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Archive for February, 2010
CCIE Rack Complete!
Feb 16th
Obviously I’m a huge proponent of Dynamips, and I will still be using it, probably more so than the physical hardware. But… I had most of this stuff lying around, so I thought I should put it to use. I’m mirroring the INE topology as best I can with what I have. Here’s my terrible picture (I’m not much of a photog):
(click image for fullsize)
R1 – 2610XM
R2 – 3640
R3 – 3640
R4 – 3725
R5 – 1760 (might replace this one)
R6 – 2801
FR Switch/BB1 – 2621 + NM-8A/S
SW1 – 3560-48
SW2 – 3560-48
SW3 – 3550-48
SW4 – 3550-48
Term Server – 2512 + 2514
BB2 – 2501
BB3 – 2514
3550 vs 3560
Feb 15th
I frequently see people asking if 3550s are sufficient for CCIE lab preparation, or if 3560s are a must. Of the top of my head I know that QoS differs between the 3550 and 3560, and also that the 3550s do not support Private VLANs. Beyond that, I can’t say much. Today I stumbled across a comparison from Internetwork Expert. This is really great information. Here’s what they’ve laid out:
Catalyst 3560 Only Features [12.2(25)SEE2]
Access Switch Device Manager (SDM) Template
IEEE 802.3af Power over Ethernet
IGMP Throttling
IPv6 (Internet Protocol Version 6)
MLD Snooping
Private VLANs
VLAN-Based QoS on Physical Ports
SRR (Shaped Round Robin)
Weighted Tail Drop (WTD)
Auto-MDIX
Weekly Open Ended Question #1
Feb 11th
I need to start working on the miscellany involved in the OEQs for the CCIE R&S. This is the first post in a weekly series of OEQs. Obviously I don’t know exactly what the CCIE questions are going to be, but I’ve found some resources with sample questions, like INE’s CCIE Blog. The plan is to post one question a week with you guys (hopefully) answering in comments. I will update previous week’s article with the answer when posting the new question the following week. First question is easy:
What is OSPF’s metric and how is it determined?
Please post answers in the comments (without Googling)!
Highlight for answer:
OSPF uses a reference bandwidth of 100 Mbps for cost calculation. The formula to calculate the cost is reference bandwidth divided by interface bandwidth. For example, in the case of Ethernet, it is 100 Mbps/10 Mbps=10.
Note: If “ip ospf cost cost” is used on the interface, it overrides this formulated cost.
Passed BGP+MPLS!
Feb 10th
The original plan was to take BGP and MPLS separately, but I was told by a few people to give the composite a try. Since my employer is picking up the tab for two attempts, I figured it couldn’t hurt to try. I was hoping to pass, but I wasn’t too confident. I passed though!
It was pretty tough, but not too bad. There was more ATM than I would have liked, but most of it was basic. Also a lot of drag and drops. The sims were ridiculously easy, which was surprising. It didn’t feel like the exam went as deep into the technologies as I expected.
So I’m a CCIP now, which is awesome. I need to celebrate a little.
BGP Multi-Exit Discriminator (MED)
Feb 8th
Today we’ll go over another important BGP topic: MED. From Cisco:
“MED is an optional nontransitive attribute. MED is a hint to external neighbors about the preferred path into an autonomous system (AS) that has multiple entry points. The MED is also known as the external metric of a route. A lower MED value is preferred over a higher value.”
So, to summarize, MED is used to influence incoming traffic from a multi-homed neighbor AS.
Here’s our diagram:
In this case we’ll say that the link between PE1 and CE1 is only a T1, while the link between PE2 and CE1 is a DS3. Obviously we will want traffic to use the faster link, the PE2-CE1 DS3.
First we’ll configure our interfaces and basic BGP:
PE1: hostname PE1 ! interface Loopback0 ip address 1.1.1.1 255.255.255.255 ! interface Serial0/0 description To PE2 ip address 10.1.1.2 255.255.255.254 ! interface Serial0/1 description To CE1 bandwidth 1500 ip address 172.16.1.2 255.255.255.254 ! router bgp 5300 no synchronization bgp log-neighbor-changes neighbor 2.2.2.2 remote-as 5300 neighbor 2.2.2.2 update-source Loopback0 neighbor 2.2.2.2 next-hop-self neighbor 172.16.1.3 remote-as 1200 no auto-summary ! ip route 2.2.2.2 255.255.255.255 10.1.1.3 PE2: hostname PE2 ! interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface Serial0/0 description To PE1 ip address 10.1.1.3 255.255.255.254 ! interface Serial0/2 description To CE1 bandwidth 45000 ip address 172.16.1.4 255.255.255.254 ! router bgp 5300 no synchronization bgp log-neighbor-changes neighbor 1.1.1.1 remote-as 5300 neighbor 1.1.1.1 update-source Loopback0 neighbor 1.1.1.1 next-hop-self neighbor 172.16.1.5 remote-as 1200 no auto-summary ! ip route 1.1.1.1 255.255.255.255 10.1.1.2 CE1: hostname CE1 ! interface Loopback0 ip address 3.3.3.3 255.255.255.255 ! interface Loopback1 ip address 192.168.1.1 255.255.255.0 ! interface Loopback2 ip address 192.168.2.1 255.255.255.0 ! interface Loopback3 ip address 192.168.3.1 255.255.255.0 ! interface Loopback4 ip address 192.168.4.1 255.255.255.0 ! interface Serial0/1 description To PE1 bandwidth 1500 ip address 172.16.1.3 255.255.255.254 ! interface Serial0/2 description To PE2 bandwidth 45000 ip address 172.16.1.5 255.255.255.254 ! router bgp 1200 no synchronization bgp log-neighbor-changes network 192.168.1.0 network 192.168.2.0 network 192.168.3.0 network 192.168.4.0 neighbor 172.16.1.2 remote-as 5300 neighbor 172.16.1.4 remote-as 5300 no auto-summary |
Which Exams for CCIP?
Feb 5th
I’ve been talking to people about the BGP and MPLS exams. From what I’m hearing, it sounds like the composite (BGP+MPLS) is actually easier than doing each exam individually. I’m finding this a bit hard to believe, but people seem pretty adamant about it. I’m hearing that there are less sims on the composite.
I’ve been focusing on BGP mostly, but MPLS has been part of the labs I’ve been using. I might just try out the composite and see how it goes since my employer is paying for two attempts per exam…
Anyone have thoughts or suggestions on the matter?
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