diff --git a/Trimester - VII/CN/dvr.py b/Trimester - VII/CN/dvr.py
new file mode 100644
index 0000000..ee26a47
--- /dev/null
+++ b/Trimester - VII/CN/dvr.py	
@@ -0,0 +1,172 @@
+"""
+Name: Atharva G. Jibhakate
+TY-CSE (Panel-5)
+E1
+PE-03
+"""
+
+class Node(object):
+    def __init__(self, name, n):
+        self.name = name
+        self.number = n
+        self.neighbours = []
+        self.routingTable = []
+
+
+# Bellman Ford's Algorithm
+class Algorithm(object):
+    @staticmethod
+    def shareRT(vertexList):
+
+        print("---------------------\n\nRouting Tables being transmitted 1 by 1:")
+
+        while True:
+            UPDATE_HAPPENED = False
+            for receiver in vertexList:
+                print("-----------------------------------------------")
+                for sender in receiver.neighbours:
+                    current_cost = 0
+                    next_hop = "#"
+                    for xyz in receiver.routingTable:
+                        if xyz[0] == sender.name:
+                            current_cost = xyz[1]
+                            next_hop = xyz[2]
+                    print(
+                        sender.name,
+                        " sends its DV to ",
+                        receiver.name,
+                        " , and is at distance ",
+                        current_cost,
+                        " from it.",
+                    )
+
+                    for i in receiver.routingTable:
+                        L1 = list(i)
+                        for j in sender.routingTable:
+                            L2 = list(j)
+                            if (i[0] == j[0]) & ((j[1] + current_cost) < i[1]):
+                                print(L1, "\t", " and ", end="")
+                                print(L2, " ", end="")
+                                L1[1] = L2[1] + current_cost
+                                L1[2] = next_hop
+                                receiver.routingTable.remove((i[0], i[1], i[2]))
+                                i = tuple(L1)
+                                receiver.routingTable.append(i)
+                                print(" updates L1 to ", i)
+                                UPDATE_HAPPENED = True
+                            else:
+                                continue
+                        # i = tuple(L1)
+                if UPDATE_HAPPENED == True:
+                    print("\n\nUPDATED ", end="")
+                    print(receiver.name, "'s Routing Table:")
+                    receiver.routingTable.sort()
+                    print(receiver.routingTable, sep="\n")
+
+            if UPDATE_HAPPENED == False:
+                break
+
+        print("STABLE STATE REACHED!")
+
+
+vertexList = []
+print("Enter number of routers:")
+n = int(input())
+for i in range(n):
+    print("Enter label for router %d " % i)
+    node = Node(input(), i)  #
+    vertexList.append(node)
+    node.routingTable.append((node.name, 0, node.name))
+
+for router in vertexList:
+    for other in vertexList:
+        if other.name != router.name:
+            router.routingTable.append((other.name, 99, other.name))
+
+
+print("Initiating....")
+
+print("Enter number of links:")
+m = int(input())
+for i in range(m):
+    print("Source Name, Destination Name, Cost:")
+    sourceLabel = Node(input(), 0)
+    destLabel = Node(input(), 0)
+    cost = int(input())
+
+    for i in vertexList:
+        if i.name == sourceLabel.name:
+            sourceLabel = i
+        if i.name == destLabel.name:
+            destLabel = i
+
+    for xyz in sourceLabel.routingTable:
+        if xyz[0] == destLabel.name:
+            earlier_cost = xyz[1]
+
+    if destLabel not in sourceLabel.neighbours:
+        sourceLabel.neighbours.append(destLabel)
+    if sourceLabel not in destLabel.neighbours:
