lab4-report - Heyook

thoughtlessskytopNetworking and Communications

Oct 29, 2013 (4 years and 15 days ago)

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Lab Four
: Dynamic Routing Protocols (RIP, OSPF, and BGP)





















Members:

Edmund Chang

70813570



Lin He

52924739


Negar Mohades



2

Prelab 4


1.) The command that configures a Linux PC as an IP router is:






echo "1" > /proc/sys/net/ip
v4/ip_forward


2.) The main differences between a distance vector routing protocol and a link state
routing protocol are:

--
link
-
state algorithms send small updates everywhere, while distance vector
algorithms send larger updates only to neighboring router
s.

--
Because they converge more quickly, link
-
state algorithms are somewhat less
prone to routing loops than distance vector algorithms.

--
link
-
state algorithms require more CPU power and memory than distance vector
algorithms.

--
Link
-
state protocols are g
enerally more scalable than distance vector protocols.


3.) The differences between an intradomain routing protocol (interior gateway
protocol IGP) and in interdomain routing protocol (exterior gateway protocol EGP)
are:

--
Intradomain Routing Protocols wor
k only within domains.

--
Interdomian Routing Protocols work within and between domains.

An example of an intradomain protocol is RIP and OSPF.

An example of an interdomain protocol is BGP.


4.) Zebra supports RIP, GDP, and OSPF routing protocols.


5.) The
process zebra updates the routing tables and exchanges routes between different routing protocols.


6.) The user starts zebra and then the specific routing protocol using for example ‘zebra start’ and then ‘ripd
start’. Then he or she telnets into the loca
lhost on the 2602 port using this command ‘telnet localhost 2602’
and then logs in and it emulates a real router OS such as the Cisco IOS.


7.) RIP 2 enabled RIP messages to carry more information, which permitted the use of a simple
authentication mechani
sm to secure table updates. More importantly, RIP 2 supported subnet masks, a
critical feature that was not available in RIP.


8.) Passive mode means that the host receives and processes incoming routing messages but does not
transmit routing messages. Act
ive routers advertise their routes (reachability information) to others; passive
routers listen and update their routes based on advertisements but do not advertise (flood). Typically,
routers run RIP in active mode, while hosts use passive mode.


9.) When

the RIP sends routing
-
update when the network topology changes. When a router receives a
routing update that includes changes to an entry, it updates its routing table to reflect the new route. After
updating its routing table, the router immediately begi
ns transmitting routing updates to inform other
network routers of the change. These updates are sent independently of the regularly scheduled updates that
RIP routers send. These independently sent updates are called triggered updates.


10.) Split
-
horizon

is a mechanism that prevents incorrect routing information from being propagated. The
split horizon rule prohibits a router from advertising a route through an interface that the router itself is
using to reach the destination. In other words, its routing

technique prevents information from exiting the
router interface from which that information was received. Split
-
horizon updates are useful in preventing
routing loops. In general, split horizon with poisoned reverse is safer than simple split horizon. If

two
gateways have routes pointing at each other, advertising reverse routes with a metric of 16 will break the
loop immediately. If the reverse routes are simply not advertised, the erroneous routes will have to be
eliminated by waiting for a timeout. How
ever, poisoned reverse does have a disadvantage: it increases the
size of the routing messages.



3

11.) Network areas usually are connected to other network areas via routers, making up a single
autonomous system. An autonomous system is a collection of netw
orks under a common administration
sharing a common routing strategy. Autonomous systems are subdivided by areas. In other words, an
autonomous systerm (AS) is a collection of IP networks under control of a single entity, typically an
Internet Serivce Prov
ider or a very large organization with redundant connections to the rest of the internet.
A unique AS number is allocated to each AS for use in BGP routing. The numbers are assigned by the
same authorities that allocate IP addresses. Types of AS are Mult
ihomed AS, Stub AS, and Transit AS.


12.) UCI’s AS # is Number 2. NACS.uci.edu has AS Number 1.


13.) A Stub AS is only connected to one other AS. For routing purposes, it could be regarded as a simple
extension of the other AS. In fact, most networks with

a single Internet connection don't have a unique AS
number assigned, and their network addresses are treated as part of the parent AS.

A Transit AS has connections to more than one other AS and allows itself to be used as a conduit
for traffic (transit t
raffic) between other AS's. Most large Internet Service Providers are transit AS's.

A Multihomed AS has connections to more than one other AS, but does not allow transit traffic to
pass, though its interior hosts may route traffic through multiple AS's. Th
is is the typical configuration for a
large corporate network with multiple redundant Internet connections, but which does not wish to pass
traffic for others.


Prelab
5


1.)
UDP and TCP use port numbers to identify applications.

A globally unique address

at the transport layer consists of the tuple
:
<IP address, port number>


2.) The s
yntax
is
:

Sender:

ttcp
-
ts
-
l500
-
n4
-
p2222
-
D 10.0.2.6

Receiver:

ttcp
-
rs
-

l500
-
n4
-
p2222


3.)

a.)
PMTU discovery is described in RFC1191. When a connection is
establishe
d, the two hosts involved exchange their TCP maximum segment size
(MSS) values. The smaller of the two MSS values is used for the connection. The
MSS for a system is usually the MTU at the link layer minus 40 bytes for the IP and
TCP headers.


That is defi
ned as the MTU (Maximum Transmission Unit) on the network seg
ment
.
Since TCP/IP is routed through many different seg
ment
, you g
et

path MTU: the
maximum size an IP packet on a specific path.


If the packet is LARGER that this valu
e
, it will be fragmented b
y the router. Now,
there is a flag that can be set to tell routers "do not fragment packet" and it is
mainly used in path MTU discovery (see below).


Path MTU discovery will tell you what the path MTU is. It is simply done as follow:
send ICMP packets with

the "do not fragment" flag set and, as long as you receive
and answer, increase the packet size. Once you've got a "Must fragment but Do Not
Fragment flag set"
answer
, you know the path MTU
.


b.) The

maximum size of a UDP diagram cannot exceed 65508, acco
rding to
experimental results.


c.) ICMP Network Unreachable. No, t
he MTU of the next is returned
.


d.)
TCP avoids fragmentation
in this way
: when a TCP connection is
established, the sender and receiver negotiates the maximum segment size (MSS),
so that n
o fragmentation occurs at their outgoing interfaces. The smaller value is
used for the MSS
.



4

4.)
34568
to

36615
.


5.)

a.) Nagle’s = This

algorithm limits the number of small segments that a TCP
sender can transmit without waiting for an acknowledgement. Th
is is accomplished
by having the receiver delay a period of time; if during this delay the receiver has
data for the sender, ACKs can be piggybacked to the data, therefore saving
transmissions of segments.




b.) Karn’s =
In Karn's algorithm, when a segmen
t is retransmitted, the
current RTO value is doubled, instead of being calculated based on previous RTO
measurements.

They are used to help with inefficiency when there are fewer
transmissions than there are characters.


6.)

a.)
Delayed acknowledgements ar
e used to keep the number of segments
with a small payload small.


b.)
Piggybacked acknowledgements are acknowledgements that "ride" with
data, in order to reduce the number of transmissions.


