 0xcc, Source IP,
 header[14] = 0x0a, Source IP,
 header[15] = 0x0c, Source IP,
-header[16] = 0xc8, Source IP,
-header[17] = 0xcc, Source IP,
-header[18] = 0x0a, Source IP,
-header[19] = 0x0e, Source IP,
+header[16] = 0xc8, Destination IP,
+header[17] = 0xcc, Destination IP,
+header[18] = 0x0a, Destination IP,
+header[19] = 0x0e, Destination IP,
+
+The value of IP_Header_Checksum comes out to be: ed1c.
 
 References:
 1. https://www.thegeekstuff.com/2012/05/ip-header-checksum/