Lab 8 – TCP Transmission Control Protocol LAB REPORT by va23823

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									                        Lab 8 – TCP: Transmission Control Protocol
                                      LAB REPORT
                                   Venkat G Grandhi
                  Computer Networks, COSC 6377, Dept of Computer Science
                                   University of Houston

Objective                                              also change the packet discard ratio we will
                                                       change these attributes during the various
       To get familiar with the basics of
                                                       scenarios.
Congestion control algorithms implemented by
                                                       4. Client: This client accesses the server_west
the TCP by building a network and comparing the
                                                       and we name it client_east. This client is a simple
performance of these algorithms through analysis
                                                       Ethernet client with a single processor (Sun ultra
of the results generated from the simulation.
                                                       333 MHz processor).
                                                       5. Applications: This is the application that the
Method
                                                       client is going to access the server for. In this case
       In this lab we create a network which uses
                                                       we use FTP application
TCP as the end to end transmission layer protocol.
                                                       6. Profile*:A profile describes user activity over a
Objects Used in the Simulated Network:
                                                       period of time. A profile consists of many
1. Server: In this simulation we use a Sun Ultra
                                                       different applications. For example, a "Human
333Mhz single processor Ethernet server, and
                                                       Resources" user profile may contain "Email",
name it as Server_West. Later in this lab we
                                                       "Web" and "Database". We can specify various
change the various attributes of this server and
                                                       loading      characteristics      for    the     different
simulate.
                                                       applications on this profile. Each application is
2. Routers: In this simulation we use a
                                                       described     in   detail     within    the    application
ethernet4_slip8_gateway. This means it is a
                                                       configuration object. The profiles created on this
gateway with 4 Ethernet ports and uses a Serial
                                                       object will be referenced by the individual
Line Input Protocol.
                                                       workstations to generate traffic.
3. IP32_Cloud: This IP cloud supports up to 32
                                                       Scenarios:
serial line interfaces and we can select the data
                                                               Here we consider three different scenarios.
rate at which the IP packets will be transmitted.
                                                           •     No_Drop           : No dropped packets.
This cloud will require equal amount of time to
                                                           •     Drop_NoFast :Packets are dropped but
route each data packet. The delay can be changed
                                                               there are no congestion control protocols
by editing the packet latency attribute. We can
                                                               in place


                                                 -1-
   •   Drop_Fast     :Packets are dropped and             Within The east subnet we have the following:
       we use Fast Recovery           to combat           We have an Ethernet client named Client_East
       congestion.                                        and a router named Router_East as shown in the
                                                          figure below.
The basic scenario is shown below:




                                                          Both the above subnets are connected to the
                                                          IP_cloud     using    a   bidirectional    PPP_DS3
                                                          bidirectional link.

In this scenario we have an Application
Configuration   Object,   Profile   Configuration
Object, Subnet (West Subnet and East Subnet),
IP32_cloud and PPP_DS3 bidirectional link.
                                                          No_Drop Scenario:

Within The west subnet we have the following:             The following changes are made in the basic

We have an Ethernet Server named Server_West              scenario to create the no drop scenario.

and a router named Router_West as shown in the            1. Application Configuration:

figure below.                                               •   Inter-Request Time = Constant (3600),
                                                                  specifies the amount of time between the
                                                                  file transfers.
                                                            •   File-Size = Constant (10000000), specifies the
                                                                  size of the file in Bytes during the file
                                                                  transfer.




                                                    -2-
2. Profile Configuration:
 • Start Time Offset = Constant (5), this offset
   refers to the time between the end of one
   application to the start of the next.
 • Duration = End of Profile, The maximum
   amount of time allowed for an application
   session before it aborts.
 • Repeatability = Once at Start Time, Specifies
   the parameters used to repeat execution of this
   profile
3. Server Configuration:
                                                               In the above graph we can see that the congestion
 • Application       supported       services        =
                                                               window    size    increases   rapidly   and   keeps
   FTP_Application. This is the application that
                                                               increasing linearly. Since there is no loss of
   the client will access the server for.
                                                               packets in this Scenario the congestion window
 • Server Address = Server_West, specifies the
                                                               increases significantly up to 135,000 by the end of
   address of the server in the network.
                                                               the simulation.
 • TCP Options = Disable fast recovery and fast
   retransmit.
4. Client Configuration:
   •   Application      supported      services      =
       FTP_Application. This is the application
       that the client will access the server for.
   •   Client Address = Client_East, specifies the
       address of the Client in the network.
   •   Application Destination Preferences =
       This defines the type of application the
       client will access and the address of the
       server                                                  In the above graph we can see that the sent
Results:                                                       segment sequence number increases linearly
                                                               because there is no loss of packets in this scenario
                                                               the receiver acknowledges all the packets and the
                                                               congestion window size increases, by the end of

                                                         -3-
the simulation the sequence number increases to            initially is in slow start phase and the congestion
36250000.                                                  window increases exponentially, when there is a
                                                           packet loss in the network the sender will not
Drop_NoFast Scenario:                                      receive any acknowledgement and senses a packet
Packets are dropped but we do not use Fast                 loss and hence the congestion window is set to 1
Retransmission and Fast Recovery techniques for            MSS and goes back to slowstart phase.
congestion control.
The configurations for this scenario remains the
same as in the No_Drop scenario but for one
change where we make the network to discard
some packets as given below.
1. Ip_32 cloud configuration:
 •   Packet Discard Ratio= 0.05% this specifies
       the percentage of packets dropped (ratio of
       packets dropped to the total packets
       submitted to this cloud multiplied by 100.)


Results:
                                                           From the above graph we can see that when ever
                                                           there is a packet loss and the congestion window
                                                           size decreases to 1 MSS there is a drop in the
                                                           sequence number during this time out, this is
                                                           because in this scenario we do not use either fast
                                                           retransmit or fast recovery techniques hence all
                                                           the packets will be sent between the packet which
                                                           caused time out and the data packet which was
                                                           currently being sent. Hence we can see a drop in
                                                           the sent sequence number whenever there is a
                                                           loss.
In the above graph we can see that the congestion
window follows a saw tooth pattern which is
typical of a practical network. Here the TCP

                                                     -4-
                                                        packet which caused time out and the data packet
                                                        which was currently being sent. Hence during this
                                                        period we do not see any increase in the sent
                                                        segment sequence number and hence we see a flat
                                                        line    during     this   period       of   time.


                                                        Drop_Fast Scenario:
                                                        In this scenario the packets are dropped and we
                                                        use Fast Recovery and fast retransmit to combat
                                                        congestion. We make the following changes to the
                                                        server configuration.
                                                        1. Server_West configuration:
Question 1.                                             TCP Options =
   Why does the segment sequence number                    •   Fast Retransmission = Enabled
remain unchanged with every drop in                        •   Fast Recovery = Reno
congestion window.
Ans.                                                    Results:




                                                        As we can see in the above graph we can see a
As mentioned earlier we can see that when there         saw tooth pattern typical to a Reno version of
is a packet loss the sender stops sending new           TCP.
packets and it sends the packets between the

                                                  -5-
We can see from above graph that it more closely
resembles the graph where there is no packet
drop. From which we can say that the growth of            and whenever there was a loss the sender would
sequence numbers in a Reno protocol is as good            send all the packets between the packet which
as the ideal transmission where there are no              caused time out and the data packet which was
packet drops.                                             currently being sent. Hence there is a delay during
                                                          transmission. Where as in case of Drop_Fast

Question 2:                                               scenario we used fast retransmit and TCP Reno, in

         Compare     the   graphs    of     three         this scenario when Reno receives duplicate
                                                          acknowledgement Reno does not go to a slow
scenarios and analyze why Drop_NoFast
                                                          start mode instead goes to a congestion avoidance
has the slowest growth in the sequence
                                                          mode. Hence more packets will be sent compared
numbers?
                                                          to Drop_NoFast scenario; hence Drop_NoFast has
From the graph below we can see that the
                                                          a slow growth in sequence numbers.
No_Drop scenario has the least delay in the
growth    of    sequence   numbers    and     the
                                                          Question 3:
Drop_NoFast has the maximum delay in the
                                                                 In Drop_NoFast scenario, obtain an
growth of sequence numbers. This is because in
                                                          overlaid graph that compares the sent
Drop_NoFast we did not use any form of
congestion control                                        segment sequence number and received
                                                          segment ack number for the Server_West.
                                                          Explain with graph.

