CCIE or Null!

My journey to CCIE!

Let’s look at: UCS B-Series Blade to IOM Connectivity

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Being a network engineer one of the things that I really wondered about in the UCS B Series was how exactly do those server blades talk the IOM, now from the IOM to the FI’s its relatively simple you’ve got physical cables. However within the UCS B-Series chassis there are no cable per-say within the chassis however the blades are connected by an 802.3kr Backplane Ethernet.

There are actually a few things that come into play when considering the bandwidth/connectivity between the blades in the B-Chassis such as:

  • IOM Model -2104XP vs 2204XP vs 2208XP and so forth
    • The IOM Model depicts the following:
      • Number of Physical connection to the upstream FI
      • Amount of Throughput that can be carried through the chassis
      • Number of 10Gb IEEE 802.3kr connection into the Chassis
  • Adapter Type – Cisco VIC 1240/1280 vs M81KR vs 3rd Party Cisco Certified Adapter vs etc
    • Affect the number of virtual interfaces
    • Determines the amount of throughput per-fabric to/from the server
  • Number of adapters populated in the blades
    • Also determines the amount of throughput per fabric.

A physical representation of the connectivity:

UCS Blade Conn


I was able to get this info from, and this page has goes into detail regarding many of the different types of connectivity. It is definitely a good reference for planning out a UCS-B Series deployment. Granted this is only in regards to network connectivity and doesn’t talk about the requirements of the actual compute hardware itself.

P.S. I’ve been updating my CCIE: Data Center Study Link Page hope your still checking out!

Written by Stephen J. Occhiogrosso

October 13, 2014 at 8:01 AM

CWNP Conference Presentations

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If it wasn’t Twitter I probably would not have known there was a CWNP conference going on, but luckily we have Twitter. Looks like it was a 3-day conference about all things wireless, I really will try and go next year.

It also looks like they posted the presentations on their website found here, I’ve looked through almost all of the presentations at this point and there are definitely some good ones in there. I hope they take a page from CiscoLive365 and post videos of the actual presentations in the future. Even if there is a small fee they would be worth it (or maybe be available certified CWNP’s?). While you can read through some of the presentations and get some valuable information from them, there are one or two that would probably offer much more insight if you could see/hear the presentation.

I really like Jerome Henry’s presentation on WLAN ‘range’, because believe it or not there are still quite a few people out there that say ‘This AP can cover 1500 sq. ft’, sure maybe it can but what will data rate be and will clients transmission be able to make it back to the AP when they start approaching the edge of the wireless cell?

Jonathan Linton’s VoWLAN, is another good one going over some best practices and design considerations.

There is also a good one on Transmit Beamforming, now I don’t want to re-type the entire page up so go check it out!

Written by Stephen J. Occhiogrosso

September 29, 2014 at 3:03 PM

Posted in Wireless

Tagged with , ,

Private VLANs when, where, & how.

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Recently PVLANs came into a design discussion, which in turn led into me reminiscing on my Route/Switch days. So naturally when I wanted to re-visit the topic if anything to make sure I still remembered everything what was important and to see if any features have been added with the new IOS’s. It’s been a while since my last PVLAN deployment so here we go!


  • Promiscuous Port – This is the ‘primary’ VLAN that can communicate with all the other Isolated & Community ports with the PVLAN environment.
  • Isolated Port – This is a ‘secondary’ VLAN that will only communicate with the ‘primary’ promiscuous VLAN. Isolated ports cannot even communicate with other isolated ports. Since we are talking about VLANs, communication is blocked at the Layer 2 perspective. (At which layer do VLANs operate at, Layer 2)
  • Community Port – This is another type of a ‘secondary’ VLAN, like Isolated ports a community port can also communicate with the ‘primary’ promiscuous VLAN. The big difference here is that a port configured in a ‘secondary’ community VLAN can also communicate with other ports configured as community ports. They will not however be able to communicate with ports configured in an ‘isolated’ VLAN.

