Category Archives: Cisco Networks

A Damn Handy Catalyst Switch Command

When it comes to working with Cisco’s Catalyst switches, there are a handful of commands that get used pretty frequently to tell what’s going on.  I’m talking about after configuration is done, and when you come back to a switch later on for whatever reason to troubleshoot or verify operational parameters. I won’t be telling you anything here that isn’t already in a slew of Cisco docs, but I am working up to a specific point.

These are very common in my world:

  • Show interface (status, counters, errors, etc)
  • Show power inline (PoE info)
  • Show CDP neigh/show LLDP neigh (connected network devices)
  • Show mac address-table (L2 addresses of connected devices)
  • Show log
  • Show VLAN (VLAN database for the switch)
  • Show run (how the switch is configured)

The list goes on, and as most of you reading this know there are also variations of the commands listed that get you more granular information- like detailed information per single interface, expanded CDP details, only the last so many log entries, etc.

Big deal, right? This is pretty basic stuff, I realize. But at the same time, I do feel compelled to give a call-out to one command that I’ve come to truly appreciate:

show interface switchport

This gem tells you a lot about an individual interface and is handy as heck when odd things might be afoot with VLANs. (It recently helped me get to the bottom of a VLAN issue involving the murky mystical VLAN 1 on a Catalyst 3650).

Here’s one instance from a production switch:

#sh interfaces gig 1/0/32 switchport
Name: Gi1/0/32
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: 8,170
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL

Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none

Now contrast that with the simpler [sh run interface] command for the same port:

interface GigabitEthernet1/0/32
description pci test or ACS
switchport trunk allowed vlan 8,170
switchport mode trunk
storm-control broadcast level pps 2k 1.5k
storm-control action shutdown
storm-control action trap
service-policy output TACTEST
end

So, the [show run] command just scrapes the surface of the actual  bigger VLAN paradigm in play for interface, while [show interface switchport] brings all of the VLAN-specific information out into the open, possibly revealing parameters not obvious through the other commands.

It’s the little things, sometimes… I like this command a lot where multiple VLANs are in use.

The Other Intent-Based Networking

Anyone who is in networking and who knows me is likely aware that I find a fair amount of fault with “Intent-Based Networking”. It has rubbed me wrong since I first heard it as the latest Cisco campaign, having been through many other flavors-of-the-month through the years. I’ve struggled to find within myself exactly what about Intent Based Networking has been pissing me off, but admit that this bogeyman in my mind has been elusive… very hard to pin down. Yet something has been stuck in my craw, I tellya.

Is it the sea of buzzwords that came with it? Is it the coincidental timing of this blog that asks us to swallow that subscriptions somehow equal innovation? (Sorry Cisco- that is a ridiculous stretch, even for you). Or this article in the same time frame telling the world all the ways Cisco is turning up the marketing heat? Sure, put it all together and to me- a customer frustrated by code bugs, feature bloat, corporate bloat, mixed messages at various Cisco levels, and the way that staying a large Cisco customer smells more expensive now than it ever has- and all of that adds to the feeling of being smothered a bit. But even all of THIS isn’t the root of my revulsion at Intent-Based Networking.

But I figured out what is bugging me about Intent-Based Networking. (It came to me like a bolt out of the blue when I was playing Sock Guy with my pug dog.)

Before I get there, let’s take a detour to this Network World Article. I have only recently learned that Intent Based Networking is not just an obnoxious marketing slogan from Cisco, but it’s also recognized as a bigger thing that I had simply never heard of in this context by that name. From the article by Brandon Butler:

Gartner Research Vice President Andrew Lerner says intent-based networking systems (IBNS) are not new, and in fact the ideas behind IBNS have been around for years. What’s new is that machine learning algorithms have advanced to a point where IBNS could become a reality soon. Fundamentally, an IBNS is the idea of a network administrator defining a desired state of the network, and having automated network orchestration software implement those policies.

“IBNS is a stark departure from the way enterprise networks are managed today,” Lerner explains in a research note describing IBNS. “Currently, translation is manual, and algorithmic validation is absent… Intent-based networking systems monitor, identify and react in real time to changing network conditions.”