7.)
TCP calucates RTO from the delay between transmission of a
segment and the
receipt of the acknowledgement for that segment.


8.)

a.) Sliding window flow control prevents the receiver from being overloaded
with data. It does this by restricting the amount of data it is willing to receive.


b.)
TCP congestion has tw
o phases: slow start and congestion avoidance. The
sender is in slow start when the congestion window (cnwd) is less than or equal to
the slow start threshold

(ssthresh). When the cnwd is bigger than the ssthresh, the
TCP sender is in the congestion avoida
nce phase. This results in the sender reducing
his sending rate.


c.)
Fast retransmit works by immediately retransmitting segments that are
presumed lost

(when three duplicate ACKs are received). It does not wait for the
timer to expire. Fast recovery work
s by dividing the slow
-
start threshold by half of
the value in the congestion window, and setting the congestion window to that value.
This occurs when the retransmission timer times out or when three duplicate ACKs
arrive.


5

Report


Questions from EXERCISE

2:

1). Explanation of the fields in the RIP message:

--

command
: the type of message

--

version
: the version of RIP used

--

routing domain
: network prefix
A set of routers exchanging routing information
within an administrative domain.

--

ip addresses: t
he network addresses of the other networks on the other side of the
router. An identifier for a computer or device on a TCP/IP network. Includes Address
Family, Route Tag(used to distinguish between internal routes and external routes), IP
Address(the IP

address for the network), Netmask(subnet mask for the network), Next
Hop(IP address of the next hop where the packets for the network should be forwarded),
and Metric(shows how many hops within the network have been traversed on the way to
the destinatio
n. A valid number is 1 to 15 and 16 is for an unreachable route.



Outputs from Step 4

‘show ip rip’ for PC1

ripd# show ip rip

Codes: R
-

RIP, C
-

connected, O
-

OSPF, B
-

BGP


(n)
-

normal, (s)
-

static, (d)
-

default, (r)
-

redistribute,


(i
)
-

interface




Network Next Hop Metric From Time

C(i) 10.0.1.0/24 0.0.0.0 1 self

R(n) 10.0.2.0/24 10.0.1.1 2 10.0.1.1 02:59

R(n) 10.0.3.0/24 10.0.1.1 3
10.0.1.1 02:59

R(n) 10.0.4.0/24 10.0.1.1 4 10.0.1.1 02:59


‘show ip rip’ for PC2

ripd# show ip rip

Codes: R
-

RIP, C
-

connected, O
-

OSPF, B
-

BGP


(n)
-

normal, (s)
-

static, (d)
-

default, (r)
-

redistribute,



(i)
-

interface




Network Next Hop Metric From Time

R(n) 10.0.1.0/24 10.0.2.1 2 10.0.2.1 02:58

C(i) 10.0.2.0/24 0.0.0.0 1 self

R(n) 10.0.3.0/24 10.0.2.2

2 10.0.2.2 02:54

R(n) 10.0.4.0/24 10.0.2.2 3 10.0.2.2 02:54


‘show ip rip’ for PC3

ripd# show ip rip

Codes: R
-

RIP, C
-

connected, O
-

OSPF, B
-

BGP


(n)
-

normal, (s)
-

static, (d)
-

default, (r)
-

redistribute,



(i)
-

interface




Network Next Hop Metric From Time

R(n) 10.0.1.0/24 10.0.3.2 3 10.0.3.2 02:58

R(n) 10.0.2.0/24 10.0.3.2 2 10.0.3.2 02:58

C(i) 10.0.3.0/24 0
.0.0.0 1 self

R(n) 10.0.4.0/24 10.0.3.3 2 10.0.3.3 02:52


6


‘show ip rip’ for PC4

ripd# show ip rip

Codes: R
-

RIP, C
-

connected, O
-

OSPF, B
-

BGP


(n)
-

normal, (s)
-

static, (d)
-

default, (r)
-

redistribute,


(i)
-

interface




Network Next Hop Metric From Time

R(n) 10.0.1.0/24 10.0.4.3 4 10.0.4.3 02:55

R(n) 10.0.2.0/24 10.0.4.3 3 10.0.4.3 02:55

R(n) 10.0.3.0/24

10.0.4.3 2 10.0.4.3 02:55

C(i) 10.0.4.0/24 0.0.0.0 1 self


Outputs from Step 5

‘netstat

rn’ for PC1

Kernel IP routing table

Destination Gateway Genmask Flags MSS Window irtt Iface

10.0.4.0

10.0.1.1 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.2.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0

10.0.3.0 10.0.1.1

255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC2

Kernel IP routing table

Destination Gateway Genmask Flags MSS Window irtt Iface

10.0.4.
0 10.0.2.2 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.2.1 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.3.0 10.0.2.2

255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC3

Kernel IP routing table

Destination Gateway Genmask Flags MSS Window irtt Iface

10.0.
4.0 10.0.3.3 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.3.2 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.3.2 255.255.255.0 UG 0 0 0 eth0

10.0.3.0 0.0.0.0

255.255.255.0 U 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC4

Kernel IP routing table

Destination Gateway Genmask Flags MSS Window irtt Iface

10.
0.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.1.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

10.0.3.0 10.0.4.3

255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


2). Differences in the output of commands:

a.

‘show ip rip’ gives a cost metric while ‘netstat

rn’ doesn’t.

b.

‘netstat

rn’ shows
the loopback interface while ‘show ip rip’ doesn’t.

It
also has netmask and interface information.


c.

‘show ip rip’ also has a time and from column and specifies if the
connection is RIP or OSPF, etc.


7


3). Output of ‘traceroute’ from Step 7

[root@PC1 floppy]
# traceroute 10.0.4.10

traceroute to 10.0.4.10 (10.0.4.10), 30 hops max, 38 byte packets



1 10.0.1.1 (10.0.1.1) 1.747 ms 0.907 ms 1.032 ms


2 10.0.2.2 (10.0.2.2) 2.689 ms 1.328 ms 1.298 ms


3 10.0.3.3 (10.0.3.3) 2.982 ms 1.704 ms 1.644 ms


4

10.0.4.10 (10.0.4.10) 3.519 ms 1.518 ms 1.383 ms


4.) Answers to questions from Step 8 with captured packets to support answers:

1.

The destination IP address of RIP packets is 224.0.0.9.

Internet Protocol, Src Addr: 10.0.1.1 (10.0.1.1), Dst Addr:
224.0.0
.9 (224.0.0.9)

2.

No, only from neighbors.

3.

Response; each router sends the RIP message to other neighbor routers to
update routing entries. This is why it was always "response".

Routing Information Protocol


Command: Response (2)


Version: RIPv2 (2)

4.

86
bytes, 2 routing entries. In each message, the network addresses on the
other side of the routers are sent to the PC.


