I’m finally back from RTP and have a stable enough Internet connection to finally write a post.  After my SP lab last week, I decided to visit some relatives in Charleston, SC to relax over the weekend before coming home.  I tried to post something on Friday, but my hotel wireless connection was terrible.  Anyways, read on for a recap.

Since the Thanksgiving weekend, I’ve been scrambling to get enough practice time in for the configuration portion of the lab.  Shortly a few days after committing payment to Cisco for the lab, the announcement for the OEQ or Core Knowledge came out which changed my studying strategy quite a bit.  At the time, I had just begun going through INE VOL2 labs before the Christmas holidays and so now I needed to come up with another game plan.  I gave myself a deadline to finish up the VOL2 labs 1 through 5 by New Years.  For the remaining 5 VOL2 labs, I was just going to read the solutions.  Once the new year began, I only labbed up mini scenarios and didn’t bother doing any full scale labs.  All I ended up doing was reading anything I could get my hands on regarding the SP lab blueprint (i.e. books, FAQs, blogs, Cisco white papers, articles, etc.).

Did all the reading help?  Yes, it did.  The set of OEQs that I received were pretty straightforward.  If you have some clue as to what you are doing in general with topics covered in the blueprint, you should be prepared.  Now I know that statement is vague and probably doesn’t really help you much, but the OEQs are really nothing to be concerned with at all.  I can’t speak for individuals who took the lab in the first 2 months, but I think the Cisco folks have finally figured it out where the OEQs are really ‘Core Knowledge’ type questions.  If I could make one suggestion to the Cisco developers, you should have the OEQs at the end of the lab.  The biggest complaint for many individuals that get a set of off-the-wall questions is they feel gypped having just forked over $1400 for only 30 minutes of completing the test.  What’s the point in continuing onward if you already knew you blew your chance at the start of your day?  Nothing you do in the configuration portion matters if you can’t get by 3 out of 4 questions.  IMHO, I think if the questions were at the end of the lab then test takers couldn’t complain since they would actually have to work through the entire day.

Unfortunately, because I spent so much time on reading, my speed was off with the configurations.  There was a lot of typing involved with my version of the lab. On top of that, I wasn’t fully rested going into the test as I would’ve liked.  I was a bit foggy having been up all night due to nerves.  Believe me, I exhausted myself before my flight out to Raleigh so I could just sleep when I arrived, but I was pretty wired and couldn’t stop thinking about 4 questions.  In the end, I fell short on the configuration end of the spectrum.

Here’s an outline on what I did for this attempt:

1) Read: Just try to understand the material you are reading.  I don’t think you need to memorize every little detail, but know the important subject matter.  Here’s a list of everything I read:
MPLS Fundamentals
MPLS VPN Architectures
MPLS VPN Architectures Volume II
Routing TCP/IP Volume I
Routing TCP/IP Volume II
Cisco FAQs
Cisco White Papers
RFCs

2) Choose a vendor workbook:  For my attempt, I used INE’s VOL1 and VOL2.  Keep in mind the material is very outdated but still relevant for this lab.  Everything you need to know is in VOL2, you just need to reference the Cisco documentation yourself to get a thorough understanding of the technology.  If I could make a suggestion to the INE folks, I think the only updates you should make for your products are:

-VOL1: Create some IS-IS labs with explanations.  I ended having to use my R&S OSPF, EIGRP, and RIP VOL1 lab scenarios to test out IS-IS.  IS-IS is extensive enough on the exam that it should be covered in your product.

-VOL2: I really liked what INE has done with the R&S and Security workbooks; they give you a brief explanation alongside the expected output.  We could really use the additional information to help reference materials for the OEQ.

3) Core Knowledge Simulator:  I ended up purchasing this product 1.5 weeks before the lab and only looked at it 2-3 days beforehand.  IMHO, the product just destroys your confidence all together because you feel like you’ve forgotten your CCNP studies.  You also get a false sense that you are required to know the granular details of the technologies.  Based on the OEQs I received, your questions are really off the mark and probably need to be scaled down just a bit.

4) Practice: I didn’t utilize the rack rentals as I had anticipated.  I ended up just using dynamips when I was labbing, which should be enough.  If you have the money to spend, go ahead and rent or buy equipment.  If you are on a shoe string budget and have a powerful enough workstation, then invest some time in dynamips or GNS3; the IOS code you should be running is 12.2S.  There’s definitely a difference in the feature sets when you are running 12.3T and 12.2S so you should be familiar with both versions.