+        destLabel.neighbours.append(sourceLabel)
+
+    sourceLabel.routingTable.remove((destLabel.name, earlier_cost, destLabel.name))
+    sourceLabel.routingTable.append((destLabel.name, cost, destLabel.name))
+    destLabel.routingTable.remove((sourceLabel.name, earlier_cost, sourceLabel.name))
+    destLabel.routingTable.append((sourceLabel.name, cost, sourceLabel.name))
+
+
+print("-----------------INITIALIZATION------------------------")
+for i in vertexList:
+    print(i.name, "'s Routing Table:")
+    i.routingTable.sort()
+    for j in i.routingTable:
+        print(j, "\t", end="")
+    print()
+
+
+algorithm = Algorithm()
+algorithm.shareRT(vertexList)
+
+while True:
+    print("Update cost of some link? Y:N")
+    opt = input()
+    if opt == "Y":
+        print("Source Name, Destination Name, Cost:")
+        sourceLabel = Node(input(), 0)
+        destLabel = Node(input(), 0)
+        cost = int(input())
+        earlier_cost = 0
+        for i in vertexList:
+            if i.name == sourceLabel.name:
+                sourceLabel = i
+            if i.name == destLabel.name:
+                destLabel = i
+
+        for xyz in sourceLabel.routingTable:
+            if xyz[0] == destLabel.name:
+                earlier_cost = xyz[1]
+
+        print(
+            "Earlier cost from ",
+            sourceLabel.name,
+            " to ",
+            destLabel.name,
+            " was ",
+            earlier_cost,
+        )
+        sourceLabel.routingTable.remove((destLabel.name, earlier_cost, destLabel.name))
+        sourceLabel.routingTable.append((destLabel.name, cost, destLabel.name))
+        destLabel.routingTable.remove(
+            (sourceLabel.name, earlier_cost, sourceLabel.name)
+        )
+        destLabel.routingTable.append((sourceLabel.name, cost, sourceLabel.name))
+        algorithm.shareRT(vertexList)
+    else:
+        break
+for i in vertexList:
+          print(i.name, "'s Routing Table:")
+          i.routingTable.sort()
+          for j in i.routingTable:
+              print(j, "\t", end="")
+          print()
+
diff --git a/Trimester - VII/CN/subnet_ss.py b/Trimester - VII/CN/subnet_ss.py
new file mode 100644
index 0000000..fcff8b3
--- /dev/null
+++ b/Trimester - VII/CN/subnet_ss.py	
@@ -0,0 +1,306 @@
+
+ip1, ip2, ip3, ip4 = input("Enter the ip address in Decimal Form\n").split(".")
+print("The IP Address id: {}.{}.{}.{}".format(ip1, ip2, ip3,ip4))
+print("Decimal Form: {}.{}.{}.{}".format(bin(int(ip1)).replace("0b", ""), bin(int(ip2)).replace("0b", ""),
+                                        bin(int(ip3)).replace("0b", ""),bin(int(ip4)).replace("0b", "") ))
+ip1 = int(ip1)
+ip2 = int(ip2)
+ip3 = int(ip3)
+ip4 = int(ip4)
+
+# print("\n\nThe given IP Address belongs to :")
+# if(ip1 >= 0 and ip1 <= 127):
+#     print("Class A")
+#     print("Default Mask: 255.0.0.0")
+# elif(ip1 > 127 and ip1 <= 191):
+#     print("Class B")
+#     print("Default Mask: 255.255.0.0")
+# elif(ip1 > 191 and ip1 <= 223):
+#     print("Class C")
+#     print("Default Mask: 255.255.255.0")
+# elif(ip1 > 223 and ip1 <= 239):
+#     print('Class D')
+#     print("No Default Mask")
+# elif(ip1 > 239 and ip1 <= 255):
+#     print('Class E')
+#     print("No Default Mask")
+
+n = int(input("\nHow many Subnet do you want?"))
+
+nb = bin(n).replace("0b", "")
+
+list1 = [1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,
+            65536, 131072, 262144, 524288, 1048576, 2097152, 4194304]
+
+nblen = len(nb)
+if n not in list1:
+    nblen = nblen + 1
+
+print("nblen = {}".format(nblen))
+
+if nblen  >= 0:
+    nblen1 = nblen-1
+else:
+    pass
+
+if (nblen  > 0 and nblen <9 ):
+    pow = 7
+    sub_mask_d = 0
+    for i in range(0, (nblen -1) ):
+        sub_mask_d = sub_mask_d + (2**pow)
+        pow = pow - 1
+elif (nblen > 8 and nblen  < 17):
+    pow = 7
+    sub_mask_d = 0
