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Weird Tracert..
gouki2005
Member Posts: 197
in CCNA & CCENT
ok look this topology
[IMG]file:///C:/Users/Gerson/AppData/Local/Temp/moz-screenshot.png[/IMG]
Router3 and 4 are running Static,Rip,Ospf
Router 0 just static
Router 2 just rip
Router 1 just ospf
this the weird thing if i do a tracert from PC0 to PC1 this the path..
1 5 ms 6 ms 6 ms 192.168.1.1
2 6 ms 7 ms 4 ms 192.168.3.2
3 9 ms 8 ms 13 ms 192.168.8.2
4 19 ms 13 ms 12 ms 192.168.2.2
so according to this this..the path..look
Hows that posible jump from router 0 to router 1 the next logic hop is 192.168.6.2 and this the router 0 Routes
S 192.168.1.0/24 [1/0] via 192.168.3.1
S 192.168.2.0/24 [1/0] via 192.168.6.2
C 192.168.3.0/24 is directly connected, Serial0/0/0
C 192.168.6.0/24 is directly connected, Serial0/0/1
you see the router doesnt know the 192.168.8.0 network
explain me..plz
[IMG]file:///C:/Users/Gerson/AppData/Local/Temp/moz-screenshot.png[/IMG]
Router3 and 4 are running Static,Rip,Ospf
Router 0 just static
Router 2 just rip
Router 1 just ospf
this the weird thing if i do a tracert from PC0 to PC1 this the path..
1 5 ms 6 ms 6 ms 192.168.1.1
2 6 ms 7 ms 4 ms 192.168.3.2
3 9 ms 8 ms 13 ms 192.168.8.2
4 19 ms 13 ms 12 ms 192.168.2.2
so according to this this..the path..look
Hows that posible jump from router 0 to router 1 the next logic hop is 192.168.6.2 and this the router 0 Routes
S 192.168.1.0/24 [1/0] via 192.168.3.1
S 192.168.2.0/24 [1/0] via 192.168.6.2
C 192.168.3.0/24 is directly connected, Serial0/0/0
C 192.168.6.0/24 is directly connected, Serial0/0/1
you see the router doesnt know the 192.168.8.0 network
explain me..plz
Comments
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Optionsmikej412 Member Posts: 10,086 ■■■■■■■■■■Look at how trace route works. It send an ICMP packet with a ttl of 1 and waits for a reply. Then is sends another with a ttl of 2 and waits for a reply... etc.
Depending on your routing configurations and routing tables there may be multiple network paths and the ICMP packets may be "load balanced" -- so you may get the first response to the ttl=1 packets from one path, the ttl=2 response from a router further along the 2nd path, etc....
Edit: hopefully I just didn't blow a homework assignment/lab where you were supposed to figure this out for yourself:mike: Cisco Certifications -- Collect the Entire Set! -
Optionswastedtime Member Posts: 586 ■■■■□□□□□□First off you need to remember 2 things. First Traceroute sends out consecutive packets with incrementing TTL (Time To Live). Second OSPF will load balance equal cost links (by default if I remember right). This is more then likely this is the routes the packets took.
With the order of them being black, red, green, and blue. -
Optionsgouki2005 Member Posts: 197wastedtime wrote: »First off you need to remember 2 things. First Traceroute sends out consecutive packets with incrementing TTL (Time To Live). Second OSPF will load balance equal cost links (by default if I remember right). This is more then likely this is the routes the packets took.
With the order of them being black, red, green, and blue.
still dont understand why the tracert doesnt show the 192.168.5.2 hop..if some packets pass there -
Optionswastedtime Member Posts: 586 ■■■■□□□□□□If you did enough traceroutes you should see all of the routes. The reason it looks like that is due to the nature of OSPF load balancing and how Traceroute commands works.
Traceroute works on the idea that a router is suppose to send a a TTL exceeded message back to the sender when the TTL reaches 0. The TTL get decremented at every router. Traceroute will send packets with incrementing Time To Live values in the IP header (ex. 1 then 2 then 3.....ect). When it gets a TTL exceeded packet back it records the round trip time and the ip of the router that sent the message back.
Due to the fact that you have OSPF running, it will load balance the packets it gets across those 3 routes (provided they have equal cost). So when the router reports back saying the TTL has exceeded it may have taken a different path then the first traceroute packet.