Am I going to take a 2nd attempt?  That depends, having just checked the availability the next possible opening at San Jose is in September.  I don’t think I’ll be flying out to other locations anymore to test.  In fact, most of the tests will be running of SJ anyways (similar to the R&S format) and conducted at nearby Pearson Vue locations in the future so it doesn’t make sense to fly out (unless of course work pays for it and everything isn’t out of my own pocket).  There are other rumors that this lab will be retired and replaced by SP Operations.  I was told that for the month of July all lab testing sites will be blocked off completely to allow major changes to the lab testing facilities as well as when the announcements will be revealed.  If I can get another test in before June, I think I’ll donate more money to Cisco.  Until I can get a close enough date, I’ll just be enjoying my time away from all the stress:

-Catching up on all my shows on the DVR

-Toying around with JNCIE-ER or JNCIE-M/T

-Creating some mini-scenarios to help cover the lacking areas of technologies

-Playing basketball on the weekends again

-Networking at Interop, CiscoLive, etc.

A few weeks ago, I had the pleasure of attending Legally Blonde The Musical with my wife.  It had been a long summer for us and so we decided that we were going to treat ourselves to a night out.  One of the songs in the play was ‘Chip On My Shoulder’ sung by the character Emmett.  The song was entertaining to say the least, but a few of the lyrics within the song really stuck in my head:

No! That’s the chip on my shoulder
I hugged my mom and told her
With the chance I’ve been given
I’m gonna be driven as hell

Though I can’t take the day off
I just think of the payoff
You need a chip on your shoulder
Little Miss Woods comma Elle

For the life of me, I couldn’t shake the words, Though I can’t take the day off…I just think of the payoff, out of my head and felt very driven for a new achievement in my career.  Watching shows off the DVR and playing video games all summer just wasn’t going to cut it.  My workload lessened so work itself had become stagnant and I figured I needed a new challenge to keep me going.

As you may know, I’ve been eligible to take the Security lab for quite some time, but the test had been eluding my interest level.  I’m usually more interested in a technology when I know it will be utilized in some form within my work environment.  Presently, my company views security technologies as a luxury and hasn’t approved any of the recommendations for new security initiatives which has really dampened my spirits with the track altogether.  IMHO, the market seems to have dried up for Cisco security technologies in SoCal.  I still have until mid-February to make up my mind about the track, but I have yet to find that spark that’s going to drive me to finish the track.

With the R&S track updating later this year to include MPLS (among other things), it only made sense that I should brush up on the technology to assess my personal knowledge of the subject matter.  After reading a few chapters this summer from MPLS Fundamentals, I found the technology to be very interesting.  I also ended up reading MPLS and VPN Architectures, Volume II and was completely hooked.  To measure my level of knowledge with the content from these 2 books, I decided to sign up for my CCIE Service Provider written exam (350-029).  I had booked the test for today and managed to pass it earlier this morning.  Aside from receiving validation of the material, I’m now eligible to take the Service Provider lab.  I feel more driven towards this track than security but some questions linger about in my head:

-Can I even afford the additional expenses? –> I just checked with my wife and she says, yes, but I have to pass the lab on the 1st try.

-Is studying even possible with my current workload? –> Not really, but I thrive on pressure.

-Could I truly commit myself to long lab hours, cramping fingers, an aching lower back, and isolation from my favorite activities (i.e. poker, basketball, mini expeditions, etc.)? –> If I wanted it badly enough, I would find a way.

-If I pursue a track, which one? –> I really have to weigh the pros/cons for each track.

My plan for now is to really think it over during the Labor Day weekend and just make a decision.  All I know is that a driving factor for me is I need a bigger payoff in life (not necessarily a monetary one).

I had to read this chapter about 4 times last week to digest the material.  The delivery of the information needs to be restructured.  It was such a hard read for me because I found that the information seems to jump around all over the place.  Unlike the previous chapter where you actually learned how the technology works, this chapter is designed to just show you how to implement features within LDP.  IMHO, you’re probably better off supplementing your studies with reading RFC 3036 to get a better understanding of LDP.  Anyways, here’s some of my notes after reading.

MPLS Fundamentals - Chapter 4: Label Distribution Protocol

Discovery
-Hello messages (UDP 646)
-LDP ID is a 6-byte field; LDP ID = LSR ID (4 bytes) + Label Space (2 bytes)
–If last 2 bytes are zero, label space is platform-wide or per-platform
–If last 2 bytes are non-zero, label space is per-interface and multiple LDP IDs are used (i.e. LC-ATM)
-LDP ID needs to be present in routing table of neighbor routers, otherwise LDP session is not formed

Session Establishment
-Hello messages (TCP 646)
-Negotiation of session parameters (i.e. timers, distribution method, VPI/VCI, and DLCI)
-LSR modes: advertisement, label retention, and LSP control mode

Label Withdrawing
-Label withdrawn if local label changes (i.e. implicit NULL –> non-reserved label)

