Lindsay Hill

Author Archives: Lindsay Hill

Warning: Site Migration

Very shortly I will be migrating my site to Github Pages. RSS feed and other URLS should stay the same, but there’s a chance some things will break, and that you might see double posts in the RSS feed. Hopefully all goes well.

I’ll post again from the other side. If you haven’t seen any new posts from me for a few days, might need to check your RSS feed setup.

The post Warning: Site Migration appeared first on Lindsay Hill.

CCIE Renewed Again – Exam 400-101 v5.1

It came around again: CCIE renewal. Last time I renewed, I wasn’t sure if I should do it again. But I gave in, passed the CCIE R&S Written Exam, and moved one step closer to Emeritus. Turns out it wasn’t that bad, and I should not have put it off for so long.

Renewal Cycle

Cisco certifications below Expert level have a 3-year renewal cycle. You can renew your CCNA or CCNP certifications at any time by sitting an exam at the same level. Your 3-year cycle restarts from the day you pass that exam.

CCIE is a little different. A CCIE certification remains valid for two years from your lab date. You can sit any CCIE-level written exam to renew your CCIE certification. At that point your validity date gets extended for another two years – note that it is another two years based upon your lab date, not the date you passed your most recent re-cert exam.

If you don’t pass a written exam during the two-year period, your status goes to “Suspended.” You then have another 12 months to pass the exam, or you completely lose your CCIE status.

My renewal date was last Continue reading

Formatting Matters

Using proper formatting can make it much easier to read code and log samples. Yet so many people don’t bother putting proper formatting around blocks of text. Take some time to learn how to format text in common applications and forums, and make things easier for those trying to help you.

What’s easier to read?


version: ‘2.0’

polo: unspecified
action: std.noop
polo: <% st2kv('marco') %>
– fail: <% $.polo != polo %>

Or this?

Which one is easier to read? Which one lets you parse key information faster? Which one clearly shows file formatting and indentation? Obvious, right?

Yet far too often, I see people paste unformatted text into Slack, GitHub comments, and web forums. They dump huge blocks of unformatted, difficult to read code and logs. Even after repeated prompts to use proper formatting, they just dump big blocks of text.

The good thing is that it’s not that hard to change the display formatting. Many applications contain shortcuts to make this easy. It’s worth your time learning a few of the tips and tricks.

Slack & GitHub

Both Slack and GitHub use a form of Markdown to make it easy Continue reading

News at Last: It’s Extreme

We have news at last: Extreme Networks is acquiring Brocade’s Data Center Networking business. This includes the SLX, VDX and MLXe routing and switching product lines, Network Visibility and Analytics products, and most importantly, my team: StackStorm.

Extreme Networks has been around a long time – they were founded in 1996, the same year as Foundry, which was acquired by Brocade in 2008, and became my business unit. They’ve had ups and downs over the years, but business is going well right now. Their share price is up, and they have been on an acquisition spree recently, acquiring Zebra Wireless, and 3 weeks ago announcing their intention to acquire Avaya Networking.

This gives them all the pieces to provide end-to-end IP networking solutions, and gives them scale to compete.

The deal is expected to close 60 days after Broadcom completes its acquisition of Brocade, which is scheduled to happen by July 30. Until then we will continue to operate as separate businesses. We don’t know exactly what it will mean for my team, but given that network automation was explicitly mentioned in investor call, we should find a good home.

The legal nature of the company means that it Continue reading


Dress codes are funny things. Everyone in Silicon Valley likes to make out they are super-relaxed, and you can wear whatever you like. “We don’t have a dress code.” But that’s not really true. There are still rules about what you can wear. People who say “we don’t care what you wear” very much do care if you wear the wrong thing.

Here’s some examples of dress codes from well-known Bay Area tech companies:

From Google:

What to wear: For most of our interviews, the dress code is casual, but your recruiter will let you know what’s most appropriate. When in doubt, be yourself and wear what makes you comfortable.

From Twitter:

What should I wear to my interview?

We have a very relaxed, welcoming, and fun environment. While we don’t have a strict dress code, we also wouldn’t recommend pajamas. Come comfortable…

At Facebook:

What is Facebook’s dress code?

There isn’t one. Wear what you are comfortable in.

When I started work, I wore a suit every day. That changed over the years, based upon where I was working, and broader industry trends. These days it’s dress shirts, trousers, and nice shoes. I like to mix Continue reading

Brocade Update: No Update

This blog has been quiet since my last post in November 2016, covering the announcement that Broadcom is acquiring Brocade, and selling off my part of the business. That was over four months ago, and many of you will be wondering what’s happening. Unfortunately I have no real news: we still don’t know what’s happening.

Originally we were unsure if the IP business would be sold in whole, or broken into parts. We can now see that it is being broken into parts: Arris is acquiring the Ruckus Wireless and ICX Switch business unit. That does not include my part of the business.

Broadcom is continuing to seek buyers for my business unit (Data Center IP, covering SLX, MLX and VDX product families, and of course StackStorm). They are also looking for buyers for the Software Business Unit (vRouter, SDN Controller, and vADC). There are no published timetables for when this process will be complete: it will be done when it’s done.

