Pete Welcher

I've been blogging on Cisco and networking topics since around 1996, and have probably written over 400 blogs by now (but who's counting?). Recent topics mostly focus on Design, Route/Switch and Data Center. Older blogs may be found in the Archive section, or not. I do try to share lessons learned the hard way with everyone. If there's a topic you'd like me to write about, please let me know!

I am now a member of the Cisco Champions Program. Cisco Champions are passionate about Cisco and happy to share what we know. My views and opinions remain my own.

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Pete Welcher

Pete Welcher

Here is a link to my detailed bio if you're curious.

In case you hadn't noticed yet, Cisco plans a big UCS related announcement for September 4 in New York City. They're calling it the "UCS Grand Slam".

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Posted by on in Wireless

I'd like to tell you a little story about something that came up recently when troubleshooting Wireless (WLAN) multicast ("IPmc"). I ran into something that was a bit unexpected ... maybe obvious to some readers, but nothing I'd ever heard about. Perhaps because sites really doing multicast video are somewhat thin in numbers, and those doing it over wireless even more so? 

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20140516-ONUGI recently had the pleasure of attending the Open Networking User Group (ONUG) conference in New York City. See also http://opennetworkingusergroup.com. My thanks go to Tech Field Day for getting me there and providing some very interesting vendor discussions. The Tech Field Day website has a page dedicated to ONUG, where you can find links to blogs posted by the other attendees. I won't repeat all those links here. 

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A blog I wrote was recently posted on blogs.cisco.com. It is about how appropriate design can prepare for automation -- and that the lesson from automation is that we should be using "cookie cutter" standard designs, where each remote site or office is not a one-off design.

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Posted by on in Software Defined Network

On Sunday afternoon 5/4/2014 I'll be heading to New York City. I'll be joining some of the Tech Field Day bloggers extraordinaire on Monday and Tuesday 5/5-6/2014, for Tech Field Day at ONUG 2014 (Open Networking User Group, NYC, 2014). 

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Posted by on in Data Center

Recently, Cisco generously provided a briefing to the CiscoChampions, updating the group with new details about Cisco ACI. The presentation was NDA until April 2, I presume coordinated with announcements to be made at InterOp. The biggest new item I noticed was OpFlex. I'll tell you what I know about OpFlex below, somewhat below the tantalizing diagram. I'll be posting this quickly in the morning, then off to various tasks. When I can, I'll look at any announcements and apply corrections if necessary. 

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Posted by on in Data Center

20140307-fig01Here in the Baltimore-DC area, we can't wait for Spring to end all the cold snowy weather we've been having. We don't quite see the signs yet. We need a new groundhog! Anybody want a used one?

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Posted by on in Data Center

20140305-nexus9000Ever since I heard that the Nexus 9K has 50% less code, I've been wondering what features were removed from the code. So I did my best to figure it out, since I haven't seen a detailed features list from Cisco yet (early days and all that). I've also noticed that in general the Nexus team historically has put out long lists of supported features, leaving me thinking "yes, that's great -- but what is NOT on the list?" Anyway, the primary focus here will be what features the N9K supports today. We'll get to that after a motivational detour (or some might say "pre-ramble"). 

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Posted by on in Data Center

20140304-fig01The Cisco announcement last November of Insieme ACI and Nexus 9K hardware gave us a plethora of choices, and left many wonder what Nexus box they should use, and where. It behooves us all to understand the Cisco Nexus product positioning, since they aren't cheap, and we don't want to paint ourselves into a corner with the wrong purchase. That's particularly important for consultants and Cisco resellers providing purchasing recommendations. This blog lays out the major considerations in picking which Nexus platform to buy, and where to use it in your datacenter. 

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20140303-fig01I get the strangest looks when I talk about POAP and ask people "Why Aren't You Using It?" Admittedly, it doesn't help that I like to pronounce acronyms like words, and POAP comes out sounding like "Pope" or perhaps "Poe-App". Perhaps it will help if I mention that POAP is the Nexus equivalent of Auto-Install for Cisco routers. I suspect that aside from not being aware of POAP, a lot of people haven't looked into what POAP can do for them. As with Auto-Install, you might have looked and found that it seemed complex. Yes, it's easy enough to paste in the configuration from the CLI, one less thing to troubleshoot. 