                                                    -6-
                                                              Question 4:
From the above graph we can see that when there
                                                                     Compare the congestion window size
is a duplicate acknowledgement as indicated by
                                                              graph from the Drop_Fast scenario and
the arrow the sender sends all the packets between
                                                              Q4_Drop_Fast_Buffer
the lost data packet and the packets that it sent but
whose acknowledgements were ignored hence the
sent sequence number decreases and then
increases as shown in the graph.


Q4_Drop_Fast_Buffer Scenario:
       This scenario is similar to the Drop_Fast
scenario but the receiver buffer size is increased
1. Client_East Configuration:
   •   Receive Buffer = 65535


Results:
                                                              From the above graph we can see that there are
                                                              sharp spikes, this is because since the receiver has
                                                              a very large buffer the sender can send more
                                                              number of packets. When the sender senses
                                                              congestion in the network, the congestion window
                                                              size decreases and will again increase linearly.
                                                        -7-
                                                          not strictly linear because TCP uses an algorithm
                                                          called Binary Increase congestion control*.
                                                          According to this protocol, the minimum window
                                                          (MIWIND) size can be estimated as the window
                                                          size at with no packet loss occurs. Since we know
                                                          the maximum window (MAWIND) size the
                                                          current window (CWIND) size is taken as the mid
                                                          point of the Minimum window size and Maximum
                                                          window size. If the sender sees packet loss at the
                                                          CWIND, the CWIND is considered as the
                                                          MAWIND and a new CWIND is calculated. This
                                                          process is repeated until there is no packet loss.
As we can see from the above graph that when we           When there is no packet loss at this CWIND then
increased the receiver window size the growth of          this is considered as the new MIWIND.
sequence numbers is very rapid compared to                         This scheme allows the bandwidth probing
Drop_Fast.                                                more aggressive if the difference between the
                                                          CWIND and Target window is very large and is
Additional Questions:                                     less    aggressive   if   the   difference   is   less.
1. Why the cwnd in congestion avoidance                   Application of this scheme results in the
stage is not strictly linear in Drop_Fast?                logarithmic increase in the congestion window
Ans.                                                      size.
                                                          *Reference: L. Xu, K. Harfoush, and I. Rhee.
                                                          Binary Increase Congestion




In the congestion avoidance phase the increase is
                                                    -8-
2. Explain the spikes in Q4_Drop_Fast_Buffer.
Ans.




                                                             As we can see from the above graph that even if
From the above graph we can see that initially               the receiver buffer size is very large there can still
there is a drop I the congestion window, this is             be congestion in the network and hence the
due    to       the   receipt   of   the   duplicate         packets may be dropped, and this may lead to
acknowledgement by the sender. At this time the              time out as the duplicate acknowledgements may
congestion window size is halved, and the                    not reach the sender.
transmission steps into the congestion avoidance
phase and hence increases linearly. When the                 Conclusion:
acknowledgement for previously unacknowledged                       In this lab we explored the various features
data is received then the congestion window is set           and versions of TCP. In the first three scenarios
to CongWin= CongWin + MSS. Hence there is                    we found out that it is possible to increase the
again a steep increase in the transmission resulting         efficiency of the network and bring it as close as
in the spike.                                                possible to the ideal network performance by use
                                                             of various congestion control algorithms, like Fast
3. Show and explain why timeout may still                    Retransmissions and Fast Recovery.
happen in Q4_Drop_Fast_Buffer.
Ans.




                                                       -9-
Lab 6 &7 – RIP: Routing Information Protocol & OSPF: Open Shortest Path First
                                  Protocol
                              Venkat G Grandhi
             Computer Networks, COSC 6377, Dept of Computer Science
                              University of Houston




                                     - 10 -
Objective

To get familiar with the working and performance of the Routing Information Protocol by building a
network and comparing its performance under various scenarios

Method
       In this lab we create a network which uses RIP as the end to end network layer protocol.


Objects Used in the Simulated Network:
1. Routers:             In this simulation we use a ethernet4_slip8_gateway. This means it is a gateway
with 4 Ethernet ports and uses a Serial Line Input Protocol.


2. 100BaseT_LAN: This is a fast Ethernet LAN in a switched topology. The object contains any number
of clients as well as one server. Client traffic can be directed to the internal server as well as external
servers.


3. 100BaseT_link:       This is a duplex link represents an Ethernet connection operating at 100 Mbps.


Scenarios:
       Here we consider three different scenarios.
   •       No_Failure   : No failure in the link connecting the routers or the subnets.
   •       Failure      : The link connecting the Router1 and Router2 fails.
   •   Q3_Recover : The failed link in the above scenario recovers.
   In all the three above scenarios we keep a watch on the routing tables of all the routers and analyze
   them for the better understanding of the routing protocol.




The basic No_Failure scenario is shown below:




                                                     - 11 -
In this scenario we have four routers and two subnets connected to each router and all the four routers are
connected to each other. The IP addresses for the routers and the subnets are automatically assigned by
Opnet.




The IP addresses by the each router can be determined from the Generic Data File (GDF) that is created
when the above network was simulated. The GDF file looks like shown below. Here we have the GDF file
for the Router1, Net 11, Net 10
                                                  - 12 -
# Node Name: Campus Network.Router1
# Iface Name         Iface Index IP Address             Subnet Mask           Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0           0           192.0.0.1          255.255.255.0        Campus Network.Net10 <-> Router1
  IF1           1           192.0.1.1          255.255.255.0        Campus Network.Net11 <-> Router1
  IF2           2           192.0.2.1          255.255.255.0        Campus Network.Router4 <-> Router1
  IF3           3           192.0.3.1          255.255.255.0        Campus Network.Router1 <-> Router2
  Loopback      12           192.0.4.1         255.255.255.0        Not connected to any link.




# Node Name: Campus Network.Net11
# Iface Name         Iface Index IP Address             Subnet Mask           Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0           0           192.0.1.2          255.255.255.0        Campus Network.Net11 <-> Router1




# Node Name: Campus Network.Net10
# Iface Name         Iface Index IP Address             Subnet Mask           Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0           0           192.0.0.2          255.255.255.0        Campus Network.Net10 <-> Router1




From the above data we can figure out the IP addresses as shown below.




                                                                      - 13 -
When this network is simulated, each router will come up with a routing table and the routing table of
Router1 is shown below.