+    for i in range(0, (nblen -1) - 8 ):
+        sub_mask_d = sub_mask_d + (2**pow)
+        pow = pow - 1
+elif(nblen > 16 and nblen < 25):
+    pow = 7
+    sub_mask_d = 0
+    for i in range(0, (nblen -1) - 16 ):
+        sub_mask_d = sub_mask_d + (2**pow)
+        pow = pow - 1
+
+
+# print("\n\nThe Default Subnet Mask is :")
+# if(ip1 >= 0 and ip1 <= 127):
+#     # print("Class A")
+#     if nblen  > 0 and nblen  < 9:
+#         print("Subnet Mask:")
+#         print("255.", end= '')
+#         print(sub_mask_d, end = '')
+#         print(".0.0")
+
+#         print("Binary Form:")
+#         print("11111111.", end='')
+#         print(bin(sub_mask_d).replace("0b", ""), end='')
+#         print(".0.0")
+#     elif nblen  > 8 and nblen  < 17:
+#         print("Subnet Mask:")
+#         print("255.255.", end= '')
+#         print(sub_mask_d, end = '')
+#         print(".0")
+
+#         print("Binary Form:")
+#         print("11111111.11111111.", end='')
+#         print(bin(sub_mask_d).replace("0b", ""), end='')
+#         print(".0")
+#     elif(nblen > 16 and nblen < 25):
+#         print("Subnet Mask:")
+#         print("255.255.255.", end= '')
+#         print(sub_mask_d, end = '')
+
+#         print("Binary Form:")
+#         print("11111111.11111111.11111111.", end='')
+#         print(bin(sub_mask_d).replace("0b", ""), end='')
+#         # print("0.0")
+#         # print(".0")
+
+# elif(ip1 > 127 and ip1 <= 191):
+#     # print("Subnet Mask:")
+#     if nblen  > 0 and nblen  < 9:
+#         print("Subnet Mask:")
+#         print("255.255.", end= '')
+#         print(sub_mask_d, end = '')
+#         print(".0")
+#     elif nblen  > 8 and nblen  < 17:
+#         print("Subnet Mask:")
+#         print("255.255.255.", end= '')
+#         print(sub_mask_d, end = '')
+#         # print(".0")
+
+# elif(ip1 > 191 and ip1 <= 223):
+#     if nblen  > 0 and nblen  < 9:
+#         print("Subnet Mask:")
+#         print("255.255.255.", end= '')
+#         print(sub_mask_d, end = '')
+#         # print(".0")
+#     else:
+#         print("Not Possible")
+# elif(ip1 > 223 and ip1 <= 239):
+#     print('Class D')
+#     print("No Subnet Mask")
+# elif(ip1 > 239 and ip1 <= 255):
+#     print('Class E')
+#     print("No Subnet Mask")
+
+# Subnetting
+na = 1
+
+for j in list1:
+    if j >= n:
+        na = j
+        break
+    
+print("na = {}".format(na))
+if(ip1 >= 0 and ip1 <= 127):
+    if nblen  > 0 and nblen  < 9:
+       sub = 0
+      
+       print("Range of each Subnets")
+       for i in range(0, n):
+            print(ip1, end='')
+            print(".",end = '')
+            print(int(sub), end = '')
+            print(".0.0", end='')
+
+            print(" - ", end='')
+
+            print(ip1, end='')
+            print(".", end='')
+            print(int(sub+ (256/na)-1), end='')
+            print(".255.255")
+            sub = sub + (256/na)
+       print("\nClass : A")
+       print("Default Mask: 255.0.0.0")
+       print("Network ID: {}.0.0.0".format(ip1))
+       print("Broadcaster ID: {}.0.0.0".format(ip1))
+       print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+       print("Range of Each Subnet: {}".format((2**(16+(8-nblen1))) ))
+       print("Total Avalable Id: {}".format( (2**(16+(8-nblen1))) -2) )
+       print("Subnet Mask: ", end='')
+       print("255.", end= '')
+       print(sub_mask_d, end = '')
+       print(".0.0")
+    elif nblen  > 8 and nblen  < 17:
+       print("\nClass : A")
+       print("Default Mask: 255.0.0.0")
+       print("Network ID: {}.0.0.0".format(ip1))
+       print("Broadcaster ID: {}.0.0.0".format(ip1))
+       print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+       print("Range of Each Subnet: {}".format((2**(16+(8-nblen1))) ))
+       print("Total Avalable Id: {}".format( (2**(16+(8-nblen1))) -2) )