Notifications
-Error - sending and receiving LSR should terminate session
-Advisory - LDP session info from peer
–Signaled Events
—Malformed PDU
—Type-length-value (TLV)
—Session keepalive timer expiration
—Unilateral session shutdown
—Initialization message events
—Events resulting from other messages
—Internal errors
—Loop detection
—Miscellaneous events

Target LDP Session
-LDP session between LSRs that are not directly connected

LDP Authentication
-Implement MD5 digest

LDP Autoconfig - Easier to use than configuring each interface separately

LDP-IGP Synchronization
-When LDP session is broken on a link, IGP still has that link as outgoing; packets are still forwarded out of that link
-Packets become unlabeled when LDP is broken; LSR is unable to forward packets and drops them
-LDP-IGP Sync ensures that link is not used to forward unlabeled traffic when LDP session is down
-OSPF is only supported IGP
-After LDP session is established and label bindings are exchanged, IGP advertises link with normal metric and traffic is label-switched across interface

LDP Session Protection
–Flapping links are detrimental because LDP and IGP need to time rebuild neighborship
–Utilizes targeted LDP sessions for protection

For me, returning back to work after a long weekend is a slow process.  I find that I need to spark my motivation in some way, so before diving in to my workload, I decided to read up on MPLS.  The main reason for reading up on MPLS (and not something else more enjoyable) was to prepare for a proposal that I needed to write up for a client.  Since terminology is often thrown around in meetings and discussions, I figured during my morning lull that it was best to solidify my knowledge of the technology.  I pretty much read through Chapters 1 & 2 fairly quickly.  Based on past experiences, the bulk of the material for Cisco Press books seems to appear in the 3rd chapter.  On that point, here are the notes I gathered:

MPLS Fundamentals - Chapter 3: Forwarding Labeled Packets

IP Lookup vs Label Lookup
-Lookup in CEF table
–IP-to-IP
–IP-to-label
-Lookup in LFIB table
–Label-to-IP
–Label-to-label

Label Operations Recap
-Pop - top label is removed; packet forwarded with remaining label stack or as an unlabeled packet
-Swap - top label is removed and replaced with a new label
-Push - top label is replaced with new label (swapped) and one or more labels are added (pushed) on top of the swapped label
-Untagged/No label - stack is removed and packet is forwarded unlabeled
-Aggregate - label stack is removed and IP lookup is performed on IP packet

Unknown Label
-LSR will drop incoming packets with an unknown top label

Reserved Labels 0 - 15
-0 - Explicit NULL Label - Maintains QoS on PHP
-1 - Router Alert Label - Present anywhere in stack except bottom; packet not forwarded in hardware will be reviewed by software process
-2 - IPv6 Explicit NULL Label
-3 - Implicit NULL Label - PHP; removes LFIB lookup for directly connected and summary
-14 - OAM Alert Label - Not used by IOS; used for failure detection, localization, and performance monitoring

IP TTL
-An 8-bit field within an IP header signifies the time a packet has to live before it is dropped;  TTL is usually 255 and decremented by 1 at each hop; When TTL reaches 0, packet is dropped by router and sends ICMP message type 11, code 0 (time exceeded) to end of LSP for delivery to originator (i.e. P-router has no knowledge of orignator routes)

MPLS TTL
-IP TTL value is copied to pushed labels
–IP-to-MPLS Behavior of MPLS TTL - Safeguard mechanism in IOS does not copy if MPLS TTL > IP TTL
–Label-to-label Behavior of MPLS TTL - Swap operation, TTL of incoming label -1 is copied to swapped label; Push operation, received MPLS TTL of top label -1 is copied to swapped and pushed labeles; Pop operation, TTL of incoming label -1 is copied to new exposed label
–P-router Behavior of MPLS TTL - Notes what the MPLS payload, a Layer 2 frame, is when the TTL expires; drops packets if not IPv4 or IPv6

MPLS MTU
-n * 4 bytes, n = # of labels
-sh mpls int det
-mpls mtu ‘1500 + (2 * 4)’
-Giant Frame
–Layer 2 frame that reaches max size for data link
-Baby Giant Frame
–Slightly bigger than max allowed
–Recommended on switches
—system jumbomtu
—system mtu
—mtu (int setting)

MPLS MRU
-Cisco proprietary; LSR is informed how big a received label packet of a certain FEC that can still be forwarded out without fragmentation; label operation determines MRU per FEC or prefix

Fragmentation
-If labeled packet exceeds outgoing MTU, the LSR strips the label stack and fragments IP; if DF-bit set, ICMP error message type 3, code 4 (Fragmentation needed and do not fragment bit set) is sent to end of LSP
-Path MTU Discovery - Orignator that receives ICMP error message type 3, code 4 lowers the size of packet and retransmits to avoid fragmentation
–Firewalls, ACLs, and routing issues can prohibit originator receipt of ICMP error message type 3, code 4