                                                - 14 -
Router name: Campus Network.Router1
at time: 600.00 seconds

ROUTE TABLE contents:
Dest. Address Subnet Mask Next Hop Interface Name Metric                  Protocol Insertion Time
 --------------- --------------- --------------- --------------- ------   -------- --------------

 192.0.0.0      255.255.255.0      192.0.0.1        IF0          0        Direct      0.000
 192.0.1.0      255.255.255.0      192.0.1.1        IF1          0        Direct      0.000
 192.0.2.0      255.255.255.0      192.0.2.1        IF2          0        Direct      0.000
 192.0.3.0      255.255.255.0      192.0.3.1        IF3          0        Direct      0.000
 192.0.4.0      255.255.255.0      192.0.4.1        Loopback      0        Direct     0.000
 192.0.7.0      255.255.255.0      192.0.2.2        IF2          1        RIP        5.000
 192.0.10.0     255.255.255.0      192.0.2.2        IF2          1        RIP        5.000
 192.0.11.0     255.255.255.0      192.0.2.2        IF2          1        RIP        5.000
 192.0.12.0     255.255.255.0      192.0.2.2        IF2          1        RIP        5.000
 192.0.8.0      255.255.255.0      192.0.3.2        IF3          1        RIP        5.000
 192.0.13.0     255.255.255.0      192.0.3.2       IF3           1        RIP        5.000
 192.0.14.0     255.255.255.0      192.0.3.2       IF3           1        RIP        5.000
 192.0.15.0     255.255.255.0      192.0.3.2       IF3           1        RIP        5.000
 192.0.5.0      255.255.255.0      192.0.3.2       IF3           2        RIP        6.428
 192.0.6.0      255.255.255.0      192.0.3.2       IF3           2        RIP        6.428
 192.0.9.0      255.255.255.0      192.0.3.2       IF3           2        RIP        6.428


To interpret this table let us consider the highlighted entry.
For Router1 to reach the network 192.0.13.0 the next hop router is 192.0.3.2 and the metric denotes the
number of hops and since the router 192.0.3.2 is one hop away from the Router1the metric is set as 1. The
insertion time determines the time at which the entry was inserted/updated in the routing table of Router1.




Total Number of Updates Graph:




                                                           - 15 -
From the above graph we can see the total number of updates in the routing table of Router1. We can see
that initially (between 0 and 6.4 ms) there were 13 updates to routing table and the following procedure
takes place.


Router1 updates itself as the subnets and the other routers are connected directly to its interfaces these
count to 5 updates (including the loopback)


Router2 and Router3 update Router1 with the subnets they are directly connected to and these counts to 8
updates



                                                  - 16 -
In the next iteration (between 6.4 s to 11 s) there are 3 updates to the routing table, during this period of
time there are actually 6 updates received by Router1 that is 3 updates from Router4 and 3 from Router2.


The routing table of each of the routers will initially be as follows.


Router1
             Net                     Next Hop Router                     No. Of Hops
192.0.0.0                                                       0
192.0.1.0                                                       0
192.0.2.0                                                       0
192.0.3.0                                                       0
192.0.4.0                                                       loopback


Router2
             Net                     Next Hop Router                     No. Of Hops
192.0.13.0                                                      0
192.0.14.0                                                      0
192.0.8.0                                                       0
192.0.3.0                                                       0
192.0.15.0                                                      Loopback


Router4
             Net                      Next Hop Router                     No. Of Hops
192.0.7.0                                                        0
192.0.11.0                                                       0
192.0.2.0                                                        0
192.0.10.0                                                       0
192.0.12.0                                                       Loopback


Router3
             Net                     Next Hop Router                     No. Of Hops


                                                     - 17 -
192.0.5.0                                                    0
192.0.6.0                                                    0
192.0.7.0                                                    0
192.0.8.0                                                    0
192.0.9.0                                                    Loopback


After forming the routing tables the routers share the tables with the adjacent routers and looking from the
view point of Router1 at the first iteration routers 2 and 4 will exchange routing tables with Router1 and
the updated table is shown below.




Router1
             Net                    Next Hop Router                 No. Of Hops
192.0.0.0                                                    0
192.0.1.0                                                    0
192.0.2.0                                                    0
192.0.3.0                                                    0
192.0.13.0                    Router2                        1
192.0.14.0                    Router2                        1
192.0.8.0                     Router2                        1
192.0.15.0                    Router2                        1
192.0.7.0                     Router4                        1
192.0.11.0                    Router4                        1
192.0.10.0                    Router4                        1
192.0.12.0                    Router4                        1


In the third iteration, the information from Router3 that was received and processed by Router2 and
Router4 during the 2nd iteration will be passed on to Router1. Router1 will now add it its routing table
paths to the subnet connected to Router3.


Router1
                                                   - 18 -
             Net       Next Hop Router          No. Of Hops
192.0.0.0                                   0
192.0.1.0                                   0
192.0.2.0                                   0
192.0.3.0                                   0
192.0.13.0         Router2                  1
192.0.14.0         Router2                  1
192.0.8.0          Router2                  1
192.0.15.0         Router2                  1
192.0.7.0          Router4                  1
192.0.11.0         Router4                  1
192.0.10.0         Router4                  1
192.0.12.0         Router4                  1
192.0.5.0          Router2                  2
192.0.6.0          Router2                  2
192.0.9.0          Router2                  2




RIP Traffic:




                                   - 19 -
We can see from the above graph that the RIP traffic sent over the network is very periodic and since there
is no change in the configuration of the network, there are constant updates periodically these are the RIP
Response messages exchanged between the routers every 30 seconds, which can also be considered as
keep-alive messages.




The Duplicate scenario with a failure in a network:
In this scenario we introduce a failure in a network, wherein the link between Router1 and Router2 fails
200 seconds into the simulation. The scenario is shown below.

                                                  - 20 -
Once the link fails we see the following changes in the routing table as shown below.
COMMON ROUTE TABLE snapshot for:

 Router name: Campus Network.Router1
   at time: 600.00 seconds

ROUTE TABLE contents:

Dest. Address Subnet Mask Next Hop Interface Name                 Metric    Protocol   Insertion Time
--------------- --------------- --------------- ---------------    ------    ------       --------------

 192.0.0.0       255.255.255.0      192.0.0.1        IF0           0        Direct        0.000
 192.0.1.0       255.255.255.0      192.0.1.1        IF1           0        Direct        0.000
 192.0.2.0       255.255.255.0      192.0.2.1        IF2           0        Direct        0.000
 192.0.3.0       255.255.255.0      192.0.3.1        IF3           0        Direct        0.000
 192.0.4.0       255.255.255.0      192.0.4.1        Loopback      0        Direct        0.000
 192.0.7.0       255.255.255.0      192.0.2.2        IF2           1        RIP           5.000
 192.0.10.0      255.255.255.0      192.0.2.2        IF2           1        RIP           5.000
 192.0.11.0      255.255.255.0      192.0.2.2        IF2           1        RIP           5.000
 192.0.12.0      255.255.255.0      192.0.2.2        IF2           1        RIP           5.000
 192.0.5.0       255.255.255.0      192.0.2.2        IF2           2        RIP           215.000
 192.0.6.0       255.255.255.0      192.0.2.2        IF2           2        RIP           215.000
 192.0.8.0       255.255.255.0      192.0.2.2        IF2           2        RIP           215.000
                                                             - 21 -
 192.0.9.0        255.255.255.0 192.0.2.2               IF2             2         RIP            215.000
 192.0.13.0       255.255.255.0 192.0.2.2               IF2             3         RIP            216.853
 192.0.14.0       255.255.255.0 192.0.2.2                IF2            3         RIP            216.853
 192.0.15.0       255.255.255.0 192.0.2.2                IF2            3         RIP            216.853