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Posted by on in Data Center

20140228-fig01The good news is that there are lots of ways to capture packets on Cisco device. That's also the bad news: there are many different ways to do differing degrees of capture, depending on the device type! No doubt this is a side effect of the independent and somewhat Darwinian nature of product groups within Cisco. I'm writing this blog as I've been exploring the packet capture side of Cisco devices as CCIE recert prep (EPC, WireShark Trace Analyzer). Packet capture is not a feature I use very often, so there's been progress that I (and you!) might not have been aware of. 

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Posted by on in Data Center

I presented a Cisco Mid-Atlantic Users Group session on "Datacenter Topics" today. It covered NSX, DFA, ACI, among other things. I even said "SDN" a couple of times. And thanks to the 80 or so people that braved snow (flurries) to attend! And those who drove 2-3 hours!

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Posted by on in Data Center

In this blog, I'd like to come at Practical SDN from a different point of view. Thanks to all those who slogged through the previous blogs in the series. I suspect those either had too much or too little information in them, depending on your point of view. Anyway, I've been mulling over my reactions to #SDN blogs, and especially some recent blogs about cross vendor abstraction. There have recently also been discussions about the idea that networking people need to learn to program, or do programming plus something. I had fun in a tweeting marathon one recent morning with @colinmcnamara and others. And Greg Ferro (@etherealmind) wrote a good blog about the topic.

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Posted by on in Data Center

I will be presenting in the CMUG (Cisco Mid-Atlantic User Group) session on Tuesday February 2/25/2014. The formal abstract and announcements are here. The location is: Loyola University Columbia Graduate Center (8890 McGaw Rd, Columbia, Maryland 21045). There will be a continental breakfast served starting at 0800, with the presentation to start at 0900. (Google maps for this on my PC is a bit odd, showing McGaw not connecting to Dobbin Road. It's fine and correct on my iPhone.)

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It's time to talk (briefly!) about how NSX, DFA, and ACI handle Security. This blog series has already covered ARP, L2 forwarding and L3 forwarding, complete with many technical details. I'm hoping this blog will be a bit shorter, making easier on me doing the writing and you the reader. I intend to focus on where there's something interesting to cover.

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Posted by on in Network Infrastructure

I've been writing up an internal NetCraftsmen QoS template for a Cisco 3850 switch. This blog relates some lab experiences with the 3850. I hope it provides some useful information for those grappling with 3850 QoS. The second half of the blog is some observations and personal philosophy about QoS. I have quite a few more such than are revealed below -- but, hey, I'm trying to write a relatively short blog for once!

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How does L3 forwarding work in NSX, DFA, and ACI? That's the topic for this blog, blog #3 in a series. The series attempts to contrast the various behaviors of NSX, DFA, and ACI. So let's jump right in and see what's happening at Layer 3. (And if you're still reading, the last two blogs took a while to write and ended up rather long -- I'm trying to avoid those pitfalls here.) 

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How does L2 forwarding work in NSX, DFA, and ACI? That's the topic for this blog, blog #2 in a series. The series attempts to contrast the various behaviors of NSX, DFA, and ACI. We'll look at L2 forwarding (bridging) and some scenarios where the behavior might not be what you expect. 

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Posted by on in General Networking

Cisco is talking up the Internet of Everything (IOE) lately, with today's focus being public sector #IOE. I'm excited about the potential, and have been watching discussions eagerly. From the news, multiple vendors at the #CES (Consumer Electronics) show in Las Vegas are talking about IOE. Intel and other vendors are making embedding technology in products easier and easier: small, powerful components lead to faster innovation. So I agree with Cisco's #CiscoCES message that #IOE is coming, and soon. 

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This blog is the first in a planned series, aimed at describing how some of the current SDN offerings (NSX, DFA, and ACI) work from a practical perspective. I'll explain the title in a moment.  (Updated 1/7/14.)

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