+       print("Subnet Mask: ", end='')
+       print("255.255.", end= '')
+       print(sub_mask_d, end = '')
+       print(".0")
+
+           
+    elif(nblen > 16 and nblen < 25):
+       print("\nClass : A")
+       print("Default Mask: 255.0.0.0")
+       print("Network ID: {}.0.0.0".format(ip1))
+       print("Broadcaster ID: {}.0.0.0".format(ip1))
+       print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+       print("Range of Each Subnet: {}".format((2**(16+(8-nblen1))) ))
+       print("Total Avalable Id: {}".format( (2**(16+(8-nblen1))) -2) )
+       print("Subnet Mask: ", end='')
+       print("255.255.255.", end= '')
+       print(sub_mask_d)
+    #    print(".0")
+        # print(".0")
+elif(ip1 > 127 and ip1 <= 191):
+    if nblen  > 0 and nblen  < 9:
+        sub = 0
+        print("Range of each Subnets")
+        for i in range(0, n):
+            print(ip1, end='')
+            print(".",end = '')
+            print(ip2, end='')
+            print(".",end = '')
+            print(int(sub), end = '')
+            print(".0", end='')
+
+            print(" - ", end='')
+
+            print(ip1, end='')
+            print(".", end='')
+            print(ip2, end='')
+            print(".", end='')
+            print(int(sub+ (256/na)-1), end='')
+            print(".255")
+            sub = sub + (256/na)
+        print("\nClass : B")
+        print("Default Mask: 255.255.0.0")
+        print("Network ID: {}.{}.0.0".format(ip1, ip2))
+        print("Broadcaster ID: {}.{}.255.255".format(ip1, ip2))
+        print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+        print("Range of Each Subnet: {}".format((2**(8+(8-nblen1))) ))
+        print("Total Avalable Id: {}".format( (2**(8+(8-nblen1))) -2) )
+        print("Subnet Mask:")
+        print("255.255.", end= '')
+        print(sub_mask_d, end = '')
+        print(".0", end= '')
+        # print(".0")
+    elif nblen  > 8 and nblen  < 17:
+       print("\nClass : B")
+       print("Default Mask: 255.0.0.0")
+       print("Network ID: {}.0.0.0".format(ip1))
+       print("Broadcaster ID: {}.0.0.0".format(ip1))
+       print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+       print("Range of Each Subnet: {}".format((2**(8+(8-nblen1))) ))
+       print("Total Avalable Id: {}".format( (2**(8+(8-nblen1))) -2) )
+       print("Subnet Mask: ", end='')
+       print("255.255.", end= '')
+       print(sub_mask_d, end = '')
+       print(".0")
+elif(ip1 > 191 and ip1 <= 223):
+    if n == 256:
+        print("Not Possible")
+    else:
+        if nblen  > 0 and nblen  < 9:
+            sub = 0
+      
+            print("Range of each Subnets")
+            for i in range(0, n):
+                    print(ip1, end='')
+                    print(".",end = '')
+                    print(ip2, end='')
+                    print(".",end = '')
+                    print(ip3, end='')
+                    print(".",end = '')
+                    print(int(sub), end = '')
+                    # print(".0", end='')
+
+                    print(" - ", end='')
+
+                    print(ip1, end='')
+                    print(".", end='')
+                    print(ip2, end='')
+                    print(".", end='')
+                    print(ip3, end='')
+                    print(".", end='')
+                    print(int(sub+ (256/na)-1), end='')
+                    print("")
+                    sub = sub + (256/na)
+
+
+                    # print("\n\n Subnet ID:  ")
+                    # print(ip1, end='')
+                    # print(".",end = '')
+                    # print(ip2, end='')
+                    # print(".",end = '')
+                    # print(ip3, end='')
+                    # print(".",end = '')
+                    # print(int(sub))
+                    # # print(".0", end='')
+
