I’m almost done with my notes on SSO, NSF, FHRPs, and server load balancing, so hang with me.  In the mean time check out this brilliant post by Kevin Bovis about troubleshooting wisdom.

I have a lot to learn from talented people like Kevin.

Many people may be confused as to why I would dedicate an entire post to network monitoring tools and their configuration.  The reason is because these topics are tested relatively heavily on the actual CCNP SWITCH Exam.  Whether you agree or disagree about the weight given to these topics given the number of others is irrelevant.  It’s covered on the exam – so take the time to understand the topics (especially IP SLA).

Here we go…

Syslog

Syslog is a network management protocol that is not unique to Cisco devices, but integrates well within IOS.  Syslog allows a network-attached device to report and log error and notification messages either locally or to a remote Syslog server.

Syslog messages are plain text sent using UDP port 514.

Every syslog message contains two parts, a severity level and a facility.  The severity level goes from 0 to 7 with 0 being the most severe to 7 being simply informational. Facilities are service identifiers that categorize events and messages for easier reporting.

The most common facilities on IOS devices include:

• IP
• OSPF
• SYS (operating system)
• IP Security (IP Sec)
• Route Switch Processor (RSP)
• Interface (IF) Read the rest of this entry »

Wow, I have to say – that last post on Inter-VLAN routing was brutal.  It’s an important topic for the CCNP SWITCH Exam, but that was long.  This week I’m focused on the high-availability topics that will be covered in the exam. 

Some technology overviews to look forward to:

•  Network Monitoring
  • Syslog
  • SNMP
  • IP SLA
• Redundant Supervisor Cards
  • Route processor redundancy
  • SSO
  • NSF
• First Hop Redundancy Protocols
  • HSRP
  • VRRP
  • GLBP

Anything I’m missing for high-availability?  Have a great week!

Aaron

VLANs require a layer 3 device between them to communicate.  Cisco recommend using layer 3 routing at the distribution layer or core layer of the multilayer switched network to terminate local VLANS, isolate network problems,  and avoid access layer issues from affecting the core.

There are 3 inter-VLAN routing device options:

• layer 3 multilayer Catalyst switch
• external router that allows trunking (router-on-a-stick)
• external router with enough interfaces for every VLAN (this doesn’t scale and is very expensive)

All Catalyst multilayer switches support the following types of layer 3 interfaces:

• Routed port – a pure layer 3 port similar to that on a router
• Switch virtual interface (SVI) – virtual routed VLAN interface for inter-VLAN routing
• Bridge virtual interface (BVI) – a layer 3 bridging interface

Inter-VLAN Routing Types // Advantages and Disadvantages

External Router (router -on-a-stick)

Advantages

• Works with almost all switches because the switches do not have to support layer 3, just VLANs and trunking
• Simple configuration (one switch port, one router interface)

Read the rest of this entry »