Questions from EXERCISE 3(A):

Output from Step 2

‘netstat

rn’ for PC1

Kernel IP routing table

Destination Gateway Genmask

Flags MSS Window irtt Iface

10.0.4.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.2.0 10.0.1.1 255.255.255.0 UG 0 0

0 eth0

10.0.3.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC2

Kernel IP routing table

Destination Gateway Genmask

Flags MSS Window irtt Iface

10.0.4.0 10.0.2.2 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.2.1 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 0.0.0.0 255.255.255.0 U 0 0

0 eth0

10.0.3.0 10.0.2.2 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC3

Kernel IP routing table

Destination Gateway Genmas
k Flags MSS Window irtt Iface

10.0.4.0 10.0.3.3 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.3.2 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.3.2 255.255.255.0 UG 0

0 0 eth0

10.0.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC4

Kernel IP routing table

Destination Gateway Genm
ask Flags MSS Window irtt Iface

10.0.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0


8

10.0.1.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.4.3 255.255.255.0 UG

0 0 0 eth0

10.0.3.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


Output from Step 5

‘netstat

rn’ for PC1

Kernel IP routing table

Destination

Gateway Genmask Flags MSS Window irtt Iface

10.0.4.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.2.0 10.0.1.1 255.
255.255.0 UG 0 0 0 eth0

10.0.3.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC2

Kernel IP routing table

Destination

Gateway Genmask Flags MSS Window irtt Iface

10.0.4.0 10.0.2.2 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.2.1 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 0.0.0.0 25
5.255.255.0 U 0 0 0 eth0

10.0.3.0 10.0.2.2 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC3

Kernel IP routing table

Destination

Gateway Genmask Flags MSS Window irtt Iface

10.0.4.0 10.0.3.3 255.255.255.0 UG 0 0 0 eth0

10.0.1.0 10.0.3.2 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.3.2
255.255.255.0 UG 0 0 0 eth0

10.0.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


‘netstat

rn’ for PC4

Kernel IP routing table

Destinati
on Gateway Genmask Flags MSS Window irtt Iface

10.0.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

10.0.1.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

10.0.2.0 10.0.4.3

255.255.255.0 UG 0 0 0 eth0

10.0.3.0 10.0.4.3 255.255.255.0 UG 0 0 0 eth0

127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo


The time it took to update the routing tables was not

too long. (few seconds!)

Questions from EXERCISE 3(B):

---

10.0.1.10 ping statistics
---

196 packets transmitted, 24 received, +113 errors, 87% packet loss, time 195235ms

rtt min/avg/max/mdev = 1.057/1.808/6.620/1.333 ms, pipe 3


The number of lost packet
s = 172.

The time it took RIP to update the routing tables is approximately 172 seconds (2 minutes
and 52 seconds).


Questions from EXERCISE 4(B):

After disconnecting PC3, the network became unreachable for a very long time. The
metric in ethereal was 16 h
ops, which means the cost is infinity.

RIP packet starting from Frame 76 reached count
-
to
-
infinity:


9

Routing Information Protocol


Command: Response (2)


Version: RIPv2 (2)


Routing Domain: 0


IP Address: 10.0.1.0,
Metric: 16


Address Fam
ily: IP (2)


Route Tag: 0


IP Address: 10.0.1.0 (10.0.1.0)


Netmask: 255.255.255.0 (255.255.255.0)


Next Hop: 0.0.0.0 (0.0.0.0)


Metric: 16


Questions from EXERCISE 4(C):

In Exercise 4b, the time of convergence was slow.
In Exercise 4c, the routers converged a
lot faster.

Exercies 4b without flash update
:

[root@PC2 root]# ping 10.0.1.10

PING 10.0.1.10 (10.0.1.10) 56(84) bytes of data.

64 bytes from 10.0.1.10: icmp_seq=1 ttl=62 time=1.16 ms

64 bytes from 10.0.1.10: icmp_seq
=2 ttl=62 time=1.05 ms

64 bytes from 10.0.1.10: icmp_seq=3 ttl=62 time=1.06 ms

64 bytes from 10.0.1.10: icmp_seq=4 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=5 ttl=62 time=0.998 ms

64 bytes from 10.0.1.10: icmp_seq=6 ttl=62 time=1.00 ms

64 bytes

from 10.0.1.10: icmp_seq=7 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icmp_seq=8 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp_seq=9 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp_seq=10 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp_seq=11 tt
l=62 time=1.02 ms

64 bytes from 10.0.1.10: icmp_seq=12 ttl=62 time=1.04 ms

64 bytes from 10.0.1.10: icmp_seq=13 ttl=62 time=1.05 ms

64 bytes from 10.0.1.10: icmp_seq=14 ttl=62 time=1.24 ms

64 bytes from 10.0.1.10: icmp_seq=15 ttl=62 time=0.983 ms

64 bytes
from 10.0.1.10: icmp_seq=16 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=17 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icmp_seq=18 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icmp_seq=19 ttl=62 time=0.999 ms

From 10.0.3.10 icmp_seq=20 Destinati
on Net Unreachable

From 10.0.3.10 icmp_seq=21 Destination Net Unreachable

From 10.0.3.10 icmp_seq=22 Destination Net Unreachable

From 10.0.3.10 icmp_seq=23 Destination Net Unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreacha
ble

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network i
s unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg:

Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

64 bytes from 10.0.1.10: icmp_seq=178 ttl=63 time=2.26 ms


10

64 bytes from 10.0.1.10: icmp_seq=179 ttl=63 time=0.768 ms

6
4 bytes from 10.0.1.10: icmp_seq=180 ttl=63 time=0.775 ms

64 bytes from 10.0.1.10: icmp_seq=181 ttl=63 time=0.681 ms

64 bytes from 10.0.1.10: icmp_seq=182 ttl=63 time=0.685 ms

64 bytes from 10.0.1.10: icmp_seq=183 ttl=63 time=0.759 ms

64 bytes from 10.0.1.
10: icmp_seq=184 ttl=63 time=0.763 ms

64 bytes from 10.0.1.10: icmp_seq=185 ttl=63 time=0.747 ms

64 bytes from 10.0.1.10: icmp_seq=186 ttl=63 time=0.730 ms

64 bytes from 10.0.1.10: icmp_seq=187 ttl=63 time=0.728 ms

64 bytes from 10.0.1.10: icmp_seq=188 ttl
=63 time=0.714 ms

64 bytes from 10.0.1.10: icmp_seq=189 ttl=63 time=0.702 ms

64 bytes from 10.0.1.10: icmp_seq=190 ttl=63 time=0.691 ms

64 bytes from 10.0.1.10: icmp_seq=191 ttl=63 time=0.773 ms

64 bytes from 10.0.1.10: icmp_seq=192 ttl=63 time=0.759 ms

64

bytes from 10.0.1.10: icmp_seq=193 ttl=63 time=0.753 ms

64 bytes from 10.0.1.10: icmp_seq=194 ttl=63 time=0.749 ms

64 bytes from 10.0.1.10: icmp_seq=195 ttl=63 time=0.734 ms

64 bytes from 10.0.1.10: icmp_seq=196 ttl=63 time=0.733 ms

64 bytes from 10.0.1.1
0: icmp_seq=197 ttl=63 time=0.713 ms

64 bytes from 10.0.1.10: icmp_seq=198 ttl=63 time=0.704 ms

64 bytes from 10.0.1.10: icmp_seq=199 ttl=63 time=0.748 ms

64 bytes from 10.0.1.10: icmp_seq=200 ttl=63 time=0.773 ms

64 bytes from 10.0.1.10: icmp_seq=201 ttl=
63 time=0.748 ms

64 bytes from 10.0.1.10: icmp_seq=202 ttl=63 time=0.749 ms

64 bytes from 10.0.1.10: icmp_seq=203 ttl=63 time=0.743 ms

64 bytes from 10.0.1.10: icmp_seq=204 ttl=63 time=1.44 ms

64 bytes from 10.0.1.10: icmp_seq=205 ttl=63 time=0.757 ms

64 b
ytes from 10.0.1.10: icmp_seq=206 ttl=63 time=0.737 ms

64 bytes from 10.0.1.10: icmp_seq=207 ttl=63 time=0.723 ms

64 bytes from 10.0.1.10: icmp_seq=208 ttl=63 time=0.723 ms

64 bytes from 10.0.1.10: icmp_seq=209 ttl=63 time=0.712 ms

64 bytes from 10.0.1.10:

