Using The Ping Command To Verify Network Connectivity; Using Loopback Commands - Cisco ASR 1000 Configuration Manual

Configuration Tasks

Using the ping Command to Verify Network Connectivity

Using the ping command, you can verify that an interface port is functioning properly. This section
provides a brief description of this command. Refer to the publications listed in the
Documentation" section on page xxvi
The ping command sends echo request packets out to a remote device at an IP address that you specify.
After sending an echo request, the system waits a specified time for the remote device to reply. Each
echo reply is displayed as an exclamation point (!) on the console terminal; each request that is not
returned before the specified timeout is displayed as a period (.). A series of exclamation points (!!!!!)
indicates a good connection; a series of periods (.....) or the messages [timed out] or [failed] indicate a
bad connection.
Following is an example of a successful ping command to a remote server with the address 10.0.0.10:
Router# ping 10.0.0.10
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 10.0.0.10, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/15/64 ms
Router#
If the connection fails, verify that you have the correct IP address for the destination and that the device
is active (powered on), and repeat the ping command.
Proceed to the next section,

Using loopback Commands

With the loopback test, you can detect and isolate equipment malfunctions by testing the connection
between the 4-Port Serial Interface SPA and a remote device such as a modem or a channel service unit
(CSU) or a data service unit (DSU). The loopback command places an interface in loopback mode,
which enables test packets that are generated from the ping command to loop through a remote device
or compact serial cable. If the packets complete the loop, the connection is good. If not, you can isolate
a fault to the remote device or compact serial cable in the path of the loopback test.
You must configure a clock rate on the port before performing a loopback test. However, if no cable is
Note
attached to the port, the port is administratively up, and the port is in loopback mode; you do not have
to configure a clock rate on the port before performing a loopback test.
Depending on the mode of the port, issuing the loopback command checks the following path:
•
•
The X.21 interface definition does not include a loopback definition. On the 4-Port Serial Interface SPA,
Note
the X.21 DTE interface does not support the loopback function. Because of the internal clock signal
present on the 4-Port Serial Interface SPAs, loopback will function on an X.21 DCE interface.
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide
18-6
"Using loopback
When no compact serial cable is attached to the 4-Port Serial Interface SPA port, or if a data
communication equipment (DCE) cable is attached to a port that is configured as line protocol up,
the loopback command tests the path between the network processing engine and the interface port
only (without leaving the network processing engine and port adapter).
When a data terminal equipment (DTE) cable is attached to the port, the loopback command tests
the path between the network processing engine and the near (network processing engine) side of
the DSU or modem to test the 4-Port Serial Interface SPA and compact serial cable. (The X.21 DTE
interface cable does not support this loopback test.)
Chapter 18
for detailed command descriptions and examples.
Commands," to finish checking network connectivity.
Configuring the 4-Port Serial Interface SPA
"Related
OL-14127-08