08-29-2009 05:17 AM - edited 03-04-2019 05:53 AM
Hi....
I have location DC and DR which are connected with two lease line running eigrp.
DC ------------------------------ DR
------------------------------
10.5.0.162 10.5.0.161
10.5.0.150 10.5.0.149
On DC Router
router eigrp 111
redistribute static
network 10.0.0.0
no auto-summary
On DC Router
router eigrp 111
redistribute connected
redistribute static
network 10.1.0.0 0.0.255.255
no auto-summary
My issue is,when I trace...why it like
149--161---141
DC#trace 10.1.0.3
Type escape sequence to abort.
Tracing the route to 10.1.0.3
1 10.5.0.149 0 msec
10.5.0.161 4 msec
10.5.0.149 0 msec
2 10.1.0.3 0 msec 4 msec 0 msec
Same thing from DR..
DR#trace 10.0.0.100
Type escape sequence to abort.
Tracing the route to 10.0.0.100
1 10.5.0.150 4 msec
10.5.0.162 0 msec
10.5.0.150 4 msec
2 192.168.3.1 0 msec 4 msec 0 msec
3 10.0.0.100 4 msec 0 msec 4 msec
I don't have any problem but i don't understand why it's like loop.
Thanx......
Solved! Go to Solution.
08-30-2009 09:49 AM
Hello Arjun,
Edison has explained what you thought was an issue.
It is wise to rate useful posts as the Edison's one. This can help other people undestand this thread has an happy end.
About traceroute:
traceroute works in the following manner
UDP packets with an high UDP port like 34xyz are sent.
First round:
TTL=1 in sent packets
send 3 packets using multiple paths if present:
first path uses path1
second path used path2
in your case third packet is sent out path1 because there is no a third path.
So what you see is the result of this activity.
Round2:
increase TTL to 2 sends out 3 packets
devices receiving packet with TTL=1 sends an icmp message telling TTL is expired.
in this way traceroute originating node finds the next-hops in the path to destination from the source ip addresses of icmp error messages received back
Hope to help
Giuseppe
08-29-2009 06:39 AM
It's not a loop but an expected behavior when having a route installed in the RIB with multiple paths - it's called load balancing the traffic.
When you traceroute, you send 3 packets - per the output one packet was sent via one path and the other packet was sent via the other path.
Issue show ip route 10.0.0.100 from the DR and you will see 2 identical paths to the destination.
HTH,
__
Edison.
08-30-2009 09:22 AM
Hi..
Thanx fir ur reply....
I tried sh ip route from DR for 10.0.0.100, it shows two path.
Can u bit explain "When you traceroute, you send 3 packets - per the output one packet was sent via one path and the other packet was sent via the other path".
I know traceroute is basic question but ur precious reply is helpful for me.
thanx....
08-30-2009 09:49 AM
Hello Arjun,
Edison has explained what you thought was an issue.
It is wise to rate useful posts as the Edison's one. This can help other people undestand this thread has an happy end.
About traceroute:
traceroute works in the following manner
UDP packets with an high UDP port like 34xyz are sent.
First round:
TTL=1 in sent packets
send 3 packets using multiple paths if present:
first path uses path1
second path used path2
in your case third packet is sent out path1 because there is no a third path.
So what you see is the result of this activity.
Round2:
increase TTL to 2 sends out 3 packets
devices receiving packet with TTL=1 sends an icmp message telling TTL is expired.
in this way traceroute originating node finds the next-hops in the path to destination from the source ip addresses of icmp error messages received back
Hope to help
Giuseppe
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