It goes on to say that IBNS, as a generic construct, has four basic aspects: Translation and validation, Automated implementation, Awareness of state, and Assurance and dynamic optimization/remediation.  Those don’t belong to Cisco, they are the make-up of the general concept of Intent Based Networking. It’s a good article and worth reading.

So back to my angst and irritation. I’ve identified two-co-equal notions that steam my clams when I hear Intent Based Networking, as laid on thick by Cisco.

#1 Irritant. I, and others, have written about being a bit insulted by “AI” as a fix to everything in networking. No one with common sense and a pulse denies that machine learning and artificial intelligence aren’t powerful concepts that can be transformative if implemented right. But… Cisco, Mist, and others tend to send the vibe “our shit is great because of AI and machine learning- we have the right buzzwords and those buzzwords alone would have your wallet salivating! Without this new magic, you suck and your networks suck and you are lost at sea and you have soooooo many problems!”

The problems with that? Some of us design and run really good networks and aren’t thirsting for some mystical deity to come scrape the dumb off of our asses. And… many of the companies and individuals behind the new network magic don’t have stellar track records of getting code and actual customer needs and wants right. To be forced into Intent-Based Networking as the only real evolutionary option does create some discomfort. The new stuff is priced way too high for what is and will remain essentially beta quality in many cases.

#2 Irritant. I’ve heard nothing in Cisco’s marketing about the other Intent-Based Networking. This is the one where CUSTOMER INTENT is for the network to actually and predictably work, with minimal code bugs, free of a gimmicky feel, and with a price structure that doesn’t write out the words “Fleece the Customer” in the sky with a smoke-writing bi-plane. What about OUR intent? Stability, predictability, and no bullshitty licensing paradigms that make sure we never really own what we buy- pretty sure that summarizes the intent of most customers… Like having a network that isn’t the cause of most of it’s own problems by the vendor not shipping problematic code? That’s intuitive, no?

Sometimes words are just words, but put “Intent Based” next to “Networking” and Maslow comes to mind- the foundationally important stuff is what the customer thinks about first.

THIS “Intent Based Networking” is more important than the other one from where I sit. The two notions don’t have to be mutually exclusive, but it feels like they are right now. From the customer perspective, we don’t just pivot from years of erratic code and odd TAC engagements to a brave new expensive and Intent-based world without great skepticism because Cisco’s new marketing army says it’s the thing to do. Tone it down and and talk WITH us, not AT us.

There- now we’ve solved it. I actually feel better getting it out.

(And don’t even get me going on the Network. Intuitive.)

 

Figuring Out What Bothers Me About Wi-Fi and “Analytics”

I’ve been to the well, my friends. And I have drank the water. 

I was most fortunate in being a participant in the by-invitation Mobility Field Day 3 event, this past week. Few events get you this close to so many primary WLAN industry companies and their technical big-guns, on such an intimate level and on their own turf. For months leading up to MFD3, something  has been bothering me about the discreet topic of “analytics” as collectively presented by the industry- but I haven’t been able to nail down my unease until this past week.

And with the help of an email I received on the trip back east after Mobility Field Day was over.

Email Subject Line: fixing the wifi sucks problem

That was the subject in the email, sent by an employee of one of the companies that presented on their analytics solution at MFD3 (Nyansa, Cisco, Aruba Networks, Fortinet, and Mist Systems all presented on their own analytics platforms). The sender of this email knew enough about me to do a little ego stroking, but not enough to know that only a matter of hours earlier I was interacting with his company’s top folks, or that I’ve already had an extensive eval with the product he’s pitching at my own site. No matter… a polite “no thanks” and I was on my way. But his email did ring a bell in my brain, and for that I owe this person a thank you.

The subject line in that email set several dominoes of realization falling for me. For example-  at least some in the WLAN industry are working hard to plant seeds in our minds that “your WLAN sucks. You NEED us.” Once that hook is set, their work in pushing the fruits of their labor gets easier. The problem is, all of our networks don’t suck. Why? These are just some of the reasons:

  • Many of our wireless networks are well-designed by trained professionals
  • Those trained professionals often have a lot of experience, and wide-ranging portfolios of successful examples of their work
  • Many of our WLAN environments are well-instrumented with vendor-provided NMS systems, monitoring systems like Solar Winds and AKIPS, and log everything under the sun to syslog power-houses like Splunk
  • We often have strong operational policies that help keep wireless operations humming right
  • We use a wealth of metrics to monitor client satisfaction (and dis-satisfaction)

To put it another way: we’re not all just bumbling along like chuckleheads waiting for some Analytics Wizard in a Can to come along and scrape the dumbness off of our asses.