         Comparing the routing tables of the No_Failure scenario and Failure scenario we can see that all
the subnets which were previously reachable by Router2 are now rerouted via Router4. Hence the number
of hops increases by 1.
         There is no change in the routing tables of Routers3 and 4 because they are not connected to
Router1 via Router2.
         Now let us look at the routing table of Router2:
Initially when there was no failure in the network the routing table of Router2 was as below:


 Router name: Campus Network.Router2
   at time: 600.00 seconds

ROUTE TABLE contents:

  Dest. Address Subnet Mask                    Next Hop         Interface Name Metric           Protocol   Insertion Time
 --------------- --------------- --------------- --------------- ------    -------- --------------

 192.0.13.0       255.255.255.0       192.0.13.1          IF0            0         Direct         0.000
 192.0.14.0       255.255.255.0       192.0.14.1          IF1            0         Direct         0.000
 192.0.3.0        255.255.255.0       192.0.3.2         IF2             0         Direct         0.000
 192.0.8.0        255.255.255.0       192.0.8.2         IF3             0         Direct         0.000
 192.0.15.0       255.255.255.0       192.0.15.1          Loopback           0        Direct         0.000
 192.0.0.0        255.255.255.0       192.0.3.1         IF2             1         RIP            5.000
 192.0.1.0        255.255.255.0       192.0.3.1         IF2             1         RIP            5.000
 192.0.2.0        255.255.255.0       192.0.3.1         IF2             1         RIP            5.000
 192.0.4.0        255.255.255.0       192.0.3.1         IF2             1         RIP            5.000
 192.0.5.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.6.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.7.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.9.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.10.0       255.255.255.0       192.0.8.1          IF3            2         RIP            6.009
 192.0.11.0       255.255.255.0       192.0.8.1          IF3            2         RIP            6.009
 192.0.12.0       255.255.255.0       192.0.8.1          IF3            2         RIP            6.009




The routing table of Router2 after the failure is shown as below:

Router name: Campus Network.Router2
   at time: 600.00 seconds

ROUTE TABLE contents:

                                                                 - 22 -
  Dest. Address Subnet Mask                    Next Hop         Interface Name Metric           Protocol   Insertion Time
 --------------- --------------- --------------- --------------- ------    -------- --------------

 192.0.13.0       255.255.255.0       192.0.13.1          IF0            0         Direct         0.000
 192.0.14.0       255.255.255.0       192.0.14.1          IF1            0         Direct         0.000
 192.0.3.0        255.255.255.0       192.0.3.2         IF2             0         Direct         0.000
 192.0.8.0        255.255.255.0       192.0.8.2         IF3             0         Direct         0.000
 192.0.15.0       255.255.255.0       192.0.15.1          Loopback           0        Direct         0.000
 192.0.5.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.6.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.7.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.9.0        255.255.255.0       192.0.8.1         IF3             1         RIP            5.000
 192.0.2.0        255.255.255.0       192.0.8.1         IF3             2         RIP            215.000
 192.0.10.0       255.255.255.0       192.0.8.1          IF3            2         RIP            215.000
 192.0.11.0       255.255.255.0       192.0.8.1          IF3            2         RIP            215.000
 192.0.12.0       255.255.255.0       192.0.8.1          IF3            2         RIP            215.000
 192.0.0.0        255.255.255.0       192.0.8.1         IF3             3         RIP            218.619
 192.0.1.0        255.255.255.0       192.0.8.1         IF3             3         RIP            218.619
 192.0.4.0        255.255.255.0       192.0.8.1         IF3             3         RIP            218.619




Here we can notice that the failure of the link lead to the change in the path and the traffic to subnets
connected to Router1 is routed via Router3. (ANSWER TO QUESTION 2).




Total Number of Updates Graph (Failure):




                                                                 - 23 -
In the above graph we can see that as soon as there is a failure Router1 updates its table with the routing
table of Router4 and hence there are seven updates in the routing table of Router1.
Even tough there have been changes in the routing table of Router3 they are of no consequence to Router1
since it does not affect the routing of data to Router2.




RIP traffic:



                                                     - 24 -
       From the above graphs we can see that there is a burst of traffic immediately when there was a
failure in the network. The Router1 and Router2 sends out the message to Router4 and Router3 informing
the loss of connection, indicated by the red arrow.
       As soon as Router1 updates its routing table at the same time Router3 would have received the
updates from Router4 and Router2 hence the it sends out its updated table out to its adjacent routers and
hence we see a second burst of traffic indicated by the green arrow.
(ANSWER TO QUESTION 1)


The Duplicate scenario with a recovery in a network:
       In this scenario the failed link between Router1 and Router2 of the previous scenario is restored
and observe the following results.
       The routing tables are restored back as it was in the No_Failure scenario.
                                                      - 25 -
Router name: Campus Network.Router1
   at time: 600.00 seconds

ROUTE TABLE contents:

  Dest. Address Subnet Mask Next Hop Interface Name                       Metric      Protocol Insertion Time
 --------------- --------------- --------------- --------------- ------    --------   --------------

 192.0.0.0         255.255.255.0        192.0.0.1          IF0            0           Direct     0.000
 192.0.1.0         255.255.255.0        192.0.1.1          IF1            0           Direct     0.000
 192.0.2.0         255.255.255.0        192.0.2.1          IF2            0           Direct     0.000
 192.0.3.0         255.255.255.0        192.0.3.1          IF3            0           Direct     0.000
 192.0.4.0         255.255.255.0        192.0.4.1          Loopback       0           Direct     0.000
 192.0.7.0         255.255.255.0        192.0.2.2          IF2            1           RIP        5.000
 192.0.10.0        255.255.255.0        192.0.2.2           IF2           1           RIP        5.000
 192.0.11.0        255.255.255.0        192.0.2.2           IF2           1           RIP        5.000
 192.0.12.0        255.255.255.0        192.0.2.2           IF2           1           RIP        5.000
 192.0.5.0         255.255.255.0        192.0.2.2          IF2            2           RIP        215.000
 192.0.6.0         255.255.255.0        192.0.2.2          IF2            2           RIP        215.000
 192.0.9.0         255.255.255.0        192.0.2.2          IF2            2           RIP        215.000
 192.0.8.0         255.255.255.0        192.0.3.2          IF3            1           RIP        425.000
 192.0.13.0        255.255.255.0        192.0.3.2           IF3           1           RIP        425.000
 192.0.14.0        255.255.255.0        192.0.3.2           IF3           1           RIP        425.000
 192.0.15.0        255.255.255.0        192.0.3.2           IF3           1           RIP        425.000




Number of Updates Graph:




                                                                    - 26 -
Comparing the above two graphs we can see that as soon as the network recovered that is the link between
Router1 and Router2 recovers. Router1 updates its routing table and we can see that there are 8 updates
made in the routing table of Router1. (ANSWER FOR QUESTION 3)




                                 OSPF- Open Shortest Path First


Objective

To get familiar with the working and performance of the Open Shortest Path First (OSPF) protocol by
building a network and comparing its performance under various scenarios

Method

                                                  - 27 -
        In this lab we create a network which uses OSPF as the end to end network layer protocol.


Objects Used in the Simulated Network:
    •   Routers:                               In this simulation we use slip8_gateway. This means it is a
        gateway which uses a Serial Line Input Protocol.
    •   PPP_DS3 Bidirectional Link:         It is a Point-to-Point-Protocol dedicated bidirectional link
        supporting data rates of about 43 Mbps.


