Why OTV and not Fabricpath for DCI,

Cisco has been fast at implementing the near-TRILL standard calling it Fabricpath which is an easy and simple way of using all of the available links. It is more of a LAN cloud, where all available links are made available & the forwarding of the frame is based on switch-id. ISIS is the protocol used to calculate the shortest path to the switch that has the efficient link to deliver the packet to the destination switch where the destination mac address is connected to.

Now lets remember to enable fabricpath you need a license which is very expensive. If you want to run OTV again you need a license. Clients often ask me why not we use the fabricpath for the interconnect also.

Now lets understand mac forwarding topology is built using fabricpath. while it might be very efficient to use within a datacenter it is not advisable to use across the DC. Here's why;

• If there is any flooding in one datacenter it is carried to the other datacenter also which is completely not desirable, needless to say if there are multiple datacenter interconected you have one hell of a problem. OTV has the upper hand as it localizes all this to a single datacenter.
• Both datacenter need to run fabricpath & all vlans needs to be configured, because it becomes one single topology. when we use OTV we only extend the required vlans and not all vlans
• Gateways cannot be local on the datacenter and there will be a single forwaring HSRP gateway for both datacenter making it inefficient in every way & the DCI link will forwarding traffic full fledged.
• The arp optimization that OTV delivers cannot be leveraged when using the fabric path

Taking into consideration the above mentioned important factors we definetly cant use fabricpath as a DCI solution. OTV is the way to go. So the use of fabricpath and OTV protocol, in their diversities, advantages and disadvantages have to be clearly understood before we design the DC

CCIE DC prep blog 4 - OTV

I love OTV. I have designed multiple data centers with OTV & I simply love the way it works & most importantly how simple it is to configure it up.  However to justify my preparation for the CCIE lab I did go though my favorite documentation on the Cisco site which can be found here.

I have always implemented the multicast mode of deployment and have never done the unicast mode. I think that is one area I need to practice using the lab setup. Most importantly i will serve as POC for my designs and also help me heavenly in the CCIE lab preparation. I want to create some labs and do some extensive troubleshooting when we use the unicast mode. I want to see the  adjacency server as it come back online what update it gives to a new client joining OTV.  I don't want to get into the details of it but nevertheless it will be a good option to try it out.

Once I start renting out labs for the full fledged exercises I think I will perform these tests. I am planning to buy INE workbooks. But unfortunately I don't have the money to buy it, so I think  I will wait for a couple of months save some money and then purchase it. We can use the INE labs only if we have their workbooks which to me makes sense. SO I think I need to save money for the workbook/racks and then go buy it. Until then it will be preparation using my pod.

I love the OTV simply because it maintains the IP boundary on each of the data center & yet extends the L2 on either side. Also I love the fact that the L2 issues are localized. The only part is that the OTV is available on the Nexus &k and it needs a license to function. I need a bit of convincing to do to my clients when I tell them the cost part for the license.

Action Item to track will include: Practice the Unicast mode of operation and create some troubleshooting scenarios for the same

CCIE DC prep blog 3 - UCS

Spent a good deal of time labbing all the LAN & SAN options.  They were basic options, good enough to give me a good understanding of the UCSM. For the lab, I initiated the FI, made the port assignments, created port-channels, vlans, performed static pinning, tested some traffic flows, assigned vlans to certain ports. Most interesting was the  implementation of the disjoint networks, I was interested in knowing how they are actually used in treat life scenarios. Some of the useful links for disjoint layer2 can be found here and here

On the SAN side i created VSANS, port-channels, performed basic SAN connectivity. I dint not go deep on the SAN side yet. I need to work it further.

I got a fair idea on the service profile creation. I explored the various options on the GUI to configure these options. However I have not worked on these topics in detail. I started losing steam on the UCS prep. Whatever I have prepared I learnt well, I will revisit the UCS configuration after a few days.

I will be moving on to some core networking concepts like OTV and Fabricpath. I will be revisiting UCS again after few days.

CCIE DC prep blog 2 - UCS

I have been lucky to work for cisco partner and the PEC is lending a helping hand in many ways. I enjoyed attending the ecamp they have on the PEC for UCS. Also a friend of mine demonstrated  how to initialise the FI and other basics of UCS.

It was interesting to learn the various models of UCS, how the B series and the C series are positioned in the market and where they can be used. Although this information  is not required for the CCIE lab exam, my job role of providing solution will require this information.

I will be working with a colleague of mine who is a expert on UCS and has desinged multiple V-Blocks. Using the GUI I think I can grasp things quickly, but the vital part will be getting to know how to use the UCS for various requirements.

I will be focussing on the following topics for the first half of the week;

Implement LAN Connectivity in a Unified Computing Environment
Configure different Port types
Implement Ethernet end Host Mode
Implement VLANs and Port Channels.
Implement Pinning and PIN Groups
Implement Disjoint Layer 2

Followed by these topics;

• Implement SAN Connectivity in a Unified Computing Environment
  Implement FC ports for SAN Connectivity
  Implement VSANs
  Implement FC Port Channels
  Implement FC Trunking and SAN pinning

• Implement Unified Computing Server Resources
  Create and Implement Service Profiles
  Create and Implement Policies
  Create and Implement Server Resource Pools
  Implement Updating and Initial Templates
  Implement Boot From remote storage
  Implement Fabric Failover 

If I can get through this information in the next one week, & have the hands on the UCS, I think i will be in great shape to get started on my job role for UCS.

Apart from this I think I will be focusing on Nexus security and OT parts this week. I know the plan is pretty intense, but this is the only way I can make inroads with the little time I have to prepare.

Enter the UCS world - CCIE DC

After 7 years, it is now to time to enter the compute part of the datacenter. It brings back good old memories of me aspiring to be a MCSE and stirving to be one. Life took a full turn and led me to the network world. It is inevitable now in the datacenter world for the compute and the network world to fuse, probably if I still have it in me I can probable consider putting effort into vmware and windows 2008 server stuff. But at the moment I  will stick to UCS :-)

Focus of today's study will be to know the currently available products, the hardware architecture & the initializing the UCS.

Couple of links from cisco for anyone starting up on UCS should include this & this.With cisco providing the UCS emulator, this will be helpful.

Documentation roadmap from cisco can be found here.

This is a monster site for UCS & his youtube channel can be found here.