icmp_seq=210 ttl=63 time=0.708 ms



---

10.0.1.10 ping statistics
---

210 packets transmitted, 52 received, +4 errors, 75% packet loss, time 209248ms

rtt min/avg/max/mdev = 0.681/0.901/2.262/0.265 ms


Exercise 4c with flash update
:

[root@PC2 root]# ping 1
0.0.1.10

PING 10.0.1.10 (10.0.1.10) 56(84) bytes of data.

64 bytes from 10.0.1.10: icmp_seq=1 ttl=62 time=4.10 ms

64 bytes from 10.0.1.10: icmp_seq=2 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icmp_seq=3 ttl=62 time=1.11 ms

64 bytes from 10.0.1.10: icmp_
seq=4 ttl=62 time=1.02 ms

64 bytes from 10.0.1.10: icmp_seq=5 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp_seq=6 ttl=62 time=1.06 ms

64 bytes from 10.0.1.10: icmp_seq=7 ttl=62 time=1.09 ms

64 bytes from 10.0.1.10: icmp_seq=8 ttl=62 time=1.00 ms

64 byt
es from 10.0.1.10: icmp_seq=9 ttl=62 time=0.976 ms

64 bytes from 10.0.1.10: icmp_seq=10 ttl=62 time=1.19 ms

64 bytes from 10.0.1.10: icmp_seq=11 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp_seq=12 ttl=62 time=1.11 ms

64 bytes from 10.0.1.10: icmp_seq=
13 ttl=62 time=0.945 ms

64 bytes from 10.0.1.10: icmp_seq=14 ttl=62 time=1.05 ms

64 bytes from 10.0.1.10: icmp_seq=15 ttl=62 time=1.06 ms

64 bytes from 10.0.1.10: icmp_seq=16 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=17 ttl=62 time=1.09 ms

64 b
ytes from 10.0.1.10: icmp_seq=18 ttl=62 time=1.18 ms

64 bytes from 10.0.1.10: icmp_seq=19 ttl=62 time=1.27 ms

64 bytes from 10.0.1.10: icmp_seq=20 ttl=62 time=1.04 ms

64 bytes from 10.0.1.10: icmp_seq=21 ttl=62 time=1.03 ms

64 bytes from 10.0.1.10: icmp_se
q=22 ttl=62 time=1.12 ms

64 bytes from 10.0.1.10: icmp_seq=23 ttl=62 time=0.964 ms


11

64 bytes from 10.0.1.10: icmp_seq=24 ttl=62 time=0.978 ms

64 bytes from 10.0.1.10: icmp_seq=25 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=26 ttl=62 time=1.08 ms

6
4 bytes from 10.0.1.10: icmp_seq=27 ttl=62 time=1.18 ms

64 bytes from 10.0.1.10: icmp_seq=28 ttl=62 time=1.19 ms

64 bytes from 10.0.1.10: icmp_seq=29 ttl=62 time=1.19 ms

64 bytes from 10.0.1.10: icmp_seq=30 ttl=62 time=1.10 ms

64 bytes from 10.0.1.10: icmp
_seq=31 ttl=62 time=1.12 ms

64 bytes from 10.0.1.10: icmp_seq=32 ttl=62 time=1.05 ms

64 bytes from 10.0.1.10: icmp_seq=33 ttl=62 time=1.04 ms

64 bytes from 10.0.1.10: icmp_seq=34 ttl=62 time=1.05 ms

64 bytes from 10.0.1.10: icmp_seq=35 ttl=62 time=1.06 ms

64 bytes from 10.0.1.10: icmp_seq=36 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=37 ttl=62 time=1.07 ms

64 bytes from 10.0.1.10: icmp_seq=38 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icmp_seq=39 ttl=62 time=1.08 ms

64 bytes from 10.0.1.10: icm
p_seq=40 ttl=62 time=1.01 ms

64 bytes from 10.0.1.10: icmp_seq=41 ttl=62 time=1.01 ms

64 bytes from 10.0.1.10: icmp_seq=42 ttl=62 time=1.01 ms

64 bytes from 10.0.1.10: icmp_seq=43 ttl=62 time=1.02 ms

64 bytes from 10.0.1.10: icmp_seq=44 ttl=62 time=1.04 ms

From 10.0.3.10 icmp_seq=45 Destination Net Unreachable

From 10.0.3.10 icmp_seq=46 Destination Net Unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unrea
chable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

