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Colby
Colby Glass has been in IT since 2002. He is currently a network engineer with a large Cisco partner and holds the CCNP, CCDP, CCIP, CCNA: Voice, CCNA, JNCIA-ER and ITILv3: Foundations certifications. He has also passed the CCIE R&S Written exam and is studying for the Lab exam.
Posts by Colby
Educational IOS Petition
Jul 7th
Greg at Etherealmind has created a petition for an educational IOS version. Details:
We the undersigned ask you to sign our petition.
We are the people who are learning about Data networking and Cisco IOS software. As students and practitioners, we need to learn theory and knowledge and then to take that knowledge and practice on Cisco IOS software.
We want to be able to practice that knowledge, and demonstrate our competence. We know that you are considering the value. This petition is to show our need for this solution. Wendel Odom discusses the possibility Cisco Considers IOS for Certifcation Self Study and we are calling for Cisco to make an option available.
This experience and knowledge we gain gives us the capability to make the most of Cisco equipment for our employers, your customers. We help drive the best return on investment, and keep the network performing in the way that your customers expect.
Studying ITILv3
Jul 4th
Sorry for the horrible lack of updates lately. I had to shift focus a bit to meet a job requirement. It’s come down from the top that everyone in the North American Network group within my company needs to get the ITILv3: Foundations cert by September of this year (ugh!). I’ve been cramming it like crazy and hope to knock the exam out in the next couple weeks. If that all works out I can get back to Cisco stuff and hopefully some decent posts.
If anyone is curious about ITIL, it’s terrible, lol. Supposedly it’s a valuable cert, so I can’t complain too much, but it’s just so boring. I love networking, so Cisco certs are actually fun for me. ITIL is just painful.
Anyway, check out my blogroll to get your networking fix.
Spanning VLANs Across the WAN
Jun 29th
A thread on Networking Forum led to some interesting conversation and a little mini-lab on my part. If you’re interesting in seeing a use for AToM in the real world, check out the thread.
This is the topology I ended up with:
To summarize, basically we ran a GRE tunnel across the WAN, then LDP and an xconnect across that. It was pretty fun to play with. So if you’re interested, check out the thread.
OSPF Summarization
Jun 18th
This post is about OSPF Summarization. We’ll be using a familiar topology and going over two ways to summarize with OSPF.
There are two conventional ways to summarize networks in OSPF, we can use the “area range” command and the “summary-address” command. “Area range” is used on the ABR to summarize networks between areas. The “summary-address” command is used on the ASBR to summarize external networks.
Here’s the topology:
I’m not going through the basic OSPF config, so assume everything is configured as the diagram suggests. On R1 I’ve added Lo11-14 and used “ospf 100 area 0″ under the respective interfaces. On R2 I’ve added Lo15-18 and used “redistribute connected subnets”. Let’s look at the RIBs on a couple routers:
First we’ll check out “sh ip route” on R1:
R1#sh ip route
...
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O E2 2.2.2.2 [110/20] via 10.1.123.2, 01:13:32, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O E2 3.3.3.3 [110/20] via 10.1.123.3, 01:12:38, FastEthernet0/0
4.0.0.0/32 is subnetted, 1 subnets
O E2 4.4.4.4 [110/20] via 10.1.123.3, 01:03:47, FastEthernet0/0
172.30.0.0/24 is subnetted, 4 subnets
O E2 172.30.6.0 [110/20] via 10.1.123.2, 00:06:11, FastEthernet0/0
O E2 172.30.7.0 [110/20] via 10.1.123.2, 00:06:11, FastEthernet0/0
O E2 172.30.5.0 [110/20] via 10.1.123.2, 00:06:11, FastEthernet0/0
O E2 172.30.8.0 [110/20] via 10.1.123.2, 00:06:11, FastEthernet0/0
C 192.168.4.0/24 is directly connected, Loopback14
10.0.0.0/24 is subnetted, 2 subnets
O IA 10.1.34.0 [110/74] via 10.1.123.3, 01:12:39, FastEthernet0/0
C 10.1.123.0 is directly connected, FastEthernet0/0
C 192.168.1.0/24 is directly connected, Loopback11
C 192.168.2.0/24 is directly connected, Loopback12
C 192.168.3.0/24 is directly connected, Loopback13 |
Lots of routes here. The ones to note are the 172s showing as External Type 2, which are R2′s loopbacks. Also notice our connected loopbacks.
OSPF Area Types: Not So Totally Stubby
Jun 18th
This is the last post in a series about OSPF Area Types. Today we’ll go over Not So Totally Stubby Areas. We’ll be using the same topology as the NSSA post, but this time we will inject a specific route (40.40.40.0/24) from the ASBR (R4) instead of a default.
Quick refresher, OSPF Not So Totally Stubby Areas have intra-area routes (Type 2 LSAs) and also external routes in the form of Type 7 LSAs, which are converted to Type 5 LSAs by the ABR. No inter-area routes (Type 3 LSAs) are permitted in a Not So Totally Stubby Area and a default route will be injected by the ABR.
(For more detailed information on LSAs and Area Types, check out this post.)
Here’s the topology:
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