In all fairness, that’s not a global message that ALL vendors are conveying.  But it does make you do a double-take when you consider that a whole bunch of data science has gone into popping up a window that identifies a client that likely needs a driver update, when those of us who have been around awhile know how to identify a client that needs a driver update by alternate means.  Sure, “analytics” does a lot more, but it all comes as a trade-off (I’ll get into that in a minute) and can still leave you short on your biggest issues.

Like in my world, where the SINGLE BIGGEST problem since 2006, hands-down and frequently catastrophic, has been the buggy nature of my WLAN vendor’s code. Yet this vendor’s new analytics do nothing to identify when one of it’s own bugs has come to call. That intelligence would be a lot more useful than some of the other stuff “analytics” wants to show.

Trade-Offs Aplenty

I’m probably too deep into this article to say “I’m really not trying to be negative…” but I’ll hazard that offering anyways. Sitting in the conference rooms of Silicon Valley and hearing from many of the industry’s finest Analytics product’s management teams is impressive and its obvious that each believes passionately in their solutions. I’m not panning concepts like AI, machine learning, data mining, etc as being un-useful as I’d be an idiot to do so. But there is a lot of nuance to the whole paradigm to consider:

  • Money spent on analytics solutions is money diverted from elsewhere in the budget
  • Another information-rich dashboard to pour through takes time away from other taskings
  • Much of the information presented won’t be actionable, and you likely could have found it in tools you already have (depending on what tools you have)
  • Unlike RADIUS/NAC, DHCP/DNS, and other critical services, you don’t NEED Analytics. If you are so bad off that you do, you may want to audit who is doing your network and how

Despite being a bit on the pissy side here, I actually believe that any of the Analytics systems I saw this week could bring value to environments where they are used, in an “accessory” role.  My main concerns:

  • Price and recurrent revenue models for something that is essentially an accessory
  • How well these platforms scale in large, complicated environments
  • False alarms, excessive notifications for non-actionable events and factors
  • Being marketed at helpdesk environments where Tier 1 support staff have zero clue how to digest the alerts and everything becomes yet another frivolous trouble ticket
  •  That a vendor may re-tool their overall WLAN product line and architecture so that Analytics is no longer an accessory but a mandatory part of operations- at a fat price
  • Dollars spent on big analytics solutions might be better allocated to network design skills,  beefy syslog environments, or to writing RFPs to replace your current WLAN pain points once and for all
  • If 3rd party analytics have a place in an industry where each WLAN vendor is developing their own

If all of that could be reconciled to my liking, much of my skepticism would boil off. I will say after this last week at MFD3, both Aruba and Fortinet did a good job of conveying that analytics plays a support role, and that it’s not the spotlight technology in a network environment.

Have a look for yourself at Arista,  Aruba, Cisco, Fortinet, Mist and Nyansa telling their analytics stories, linked to from the MFD3 website.

Thanks for reading.

Another Example of How Important Wire is to Wireless

A house built on a shaky foundation cannot endure. And a WLAN built on a shaky wiring foundation likewise cannot endure, I tellya. My friends, is your foundation shaky? Is it? CHECK YOUR FOUNDATION NOW. (I happen to sell foundation-strengthening herbal supplements on the side, if you need that sort of thing…)

I’ve long been a proponent of recognizing installed UTP as a vital component in the networking ecosystem. Too many people take Layer 1 for granted, and forgivable sins of of our 10 Mbps and Fast Ethernet pasts won’t fly in a Gig world. Toolmakers like Fluke Networks sell cable certification testers that take the guesswork out of whether a given cable run can be relied on to perform as expected. Don’t use one of these testers at time of cable installation, and you are only assuming you have a good station cable.

