Traceroute will always send three packets for each TTL. In other words, it will begin by sending three packets with a TTL of 1, and then another three with a TTL of 2, another three with a TTL of 3 and so on until it gets to the destination. For each iteration, it gets a response back from whatever router it reaches with that TTL value.
Now keeping that in mind, let’s take a look at the routing table of R5:
18.104.22.168/32 is subnetted, 1 subnets
O 22.214.171.124 [110/3] via 192.168.45.4, 00:04:26, GigabitEthernet0/1
[110/3] via 192.168.35.3, 00:04:26, GigabitEthernet0/2
126.96.36.199/32 is subnetted, 1 subnets
O 188.8.131.52 [110/2] via 192.168.35.3, 00:04:26, GigabitEthernet0/2
184.108.40.206/32 is subnetted, 1 subnets
O 220.127.116.11 [110/2] via 192.168.45.4, 00:04:26, GigabitEthernet0/1
18.104.22.168/32 is subnetted, 1 subnets
C 22.214.171.124 is directly connected, Loopback0
126.96.36.199/32 is subnetted, 1 subnets
B 188.8.131.52 [200/0] via 192.168.12.1, 00:03:22
184.108.40.206/32 is subnetted, 1 subnets
C 220.127.116.11 is directly connected, Loopback5
B 192.168.12.0/24 [200/0] via 18.104.22.168, 00:03:27
O 192.168.23.0/24 [110/2] via 192.168.35.3, 00:04:26, GigabitEthernet0/2
O 192.168.24.0/24 [110/2] via 192.168.45.4, 00:04:26, GigabitEthernet0/1
192.168.35.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.35.0/24 is directly connected, GigabitEthernet0/2
L 192.168.35.5/32 is directly connected, GigabitEthernet0/2
192.168.45.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.45.0/24 is directly connected, GigabitEthernet0/1
L 192.168.45.5/32 is directly connected, GigabitEthernet0/1
Now remember, that OSPF is being run within AS2, and by default, equal cost load balancing is enabled. So when R5 pings 22.214.171.124, we can see what happens when we look at the routing table:
- There is an entry for 126.96.36.199 which is learned via BGP. It can be reached via 192.168.12.1 which is the next hop eBGP router
- How do we reach 192.168.12.1? There is another BGP route that tells us we can reach it via 188.8.131.52.
- How do we reach 184.108.40.206? There are two OSPF equal cost routes that get us there, via 192.168.35.3 and 192.168.45.4.
Equal cost load balancing, when using something like traceroute (which uses UDP) will take place on a per packet basis. So, packets are alternated between the two routes. This is why you see responses alternating between the two possible paths you can take.
In the last entry, all three responses came from Fa0/0 on R1, so they weren’t explicitly stated. But you can see this from the three response times that are indicated.
I hope this has been helpful!