The types of problems that typically occur with networks involve connectivity and performance. This section also contains precautionary notices that you must read for the safe operation of the switch. The switch supports a diverse range of network architectures and protocols, some of which maintain and monitor connectivity and isolate connectivity faults.
In addition, the switch supports a wide range of diagnostic tools that you can use to monitor and analyze traffic, capture and analyze data packets, trace data flows, view statistics, and manage event messages.
Certain protocols and tools are tailored for troubleshooting specific switch network topologies. Other tools are more general in their application and you can use them to diagnose and monitor ingress and egress traffic on the switch.
If connectivity problems occur and the source of the problem is unknown, it is usually best to follow the Open Systems Interconnection (OSI) network architecture layers. Confirm that your physical environment, such as the cable and port connections, operates without failures before moving up to the network and application layers.
To gather information about a problem, consider the following information:
Consider the OSI model when you troubleshoot. Start at Layer 1 and move upwards. The Address Resolution Protocol (ARP) can cause problems; ARP operates at Layer 2 to resolve MAC addresses to IP addresses (Layer 3).
Device-specific tools and protocols can help you gather information. This document outlines switch-specific tools.
You can use client- and server-based tools from Microsoft, Linux, and UNIX. For example, you can use Windows tools like ifconfig, ipconfig, winipcfg, and route print to obtain IP information and routing tables. Servers also maintain route tables.
The following command output shows example output of the route print command.
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\jsmith>route print
===============================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 12 f0 74 2a 87 ...... Broadcom NetLink (TM) Gigabit Ethernet - Packet
Scheduler Miniport
0x3 ...00 14 38 08 19 c6 ...... Broadcom NetXtreme Gigabit Ethernet - Packet
Scheduler Miniport
0x4 ...44 45 53 54 42 00 ...... IPSECSHM Adapter - Packet Scheduler
Miniport
===============================================================================
===============================================================================
Active Routes:
Interface
Network Destination Netmask Gateway Metric
0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.102 26
0.0.0.0 0.0.0.0 207.179.154.100 207.179.154.100 1
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
192.168.0.0 255.255.255.0 192.168.0.102 192.168.0.102 25
192.168.0.0 255.255.255.0 207.179.154.100 207.179.154.100 1
192.168.0.102 255.255.255.255 127.0.0.1 127.0.0.1 25
192.168.0.255 255.255.255.255 192.168.0.102 192.168.0.102 25
198.164.27.30 255.255.255.255 192.168.0.1 192.168.0.102 1
207.179.154.0 255.255.255.0 207.179.154.100 207.179.154.100 30
207.179.154.100 255.255.255.255 127.0.0.1 127.0.0.1 30
207.179.154.255 255.255.255.255 207.179.154.100 207.179.154.100 30
224.0.0.0 240.0.0.0 192.168.0.102 192.168.0.102 25
224.0.0.0 240.0.0.0 207.179.154.100 207.179.154.100 1
255.255.255.255 255.255.255.255 192.168.0.102 192.168.0.102 1
255.255.255.255 255.255.255.255 207.179.154.100 3 1
255.255.255.255 255.255.255.255 207.179.154.100 207.179.154.10 1
Default Gateway:207.179.154.100
==============================================================================
Persistent Routes: None
Other network problems can give the impression that a device has a problem. For instance, problems with a Domain Name Service (DNS) server, another switch, firewall, or access point can can appear to be routing problems.