Traceroute; Ping; Trace - Avaya 8800 Troubleshooting Manual

Troubleshooting tool fundamentals

Traceroute

Traceroute determines the path a packet takes to reach a destination by returning the
sequence of hops (IP addresses) the packet traverses.
According to RFC 1393, traceroute operates by: "sending out a packet with a Time To Live
(TTL) of 1. The first hop then sends back an ICMP error message indicating that the packet
could not be forwarded because the TTL expired. The packet is then resent with a TTL of 2,
and the second hop returns the TTL expired. This process continues until the destination is
reached. The purpose behind this is to record the source of each ICMP TTL exceeded
message to provide a trace of the path the packet took to reach the destination."

Ping

Ping is a simple and useful diagnostic tool used to determine reachability. When using Ping,
the switch sends an ICMP Echo Request to a destination IP address. If the destination receives
the packet, it responds with an ICMP Echo Response.
If a Ping test is successful, the destination you are having difficulty reaching is alive and
reachable. Even if a router is reachable, it can have improperly working interfaces or corrupted
routing tables.

Trace

Trace commands provide detailed data collection about software modules on the Avaya
Ethernet Routing Switch 8800/8600. The trace toolset traces multiple modules simultaneously
and provides options to specify the verbosity level of the output.
Enable trace logging through the bootconfig trace-logging flag. This command causes the trace
output to be captured in systrace files in the PCMCIA card (or in external flash on the 8895
SF/CPU) of the primary CPU. Any trace run with this flag set to true is copied to the PCMCIA
(or external flash) under filename systrace.
Caution:
Risk of traffic loss
Using the trace tool inappropriately can cause primary CPU lockup conditions, loss of access
to the switch, loss of protocols, and service degradation.
While these occurrences are uncommon, when using the trace level tool, minimize this risk.
Avaya recommends the following:
• Where trace data is required concurrently from multiple modules, troubleshoot during a
maintenance window, if feasible. Use a maintenance window period if the switch is stable
42 Troubleshooting
Comments? infodev@avaya.com
July 2013