298
C
HAPTER
12: I
NTERNET
P
ROTOCOL
(IP)
Layer 2
Switching
Modules
✓
Multilayer
Switching
Modules
ip traceRoute
Tracks a route from Multilayer Switching Module to a specified
destination using default options.
Valid Minimum Abbreviation
ip t
Important Considerations
■
TraceRoute information includes all of the nodes in the network
through which a packet passes to get from its origin to its destination.
It uses the IP time-to-live (TTL) field in UDP probe packets to elicit an
Internet Control Message Protocol (ICMP) Time Exceeded message
from each gateway to a host.
■
To track the route of an IP packet, traceRoute launches User Datagram
Protocol (UDP) probe packets with a small TTL value and then listens
for an ICMP Time Exceeded reply from a gateway. Probes start with a
small TTL of 1 and increase the value by 1 until one of the following
events occurs:
■
The module receives a
Port Unreachable
message, which
indicates that the packet reached the host.
■
The probe exceeds the maximum number of hops (default
30
).
■
At each TTL setting, the module launches three UDP probe packets,
and the traceRoute display shows a line with the TTL value, the
address of the gateway, and the round-trip time of each probe. If a
probe answers from different gateways, the traceRoute feature prints
the address of each responding system. If no response occurs in the
3-second timeout interval, traceRoute displays an asterisk (
*
) for that
probe. Other characters that can be displayed include the following:
■
!N
— Network is unreachable
■
!H
— Host is unreachable
■
!P
— Protocol is unreachable
■
!F
— Fragmentation is needed
■
!<n>
— Unknown packet type
■
You can either supply the host name or IP address as part of the
command string, or you can supply the information at the prompt.
Summary of Contents for 4007
Page 1: ...http www 3com com Switch 4007 Command Reference Guide Part No 10013693 Published May 2000...
Page 14: ......
Page 22: ...22 ABOUT THIS GUIDE...
Page 34: ...34 CHAPTER 1 ADMINISTRATION OVERVIEW...
Page 78: ...78 CHAPTER 4 SIMPLE NETWORK MANAGEMENT PROTOCOL SNMP...
Page 100: ...100 CHAPTER 5 ETHERNET PORTS...
Page 174: ...174 CHAPTER 9 RESILIENT LINKS...
Page 322: ...322 CHAPTER 13 VIRTUAL ROUTER REDUNDANCY VRRP...
Page 476: ...476 CHAPTER 16 INTERNET PACKET EXCHANGE IPX...
Page 552: ...552 CHAPTER 18 QUALITY OF SERVICE QOS AND RESOURCE RESERVATION PROTOCOL RSVP...
Page 566: ...566 APPENDIX A TECHNICAL SUPPORT...