I just had an interesting situation come up that I helped a very skilled field tech with. He was working in several different small buildings, each serviced by a Cisco Catalyst Switch and a handful of 3802 802.11ac access points. The switches and cable had been in place for years, and the APs for many months, all with no issues whatsoever.

Then, we changed out the old 3560X switches for shiny new 3650s (curse you Cisco for your bizarre fascination with part numbers so close together), and suddenly some APs weren’t working any more. Between us, we checked all switch settings, POST reports, CDP tables, logs, etc- everything you can dream up on the switch. We put the APs that weren’t working back on the old switches, and they came right up. Hmmm… thoughts turned to PoE/code bugs, but then I went a-Googlin’ before consulting TAC.

I found this document that put me on the path to righteousness. Though we weren’t having “PoE Imax Errors”, a couple of nuggets jumped out at me about our new switches.

PoE Imax

Holy guacamole- We got us a situation! But wait… THERE’S MORE!

PoE Imax2

Shazam! Which, of course, translates in Esperanto to “maybe your cable is actually kind of iffy, and all the CDP stuff that happens at the milliwatt level before PoE gets delivered worked OK with your old switch but not with the new one that has the enhanced PoE controller”.

If you don’t know that the newer switch does PoE differently, you might wrongly assume that your cabling is “good” because the APs worked on it when those APs used the old switches connected to that wiring. By now, you can probably guess where I’m headed…

Our tech tested the cabling on the new-switch-problem APs and in each case found that they needed help to work with the new switch. He re-terminated and tested each, with the APs then coming up with no issues. I have no doubt that this cable was certified 10-12 years ago, but in that time a lot can happen to either end of those cables depending on the environments where they are used.

Live and learn!

 

 

Cisco’s Latest AP is Mind-Blowing (and a quick history lesson)

Aironet 4800 Access PointFeast your eyes on that little Chiclet-looking thing… No image can do justice to Cisco’s latest powerhouse AP. That innocuous looking image represents a full 5.6 pounds (2.5 kg) of all kinds of Cisco’s latest technology in the company’s new 4800-series access point. You got 4×4 802.11ac Wave 2 radio wizardry,  a built-in hyperlocation antenna array, and BLE beacon capability. And… regardless of whether you buy into Cisco’s DNA Center story, the new 4800 has a lot of DNA-oriented functionality. It’s big in size, functionality, and at least for a while- price.

You don’t need me regurgitating the entire data sheet- that can be viewed here. You’ll also want to hear the full story of the 4800 and DNA Center when you get a chance, because it’s nothing less than fascinating. (My own take: DNA-C might be revolutionary- but I’d rather see new controllers with a new WLC operating system rather than bolting DNA-C’s future-looking promise onto yesterday’s fairly buggy wireless parts and pieces. That’s just me speaking from experience- take it or leave it).

I’ve seen the 4800 with the outside cover removed, and even that is profoundly thought-provoking when your eyes take in how much is really going on with the various antennas- get a look at that if you can (I’m not comfortable sharing the images I’ve seen, not sure where NDA starts and stops on that).

So a huge access point story is afoot, and I applaud Cisco on that bad-lookin’ mammajamma. But I also got sparkley-eyed by something else fairly nerdy while looking through 4800 materials and links to other links.

Here’s a screen grab of the 4800 power specs:

4800 power

Nothing real exciting there, right? New APs generally need the latest PoE+, and we’re a few years into that story. But I somehow stumbled across this document, that shows this picture:

and it took me way back to my own early days of wireless. My WLAN career started with a 4-AP deployment of those 350s, which ran the VxWorks for an operating system and had only 802.11b radios… (cue the flashback music here).

Also included in that doc is this brief history of PoE:

PoE Hist

As I read that over, my mind goes back to all of the Cisco APs that have come and gone in my own environment- 350, 1130, 1200, 2600, 3500, 3600, 3700, and our latest in production, the 3800. In this list, there have been multiple models from the different series of AP leading to the thousands of APs that are now deployed in my world.

On the operating system side, VxWorks became IOS, and in turn AireOS. Now we have AP-COS on the latest Wave 2 APs (don’t Google “AP-COS”, most of what comes back is bug-related, sadly).