 Scenarios:
        Here we consider three different scenarios.
   •    No_Areas       : There routers are not divided into areas
   •    Areas          : The Routers are divided into 3 areas (area 0, 1 and 2, 0 being the backbone).
   •    Balanced       :




Scenario1: No_Areas
In this scenario we have 8 Slip8_gtwy routers connected as shown in the figure below. We use PPP_DS3
bidirectional links to connect all the 8 routers.




                                                      - 28 -
Each link is assigned costs as in the case of OSPF the routing metric is not the number of hops as in the
RIP. The costs are calculated using the following formula.
                      Cost = Reference Bandwidth
                               Link Bandwidth




The costs for the links are shown as in the following diagram.




                                                   - 29 -
We then need to create traffic from RouterA to RouterC indicated by blue line and from RouterB to
RouterH indicated by the red line, as shown in the figure below.




Now based on the cost set by us in the previous step OSPF calculates the least cost between the two points
before routing the traffic.
Hence when the traffic from RouterA to RouterC is routed it takes the route indicated by the thick blue
line. The cost adds up to (A-D= 5, D-E=5, E-C=5) 5+5+5=15.
                                                  - 30 -
Similarly when the traffic from RouterB to RouterH is routed it takes the following path.




The cost of this path adds up to (20+5+5+10) = 40. Which is the least cost between the two routers.


Scenario2: Areas
This scenario is the duplicate scenario of the No_Area scenario hence the link costs remains the same but
the only difference is that the eight routers are divided into 3 areas as follows.

                                                     - 31 -
                            Areas                   Routers
                               0               D, E (Backbone)
                               1                  A, B and C
                               2                  F, G and H




The OSPF now calculates the new routing paths based on an additional parameter that is areas hence the
traffic flow from RouterA to RouterC changes from A-D-E-C to A-C even if the cost of A-C direct link is
more. This is shown in the following figure by the thick blue dotted line.




                                                   - 32 -
Scenario3: Balanced
In this scenario if the traffic between two routers can take different paths and if all the paths have the same
cost then the traffic is distributed equally among the paths. In the following figure we can see that the
traffic from RouterB to RouterC can take two different paths with the same cost hence the traffic is
distributed on among the two routes.




Question 1:


                                                    - 33 -
                 In the No_Areas scenario we do not have any areas defined hence all the 8 routers fall in the same
      area, the OSPF routing protocol therefore calculates the shortest path between the routers and sends the
      traffic.
                 In the Area scenario OSPF calculates the new routing paths based on an additional parameter that
      is area information hence the traffic flow from RouterA to RouterC changes from A-D-E-C (15) to A-C
      even if the cost of A-C (20) direct link is more. This is shown in the following figure by the thick blue
      dotted line.
                 In the Balanced scenario if the traffic between two routers can take different paths and if all the
      paths have the same cost then the traffic is distributed equally among the paths. In the following figure we
      can see that the traffic from RouterB to RouterC can take two different paths with the same cost hence the
      traffic is distributed on among the two routes.


      Question 2:
      No_Areas Scenario:
#
# Purpose: Contains IP address information for all active
#       interfaces in the current network model.
#       (created by exporting this information from the model.)
#

# Node Name: Campus Network.RouterA
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.1.2         255.255.255.0 Campus Network.RouterA <-> RouterB
  IF1            1          192.0.2.2         255.255.255.0 Campus Network.RouterA <-> RouterC
  IF2            2          192.0.5.2         255.255.255.0 Campus Network.RouterA <-> RouterD
  Loopback      8          192.0.16.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterB
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.1.1         255.255.255.0 Campus Network.RouterA <-> RouterB
  IF1            1          192.0.8.2         255.255.255.0 Campus Network.RouterB <-> RouterC
  Loopback       8          192.0.13.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterC
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.2.1         255.255.255.0 Campus Network.RouterA <-> RouterC
  IF1            1          192.0.8.1         255.255.255.0 Campus Network.RouterB <-> RouterC
  IF2            2          192.0.9.1         255.255.255.0 Campus Network.RouterC <-> RouterE
  Loopback       8          192.0.12.1          255.255.255.0 Not connected to any link.


                                                             - 34 -
# Node Name: Campus Network.RouterD
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.3.2         255.255.255.0 Campus Network.RouterD <-> RouterE
  IF1            1          192.0.4.1         255.255.255.0 Campus Network.RouterD <-> RouterF
  IF2            2          192.0.5.1         255.255.255.0 Campus Network.RouterA <-> RouterD
  Loopback       8          192.0.15.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterE
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.3.1         255.255.255.0 Campus Network.RouterD <-> RouterE
  IF1            1          192.0.9.2         255.255.255.0 Campus Network.RouterC <-> RouterE
  IF2            2          192.0.10.1         255.255.255.0 Campus Network.RouterE <-> RouterG
  Loopback       8          192.0.14.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterF
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.4.2         255.255.255.0 Campus Network.RouterD <-> RouterF
  IF1            1          192.0.6.1         255.255.255.0 Campus Network.RouterF <-> RouterG
  IF2            2          192.0.7.1         255.255.255.0 Campus Network.RouterF <-> RouterH
  Loopback           8          192.0.17.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterG
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.6.2         255.255.255.0 Campus Network.RouterF <-> RouterG
  IF1            1          192.0.10.2         255.255.255.0 Campus Network.RouterE <-> RouterG
  IF2            2          192.0.11.1         255.255.255.0 Campus Network.RouterG <-> RouterH
  Loopback      8          192.0.18.1          255.255.255.0 Not connected to any link.


# Node Name: Campus Network.RouterH
# Iface Name        Iface Index IP Address              Subnet Mask         Connected Link
# ----------   ----------- --------------- --------------- ----------------
  IF0            0          192.0.7.2         255.255.255.0 Campus Network.RouterF <-> RouterH
  IF1            1          192.0.11.2         255.255.255.0 Campus Network.RouterG <-> RouterH
  Loopback       8          192.0.19.1          255.255.255.0 Not connected to any link.




     From the GDF we can figure the IP addresses of the links, as shown in the figure below.




                                                          - 35 -
From the simulation log for RouterA we can interpret the routing table as follows:
Router name: Campus Network.RouterA
    at time: 600.00 seconds
ROUTE TABLE contents:
  Dest. Address Subnet Mask Next Hop Interface Name                 Metric     Protocol   Insertion Time
 --------------- --------------- - -------------- ---------------    ------   --------      --------------
 192.0.1.0        255.255.255.0 192.0.1.2              IF0          0         Direct       0.000
 192.0.2.0        255.255.255.0 192.0.2.2              IF1          0         Direct       0.000
 192.0.5.0        255.255.255.0 192.0.5.2              IF2          0         Direct       0.000
 192.0.16.0       255.255.255.0 192.0.16.1             Loopback     0         Direct       0.000
 192.0.15.0       255.255.255.0 192.0.5.1              IF2          5         OSPF          36.496
 192.0.3.0        255.255.255.0 192.0.5.1              IF2          10        OSPF           36.496
 192.0.4.0        255.255.255.0 192.0.5.1              IF2          10        OSPF           36.496
 192.0.17.0       255.255.255.0 192.0.5.1              IF2          10        OSPF           36.496
 192.0.6.0        255.255.255.0 192.0.5.1              IF2          20        OSPF           36.496
 192.0.7.0        255.255.255.0 192.0.5.1              IF2          20        OSPF           36.496
 192.0.18.0       255.255.255.0 192.0.5.1              IF2          15        OSPF           36.496
 192.0.10.0       255.255.255.0 192.0.5.1              IF2          15        OSPF           36.496
 192.0.11.0       255.255.255.0 192.0.5.1              IF2          25        OSPF           36.496
 192.0.19.0       255.255.255.0 192.0.5.1              IF2          20        OSPF           36.496
 192.0.13.0       255.255.255.0 192.0.1.1              IF0          20        OSPF           36.496
 192.0.8.0        255.255.255.0 192.0.5.1              IF2          35        OSPF           36.496
 192.0.14.0       255.255.255.0 192.0.5.1              IF2          10        OSPF           36.496
 192.0.9.0        255.255.255.0 192.0.5.1              IF2          15        OSPF           36.496
 192.0.12.0       255.255.255.0 192.0.5.1              IF2          15        OSPF           36.496
Hence for RouterA to send a packet in the No_Area scenario to various destinations are given below.
    •    To destination link 1 its next hop is interface 1.2, the cost is 0
    •    To destination link 2 its next hop is interface 2.2, the cost is 0

