-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
1/6
Basic Networking
Assignment 2 Part B
Submitted By
IC 70075P Capt Aditya DebOACT 22
traceroute Command
1. The traceroute command is used to discover the routes that
packets actually takewhen traveling to their destination. The
device (for example, a router or a PC) sends outa sequence of User
Datagram Protocol (UDP) datagrams to an invalid port address atthe
remote host.
Function
2. Three datagrams are sent, each with a Time-To-Live (TTL)
field value set to one.The TTL value of 1 causes the datagram to
"timeout" as soon as it hits the first router inthe path; this
router then responds with an ICMP Time Exceeded Message
(TEM)indicating that the datagram has expired.
3. Another three UDP messages are now sent, each with the TTL
value set to 2,which causes the second router to return ICMP TEMs.
This process continues until the
packets actually reach the other destination. Since these
datagrams are trying to accessan invalid port at the destination
host, ICMP Port Unreachable Messages are returned,indicating an
unreachable port; this event signals the Traceroute program that it
isfinished.
-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
2/6
5. tracert Command Syntax.
tracert [-d] [-hMaxHops] [-wTimeOut ] [-4] [-6] target [/?]
-d = This option prevents tracert from resolving IP addresses to
hostnames, oftenresulting in much faster results.-hMaxHops = This
tracert option specifies the maximum number of hops in thesearch
for thetarget. If you do not specify MaxHops, and targethas not
beenfound by 30 hops, tracert will stop looking.
-wTimeOut= You can specify the time, in milliseconds, to allow
each replybefore timeout using this tracert option.-4 = This option
forces tracert to use IPv4 only.-6 = This option forces tracert to
use IPv6 only.target= This is the destination, either an IP address
or hostname.
6. ISP Networks in Asia (www.iitd.ac.in) Identified within the
Continent.
(a) 115.113.165.241 static-mumbai.vsnl.net.in(b) 14.140.113.30
static-delhi-vsnl.net.in(c) Yes, the largest delays occur at the
peering interfaces between ISPs.
7. Min RTT and Std Deviation of RTT of Three Destinations
.(complete findings are att as Appx)
www.iitd.ac.in www.uni-ulm.edu www.cs.ucla.edu
1955h20 Mar2013
Min RTT Std
Deviation
Min RTT Std
Deviation
Min RTT Std
Deviation
51 ms 0.577 146 ms 1.414 213 ms 0.577
2055h
-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
3/6
to record the source of each ICMP TTL exceeded message to
provide a trace ofthe path the packet took to reach the
destination.
(b) The advantage of this algorithm, is that every router
already has the abilityto send TTL exceeded messages. No special
code is required. Thedisadvantages are the number of packets
generated (2n, where n is the numberof hops), the time it takes to
duplicate all the nearer hops with each successivepacket, and the
fact that the path may change during this process. Also,
thisalgorithm does not trace the return path, which may differ from
the outboundpath.
10. Reasons for Request timed out error.
(a) Request timed out erroroccurs because the server at hop for
is notaccepting Internet Control Message Protocol (ICMP) traffic.
As a result it ignoresTraceroutes request for information. As you
can see, however, it has still sent thedata to the next hop as
there are results that follow.
(b) The Request timed out error message is usually nothing to
worry about,as many network providers may disable ICMP traffic if
their network is underheavy load.
11. Why does traceroute not find complete paths (but only ***)
to some hosts thatyou can ping?
Ans.
1. If an asterisk (*) appears for RTT, then a packet was not
returned within theexpected timeframe it has following reason to
it:-
(a) Many Internet routers intentionally discard ping or
traceroute packets, butthis has no bearing on applications that use
these routers This practice is called
-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
4/6
forward route and the return route often follow different paths.
If there is aproblem on the return route, it may not be evident in
the command output.
There may be a connection problem at that particular system or
the nextsystem.
-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
5/6
www.iitd.ac.in www.uni-ulm.edu www.cs.ucla.edu
20 Mar20131955h
20 Mar20132055h
-
7/27/2019 Traceroute Assignment_Capt Aditya Deb
6/6
20 Mar2155h