It’s interesting to reflect back, on operating systems, PoE, radio technologies, and feature sets. As Wi-Fi has gotten more pervasive, it has also gotten more complicated on every level. Seldom is the latest access point THE story any more, now it’s about all of the features that come with the whole ecosystem that the vendor wants that access point to operate in- if we as customers buy into the bigger story.  I’m not passing judgement on anything with that statement, or intentionally waxing nostalgic (well, maybe a little bit).

It’s pretty neat how one image or a certain document can suddenly flash your your entire wireless history before your eyes.

Good stuff.

A WLAN Doer Contemplates the Cisco/Apple Partnership

I’ve been in the wireless game with Cisco products since long before thin was in. These days, I support many thousands of access points and tens of thousands of Wi-Fi clients on those APs. At least half of those client devices are Apple products, and in some spaces in my environment, as many as 85% of all clients are Apple. Obviously, I hope for the best of outcomes from the new Cisco and Apple partnership, as my customers would benefit from those positive outcomes. There’s no meanness intended in what follows, just reflection on days past and what I hope comes of these two market leaders becoming more collaborative.

Code Counts as Much as Hardware

Cisco and Apple both put out beautiful hardware with premium price tags. Many purists who worship either or both companies have a hard time believing that anything defective could come in hardware that is so robustly built, pretty, and expensive. If my iDevice isn’t working, your network MUST be to blame. And if my WLAN is acting up, it must have been designed wrong because Cisco code isn’t cheap… and it comes from the market leader, by golly. Both Cisco and Apple are at the top of their games as measured by volume of devices in many large and small WLAN environments. And both frequently, too often, put out mediocre (or horrible) code that leaves people like me holding a bag full of smelly network pain.

In Cisco’s case, their WLAN controller code is just short of being chronically buggy, and a culture of “get it out the door and let our customers QA it!” seems to rule the product line. (Greg Ferro sums it up nicely in the opening paragraph of this article.) It’s not uncommon to spend days on the phone with TAC only to find out that randomly rebooting controllers or some oddball client behavior is actually a known bug.

For Apple, you never know what you’re going to get related to Wi-Fi behavior with OS and iOS upgrades and patches. Release notes are scant, and it seems that the Wi-Fi area of Apple devices is always being tinkered with back on the mothership. From a history of sticky-client behavior to curve-balls in how you are “allowed” to configure profiles to decidedly non-enterprise quality gimmicks like Bonjour, it has been an interesting ride administering business networks that have lots of Apple wireless clients on them. (This is not just me ranting, the Apple support forums are chock full of frustrations with Wi-Fi client behavior through the years.)

Features? What About Standards (and stability)?

Cisco networks also have to support a lot of non-Apple client devices. Making Apple’s consumer-centric AirPlay/Bonjour feature sets work in large business enterprises can be a nightmare. And though Cisco (and other vendors that do similar) mean well with mechanisms like band-steering and load balancing across APs, these enhancements cause their share of problems in the Wild West of widely varying client types found on big WLAN networks. It would be nice to see more focus on standards-based interoperability and feature sets rather than vendor-proprietary juju.

Looking Forward

I used to marvel a bit at Apple’s mastery of talking out of both sides of their corporate mouth when it came to their place under the network sun. Sometimes they were unequivocally not an Enterprise company, and sometimes they were. It seemed to depend on the audience, and how well their unyielding way of doing things fit into the general networking landscape where they were trying to gain specific market share. Now, with the Cisco alliance in play, Apple is emphatically stating that they are an Enterprise player. Hopefully, the company gives strong consideration to what that means to all of the users who love Apple gear but get frustrated because too much of the “Living Room, Single Class C Subnet Network” mentality is in play.

From the Cisco side, ideally my Wi-Fi vendor won’t skew their already frequently-frustrating code too far in the Apple direction at the expense of the rest of the client devices that have no use for Apple-specific features. Also ideally, Cisco would also find a way to end the code bug madness before it starts tweaking WLCs to do magic things for iDevices, lest bugs beget bugs.

This could be absolutely wonderful for environments like mine, or it could just be more of the same- but disappointingly amplified. I’m crossing fingers that both companies get it right…