                                                             - 36 -
    •    To destination link 3 its next hop is interface 5.1, the cost is 10
    •    To destination link 4 its next hop is interface 5.2, the cost is 10
    •    To destination link 5 its next hop is interface 5.2, the cost is 0
    •    To destination link 6 its next hop is interface 5.1, the cost is 20
    •    To destination link 7 its next hop is interface 5.1, the cost is 20
    •    To destination link 8 its next hop is interface 5.1, the cost is 35
    •    To destination link 9 its next hop is interface 5.1, the cost is 15
    •    To destination link 10 its next hop is interface 5.1, the cost is 15
    •    To destination link 11 its next hop is interface 5.1, the cost is 25


The routing information about routers at RouterA is as below:
    •    To RouterB the next hop is RouterB, the cost is 20
    •    To RouterC the next hop is RouterD, the cost is 15
    •    To RouterD the next hop is RouterD, the cost is 5
    •    To RouterE the next hop is RouterD, the cost is 10
    •    To RouterF the next hop is RouterD, the cost is 10
    •    To RouterG the next hop is RouterD, the cost is 15
    •    To RouterH the next hop is RouterD, the cost is 20


Areas Scenario:
COMMON ROUTE TABLE snapshot for:
 Router name: Campus Network.RouterA
  at time: 600.00 seconds
ROUTE TABLE contents:

  Dest. Address Subnet Mask               Next Hop         Interface Name Metric      Protocol Insertion Time
 --------------- --------------- --------------- --------------- ------ -------- --------------

 192.0.1.0     255.255.255.0     192.0.1.2       IF0          0         Direct       0.000
 192.0.2.0     255.255.255.0     192.0.2.2       IF1          0         Direct       0.000
 192.0.5.0     255.255.255.0     192.0.5.2       IF2          0         Direct       0.000
 192.0.16.0    255.255.255.0     192.0.16.1       Loopback    0         Direct       0.000
 192.0.13.0    255.255.255.0     192.0.1.1       IF0          20        OSPF          36.496
 192.0.8.0     255.255.255.0     192.0.2.1       IF1          40        OSPF           36.496
                                 192.0.1.1       IF0          40        OSPF           36.496
 192.0.12.0    255.255.255.0     192.0.2.1       IF1          20        OSPF          36.496
 192.0.9.0     255.255.255.0     192.0.5.1       IF2          15        OSPF           36.496
 192.0.14.0    255.255.255.0     192.0.5.1       IF2          10        OSPF          36.496
 192.0.3.0     255.255.255.0     192.0.5.1       IF2          10        OSPF           36.496
 192.0.10.0    255.255.255.0     192.0.5.1       IF2          15        OSPF          36.496

                                                               - 37 -
 192.0.17.0   255.255.255.0   192.0.5.1   IF2        10        OSPF          36.496
 192.0.4.0    255.255.255.0   192.0.5.1   IF2        10        OSPF           36.496
 192.0.15.0   255.255.255.0   192.0.5.1   IF2        5         OSPF          36.496
 192.0.18.0   255.255.255.0   192.0.5.1   IF2        15        OSPF          36.496
 192.0.11.0   255.255.255.0   192.0.5.1   IF2        25        OSPF          36.496
 192.0.19.0   255.255.255.0   192.0.5.1   IF2        20        OSPF          36.496
 192.0.7.0    255.255.255.0   192.0.5.1   IF2        20        OSPF           36.496
 192.0.6.0    255.255.255.0   192.0.5.1   IF2        20        OSPF           36.496


    •   To destination link 1 its next hop is interface 1.2, the cost is 0
    •   To destination link 2 its next hop is interface 2.2, the cost is 0
    •   To destination link 3 its next hop is interface 5.1, the cost is 10
    •   To destination link 4 its next hop is interface 5.2, the cost is 10
    •   To destination link 5 its next hop is interface 5.2, the cost is 0
    •   To destination link 6 its next hop is interface 5.1, the cost is 20
    •   To destination link 7 its next hop is interface 5.1, the cost is 20
    •   To destination link 8 its next hop is interface 5.0, the cost is 40
    •   To destination link 9 its next hop is interface 5.1, the cost is 15
    •   To destination link 10 its next hop is interface 5.1, the cost is 15
    •   To destination link 11 its next hop is interface 5.1, the cost is 25


The routing information about routers at RouterA is as below:
    •   To RouterB the next hop is RouterB, the cost is 20
    •   To RouterC the next hop is RouterD, the cost is 20
    •   To RouterD the next hop is RouterD, the cost is 5
    •   To RouterE the next hop is RouterD, the cost is 10
    •   To RouterF the next hop is RouterD, the cost is 10
    •   To RouterG the next hop is RouterD, the cost is 15
    •   To RouterH the next hop is RouterD, the cost is 20




Balanced Scenario:

COMMON ROUTE TABLE snapshot for:
                                                      - 38 -
 Router name: Campus Network.RouterA
    at time: 600.00 seconds
ROUTE TABLE contents:
  Dest. Address Subnet Mask               Next Hop         Interface Name Metric      Protocol Insertion Time
 --------------- --------------- --------------- --------------- ------ -------- --------------

 192.0.1.0      255.255.255.0    192.0.1.2       IF0          0         Direct       0.000
 192.0.2.0      255.255.255.0    192.0.2.2       IF1          0         Direct       0.000
 192.0.5.0      255.255.255.0    192.0.5.2       IF2          0         Direct       0.000
 192.0.16.0     255.255.255.0    192.0.16.1       Loopback    0         Direct       0.000
 192.0.15.0     255.255.255.0    192.0.5.1       IF2          5         OSPF          36.496
 192.0.3.0      255.255.255.0    192.0.5.1       IF2          10        OSPF           36.496
 192.0.4.0      255.255.255.0    192.0.5.1       IF2          10        OSPF           36.496
 192.0.17.0     255.255.255.0    192.0.5.1       IF2          10        OSPF          36.496
 192.0.6.0      255.255.255.0    192.0.5.1       IF2          20        OSPF           36.496
 192.0.7.0      255.255.255.0    192.0.5.1       IF2          20        OSPF           36.496
 192.0.18.0     255.255.255.0    192.0.5.1       IF2          15        OSPF          36.496
 192.0.10.0     255.255.255.0    192.0.5.1       IF2          15        OSPF          36.496
 192.0.11.0     255.255.255.0    192.0.5.1       IF2          25        OSPF          36.496
 192.0.19.0     255.255.255.0    192.0.5.1       IF2          20        OSPF          36.496
 192.0.13.0     255.255.255.0    192.0.1.1       IF0          20        OSPF          36.496
 192.0.8.0      255.255.255.0    192.0.5.1       IF2          35        OSPF           36.496
 192.0.14.0     255.255.255.0    192.0.5.1       IF2          10        OSPF          36.496
 192.0.9.0      255.255.255.0    192.0.5.1       IF2          15        OSPF           36.496
 192.0.12.0     255.255.255.0    192.0.5.1       IF2          15        OSPF            36.496




