Revision as of 09:24, 6 June 2010

Introduction to Network Maintenance

understanding Maintenance Mode

Introducing network maintenance

• Hardware and software installation and configuration.
• Troubleshooting problem reports.
• Monitoring and tuning network performance.
• Planning for network expansion.
• Documenting the network and any changes made to the network.
• Ensuring compliance with legal regulations and corporate policies.
• Securing the network against internal and external threats.

Proactive Versus Reactive Network Maintenance

• Structured tasks: Performed as a predefined plan.
• Interrupt driven tasks: Involve resolving issues as they are reported.

Well Known Network Maintenance Models

PPDIOO Life Cyclus

FCAPS

Identifying Common Maintenance Procedures

Routine maintenance tasks

• Configuration Changes
• Replacement of older or failed hardware
• Scheduled backups
• Updating Software
• Monitoring network performance

Managing Network changes

• Who is responsible for authorizing network changes
• Which tasks should only be performed during scheduled maintenance windows
• What procedures should be followed prior making a change (Backup etc.)
• What measurable criteria determine the success or failure of a network change
• How will a network change be documented, and who is responsible for the documentation
• How will a roll-back plan be created prior to the change.
• Under what circumstances can formalized change management policies be overridden, and what authorization is required.

Maintaining Network Documentation

Logical Topology Diagram

Shows the interconnection between network segments. The protocols used and how end users interface with the network. (No physical locations)

Physical Topology Diagram

Show how geographical areas - floors in a building - interconnect. The diagram reflects where various network components are physically located.

Listning of Interconnections

A listing of interconnections. Ports on which devices to where. Fx. in a spreadsheet. Circuit ID's for ISP connections might be included.

Inventory of Network Equipment

Manufacturer, model, version of OS, licensing organizational tag etc.

IP Address assignments

Document IP plan.

Configuration Information

When a configuration change is made the current configuration should be backup up. Have generations of backed up configurations. could be useful. Use a logical name system to the backups. (Date etc.) Also remember to backup software. (Versions etc.)

Original design Documents

Documents created during the initial design might provide insight in the decisions the designers made. Plans for future expansions etc.

Restoring after failure

• Duplicate hardware
• OS and application software for the device. (Check licensing)
• Restore backup from failed device.

The Network Maintenance Toolkit

Basic Network Maintenance Tools

From very expensive to free tools. Vary in complexity.

CLI Tools

Cisco IOS CLI

GUI Tools

• CCP: Cisco Configuration Professional
• CCA: Cisco Configuration Assistant
• CNA: Cisco Network Assistant
• SDM: Cisco Security Device Manager

Backup Tools

Cisco IOS Backup

Example 1: Backing up manually

R1# <input>copy startup-config ftp://kevin:dj7jS@192.168.22.33</input>
Address or name of remote host [ 192.168.22.33]? 
Destination file name [r1-confg]?
Writing R1-confg !!!
3458 bytes copied in 3.443 secs (1243 bytes/sec)

Example 2: Predefined ftp username/password

Define password

R1# <input>configure terminal</input>
R1(config)#<input>ip ftp username kevin</input>
R1(config)#<input>ip ftp password dj7jS</input>

Backing up without specifying login credentials

R1# <input>copy startup-config ftp://192.168.22.33</input>
Address or name of remote host [ 192.168.22.33]? 
Destination file name [r1-confg]?
Writing R1-confg !!!
3458 bytes copied in 3.443 secs (1243 bytes/sec)

Example 3: Backing up automatically

Backup up every 1440 minuttes. 60*24=1440

!
ip ftp username kevin
ip ftp password dj7jS
!
archive
 path ftp://192.168.2.33/R1-config
 write-memory
 time-period 1440

Viewing

R1#<input>show archive</input>
The next archive file will be named ftp://192.168.2.33/R1-confg-4
 Archive #  Name
   0
   1       ftp://192.168.2.33/R1-confg-1
   2       ftp://192.168.2.33/R1-confg-2
   3       ftp://192.168.2.33/R1-confg-3 <- Most Recent
   4
   5
   6
   7
   8
   9
   10
   11
   12
   13
   14

Restoring an Archived Configuration

R1# <input> configure replace ftp://192.168.22.33/R1-confg-2</input>
This will apply all necessary additions and deletions
to replace the current running configuration with the
contents of the specified configuration file, which is
assumed to be a complete configuration, not a partial
configuration. Enter Y if you are sure you want to proceed. ? [no] <input>Y</input>
Loading R1-confg-2
[OK - 3113/4096 bytes]

Logging tools

See Syslog

Logging setup

Heimdal#<input>show logging history</input>
Syslog History Table:1 maximum table entries,
saving level warnings or higher
 9236 messages ignored, 0 dropped, 0 recursion drops
 9764 table entries flushed
 SNMP notifications not enabled
   entry number 9765 : LINK-3-UPDOWN
    Interface GigabitEthernet0/7, changed state to up
    timestamp: 169726960

Configure logging

In the example below all log messages from log level 4 (warnings) or less is buffered in max. 4096 bytes Ram and sent to log server 172.16.4.16 and same log levels to console. Set use of Router Ram to max. 4096 warnings newest

!
logging buffered 4096 warnings
logging console warnings
!
logging 172.16.4.16

Kiwi log server software for windows: http://kiwisyslog.com

Network Time Protocol

NTP setup

!
clock timezone EST - 5
clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
ntp server 172.16.4.16

Network Documentation tools

• Trouble Ticket Reporting System
• Wiki

Incident recovery tools

• Cisco Works RME (Resource Manager Essentials)
• Cisco Works LMS (Lan Manager Solutions)

Monitoring and Measuring Tools

• Cisco IOS NetFlow
• SNMP
• Assuring compliance with a SLA (Service Level Agreement)
• Trend monitoring (Bandwidth, CPU utilization)
• Troubleshooting performance issues - Compare to "normal/baseline" utilization.

Links

• Cisco most used Support tools