ping: sendmsg: Network is unreachable

64 bytes from 10.0.1.10: icmp_seq=204 ttl=63 time=1.51 ms

64 bytes from 10.0.1.10: icmp_seq=205 t
tl=63 time=0.728 ms

64 bytes from 10.0.1.10: icmp_seq=206 ttl=63 time=0.724 ms

64 bytes from 10.0.1.10: icmp_seq=207 ttl=63 time=0.731 ms

64 bytes from 10.0.1.10: icmp_seq=208 ttl=63 time=0.725 ms

64 bytes from 10.0.1.10: icmp_seq=209 ttl=63 time=0.714 ms

64 bytes from 10.0.1.10: icmp_seq=210 ttl=63 time=0.691 ms

64 bytes from 10.0.1.10: icmp_seq=211 ttl=63 time=0.693 ms

64 bytes from 10.0.1.10: icmp_seq=212 ttl=63 time=0.688 ms

64 bytes from 10.0.1.10: icmp_seq=213 ttl=63 time=0.685 ms

64 bytes from 10.0.1
.10: icmp_seq=214 ttl=63 time=0.677 ms

64 bytes from 10.0.1.10: icmp_seq=215 ttl=63 time=0.682 ms

64 bytes from 10.0.1.10: icmp_seq=216 ttl=63 time=0.674 ms

64 bytes from 10.0.1.10: icmp_seq=217 ttl=63 time=0.756 ms

64 bytes from 10.0.1.10: icmp_seq=218 tt
l=63 time=0.748 ms

64 bytes from 10.0.1.10: icmp_seq=219 ttl=63 time=0.741 ms

64 bytes from 10.0.1.10: icmp_seq=220 ttl=63 time=0.732 ms

64 bytes from 10.0.1.10: icmp_seq=221 ttl=63 time=0.730 ms

64 bytes from 10.0.1.10: icmp_seq=222 ttl=63 time=0.728 ms

6
4 bytes from 10.0.1.10: icmp_seq=223 ttl=63 time=0.723 ms

64 bytes from 10.0.1.10: icmp_seq=224 ttl=63 time=0.712 ms

64 bytes from 10.0.1.10: icmp_seq=225 ttl=63 time=0.730 ms

64 bytes from 10.0.1.10: icmp_seq=226 ttl=63 time=0.715 ms

64 bytes from 10.0.1.
10: icmp_seq=227 ttl=63 time=0.696 ms

64 bytes from 10.0.1.10: icmp_seq=228 ttl=63 time=0.703 ms

64 bytes from 10.0.1.10: icmp_seq=229 ttl=63 time=0.704 ms

64 bytes from 10.0.1.10: icmp_seq=230 ttl=63 time=0.698 ms

64 bytes from 10.0.1.10: icmp_seq=231 ttl
=63 time=0.693 ms

64 bytes from 10.0.1.10: icmp_seq=232 ttl=63 time=0.676 ms

64 bytes from 10.0.1.10: icmp_seq=233 ttl=63 time=0.752 ms

64 bytes from 10.0.1.10: icmp_seq=234 ttl=63 time=0.753 ms



---

10.0.1.10 ping statistics
---


12

234 packets transmitted,
75 received, +2 errors, 67% packet loss, time 233531ms

rtt min/avg/max/mdev = 0.674/0.978/4.104/0.414 ms


Questions from EXERCISE 5(C):

1.)

30 packets, 30 seconds.

2.)

Asdf (still looking for ethereal output from other people in class)

Hello Packet:

Internet Proto
col, Src Addr: 10.0.1.1 (10.0.1.1), Dst Addr: 224.0.0.5 (224.0.0.5)


Version: 4


Header length: 20 bytes


Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)


0000 00.. = Differentiated Services Codepoint: Default (0x00)



.... ..0. = ECN
-
Capable Transport (ECT): 0


.... ...0 = ECN
-
CE: 0


Total Length: 68


Identification: 0x3555 (13653)


Flags: 0x00


.0.. = Don't fragment: Not set


..0. = More fragments: Not set


Fragment offset: 0


T
ime to live: 1


Protocol: OSPF (0x59)


Header checksum: 0x9906 (correct)


Source: 10.0.1.1 (10.0.1.1)


Destination: 224.0.0.5 (224.0.0.5)

Open Shortest Path First


OSPF Header


OSPF Version: 2


Message Type: Hello Packet (1)



Packet Length: 48


Source OSPF Router: 10.0.1.1 (10.0.1.1)


Area ID: 0.0.0.1


Packet Checksum: 0xd093 (correct)


Auth Type: Null


Auth Data (none)


OSPF Hello Packet


Network Mask: 255.255.255.0


He
llo Interval: 10 seconds


Options: 0x2 (E)


Router Priority: 1


Router Dead Interval: 40 seconds


Designated Router: 10.0.1.2

Backup Designated Router: 10.0.1.1


Active Neighbor: 10.0.1.2




Update Packet:

Internet Protoc
ol, Src Addr: 10.0.1.2 (10.0.1.2), Dst Addr: 224.0.0.5 (224.0.0.5)


Version: 4


Header length: 20 bytes


Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)


0000 00.. = Differentiated Services Codepoint: Default (0x00)



.... ..0. = ECN
-
Capable Transport (ECT): 0


.... ...0 = ECN
-
CE: 0


Total Length: 84


Identification: 0x3706 (14086)


Flags: 0x00


.0.. = Don't fragment: Not set


..0. = More fragments: Not set


Fragment offset: 0


Ti
me to live: 1


Protocol: OSPF (0x59)


Header checksum: 0x9744 (correct)


Source: 10.0.1.2 (10.0.1.2)


Destination: 224.0.0.5 (224.0.0.5)

Open Shortest Path First


OSPF Header


OSPF Version: 2


13


Message Type: LS Update (4)



Packet Length: 64


Source OSPF Router: 10.0.1.2 (10.0.1.2)


Area ID: 0.0.0.1


Packet Checksum: 0x4563 (correct)


Auth Type: Null


Auth Data (none)


LS Update Packet


Number of LSAs: 1


LS Type: Router
-
L
SA


LS Age: 2 seconds


Options: 0x22 (E/DC)


Link
-
State Advertisement Type: Router
-
LSA (1)


Link State ID: 10.0.4.4


Advertising Router: 10.0.4.4 (10.0.4.4)


LS Sequence Number: 0x80000016



LS Checksum: cef5


Length: 36


Flags: 0x00


Number of Links: 1


Type: Transit ID: 10.0.5.6 Data: 10.0.5.8 Metric: 10


IP address of Designated Router: 10.0.5.6



Link Data: 10.0.5.8


Link Type: 2
-

Connection to a transit network


Number of TOS metrics: 0


TOS 0 metric: 10



Acknowledge

Packet:


Internet Protocol, Src Addr: 10.0.1.1 (10.0.1.1), Dst Addr: 224.0.0.5 (
224.0.0.5)


Version: 4


Header length: 20 bytes


Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)


0000 00.. = Differentiated Services Codepoint: Default (0x00)


.... ..0. = ECN
-
Capable Transport (ECT): 0


.
... ...0 = ECN
-
CE: 0


Total Length: 64


Identification: 0x355c (13660)


Flags: 0x00


.0.. = Don't fragment: Not set


..0. = More fragments: Not set


Fragment offset: 0


Time to live: 1


Protocol: OSPF (0x59)


Header check
sum: 0x9903 (correct)


Source: 10.0.1.1 (10.0.1.1)


Destination: 224.0.0.5 (224.0.0.5)

Open Shortest Path First


OSPF Header


OSPF Version: 2


Message Type: LS Acknowledge (5)


Packet Length: 44


Source OSPF Router: 10.
0.1.1 (10.0.1.1)


Area ID: 0.0.0.1


Packet Checksum: 0x6591 (correct)


Auth Type: Null


Auth Data (none)


LSA Header


LS Age: 2 seconds


Options: 0x22 (E/DC)


Link
-
State Advertisement Type: Router
-
LSA (1)


Link State ID: 10.0.4.4


Advertising Router: 10.0.4.4 (10.0.4.4)


LS Sequence Number: 0x80000016


LS Checksum: cef5


Length: 36



3.)


Link state database of PC2 output:


14


PC2# show ip ospf database




OSPF Router with

ID (10.0.1.2)




Router Link States (Area 0.0.0.1)



Link ID ADV Router Age Seq# CkSum Link count

10.0.1.1 10.0.1.1 691 0x800000dc 0x8681 2

10.0.1.2 10.0.1.2 669 0x8000000b 0x0fbd 2

10.0.3.
1 10.0.3.1 1120 0x80000011 0xccd8 2

10.0.3.2 10.0.3.2 878 0x8000000f 0x8459 1

10.0.3.4 10.0.3.4 622 0x80000008 0x16c0 2

10.0.4.3 10.0.4.3 1549 0x8000000b 0x7b1c 2

10.0.4.4 10.0.4.4 56
5 0x80000016 0xcef5 1

10.0.6.7 10.0.6.7 536 0x8000000e 0x6353 2




Net Link States (Area 0.0.0.1)



Link ID ADV Router Age Seq# CkSum

10.0.1.2 10.0.1.2 690 0x80000006 0x59c8

10.0.2.3 1
0.0.3.1 1885 0x8000000e 0x449e

10.0.3.4 10.0.3.4 643 0x80000006 0x5db6

10.0.5.6 10.0.4.3 1804 0x8000000c 0x567e

10.0.6.6 10.0.4.3 1549 0x80000005 0xb531



4.)