    •    To destination link 1 its next hop is interface 1.2, the cost is 0
    •    To destination link 2 its next hop is interface 2.2, the cost is 0
    •    To destination link 3 its next hop is interface 5.1, the cost is 10
    •    To destination link 4 its next hop is interface 5.1, the cost is 10
    •    To destination link 5 its next hop is interface 5.2, the cost is 0
    •    To destination link 6 its next hop is interface 5.1, the cost is 20
    •    To destination link 7 its next hop is interface 5.1, the cost is 20
    •    To destination link 8 its next hop is interface 5.1, the cost is 35
    •    To destination link 9 its next hop is interface 5.1, the cost is 15
    •    To destination link 10 its next hop is interface 5.1, the cost is 15
    •    To destination link 11 its next hop is interface 5.1, the cost is 25


The routing information about routers at RouterA is as below:
    •    To RouterB the next hop is RouterB, the cost is 20
    •    To RouterC the next hop is RouterD, the cost is 15
    •    To RouterD the next hop is RouterD, the cost is 5
                                                               - 39 -
      •      To RouterE the next hop is RouterD, the cost is 10
      •      To RouterF the next hop is RouterD, the cost is 10
      •      To RouterG the next hop is RouterD, the cost is 15
      •      To RouterH the next hop is RouterD, the cost is 20


Question 3:


[Router Links Advertisements for Area 0.0.0.0]
Link state advertisement list size: 8
----------------------------------
LSA Type: Router Links, Link State ID: 192.0.15.1, Adv Router ID: 192.0.15.1 Sequence Number: 50, LSA Age: 5
LSA Timestamp: 24.546
 Link Type: Stub Network, Link ID: 192.0.15.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.14.1, Link Data: 192.0.3.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.3.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.4.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.4.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.5.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.5.0, Link Data: 255.255.255.0, Link Cost: 5,


LSA Type: Router Links, Link State ID: 192.0.17.1, Adv Router ID: 192.0.17.1 Sequence Number: 51, LSA Age: 5
LSA Timestamp: 24.546
 Link Type: Stub Network, Link ID: 192.0.17.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.15.1, Link Data: 192.0.4.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.4.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.6.1, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.6.0, Link Data: 255.255.255.0, Link Cost: 10,
 Link Type: Point-To-Point, Link ID: 192.0.19.1, Link Data: 192.0.7.1, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.7.0, Link Data: 255.255.255.0, Link Cost: 10,


LSA Type: Router Links, Link State ID: 192.0.18.1, Adv Router ID: 192.0.18.1 Sequence Number: 52, LSA Age: 7
LSA Timestamp: 24.931
 Link Type: Stub Network, Link ID: 192.0.18.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.6.2, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.6.0, Link Data: 255.255.255.0, Link Cost: 10,
 Link Type: Point-To-Point, Link ID: 192.0.14.1, Link Data: 192.0.10.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.10.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.19.1, Link Data: 192.0.11.1, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.11.0, Link Data: 255.255.255.0, Link Cost: 10,


LSA Type: Router Links, Link State ID: 192.0.19.1, Adv Router ID: 192.0.19.1 Sequence Number: 53, LSA Age: 6
LSA Timestamp: 24.931
 Link Type: Stub Network, Link ID: 192.0.19.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.7.2, Link Cost: 10,

                                                                      - 40 -
 Link Type: Stub Network, Link ID: 192.0.7.0, Link Data: 255.255.255.0, Link Cost: 10,
 Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.11.2, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.11.0, Link Data: 255.255.255.0, Link Cost: 10,


LSA Type: Router Links, Link State ID: 192.0.16.1, Adv Router ID: 192.0.16.1 Sequence Number: 130, LSA Age: 3
LSA Timestamp: 27.916
 Link Type: Stub Network, Link ID: 192.0.16.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.13.1, Link Data: 192.0.1.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.1.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.2.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.2.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.15.1, Link Data: 192.0.5.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.5.0, Link Data: 255.255.255.0, Link Cost: 5,


LSA Type: Router Links, Link State ID: 192.0.13.1, Adv Router ID: 192.0.13.1 Sequence Number: 131, LSA Age: 3
LSA Timestamp: 27.916
 Link Type: Stub Network, Link ID: 192.0.13.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.1.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.1.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.8.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.8.0, Link Data: 255.255.255.0, Link Cost: 20,


LSA Type: Router Links, Link State ID: 192.0.14.1, Adv Router ID: 192.0.14.1 Sequence Number: 49, LSA Age: 8
LSA Timestamp: 32.916
 Link Type: Stub Network, Link ID: 192.0.14.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.15.1, Link Data: 192.0.3.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.3.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.9.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.9.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.10.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.10.0, Link Data: 255.255.255.0, Link Cost: 5,


LSA Type: Router Links, Link State ID: 192.0.12.1, Adv Router ID: 192.0.12.1 Sequence Number: 48, LSA Age: 7
LSA Timestamp: 32.916
 Link Type: Stub Network, Link ID: 192.0.12.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.2.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.2.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.13.1, Link Data: 192.0.8.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.8.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.14.1, Link Data: 192.0.9.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.9.0, Link Data: 255.255.255.0, Link Cost: 5,




Once the RouterA receives the link state advertisements from all the routers it calculates the shortest path
using the Dijkstra’s Algorithm. The paths are calculated and the map is shown below.



                                                                      - 41 -
Question 4:
       This scenario is a duplicate of the No_Areas scenario; in this scenario we simulate failure of the
link connecting RouterD and RouterE. The failure occurs 100 seconds after the simulation has started.




The link state table for the RouterA is shown below



Link State Database snapshot for:
 Router Name: RouterA
   at time: 600.00

                                                 - 42 -
[Router Links Advertisements for Area 0.0.0.0]
Link state advertisement list size: 8
----------------------------------
LSA Type: Router Links, Link State ID: 192.0.17.1, Adv Router ID: 192.0.17.1 Sequence Number: 51, LSA Age: 5
LSA Timestamp: 24.546
  Link Type: Stub Network, Link ID: 192.0.17.1, Link Data: 255.255.255.0, Link Cost: 0,
  Link Type: Point-To-Point, Link ID: 192.0.15.1, Link Data: 192.0.4.2, Link Cost: 5,
  Link Type: Stub Network, Link ID: 192.0.4.0, Link Data: 255.255.255.0, Link Cost: 5,
  Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.6.1, Link Cost: 10,
  Link Type: Stub Network, Link ID: 192.0.6.0, Link Data: 255.255.255.0, Link Cost: 10,
  Link Type: Point-To-Point, Link ID: 192.0.19.1, Link Data: 192.0.7.1, Link Cost: 10,
  Link Type: Stub Network, Link ID: 192.0.7.0, Link Data: 255.255.255.0, Link Cost: 10,

LSA Type: Router Links, Link State ID: 192.0.18.1, Adv Router ID: 192.0.18.1 Sequence Number: 52, LSA Age: 7
LSA Timestamp: 24.931
 Link Type: Stub Network, Link ID: 192.0.18.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.6.2, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.6.0, Link Data: 255.255.255.0, Link Cost: 10,
 Link Type: Point-To-Point, Link ID: 192.0.14.1, Link Data: 192.0.10.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.10.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.19.1, Link Data: 192.0.11.1, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.11.0, Link Data: 255.255.255.0, Link Cost: 10,

