CCIE Pursuit Blog

July 15, 2009

Core Knowledge Question of the Day: 15 July 2009

A port in the Spanning Tree state of ‘blocking’ does not allow any type of traffic – true or false?

Highlight for answer: False – BPDUs are still allowed over the link.

July 14, 2009

Core Knowledge Question of the Day: 14 July 2009

Does an OSFP stub explicitly filter Type-4 LSAs, or is their absence in an OSPF stub area simply due to being unnecessary because the Type-5 LSAs have been filtered?

Highlight for answer: Actually, I don’t know the answer to this question.  I was thinking about it today.  In an OSFP stub area Type-5 LSAs are explicitly filtered.  There are no Type-4 LSAs present either.  I don’t know if they are explicitly filtered, or they are just never generated because the Type 5 LSA is filtered/never created?  It’s my understanding (possibly a misunderstanding) that the ASBR generates the Type-4 LSA, so…it must be explicity filtered at the ABR, right? <–This is WRONG! 🙂


Thank you for the comments (big ups to Ivan P, Zeeshan, and Pavel Sefanov).  I think that I have this cleared up in my head now:

The ABR generates the Type-4 LSA. If the area is configured as a stub area, the ABR filters the Type-5 LSAs(generated by the ASBR) and does not generate a Type-4 LSA. So, technically, an OSPF stub configuration only explicitly filters Type-5 LSAs, but it implicitly filters Type-4 LSAs as well as there is no need for the ABR to generate a Type-4 LSA.

So if you were to tell a co-worker that both Type-5 and Type-4 LSAs are filtered, you would be technically wrong.  😦

Ivan Pepelnjak from Cisco IOS Hints and Tricks wrapped it up nicely:

To make it more explicit: the type-4 LSA is the glue that ties together a type-5 LSA originated by an out-of-area ASBR with the ABR flooding type-5 into the area. If there are no type-5 LSAs, type-4 LSAs are not needed (you will also not see them for ASBRs in the same area).

July 13, 2009

Core Knowledge Question of the Day: 13 July 2009

What are the two tables that CEF utilizes to switch packets?

Highlight for answer: Forwarding Information Base(FIB) and [CEF] adjacency table.

July 12, 2009

Core Knowledge Question of the Day: 12 July 2009

What are the three tables that EIGRP uses?

Highlight for answer: EIGRP neighbor table, EIGRP topology table, and the IP routing table.

July 11, 2009

Core Knowledge Question of the Day: 11 July 2009

Which Spanning Tree convergence improvement utilizes Root Link Query (RLQ) BPDUs to detect indirect link failures?

Highlight for answer: BackboneFast

July 8, 2009

Cisco Certified Architect Certification

Filed under: Cisco,Cisco Certification — cciepursuit @ 9:20 am
Tags: , ,

One of the new certifications announced at Networkers this month is the Cisco Certified Architect.  With the requirement to be a CCIE* as well as a CCDE(of which there are only a handful) and a FIFTEEN THOUSAND DOLLAR price tag, this certification is so far above my means that I can’t see myself going that route anytime in the near future.  The impact that adding another high level certification has on the CCIE is something that does concern me.

Until last year, the CCIE was the pinnacle of the Cisco certification mountain.  Then came the CCDE.  Although it is supposed to be a peer of the CCIE (basically the Design track of the CCIE program) the difference in naming, testing, and – more importantly – the unique(and still rare) numbering convention gives the impression – whether true or not – that this certification is positioned a step above the CCIE.  Now Cisco has added yet another certification above the CCIE and the CCDE, so in the span of a little more than a year, the CCIE has now become Cisco’s THIRD highest certification.

I don’t have a lot to say about the new program, but I strongly suggest that you read Jememy Filliben’s take on the Cisco Certified Architect.  Jeremy is one of the rare currently qualified candidates for that certification. His post is very well written and thorough.  He even discusses the affect of the new program on the CCIE.

*The Cisco Certified Architect page only specifies that a CCDE is required, but I’ve heard from multiple sources that both a CCIE and a CCDE are required.

UPDATE: I need to learn to read better.  The initial reports from Networkers indicated that you needed BOTH a CCIE and a CCDE to become a CCA candidate.  Cisco’s site as well as Jeremy’s article state that you need an active CCDE, and 10 years of experience.  My bad.  😦

Core Knowledge Question of the Day: 08 July 2009

Which Cisco-supported PIM mode uses shared trees?

Highlight for answer: PIM Spare Mode (also PIM Sparse-Dense mode)

July 7, 2009

The Reason Behind the Core Knowledge Section?

Filed under: Cisco,Cisco Certification — cciepursuit @ 11:37 am
Tags: , , , , ,

CCIE Journey recently attended Networkers in SF and has a nice recap of the event, particularly from a CCIE candidate’s perspective.  Definitely surf on over and give it a read.

There was a lot of speculation that the recent introduction of the Core Knowledge section to the CCIE lab was to curb cheating via leaked or brain-dumped labs.  A lot of that speculation centered around the Beijing, China lab location.  CCIE Journey’s post contains a nugget that may give validation to some of that speculation:

Monday was my eight hour lab day with a lab written by a proctor just for Cisco Live. We learned a lot in that class. We learned that the pass rate of the Beijing lab was running at 90% before they implemented the open-ended questions.

CCIE Journey shares my concern that we’re all now paying the price for possible rampant cheating at a specific location.  There is a possible bright side to this though:

He [the proctor] also hinted that the open-ended questions were a quick band aid for stopping the brain dumps and might come off in the near future. Maybe the troubleshooting section of the 4.0 lab will be enough?

I think that this makes sense.  Troubleshooting is a better filter than a four question quiz.  I tend to doubt that the Core Knowledge section will go away though.  The Core Knowledge questions are only ever used one time.  This means that they are essentially “un-dumpable”.  Of course, it also means that the questions may have the tendency to become more and more difficult as the obvious questions are used and discarded.

Core Knowledge Question of the Day: 07 July 2009

What is the effect of issuing the exec level command ‘terminal monitor’?

Highlight for answer: This command will enable the device to send log messages to telnet sessions.

July 6, 2009

Core Knowledge Question of the Day: 06 July 2009

What are unsolicited messages sent from an SNMP agent to an SNMP management station called?

Highlight for answer:  SNMP traps.  SNMP informs fit this description as well.

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