Updated packet contains numbers of LSA and the time

that the LSA entries stay
there. In addition, it also showed the number of links which are Stub and Transit.

5.)

Answers from Step 5 and Step 9


1. 19 seconds for OSPF "update" message


2. 15 OSPF messages including "Hello" and "Update & Acknowledge" messa
ges before it's
connected


3. OSPF Update message


4. Periodically, each router broadcast LSA to surrounding hosts by using OSPF update and hosts
which got updated, will use "acknowledge" OSPF to acknowledge that it got updated.


5. It is using IP (int
ernet Protocol) |IP | OSPF in Data|


6. broadcast address


7. 30 packets 19 secs


8. Yes; all of the OSPF databases are all the same because it's flooded.


Questions from EXERCISE 6:

1.)

Asdf (still looking for ethereal output from other people in class)


Different types of OSPF packets that we did not see in part 5 are LS request and DB
Descr.

Open Shortest Path First


OSPF Header


OSPF Version: 2


Message Type: DB Descr.
(2)


Packet Length: 32


Source OSPF Router: 10.0.1.2

(10.0.1.2)


Area ID: 0.0.0.0 (Backbone)


Packet Checksum: 0xbc2d (correct)


Auth Type: Null


Auth Data (none)


OSPF DB Description


Interface MTU: 1500


Options: 0x2 (E)


Flags: 0x7 (MS/M/I)


DD S
equence: 1109126319


Open Shortest Path First


OSPF Header


OSPF Version: 2


15


Message Type: LS Request (3)


Packet Length: 36


Source OSPF Router: 10.0.1.1 (10.0.1.1)


Area ID: 0.0.0.0 (Backbone)


Packet Checksum
: 0xdcd2 (correct)


Auth Type: Null


Auth Data (none)


Link State Request


Link
-
State Advertisement Type: Router
-
LSA (1)


Link State ID: 10.0.1.2


Advertising Router: 10.0.1.2 (10.0.1.2)


2.)

All link state databases:

PC1
ospfd# show ip ospf database




OSPF Router with ID (10.0.1.1)




Router Link States (Area 0.0.0.0)



Link ID ADV Router Age Seq# CkSum Link count

10.0.1.1 10.0.1.1 583 0x80000003 0x53c3 1

10.0.1.2

10.0.1.2 571 0x80000003 0x51c2 1




Net Link States (Area 0.0.0.0)



Link ID ADV Router Age Seq# CkSum

10.0.1.1 10.0.1.1 583 0x80000001 0x73b5




Summary Link States (Area 0.0.0
.0)



Link ID ADV Router Age Seq# CkSum Route

10.0.2.0 10.0.1.1 273 0x80000001 0xcf6b 10.0.2.0/24

10.0.3.0 10.0.1.1 273 0x80000001 0xce6a 10.0.3.0/24

10.0.4.0 10.0.1.1 242 0x80000004 0xbd77
10.0.4.0/24

10.0.5.0 10.0.1.2 571 0x80000001 0xa88e 10.0.5.0/24

10.0.6.0 10.0.1.2 138 0x80000004 0xa190 10.0.6.0/24

10.0.7.0 10.0.1.2 551 0x80000001 0x9c97 10.0.7.0/24


PC2 ospfd# show ip ospf database




OSPF Router with ID (10.0.1.2)




Router Link States (Area 0.0.0.0)



Link ID ADV Router Age Seq# CkSum Link count

10.0.1.1 10.0.1.1 918 0x80000003 0x53c3 1

10.0.1.2 10.0.1.2 904 0x80000003
0x51c2 1




Net Link States (Area 0.0.0.0)



Link ID ADV Router Age Seq# CkSum

10.0.1.1 10.0.1.1 918 0x80000001 0x73b5




Summary Link States (Area 0.0.0.0)



Link ID ADV Router
Age Seq# CkSum Route

10.0.2.0 10.0.1.1 608 0x80000001 0xcf6b 10.0.2.0/24

10.0.3.0 10.0.1.1 608 0x80000001 0xce6a 10.0.3.0/24

10.0.4.0 10.0.1.1 577 0x80000004 0xbd77 10.0.4.0/24

10.0.5.0 10.0.1.2

904 0x80000001 0xa88e 10.0.5.0/24

10.0.6.0 10.0.1.2 471 0x80000004 0xa190 10.0.6.0/24

10.0.7.0 10.0.1.2 884 0x80000001 0x9c97 10.0.7.0/24




Router Link States (Area 0.0.0.2)



Link ID ADV Router

Age Seq# CkSum Link count

10.0.1.2 10.0.1.2 480 0x80000006 0xe918 1

10.0.6.6 10.0.6.6 475 0x80000006 0x6728 2

10.0.6.7 10.0.6.7 482 0x80000007 0x5e3f 2

10.0.7.8 10.0.7.8 788 0x8000000
3 0x6f16 2


16




Net Link States (Area 0.0.0.2)



Link ID ADV Router Age Seq# CkSum

10.0.5.8 10.0.7.8 478 0x80000004 0x8e38

10.0.6.7 10.0.6.7 476 0x80000002 0x9d60

10.0.7.8 10.0.7.8

788 0x80000001 0xb81f




Summary Link States (Area 0.0.0.2)



Link ID ADV Router Age Seq# CkSum Route

10.0.1.0 10.0.1.2 904 0x80000001 0xd466 10.0.1.0/24

10.0.2.0 10.0.1.2 602 0x80000001
0x2e02 10.0.2.0/24

10.0.3.0 10.0.1.2 602 0x80000001 0x2d01 10.0.3.0/24

10.0.4.0 10.0.1.2 571 0x80000004 0x1c0e 10.0.4.0/24


PC3 ospfd# show ip ospf database




OSPF Router with ID (10.0.3.4)




Router Link

States (Area 0.0.0.1)



Link ID ADV Router Age Seq# CkSum Link count

10.0.1.1 10.0.1.1 646 0x8000000c 0x57b4 1

10.0.3.3 10.0.3.3 669 0x80000007 0x9d19 2

10.0.3.4 10.0.3.4 646 0x8000000b 0x0
1bd 2

10.0.4.5 10.0.4.5 640 0x80000005 0xedbe 2




Net Link States (Area 0.0.0.1)



Link ID ADV Router Age Seq# CkSum

10.0.2.1 10.0.1.1 646 0x80000004 0xc743

10.0.3.4 10.0.3.4
748 0x80000002 0x799c

10.0.4.4 10.0.3.4 645 0x80000002 0x937e




Summary Link States (Area 0.0.0.1)



