System information

Troubleshooting Frame Relay Connections 18-407
Frame Relay: Cannot ping End-to-End
Frame Relay: Cannot ping End-to-End
Symptom: Attempts to ping devices on a remote network across a Frame Relay connection fail.
Table 18–3 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table 18-3 Frame Relay: Cannot ping End-to-End
Possible Problem Solution
Split horizon problem In a hub-and-spoke Frame Relay environment, you must configure
subinterfaces in order to avoid problems with split horizon. For detailed
information on configuring subinterfaces, refer to the Cisco IOS Wide-Area
Networking Configuration Guide and Wide-Area Networking Command
Reference.
Frame Relay subinterfaces provide a mechanism for supporting partially
meshed Frame Relay networks. Most protocols assume transitivity on a
logical network; that is, if station A can talk to station B, and station B can
talk to station C, then station A should be able to talk to station C directly.
Transitivity is true on LANs, but not on Frame Relay networks, unless A is
directly connected to C.
Additionally, certain protocols such as AppleTalk and transparent bridging
cannot be supported on partially meshed networks because they require split
horizon, in which a packet received on an interface cannot be transmitted out
the same interface even if the packet is received and transmitted on different
virtual circuits.
Configuring Frame Relay subinterfaces ensures that a single physical
interface is treated as multiple virtual interfaces. This capability allows us to
overcome split horizon rules. Packets received on one virtual interface can
now be forwarded out another virtual interface, even if they are configured on
the same physical interface.
Subinterfaces address the limitations of Frame Relay networks by providing a
way to subdivide a partially meshed Frame Relay network into a number of
smaller, fully meshed (or point-to-point) subnetworks. Each subnetwork is
assigned its own network number and appears to the protocols as if it is
reachable through a separate interface. (Note that point-to-
point subinterfaces can be unnumbered for use with IP, reducing the
addressing burden that might otherwise result.)
No default gateway on workstation
Step 1 From the local workstation or server, try to ping the remote
workstation or server. Make several attempts to ping the remote
device if the first ping is unsuccessful.
Step 2 If all your attempts fail, check whether the local workstation or
server can ping the local router’s Frame Relay interface.
Step 3 If you are unable to ping the local interface, check the local
workstation or server to see whether it is configured with a default
gateway specification.
Step 4 If there is no default gateway specified, configure the device with a
default gateway. The default gateway should be the address of the
local router’s LAN interface.
For information on viewing or changing the workstation or server’s default
gateway specification, refer to the vendor documentation.