+                    # print("Broadcaster ID:  ")
+                    # print(ip1, end='')
+                    # print(".", end='')
+                    # print(ip2, end='')
+                    # print(".", end='')
+                    # print(ip3, end='')
+                    # print(".", end='')
+                    # print(int(sub+ (256/na)-1), end='')
+                    # print("/n/n")
+
+
+            print("\nClass : C")
+            print("Default Mask: 255.255.255.0")
+            print("Network ID: {}.{}.{}.0".format(ip1, ip2, ip3))
+            print("Network ID: {}.{}.{}.255".format(ip1, ip2, ip3))
+            print("Total Bits Borrowed/Fixed: {}".format(nblen1))
+            print("Range of Each Subnet: {}".format(int(256/na) ))
+            print("Total Avalable Id: {}".format((int(256/na)-2)) )
+            print("Subnet Mask: ", end='')
+            print("255.255.255.", end= '')
+            print(sub_mask_d, end = '')
+
+            
+elif(ip1 > 223 and ip1 <= 239):
+    print("Error")  
+elif(ip1 > 239 and ip1 <= 255):
+    print("Error")
+   
\ No newline at end of file
diff --git a/Trimester - VII/CN/tcp_client.c b/Trimester - VII/CN/tcp_client.c
new file mode 100644
index 0000000..e43d8a3
--- /dev/null
+++ b/Trimester - VII/CN/tcp_client.c	
@@ -0,0 +1,64 @@
+#include <netdb.h> 
+#include <stdio.h> 
+#include <stdlib.h> 
+#include <string.h> 
+#include <sys/socket.h> 
+#define MAX 80 
+#define PORT 8080 
+#define SA struct sockaddr 
+void func(int sockfd) 
+{ 
+	char buff[MAX]; 
+	int n; 
+	for (;;) { 
+		bzero(buff, sizeof(buff)); 
+		printf("Enter the string : "); 
+		n = 0; 
+		while ((buff[n++] = getchar()) != '\n') 
+			; 
+		write(sockfd, buff, sizeof(buff)); 
+		bzero(buff, sizeof(buff)); 
+		read(sockfd, buff, sizeof(buff)); 
+		printf("From Server : %s", buff); 
+		if ((strncmp(buff, "exit", 4)) == 0) { 
+			printf("Client Exit...\n"); 
+			break; 
+		} 
+	} 
+} 
+
+int main() 
+{ 
+	int sockfd, connfd; 
+	struct sockaddr_in servaddr, cli; 
+
+	// socket create and varification 
+	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
+	if (sockfd == -1) { 
+		printf("socket creation failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("Socket successfully created..\n"); 
+	bzero(&servaddr, sizeof(servaddr)); 
+
+	// assign IP, PORT 
+	servaddr.sin_family = AF_INET; 
+	servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 
+	servaddr.sin_port = htons(PORT); 
+
+	// connect the client socket to server socket 
+	if (connect(sockfd, (SA*)&servaddr, sizeof(servaddr)) != 0) { 
+		printf("connection with the server failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("connected to the server..\n"); 
+
+	// function for chat 
+	func(sockfd); 
+
+	// close the socket 
+	close(sockfd); 
+} 
+
diff --git a/Trimester - VII/CN/tcp_server.c b/Trimester - VII/CN/tcp_server.c
new file mode 100644
index 0000000..d202589
--- /dev/null
+++ b/Trimester - VII/CN/tcp_server.c	
@@ -0,0 +1,95 @@
+#include <stdio.h> 
+#include <netdb.h> 
+#include <netinet/in.h> 
+#include <stdlib.h> 
+#include <string.h> 
+#include <sys/socket.h> 
+#include <sys/types.h> 
+#define MAX 80 
+#define PORT 8080 
+#define SA struct sockaddr 
+
+// Function designed for chat between client and server. 
+void func(int sockfd) 
+{ 
+	char buff[MAX]; 
+	int n; 
+	// infinite loop for chat 
+	for (;;) { 
+		bzero(buff, MAX); 
+
+		// read the message from client and copy it in buffer 
+		read(sockfd, buff, sizeof(buff)); 
+		// print buffer which contains the client contents 
+		printf("From client: %s\t To client : ", buff); 
+		bzero(buff, MAX); 
+		n = 0; 
+		// copy server message in the buffer 
+		while ((buff[n++] = getchar()) != '\n') 
+			; 
+
+		// and send that buffer to client 
+		write(sockfd, buff, sizeof(buff)); 
+
+		// if msg contains "Exit" then server exit and chat ended. 