LSA Type: Router Links, Link State ID: 192.0.19.1, Adv Router ID: 192.0.19.1 Sequence Number: 53, LSA Age: 6
LSA Timestamp: 24.931
 Link Type: Stub Network, Link ID: 192.0.19.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.7.2, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.7.0, Link Data: 255.255.255.0, Link Cost: 10,
 Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.11.2, Link Cost: 10,
 Link Type: Stub Network, Link ID: 192.0.11.0, Link Data: 255.255.255.0, Link Cost: 10,

LSA Type: Router Links, Link State ID: 192.0.16.1, Adv Router ID: 192.0.16.1 Sequence Number: 130, LSA Age: 3
LSA Timestamp: 27.916
 Link Type: Stub Network, Link ID: 192.0.16.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.13.1, Link Data: 192.0.1.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.1.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.2.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.2.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.15.1, Link Data: 192.0.5.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.5.0, Link Data: 255.255.255.0, Link Cost: 5,

LSA Type: Router Links, Link State ID: 192.0.13.1, Adv Router ID: 192.0.13.1 Sequence Number: 131, LSA Age: 3
LSA Timestamp: 27.916
 Link Type: Stub Network, Link ID: 192.0.13.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.1.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.1.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.8.2, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.8.0, Link Data: 255.255.255.0, Link Cost: 20,

LSA Type: Router Links, Link State ID: 192.0.12.1, Adv Router ID: 192.0.12.1 Sequence Number: 48, LSA Age: 7
LSA Timestamp: 32.916
 Link Type: Stub Network, Link ID: 192.0.12.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.2.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.2.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.13.1, Link Data: 192.0.8.1, Link Cost: 20,
 Link Type: Stub Network, Link ID: 192.0.8.0, Link Data: 255.255.255.0, Link Cost: 20,
 Link Type: Point-To-Point, Link ID: 192.0.14.1, Link Data: 192.0.9.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.9.0, Link Data: 255.255.255.0, Link Cost: 5,

LSA Type: Router Links, Link State ID: 192.0.15.1, Adv Router ID: 192.0.15.1 Sequence Number: 381, LSA Age: 4
LSA Timestamp: 105.000
 Link Type: Stub Network, Link ID: 192.0.15.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.17.1, Link Data: 192.0.4.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.4.0, Link Data: 255.255.255.0, Link Cost: 5,

                                                          - 43 -
 Link Type: Point-To-Point, Link ID: 192.0.16.1, Link Data: 192.0.5.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.5.0, Link Data: 255.255.255.0, Link Cost: 5,

LSA Type: Router Links, Link State ID: 192.0.14.1, Adv Router ID: 192.0.14.1 Sequence Number: 382, LSA Age: 4
LSA Timestamp: 105.000
 Link Type: Stub Network, Link ID: 192.0.14.1, Link Data: 255.255.255.0, Link Cost: 0,
 Link Type: Point-To-Point, Link ID: 192.0.12.1, Link Data: 192.0.9.2, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.9.0, Link Data: 255.255.255.0, Link Cost: 5,
 Link Type: Point-To-Point, Link ID: 192.0.18.1, Link Data: 192.0.10.1, Link Cost: 5,
 Link Type: Stub Network, Link ID: 192.0.10.0, Link Data: 255.255.255.0, Link Cost: 5,




Routing Table of RouterA
COMMON ROUTE TABLE snapshot for:
 Router name: Campus Network.RouterA
    at time: 600.00 seconds
ROUTE TABLE contents:
Dest. Address Subnet Mask Next Hop               Interface Name        Metric     Protocol    Insertion Time
 --------------- --------------- ---------------    ---------------     ------     --------     --------------

 192.0.1.0       255.255.255.0  192.0.1.2             IF0             0          Direct       0.000
 192.0.2.0       255.255.255.0  192.0.2.2             IF1             0          Direct       0.000
 192.0.5.0       255.255.255.0  192.0.5.2             IF2             0          Direct       0.000
 192.0.16.0      255.255.255.0  192.0.16.1             Loopback       0          Direct       0.000
 192.0.17.0      255.255.255.0  192.0.5.1             IF2             10         OSPF           106.496
 192.0.4.0       255.255.255.0  192.0.5.1             IF2             10         OSPF           106.496
 192.0.6.0       255.255.255.0  192.0.5.1             IF2             20         OSPF           106.496
 192.0.7.0       255.255.255.0  192.0.5.1             IF2             20         OSPF           106.496
 192.0.18.0      255.255.255.0  192.0.5.1             IF2             20         OSPF           106.496
 192.0.10.0      255.255.255.0  192.0.5.1             IF2             25         OSPF           106.496
 192.0.11.0      255.255.255.0  192.0.5.1             IF2             30         OSPF           106.496
 192.0.19.0      255.255.255.0  192.0.5.1             IF2             20         OSPF           106.496
 192.0.13.0      255.255.255.0  192.0.1.1             IF0             20         OSPF           106.496
 192.0.8.0       255.255.255.0  192.0.2.1             IF1             40         OSPF           106.496
                                192.0.1.1              IF0             40         OSPF           106.496
 192.0.12.0       255.255.255.0 192.0.2.1              IF1             20         OSPF           106.496
 192.0.9.0       255.255.255.0 192.0.2.1              IF1             25         OSPF           106.496
 192.0.15.0       255.255.255.0 192.0.5.1              IF2             5         OSPF           106.496
 192.0.14.0       255.255.255.0 192.0.5.1              IF2             25         OSPF           106.496
                                192.0.2.1              IF1             25         OSPF           106.496



     •    To destination link 1 its next hop is interface 1.2, the cost is 0
     •    To destination link 2 its next hop is interface 2.2, the cost is 0
     •    FAILED To destination link 3 its next hop is interface 5.1, the cost is 10
     •    To destination link 4 its next hop is interface 5.1, the cost is 10
     •    To destination link 5 its next hop is interface 5.2, the cost is 0
     •    To destination link 6 its next hop is interface 5.1, the cost is 20
     •    To destination link 7 its next hop is interface 5.1, the cost is 20
     •    To destination link 8 its next hop is interface 2.1, the cost is 40
     •    To destination link 9 its next hop is interface 5.1, the cost is 25
                                                        - 44 -
   •   To destination link 10 its next hop is interface 5.1, the cost is 25
   •   To destination link 11 its next hop is interface 5.1, the cost is 30




The routing information about routers at RouterA is as below:
   •   To RouterB the next hop is RouterB, the cost is 20
   •   To RouterC the next hop is RouterD, the cost is 20
   •   To RouterD the next hop is RouterD, the cost is 5
   •   To RouterE the next hop is RouterC, the cost is 25
   •   To RouterF the next hop is RouterD, the cost is 10
   •   To RouterG the next hop is RouterD, the cost is 20
   •   To RouterH the next hop is RouterD, the cost is 20




                                                    - 45 -
Question 5:
The graph for the traffic sent in bits/sec for the No_Areas scenario and Q4_No_Areas_Failures scenarios
are as shown below.




The Q4_No_Areas_Failure graph shows that at time 100sec there is a second peak marked by the circle.
This surge in the traffic is due to the to the failure of link between RouterD and RouterE at the 100th


                                                - 46 -
second of the simulation hence there is a large amount of information exchanged by the routers and this
information will be used to construct the new routing tables of the individual routers.




                                                   - 47 -

								
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