Cisco CCNA - CCNP Certification Exam: Same Command, Different Results

As a CCNA or CCNP, one thing you've got to habituated to is that alteration is constant. Cisco regularly issues new IOS editions, no to mention the numerous different varieties of hardware they generate! While it's always good to have "the latest and the greatest" while it comes to routers, switches, firewalls, etc., we have to be arranged for the truth that not all our clients are going to have that latest and greatest!

For example, there are still very a few Catalyst 5000 switches out there buzzing away, and if you're used to working on IOS-driven switches like the 2950, the same command can have dramatically different results.

Let's mention you're going to analyze the spanning tree protocol (STP) install of a current customer. You're used to working with newer 2950 switches, and you've always escape show span ashore those switches to display spanning-tree information. Then, you run show span aboard a Catalyst 5000 - and someone favor this shows:

alternate (enable) show span

Destination : Port 6/1

Admin Source : Port 6/2

Oper Source : Port 6/2

Direction : transmit/receive

Incoming Packets: maimed

Learning : enabled

Multicast : qualified

Filter : -

Status : active

Total regional span sessions: 1

What's going on here?

The mandate show span on a 5000 will not show spanning tree stats - instead, what you're going to see are statistics relating to Switched Port ANalyzer (SPAN). Surprise!

Consider one sample where you're used to running show span on 5000 switches to discern SPAN information. When you run that on a 2950, you know now what you're going to get - spanning tree information! To get SPAN stats on a 2950, you'll need to run show monitor conference, followed by the SPAN conference digit.

SW1#show monitor session 1

Session 1

---------

Type : Local Session

Source Ports :

Both : Fa0/1

Destination Ports : Fa0/2

Encapsulation : Native

Ingress: Disabled

As a CCNA and CCNP, this is 1 of those entities you just have to get used to. Commands are working to be assorted, occasionally radically so, between models. That's why you absence to be skillful with both IOS Help and Cisco's online documentation site. IOS Help is simple, merely the online doc site take a little getting used to. Once you learn how to guide namely site, a globe of Cisco knowledge is by your fingertips.

Besides, when you sit for the CCIE laboratory examination, that will be the only friend you have! And a invaluable friend it can be - you're just going to have to confidence me on that one. :)