I am trying to send a ping from one subnet to another in cisco packet tracer. The PC sends the packet to the switch, and then to the router of the same subnet via gigabitEthernet (192.168.24.1) and then is sent to the main router of the network on serial connection, from the serial address 192.168.16.1 to the serial on main router 192.168.16.2. The router should then send it to the next subnet, 192.168.24.1, but instead it continiously bounces back between the original subnet router and the main subnet router. Any help with this would be appreciated, thanks!
Cisco – Packets stuck between two routers
ciscosubnet
Related Solutions
As you mentioned, your static routes break, because there is no existing way to force failover to the WAN link at both sites when one site looses the uplink to the internet.
The best solution to this problem is to set up some form of routed tunnel (sourced from the ISP-link addresses on R1 and R2 in the diagram) through the internet, run a dynamic routing protocol (OSPF / EIGRP) through your tunnel and backup WAN, and set the routing metrics for the WAN link to be much higher.
Since you source the tunnel from the internet links on both sides, if either side looses internet connectivity the tunnel breaks (and the IGP recoverges to your WAN link). If you do this, be sure that PMTUD works through the tunnel so the tunnel overhead is accounted for. This kind of inter-office encrypted VPN is quite common, so it's a familiar topology for anyone who has to support this network in the future.
The issue you face with your existing design is that all your inter-office traffic traffic seems to be unencrypted (at least if I read your question at face-value). If you are not already doing so, I would strongly recommend that you encrypt all traffic between your corporate sites, if it's going through the internet.
One of the jobs of a router is to connect networks that have physically different transmission media. Twisted-pair Ethernet is extremely common these days, but fiber (Ethernet, SONET/OC, and others) is used for most high-speed or long-distance runs, and different types of layer-2 and layer-1 networks have been used in the past and are still in use today, such as T1/T3 lines, ISDN, and Token Ring.
For historical reasons, serial cables such as HSSI may be used to connect equipment such as T1/T3 terminating devices. These will show up as interface SerialN, and you can get detailed information on the hardware installed in a router with show controllers serial.
Unfortunately, "DCE/DTE" technically applies to a number of different hardware signaling schemes. In the context of networking, it's most likely to refer to a serial interface that's used to connect to a WAN drop.
In the case of your simulator, you should practice with both types of interfaces. In most business networks, the "inside" interfaces will be Ethernet, while the WAN interface will be either serial or Ethernet depending on what service the telco is providing, and you'll need to be able to configure either one.
Best Answer
The answer will almost certainly be found in the routing table of the router that sends the packet in an unexpected direction. In your case that seems to be the "central router".
Assuming you are using static routes I suspect the most likely explanation is that you made a typo when setting up the route.