03-12-2015 03:04 AM - edited 03-07-2019 11:03 PM
Hi
Please see attached diagram.
When I traceroute from the Cisco 892 router (on the top) to an 10.31.48.0 address the packages is looped between the two cisco 2821 routers two times before the package is delivered.
Type escape sequence to abort.
Tracing the route to 10.31.48.2
VRF info: (vrf in name/id, vrf out name/id)
1 172.20.1.2 0 msec
172.20.1.1 0 msec
172.20.1.2 0 msec
2 10.31.45.2 12 msec
10.31.45.7 4 msec
10.31.45.2 4 msec
The package should go from the 172.20.1.2 directly to 10.31.45.2 or 10.31.45.7 and then to the end host. The traceroute shows that the package is bounced two times.
Any suggestions?
Best Regards, Steffen.
Solved! Go to Solution.
03-12-2015 03:53 AM
If it was a loop, your ping would not work. The output you get is as a result of the probes used in a traceroute. This link seems to give a reasonable explanation:http://www.dasblinkenlichten.com/why-does-my-traceroute-look-like-that/
Just so you can see, run an extended ping on the 892 like below and share output here.
Cisco-892#ping Protocol [ip]: Target IP address: 10.31.48.1 Repeat count [5]: Datagram size [100]: Timeout in seconds [2]: Extended commands [n]: y Source address or interface: Type of service [0]: Set DF bit in IP header? [no]: Validate reply data? [no]: Data pattern [0xABCD]: Loose, Strict, Record, Timestamp, Verbose[none]: r Number of hops [ 9 ]: 3 Loose, Strict, Record, Timestamp, Verbose[RV]: Sweep range of sizes [n]:
03-12-2015 03:29 AM
Hello Steffen,
This is load balanced via equal cost routes rather than looping.
03-12-2015 03:33 AM
So its expexted behavior that the package bouches between the equal cost routers?
03-12-2015 03:53 AM
If it was a loop, your ping would not work. The output you get is as a result of the probes used in a traceroute. This link seems to give a reasonable explanation:http://www.dasblinkenlichten.com/why-does-my-traceroute-look-like-that/
Just so you can see, run an extended ping on the 892 like below and share output here.
Cisco-892#ping Protocol [ip]: Target IP address: 10.31.48.1 Repeat count [5]: Datagram size [100]: Timeout in seconds [2]: Extended commands [n]: y Source address or interface: Type of service [0]: Set DF bit in IP header? [no]: Validate reply data? [no]: Data pattern [0xABCD]: Loose, Strict, Record, Timestamp, Verbose[none]: r Number of hops [ 9 ]: 3 Loose, Strict, Record, Timestamp, Verbose[RV]: Sweep range of sizes [n]:
03-12-2015 04:01 AM
Output here
Vonsild-892#ping Protocol [ip]: Target IP address: 10.31.48.2 Repeat count [5]: Datagram size [100]: Timeout in seconds [2]: Extended commands [n]: y Source address or interface: 10.31.103.1 Type of service [0]: Set DF bit in IP header? [no]: Validate reply data? [no]: Data pattern [0xABCD]: Loose, Strict, Record, Timestamp, Verbose[none]: r Number of hops [ 9 ]: 3 Loose, Strict, Record, Timestamp, Verbose[RV]: Sweep range of sizes [n]: Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.31.48.2, timeout is 2 seconds: Packet sent with a source address of 10.31.103.1 Packet has IP options: Total option bytes= 15, padded length=16 Record route: <*> (0.0.0.0) (0.0.0.0) (0.0.0.0) Reply to request 0 (4 ms). Received packet has options Total option bytes= 16, padded length=16 Record route: (172.20.1.103) (10.31.45.217) (10.31.48.2) <*> End of list Reply to request 1 (4 ms). Received packet has options Total option bytes= 16, padded length=16 Record route: (172.20.1.103) (10.31.45.219) (10.31.48.7) <*> End of list Reply to request 2 (8 ms). Received packet has options Total option bytes= 16, padded length=16 Record route: (172.20.1.103) (10.31.45.217) (10.31.48.7) <*> End of list Reply to request 3 (4 ms). Received packet has options Total option bytes= 16, padded length=16 Record route: (172.20.1.103) (10.31.45.219) (10.31.48.2) <*> End of list Reply to request 4 (1 ms). Received packet has options Total option bytes= 16, padded length=16
03-12-2015 04:06 AM
03-12-2015 04:09 AM
Glad that helped. You can also see in the extended ping output, path goes via .217 and then .291
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