MPLS Exam Cram

This is the start of notes on my cramming for the MPLS exam. It will consist of new or interesting MPLS information that I need to commit to memory.

• Multiple labels can be inserted, and the bottom-of-stack bit is set on the last label
• Labels consist of a 20 bit label, 3 bit experimental field, 1 bit bottom-of-stack indicator, and 8 bit TTL
• Ethertypes: 0x0800 is IP, 0x8847 is unicast with at least one label, 0x8848 is multicast with at least one label
• More than one label is used for VPNs and TE
• An LSR can push, swap, or pop labels
• MPLS is split into the control plane and data plane
• FEC: Packets forwarded based upon a common characteristic
• For Unicast IP Routing, an IP routing protocol and a Label distribution protocol are required
• Label distribution protocols match labels with networks
• FEC is the destination network
• PIM can be used for multicast, and the FEC is the destination multicast address
• TE requires OSPF or IS-IS with extensions
  
• RSVP or CR-LDP establishes tunnels and propagates labels
• With QoS, the FEC is the destination network and CoS
• In VPNs, two labels are used: Top points to egress router, second points to the outgoing interface on the egress router, or a routing table
  
• FEC is the site descriptor or VPN routing table

BSCI Complete

The exam ended up more or less as I was expecting. Some parts were relatively easy, some were a pain, and always an overabundance of annoying questions that seem more to be out to test attention to detail rather than knowledge.

My score was a bit higher than on QoS, and passing, but still low enough where I'm not concerned that I overstudied for the exam.

On to BGP+MPLS, which will complete the CCIP. After that it's finally onto the SP Written, which will renew my CCIE certification.

Even though I'm planning on doing the SP lab after that, it is a little tempting to just knock out all of the professional level exams. I have enough experience in Voice and Security as well where I could probably hit an exam every couple of weeks and have the CCVP and CCSP complete by the end of the year.

The CCIE lab is just such a time and energy suck. But I'm leaning toward going ahead and studying for the lab sonner rather than later. There are three main reasons for this.

First, I'll be freshest on the lab material after just studying for the CCIP and written. If I switch tracks I'll probably have to relearn a few things.

Second, assuming I eventually pass the Service Provider lab, I can then jump right into the CCSP, which would give me a break before working on the Security lab. I'm definitely saving voice for fourth just because it has the reputation for being the toughest. Storage would be last since I have absolutely no experience with it and it will probably take me a lot longer.

BSCI Exam - 642-901

Ok, the very fact that I have to take this exam is a little strange. I have been a CCNP since 2004 and am a CCIE. Why don't these fill the "routing" exam requirements?"

According to the certification progress website, the version of BSCI exam I passed over 4 years ago is too outdated to count. So I have to knock this exam out instead.

As far as I can tell, there is only one topic that isn't covered by the R&S written: IS-IS. I'm guessing they're just going to be asking questions about the intricacies of L1, L2, and L1/L2 behavior.

Aside from that, I'll need to brush up on all the "booksmart" material such as timers and metric computation.

I think I'm going to shoot to have this knocked out by Friday.

I have my weekends back

On Friday I completed my final presentation for my Master's Project at Towson University in Maryland. For the first time in over 5 years I don't have any studying or homework to worry about over the weekend. All the more time to spend studying for CCIE #2? Nah, I think I'm going to be taking a few weekends for myself until I knock out the written and am ready to start working on the lab.

CCIE Worldwide Statistics

It's official, North America no longer holds most CCIEs. As of the recently released statistics here, Asia now has more.

QoS Exam Passed

Wow, all I can say is do not underestimate this exam. I knew it wasn't going to be simple, but it was much more challenging than I expected. If I missed one more question I would have failed. Actually, before I saw the congratulations message, I thought I was going to be rescheduling this thing.

I'm off to do my Master's presentation on Friday, so I won't be starting to study for another exam until next week sometime.

QoS exam 642-642

I'm feeling pretty good about this exam and will take it either next week or the following week. It's amazing how much LESS material there is in a professional level exam vs an expert level one.

As there's a lot of overlap with my R&S CCIE and my previous voice experience, I'm not stressing out much over this. Of course, there's always the fear of taking it for granted and failing and wondering how the heck I can pass the CCIE written and Lab and bomb the QoS exam.

Anyway--here are the topics I need to commit to memory:

• Higher drop precedence means more likely to be dropped. But higher IP precedence means less likely do be dropped. Huh? Who designs this stuff anyway? Just remember, AF11 will be dropped before AF21; however AF12 will be dropped before AF11. That last number means drop precedence, as in higher priority to be dropped. Whereas the first number means the traffic itself is higher priority, and less likely to be dropped. It makes me think they designed it this way simply because they knew they'd get a few good test questions out of it.
• RTP Header Compression also compresses the UDP and IP headers, and therefore must be enabled on both sides of a link. Could the name be any more misleading?
• COPS, aside from one of my wife's favorite TV shows, is a protocol that allows centralized monitoring and control of RSVP. Bad packets, bad packets, what'cha gonna do? What'cha gonna do when QoS comes for you?
• ECN is like frame-relay adaptive shaping, except it's not shaping and there's no frame-relay. If a router is nearing congestion, it can use the last two bits of the ToS field to notify the upstream host. Then the upstream host relays this information to the sender. Finally, the sender slows down sending. It's like FECN and BECN, and like being issued a warning before WRED steps in and destroys your packet.
• BGP can use communities to propagate QoS policy information (bgp-policy command)