Link ID ADV Router Age Seq# CkSum Route

10.0.1.0 10.0.1.1 1179 0x80000001 0xda61 10.0.1.0
/24

10.0.5.0 10.0.1.1 962 0x80000001 0x131b 10.0.5.0/24

10.0.6.0 10.0.1.1 528 0x80000004 0x0c1d 10.0.6.0/24

10.0.7.0 10.0.1.1 942 0x80000001 0x0724 10.0.7.0/24


PC4 ospfd# show ip ospf database




OSPF Rou
ter with ID (10.0.6.7)




Router Link States (Area 0.0.0.2)



Link ID ADV Router Age Seq# CkSum Link count

10.0.1.2 10.0.1.2 608 0x80000006 0xe918 1

10.0.6.6 10.0.6.6 600 0x80000006 0x6728 2

10.0.6.7 10.0.6.7 606 0x80000007 0x5e3f 2

10.0.7.8 10.0.7.8 913 0x80000003 0x6f16 2




Net Link States (Area 0.0.0.2)



Link ID ADV Router Age Seq# CkSum

10.0.5.8 10.0.7.8 603

0x80000004 0x8e38

10.0.6.7 10.0.6.7 600 0x80000002 0x9d60

10.0.7.8 10.0.7.8 913 0x80000001 0xb81f




Summary Link States (Area 0.0.0.2)



Link ID ADV Router Age Seq# CkSum Route

10.0.1.0

10.0.1.2 1032 0x80000001 0xd466 10.0.1.0/24

10.0.2.0 10.0.1.2 729 0x80000001 0x2e02 10.0.2.0/24

10.0.3.0 10.0.1.2 729 0x80000001 0x2d01 10.0.3.0/24

10.0.4.0 10.0.1.2 698 0x80000004 0x1c0e 10.0.4.0/24


Router1#show ip ospf database


17




OSPF Router with ID (10.0.3.3) (Process ID 1)




Router Link States (Area 1)



Link ID ADV Router Age Seq# Checksum Link count

10.0.1.1 10.0.1.1 467

0x8000000C 0x57B4 1

10.0.3.3 10.0.3.3 490 0x80000007 0x9D19 2

10.0.3.4 10.0.3.4 469 0x8000000B 0x1BD 2

10.0.4.5 10.0.4.5 463 0x80000005 0xEDBE 2




Net Link States

(Area 1)



Link ID ADV Router Age Seq# Checksum

10.0.2.1 10.0.1.1 467 0x80000004 0xC743

10.0.3.4 10.0.3.4 571 0x80000002 0x799C

10.0.4.4 10.0.3.4 468 0x80000002 0
x937E




Summary Net Link States (Area 1)



Link ID ADV Router Age Seq# Checksum

10.0.1.0 10.0.1.1 1002 0x80000001 0xDA61

10.0.5.0 10.0.1.1 785 0x80000001 0x131B

10.0.6.0

10.0.1.1 349 0x80000004 0xC1D

10.0.7.0 10.0.1.1 766 0x80000001 0x724


Router2#show ip ospf database




OSPF Router with ID (10.0.4.5) (Process ID 1)




Router Link States (Area 1)



Link

ID ADV Router Age Seq# Checksum Link count

10.0.1.1 10.0.1.1 430 0x8000000C 0x57B4 1

10.0.3.3 10.0.3.3 455 0x80000007 0x9D19 2

10.0.3.4 10.0.3.4 433 0x8000000
B 0x1BD 2

10.0.4.5 10.0.4.5 426 0x80000005 0xEDBE 2




Net Link States (Area 1)



Link ID ADV Router Age Seq# Checksum

10.0.2.1 10.0.1.1 430 0x80000004 0xC743

10.0.3
.4 10.0.3.4 534 0x80000002 0x799C

10.0.4.4 10.0.3.4 432 0x80000002 0x937E




Summary Net Link States (Area 1)



Link ID ADV Router Age Seq# Checksum

10.0.1.0 10.0.
1.1 965 0x80000001 0xDA61

10.0.5.0 10.0.1.1 748 0x80000001 0x131B

10.0.6.0 10.0.1.1 313 0x80000004 0xC1D

10.0.7.0 10.0.1.1 730 0x80000001 0x724


Router3#show ip ospf database




OSPF Router with ID (10.0.6.6) (Process ID 1)




Router Link States (Area 2)



Link ID ADV Router Age Seq# Checksum Link count

10.0.1.2 10.0.1.2 212 0x80000006 0xE918 1

10.0.6.
6 10.0.6.6 205 0x80000006 0x6728 2

10.0.6.7 10.0.6.7 212 0x80000007 0x5E3F 2

10.0.7.8 10.0.7.8 519 0x80000003 0x6F16 2




Net Link States (Area 2)



Link ID ADV
Router Age Seq# Checksum

10.0.5.8 10.0.7.8 209 0x80000004 0x8E38

10.0.6.7 10.0.6.7 206 0x80000002 0x9D60

10.0.7.8 10.0.7.8 519 0x80000001 0xB81F


18




Summary
Net Link States (Area 2)



Link ID ADV Router Age Seq# Checksum

10.0.1.0 10.0.1.2 636 0x80000001 0xD466

10.0.2.0 10.0.1.2 333 0x80000001 0x2E02

10.0.3.0 10.0.1.2 333

0x80000001 0x2D01

10.0.4.0 10.0.1.2 304 0x80000004 0x1C0E


Router4#show ip ospf database




OSPF Router with ID (10.0.7.8) (Process ID 1)




Router Link States (Area 2)



Link ID ADV Router Ag
e Seq# Checksum Link count

10.0.1.2 10.0.1.2 294 0x80000006 0xE918 1

10.0.6.6 10.0.6.6 288 0x80000006 0x6728 2

10.0.6.7 10.0.6.7 294 0x80000007 0x5E3F 2

10.0.7.8 1
0.0.7.8 599 0x80000003 0x6F16 2




Net Link States (Area 2)



Link ID ADV Router Age Seq# Checksum

10.0.5.8 10.0.7.8 289 0x80000004 0x8E38

10.0.6.7 10.0.6.7 288

0x80000002 0x9D60

10.0.7.8 10.0.7.8 599 0x80000001 0xB81F




Summary Net Link States (Area 2)



Link ID ADV Router Age Seq# Checksum

10.0.1.0 10.0.1.2 718 0x80000
001 0xD466

10.0.2.0 10.0.1.2 416 0x80000001 0x2E02

10.0.3.0 10.0.1.2 416 0x80000001 0x2D01

10.0.4.0 10.0.1.2 386 0x80000004 0x1C0E


3.)

Answers to questions from Step 4:


1. Instead of knowing
all network connections, hosts only know the hosts in their own areas,
relying on the border gateways to reach other areas.


2. Routers in Area 1 do not know about routers in Area 2. They know only up the the border
-
line
router that sits between their are
a and the backbone area.


3. The border
-
line router between Area 1 and Area 0 knows all the routers in Area 1 and the
border
-
line router between Area 2 and Area 0. The border
-
line router between Area 2 and Area 0
knows all the routers in Area 2 and the bo
rder
-
line router between Area 1 and Area 0.


