Update 'Test_Cases/Test_Case1/readme'

Test_Cases/Test_Case1/readme

@@ -5,7 +5,7 @@ The values for the header fields are:
 1. Verison = 4, to indicate IPv4 version is used.
 2. IHL = 5, which indicates 20 bytes.
 3. Type of Service = 0,
-4. Total Window size = 40, which is 28 in hex. The total windows size contains the total lenght of IP header plus data.
+4. Total Length = 40, which is 28 in hex. The total windows size contains the total lenght of IP header plus data.
 5. Identification = 0001,
 6. Flags = All flags are set to zero,
 7. Fragment Offset = For now, there is no fragment offset so, this value is set to 0.
@@ -28,6 +28,32 @@ For the FIN+ACK packet, the FIN and ACK flags in the header have a value of 1.
 (i) Concatenate TCP Pseudo header (Protocol, Source IP, Destination IP, Total Length) with TCP header and TCP data. This creates a big integer.
 (ii) Convert this integer to binary and compute bit wise 1's complement. 
 
+The value of header comes out to be:
+header = {}
+header[0] = 0x45, Version, IHL
+header[1] = 0x00, TOS, 
+header[2] = 0x00, Total Length,
+header[3] = 0x28, Total Length, 
+header[4] = 0x00, Identification,
+header[5] = 0x01, Identification,
+header[6] = 0x00, Flags + Fragment Offset,
+header[7] = 0x00, Flags + Fragment Offset,
+header[8] = 0x28, TTL
+header[9] = 0x06, Protocol
+header[10] = 0x00, Header Checksum
+header[11] = 0x00, Header Checksum
+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,
+
+
+
+
 References:
 1. https://www.thegeekstuff.com/2012/05/ip-header-checksum/
 2. https://www.tutorialspoint.com/calculation-of-tcp-checksum