Corrections welcome.

Study Questions

• Why would you ever want to summarize routes?

Summarizing routes minimizes the routes advertised to the network.  For example, instead of advertising 192.168.0.0/24, 192.168.1.0/24…192.168.n.0/24, a router can advertise a single route to 192.168.0.0/16.  Keeping routing tables small saves hardware resources, minimizes convergence times, helps avoid route flapping, and makes the routing table easier to read for humans.

• When will an EIGRP router auto-summarize a route?

If a router has interfaces that that are in different classes of network (Class A, B, C), then that router will auto-summarize those routes up to the classful boundary.  For example, if you have a 10.0.0.1/24 and a 192.168.100.1/30, the router will advertise 10.0.0.0/8 and 192.168.100.0/24.

Or neighborships, as they call it in the book.  What a terrible word.

Study Questions

• What settings must match between two routers in order to become EIGRP neighbors?

Both routers must be in the same primary subnet Both routers must be configured to use the same k-values Both routers must in the same AS Both routers must have the same authentication configuration (within reason) The interfaces facing each other must not be passive

Study Questions

• How do you keep EIGRP from killing your WAN?

You can use the ip bandwidth-percent eigrp AS X command to limit the amount of bandwidth that EIGRP uses to update neighbors.

• How does EIGRP calculate how much bandwidth it can use for each frame relay PVC?

By default, EIGRP takes 50% of the (sub)interface’s configured bandwidth (with the bandwidth command) to use for updates on NBMA (non-broadcast mutliaccess) networks like frame relay.  This value is divided equally among all the PVC configured on that interface.

I’ve seen and used the command before, but I’ve never really seen any use of the show ip protocols command until tonight while reading up for my ROUTE test.  There’s a lot of good information in the output, and, from the way the book is reading, this is a great candidate for use in a lab question.

To check it out a bit, I set up a small network with four routers connected only to a single Ethernet segment.  I set up one router to run EIGRP, OSPF, and BGP to each one of the other routers just so I could see the output for the different routing protocols.  Here’s what puked out after struggling with GNS for a few minutes.

Last time, we talked about a nifty little lab I set up for redistribution and how the OSPF ASBRs acted a little differently than I expected.  This time, let’s look at how changing external OSPF routes to a metric-type of 1 (E1) affects the routing tables.

Here’s the network again.

The static routes are being redistributed into their respective IGPs, and EIGRP is being redistributed into OSPF.  Let’s look at the routing table on R1.

I just got back from Global Knowledge’s ROUTE class, and I must say that it was a great class.  John Barnes puts on quite the show and is the best instructor I’ve ever had.  I digress, though.

One of the topics we covered was route redistribution, so I went back to the hotel one night and fired off this network in GNS3 to study a bit.

The object was to see how redistributing statics into OSPF and into EIGRP differ.  It was also an opportunity to see how EIGRP redistributes into OSPF (and OSPF into EIGRP, but I didn’t make it that far).  To do that, I redistributed 10.10.10.0/24 from R1 into OSPF and 10.10.20.0/24 from R4 into EIGRP.  I then had R2 and R5 redistribute all EIGRP routes into OSPF.  It’s a nice mix, but I saw some weirdness in the paths to 10.10.20.0/24.

Just because I like giving more money to Pearson Vue, I took the BCMSN test today to see how I would do.  I passed with no problem.

In my mind, the CCNP is a technical certification, so I expect to be tested on technical topics.  Are there topics beyond technology that P-levels should know?  Of course there are, but I really don’t think whole chunks of the test should be about a preparation plan and rollback procedures.  The BCMSN had a lot more technical questions at a much higher level of expertise; it seems much better suited to the CCNP track than the SWITCH test did.

I did my standard 2ish-hour drive to the closest testing center today to take the SWTCH test (642-813).  Utter failure.  That’s 3 for those scoring at home.

The test was the absolute worst I’ve ever taken.  I know that I complain a lot, but this is totally justified in my eyes.  My 4th grade spelling tests were better than this.  I’ve seen kindergarten plays with better production value.

First of all, it was poorly written.  Whoever wrote those questions has a few pieces of information about English sentence structure missing from their skill set.  A sentence needs a verb, right?  Well, a lot of the sentences were missing those.  It’s kind of important to know what the whole point of the sentence is, or is that too much to ask?  The “drag this over here” exercise questions all started with the same 13-word phrase that left the question so long that it was unreadable.  A couple of commas would have been nice in some.  Others I just had to infer from the answers what they were trying to ask.

Certain divisions of the company tend to shoot themselves in the foot by kicking off large file transfers during business hours, so I had a thought that maybe we could use time-based ACLs to do some QoSing for those guys. I fired up GNS3 with a 3600 running 12.4(25b) with some virtual PCs on it’s Ethernet interfaces.

time-range BUSINESSHOURS
 periodic daily 8:00 to 17:00
!
ip access-list extended PINGS
 permit icmp any any time-range BUSINESSHOURS
!
class-map match-all PINGS
 match access-group name PINGS
!
policy-map PM-F0/0-OUT
 class PINGS

First, I set the router’s time to outside of the time range and sent some pings over.