+		if (strncmp("exit", buff, 4) == 0) { 
+			printf("Server Exit...\n"); 
+			break; 
+		} 
+	} 
+} 
+
+// Driver function 
+int main() 
+{ 
+	int sockfd, connfd, len; 
+	struct sockaddr_in servaddr, cli; 
+
+	// socket create and verification 
+	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
+	if (sockfd == -1) { 
+		printf("socket creation failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("Socket successfully created..\n"); 
+	bzero(&servaddr, sizeof(servaddr)); 
+
+	// assign IP, PORT 
+	servaddr.sin_family = AF_INET; 
+	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); 
+	servaddr.sin_port = htons(PORT); 
+
+	// Binding newly created socket to given IP and verification 
+	if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) { 
+		printf("socket bind failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("Socket successfully binded..\n"); 
+
+	// Now server is ready to listen and verification 
+	if ((listen(sockfd, 5)) != 0) { 
+		printf("Listen failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("Server listening..\n"); 
+	len = sizeof(cli); 
+
+	// Accept the data packet from client and verification 
+	connfd = accept(sockfd, (SA*)&cli, &len); 
+	if (connfd < 0) { 
+		printf("server acccept failed...\n"); 
+		exit(0); 
+	} 
+	else
+		printf("server acccept the client...\n"); 
+
+	// Function for chatting between client and server 
+	func(connfd); 
+
+	// After chatting close the socket 
+	close(sockfd); 
+} 
+
diff --git a/Trimester - VII/CN/udp_client.c b/Trimester - VII/CN/udp_client.c
new file mode 100644
index 0000000..a019c4a
--- /dev/null
+++ b/Trimester - VII/CN/udp_client.c	
@@ -0,0 +1,50 @@
+// Client side implementation of UDP client-server model 
+#include <stdio.h> 
+#include <stdlib.h> 
+#include <unistd.h> 
+#include <string.h> 
+#include <sys/types.h> 
+#include <sys/socket.h> 
+#include <arpa/inet.h> 
+#include <netinet/in.h> 
+
+#define PORT	 8080 
+#define MAXLINE 1024 
+
+// Driver code 
+int main() { 
+	int sockfd; 
+	char buffer[MAXLINE]; 
+	char *hello = "Hello from client"; 
+	struct sockaddr_in	 servaddr; 
+
+	// Creating socket file descriptor 
+	if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) { 
+		perror("socket creation failed"); 
+		exit(EXIT_FAILURE); 
+	} 
+
+	memset(&servaddr, 0, sizeof(servaddr)); 
+	
+	// Filling server information 
+	servaddr.sin_family = AF_INET; 
+	servaddr.sin_port = htons(PORT); 
+	servaddr.sin_addr.s_addr = INADDR_ANY; 
+	
+	int n, len; 
+	
+	sendto(sockfd, (const char *)hello, strlen(hello), 
+		MSG_CONFIRM, (const struct sockaddr *) &servaddr, 
+			sizeof(servaddr)); 
+	printf("Hello message sent.\n"); 
+		
+	n = recvfrom(sockfd, (char *)buffer, MAXLINE, 
+				MSG_WAITALL, (struct sockaddr *) &servaddr, 
+				&len); 
+	buffer[n] = '\0'; 
+	printf("Server : %s\n", buffer); 
+
+	close(sockfd); 
+	return 0; 
+} 
+
diff --git a/Trimester - VII/CN/udp_server.c b/Trimester - VII/CN/udp_server.c
new file mode 100644
index 0000000..fe15316
--- /dev/null
+++ b/Trimester - VII/CN/udp_server.c	
@@ -0,0 +1,59 @@
+// Server side implementation of UDP client-server model 
+#include <stdio.h> 
+#include <stdlib.h> 
+#include <unistd.h> 
+#include <string.h> 
+#include <sys/types.h> 
+#include <sys/socket.h> 
+#include <arpa/inet.h> 
+#include <netinet/in.h> 
+
+#define PORT	 8080 
+#define MAXLINE 1024 
+
+// Driver code 
+int main() { 
+	int sockfd; 
+	char buffer[MAXLINE]; 
+	char *hello = "Hello from server"; 
+	struct sockaddr_in servaddr, cliaddr; 
+	
+	// Creating socket file descriptor 
+	if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) { 
+		perror("socket creation failed"); 
+		exit(EXIT_FAILURE); 
+	} 
+	
+	memset(&servaddr, 0, sizeof(servaddr)); 
+	memset(&cliaddr, 0, sizeof(cliaddr)); 
+	
+	// Filling server information 
+	servaddr.sin_family = AF_INET; // IPv4 
+	servaddr.sin_addr.s_addr = INADDR_ANY; 
+	servaddr.sin_port = htons(PORT); 
+	
+	// Bind the socket with the server address 
+	if ( bind(sockfd, (const struct sockaddr *)&servaddr, 
+			sizeof(servaddr)) < 0 ) 
+	{ 
+		perror("bind failed"); 
+		exit(EXIT_FAILURE); 
+	} 
+	
+	int len, n; 
+
+	len = sizeof(cliaddr); //len is value/resuslt 
+
+	n = recvfrom(sockfd, (char *)buffer, MAXLINE, 
+				MSG_WAITALL, ( struct sockaddr *) &cliaddr, 
+				&len); 
+	buffer[n] = '\0'; 
+	printf("Client : %s\n", buffer); 
+	sendto(sockfd, (const char *)hello, strlen(hello), 
+		MSG_CONFIRM, (const struct sockaddr *) &cliaddr, 
+			len); 
+	printf("Hello message sent.\n"); 
+	
+	return 0; 
+} 
+