4. IP routers in areas 1 and 2 will just send datagrams through their respective gateways, PC1
and PC2.

4.)

The output of the command is the border router PC1 that lies between Area 1 and
the backbone area.

Output
of
Router1#show ip ospf border
-
routers:



OSPF Process 1 internal Routing Table



Codes: i
-

Intra
-
area route, I
-

Inter
-
area route



i 10.0.1.1 [10] via 10.0.2.1, FastEthernet0/1, ABR, Area 1, SPF 11


Questions from EXERCISE 7(A):

1.) Answers to Step 7:

1
.) KeepAlive
-

Message sent by one network device to inform another network device
that the virtual circuit between the two is still active.


Open
-

open soft connection


Update
-

Routing table update

2.) BGP uses TCP to establish a reliable connection

between two BGP speakers on port
179. Exactly one TCP session is established between each peer for each BGP session.

19

No routing information can be exchanged until the TCP session has been established.
This implies that each BGP speaker must have workin
g IP connectivity between them
first, which is usually provided by a directly connected interface or the IGP. For added
security, MD5 signatures can be used to authenticate each TCP segment.

3.) 10.0.4.1/28

4.) Router1 10.0.4.1, Router2 10.0.4.2, and Rout
er3 10.0.4.3

2.) BGP update messages contain the AS
-
PATHBorder Gateway Protocol


Border Gateway Protocol


UPDATE Message


Marker: 16 bytes


Length: 52 bytes


Type: UPDATE Message (2)


Unfeasible routes length: 0 bytes



Total path attribute length: 25 bytes


Path attributes


ORIGIN: IGP (4 bytes)


Flags: 0x40 (Well
-
known, Transitive, Complete)


0... .... = Well
-
known


.1.. .... = Transitive



..0. .... = Complete


...0 .... = Regular length


Type code: ORIGIN (1)


Length: 1 byte


Origin: IGP (0)


AS_PATH: 100 (7 bytes)


Flags: 0x40 (Well
-
known,
Transitive, Complete)


0... .... = Well
-
known


.1.. .... = Transitive


..0. .... = Complete


...0 .... = Regular length



Type code: AS_PATH (2)


Lengt
h: 4 bytes


AS path: 100


AS path segment: 100


Path segment type: AS_SEQUENCE (2)


Path segment length: 1 AS


Path segment value: 100
...

3.)

They constantly

exchange AS
-
PATH information, which contains the next hop to get
to other destinations.

...

NEXT_HOP: 10.0.4.1 (7 bytes)


Flags: 0x40 (Well
-
known, Transitive, Complete)


0... .... = Well
-
known


.1.. ...
. = Transitive


..0. .... = Complete


...0 .... = Regular length


Type code: NEXT_HOP (3)


Length: 4 bytes


Next hop: 10.0.4.1 (10.0.4.1)


MULTI_EXIT_DISC: 0 (7 b
ytes)


Flags: 0x80 (Optional, Non
-
transitive, Complete)


1... .... = Optional


.0.. .... = Non
-
transitive


..0. .... = Complete


...0 .... = Regular length



Type code: MULTI_EXIT_DISC (4)


Length: 4 bytes


Multiple exit discriminator: 0


Network layer reachability information: 4 bytes


10.0.1.0/24


NLRI prefix length: 24


NLRI

prefix: 10.0.1.0 (10.0.1.0)


...


Questions from EXERCISE 7(B):

Step 4 Answers:


20

1.) From the only notification message of BGP packets, we found out that there is Error
Code stated that Hold Timer is expired. Here, routers must maintain a TCP session wit
h
their neighbors since we were using BGP and AS topology. If a TCP session is
terminated for any reason, the routing information learnt from that session is deleted. All
routing updates contain the originating AS number. In our lab result, it seems like
AS200 tried to keep TCP session with AS100 but since AS100 was disconnected, it was
notified and it sent update to AS300.


2.)

BGP Update message and notification message.

Border Gateway Protocol


UPDATE Message


Marker: 16 bytes


Length: 52 b
ytes


Type: UPDATE Message (2)


Unfeasible routes length: 0 bytes


Total path attribute length: 25 bytes


Path attributes


ORIGIN: IGP (4 bytes)


Flags: 0x40 (Well
-
known, Transitive, Complete)



0... .... = Well
-
known


.1.. .... = Transitive


..0. .... = Complete


...0 .... = Regular length


Type code: ORIGIN (1)


Length: 1 byte


Origin
: IGP (0)


AS_PATH: 200 (7 bytes)


Flags: 0x40 (Well
-
known, Transitive, Complete)


0... .... = Well
-
known


.1.. .... = Transitive


..0. .... = Complete


.
..0 .... = Regular length


Type code: AS_PATH (2)


Length: 4 bytes


AS path: 200


AS path segment: 200


Path segment type: AS_SEQUENCE (2)


Path s
egment length: 1 AS


Path segment value: 200


NEXT_HOP: 10.0.4.2 (7 bytes)


Flags: 0x40 (Well
-
known, Transitive, Complete)


0... .... = Well
-
known


.1.. .... = Transitiv
e


..0. .... = Complete


...0 .... = Regular length


Type code: NEXT_HOP (3)


Length: 4 bytes


Next hop: 10.0.4.2 (10.0.4.2)


MULTI_EXIT_DISC: 0 (7 bytes)



Flags: 0x80 (Optional, Non
-
transitive, Complete)


1... .... = Optional


.0.. .... = Non
-
transitive


..0. .... = Complete


...0 .... = Regular length


Type c
ode: MULTI_EXIT_DISC (4)


Length: 4 bytes


Multiple exit discriminator: 0


Network layer reachability information: 4 bytes


10.0.2.0/24


NLRI prefix length: 24


NLRI prefix: 10.0
.2.0 (10.0.2.0)

21

CHECKLIST FORM FOR LAB 4

Prelab 4 question sheet

Checkoff for Part 1

Checkoff for Part 2

Checkoff for Part 3

Checkoff for Part 4

Checkoff for Part 5

Checkoff for Part 6

Checkoff for Part 7


Feedback sheet


Lab report



22

FEEDBACK FO
RM FOR LAB 4



Difficulty

Interest Level

Time to Complete

Part 1

Configuring RIP on
a Cisco router

1

2

63 minutes

Part 2

Configuring RIP on
a Linux PC

1

2

50 minutes

Part 3

Reconfiguring the
topology in RIP

1

0

40 minutes

Part 4

Count
-
to
-
infinity
probl
em in RIP

1

1

40 minutes

Part 5

Configuring Open
Shortest Path First
(OSPF)

-
1

-
1

40 minutes

Part 6

Hierarchical routing
in OSPF

0

1

37 minutes

Part 7

Configuring the
Border Gateway
Protocol (BGP)

1

1

45 minutes


What I liked about this lab:


-
I liked
the fact that it showed us how static IP routes are made and how routers
are configured using IOS.


What I disliked about this lab:


-
The report questions were a little long and required extra research.


My suggestion to improve this lab:


-
Make clearer qu
estions and maybe a standard of what data to show since some of
the captures are huge but I am not sure what parts they want to see even though I know
which ones are relevant to my answers.