Traffic Flows:

Since these Private VLANs operate at layer 2 it is worth pointing out some specific traffic flows, after all it is worth considering the implication of this isolation and typical broadcast/multicast flows:

  • Broadcast Traffic
    • The promiscuous port will forward broadcast traffic to all isolated & community ports. (Including trunks)
    • The Isolated port will only forward the broadcast to a promiscuous port. (Including trunks)
    • Community ports will forward broadcast to the promiscuous & other community ports. (Including trunks)

Configuration & Topology:



  1. The configuration is not too bad, you’ll notice the first thing we do is set the VTP to transparent mode. If you are running VTP v1 or v2 this needs to be done.
  2. Next we create a VLAN like normal, however under the vlan configuration, we set the PVLAN mode. Here we are setting VLAN 888 to be a ‘primary’ promiscuous VLAN.
  3. Next we create VLAN 871, and designate it as a ‘secondary’ isolated VLAN
  4. Followed by us creating VLAN 861, and marking is as a ‘secondary’ community VLAN.
  5. Once we finished creating our ‘primary’ & ‘secondary’ VLANs we need to associate our ‘secondary VLANs’ to our ‘primary’ VLAN.

To re-cap, we set the VTP mode to transparent, created and assigned out promiscuous VLAN along with creating and associated our isolated & community VLANs, not too bad right?

Now that our VLANs are defined lets map these Layer2 private VLANs to a Layer-3 SVI:

PVLAN Mapping

So there, we created the SVI for VLAN 888 (The primary VLAN) and we associated the ‘secondary’ VLANs to the SVI with the private-vlan mapping add command. You’ll also notice the system message stating that our mapping was successful.

Now, that we have Layer-3 mapping lets go ahead and assigned a few ports to our private VLANs.


Here we, enter interface fa1/0/20, set the switchport mode to private-vlan host and configure port 20 to be an isolated port. (By placing this port in the isolated PVLAN)

Port fa1/0/21 on the other hand is configured to be in the ‘community’ VLAN.

Next, we are going to configure Port Fa1/0/22 to be a promiscuous so it can communicate with ports in both VLAN 861 & 871:



Verifying the PLVLAN configuration is simple enough:

show int private-vlan mapping  – Verify your Layer2 to Layer3 mappings


show int switchport – Verify Layer2 switchport parameters



show vlan private-vlan - Verify PVLAN setttings & ports.

PVLAN show1

Written by Stephen J. Occhiogrosso

September 22, 2014 at 8:35 AM

Posted in Route-Switch

Tagged with , ,

SolarWinds Thwack Ambassador for VoIP Management

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I know I’ve been quiet of my blog this month, but that’s not because I’ve forgetting about this site! For the month of September I’m spending some extra time over at Thwack, this is SolarWinds community where everyone likes to get together and talk about network management. I’ve talked about Network Management quite a bit on this blog in broad topics, and during September at Thwack I get focus on VoIP Network Management.

That announcement aside, the Thwack community is great! I’ve been member of the community for many years (Unfortunately under a few different accounts until I nailed one down a single account). Especially if you are SolarWinds user here are a few highlights of the community:

  • Content Exchange – There is a good chance if you are looking for a particular report or custom poller someone else may have already thought about it to, and there also a chance that it might be available in the context exchange  available to be downloaded an imported into your SolarWinds platform.
  • Feature Request – Got an idea that will make a SolarWinds product easier or better enter this section, the more users that agree with your idea the better a chance it may get implemented into the system
  • Great discussions & news updates from SolarWinds – There are many forums on Thwack that focus on different areas of network and systems management, with many great discussions going on. SolarWinds is also great at keeping their users in the know in regards to updates and possible upcoming features.

So far my posts have been about the following:

Come join the discussions!


Written by Stephen J. Occhiogrosso

September 19, 2014 at 11:06 AM

Posted in SolarWinds

Tagged with , ,

VN-Tag you are becoming more maintstream.

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VN-Tag, typically was a technology only seen in the Data Center (When using Nexus 2000 series FEXs)  however this has started changing. If you check out Cisco’s new 6800’s series Catalyst switch you’ll see they are now pushing a new ‘instant access’ model. This new model allows us to deploy ‘dumb’ switches that are centrally managed by the main 6800 Chassis essentially making those switches act as ‘external linecards’. Now in the Data Center this is nothing new, sounds just like the Nexus 2000 Series Fabric Extenders (FEX’s) right? Well, they are a little more similar then you think deep down. VN-Tag is the technology used by Nexus 2k FEX’s with their upstream parent switch, that same VN-Tag is also being utilized in the Cisco 6800 Series with its downstream external switches.

The VN-Tag technology itself simply adds an additional header to the packet as it traverses between the ‘Instant Access’ (Or FEX) and the it’s parent switch, where all the switching occurs. It is important to call-out the ‘Instant Access’ switches do NOT do any local switches (once again just like Nexus 2k FEX) all the information is forwarded up the 6500 or 6800 chassis where the packet will get switched or routed accordingly.

Let’s take a quick look at the VN-Tag information itself:


Surprisingly it’s nothing more than an additional 6-bytes. The fields are as follows:

  • EtherType [16-bits] = 0x8926
  • Destination Bit [1-bit] – Indicates which direction the frame is flowing.
  • Pointer bit [1-bit] -
  • Destination VIF – [14-bits] – Identifies the destination port.
  • Looped – Identifies the source vNIC, ment to identify multicast frames to ensure it is not forwarded back to where it originated.
  • Reserved [2-bits] – For future use.
  • Source VIF [12-bits] – vif_id of the downstream port.
  • Version [2-bits] – Set to 0

Expanding the VN-Tag to products outside of the Nexus line is definitely a great move, and it definitely has great use-cases in many large enterprises that want a more consolidated approach for management, after all this easy way to cut down on your Layer-2 spanning-tree topology. You can also cut down on configuration/implementation time, since this technology allows you to pre-provision the ports on an Instant Access before it is actually connected to the chassis.


Additional Info:

Cisco Instant Access White Paper

IEEE  802.1Q Whitepaper


P.S. - This was a blog post I had start middle/late last year when the 6800 & Instant Access were first announced. Finally got around to finishing it better late than never right?

Written by Stephen J. Occhiogrosso

August 27, 2014 at 11:34 AM

Posted in Cisco

Tagged with ,

FC vs FCoE

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FC vs FCoE infrastructure, usually a common debate when designing the network infrastructure of a new Data Center or new part of a Data Center, after all the advantages of running a converged storage & IP network are hard to turn down. Many of us are probably already aware of the why FCoE is always good option vs the traditional dedicated FC design, but I wanted to point out one interesting  fact that make FCoE more efficient and that fact stems down the Ethernet transport.

When FC frames are sent over a Fibre Channel network they are placed onto the physical medium in 8b/10b encoding which has an overhead of 25% to ensure the signal is sent successfully. (and intact with no corruption, essentially for every 8-bits, 2-bits are used to ensure the signal is still intact think of this an CRC or FCS for the electrical signals)

When we consider Ethernet, it is sent over the wire with a 64b/66b encoding, about a 3% overhead as the information hits the physical medium. So while FCoE may encapsulate the already large FC Frame with additional header & trailers FCoE from physical perspective is much more efficient means transmission. (So for every 64-bits sent to the wire, 2-bits are used for this ‘error checking’ and much better ratio than 8b/10b)

The 8b/10b encoding is used for 1, 2, 4, & 8 Gb Fibre Channel, the new 10+Gb Fibre Channel technologies are relying on 64b/66b encoded, which may tip the scales. However the converged infrastructure & cabling make FCoE the better option for most environments from a cost management perspective.

Random tidbit:

This is also an aspect the differentiates 100Mbps from 1Gbps from 10Gbps

  • 100Mb Ethernet –  4b/5b encoding
  • 1Gb Ethernet – 8b/10b encoding
  • 10Gb Ethernet – 64b/66b encoding


Written by Stephen J. Occhiogrosso

August 17, 2014 at 11:41 AM

VMworld sessions up for viewing. It’s free to!

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How’s that for a topic out of left field, never before seen on my blog. VMWare! Well, I got wind that WMworld sessions are available to watch for free so I just wanted to spread the word. All you need to do is create an account, you can find the sessions here. I’ll say It’s nice see vendors continue this trend, Cisco is already doing that with their CiscoLive365 site.

Written by Stephen J. Occhiogrosso

August 10, 2014 at 10:11 AM


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