This means that I still don’t know what’s going to happen to me. My visa is tied to my employer. A change in employer could mean I have to leave the United States. Continue reading


The news is public: Broadcom is acquiring Brocade, my employer. Official announcement here, and some (unofficial) commentary here. What’s happening, and what does it mean for me? There’s limits to what I can say – either because I don’t have the answers, or because it’s not public. But here’s a little bit of info for readers wondering what will happen to me.

What’s Happening?

Broadcom has announced its intention to acquire Brocade for approximately $5.5 billion:

This morning we announced a definitive agreement under which Broadcom will acquire Brocade. Broadcom believes the SAN business is a strong complement to its portfolio of enterprise storage and networking solutions, and its intention is to continue to deliver the market-leading storage networking solutions and innovation for which Brocade is so well known.

When will this happen?

Closing of the transaction is presently expected in the second half of Broadcom’s fiscal year 2017, which ends in October 2017, and is subject to regulatory approvals in various jurisdictions, customary closing conditions as well as the approval of Brocade’s stockholders.

What about the IP business?

This is the tricky bit. Broadcom is well-known as a maker of “merchant silicon,” used by many networking Continue reading

VRF-Aware SNMP on Brocade VDX

SNMP was not designed with VRFs in mind. Querying the routing table via SNMP did not take into account the idea of having multiple routing tables. But clearly it’s something people want to do, so some clever engineers figured out how to shoe-horn VRF contexts in. This week a customer asked me how to query the routing table for the non-default VRF on Brocade VDX switches. Here’s how to do it:

VRF Configuration

I’m using a Brocade 6940 running NOS 7.0.1 here. Note that SNMP configuration changed around NOS 6.x, so if you’re running something older this may work differently.

For this lab I have Loopback 1 in the default VRF, with an IP of I’ve created another VRF called “internet”, and put Loopback 2 in that VRF, with IP Now I have two different routing tables:

VDX6940-204063# sh run rb 1 int loop 1
rbridge-id 1
interface Loopback 1
no shutdown
ip address
VDX6940-204063# sh ip route
Total number of IP routes: 1
Type Codes - B:BGP D:Connected O:OSPF S:Static U:Unnumbered +:Leaked route; Cost - Dist/Metric
BGP Codes - i:iBGP e:eBGP
OSPF Codes -  Continue reading

Don’t Trust Hotel Currency Conversion

Experienced travelers will already know this, but it bears repeating: Don’t trust your hotel to perform currency conversions for credit card transactions. They will rip you off. Leave it to the credit card company.

A few months ago I stayed at a Sheraton hotel in Australia. They swiped my credit card when I checked in, and on check out they asked if I wished to pay with that same card. I did, so I didn’t need to swipe my card again. They sent me an invoice for approximately $265 AUD.

A few weeks later I was processing my expenses, and I realised I’d been charged over $300 NZD. With the exchange rate at the time, it should have been about $275. Looking closer, I realised that they had charged me in New Zealand dollars. They should have charged me in Australian dollars, and let my credit card company sort out the exchange rate.

What’s going on?

Some hotels offer you a choice of currency when paying your bill. This should be an option when you enter your PIN. Do not take this option. It is almost never a good idea. Your credit card company will charge you a fee for Continue reading

When the IPv6 Data Changes, so Should Your Opinion

Sky UK recently completed their rollout of IPv6. The uptake statistics are quite remarkable. If you think that people don’t have IPv6-capable devices, or that their home routers can’t handle IPv6…you really need to look at the data, and re-think your opinion.

APNIC has a long-running program collecting data on IPv6 client capability/preference by country and ASN. This graph shows the data for Great Britain:


So a year ago we had ~5% takeup, and now it’s 20-25%. And here’s the reason for that big jump from April this year – this graph shows the data for AS5607, BSkyB:


So > 80% of clients on the BSkyB network are IPv6-capable.

If someone tells you that people don’t have IPv6-capable devices, or routers: the data does not back that up. A few years ago that may have been true, but people don’t access the Internet using Windows XP desktops anymore: They use iOS and Android mobile devices. These have short replacement lifecycles, so people tend to be running newer versions. These are capable of using IPv6, and will prefer it if it is available.

The other related trend is that people have more wireless devices at home, and they have Continue reading

Time to move away from HPE Software

If you are still using HPE Software, you should actively plan to migrate away. The recent divestiture does not look good to me – I think existing customers are going to get soaked. Plan your migration now.

I’ve said it before, that I retain a soft spot for Hewlett-Packard. They gave me my first professional job out of university. I served my sentence doing HP OpenView consulting, and HP-UX Administration, but still: it got me started. Once you have some professional experience, it’s much easier to move to the next role.

It saddens me to watch HP’s ongoing struggles. It’s sad to watch a big ship get broken up for parts. But things had to change. They need to do something to adapt to the realities of modern IT demands.

There was one line in the recent announcement about divesting HPE’s software assets that stood out to me:

Micro Focus expects to improve the margin on HPE’s software assets by approximately 20 percentage points by the end of the third full financial year following the closing of the transaction

(Emphasis added).

It has been clear for a while that HP Software was no longer a core asset for HPE. It Continue reading

Stop using mobiles for conference calls

Stop using legacy mobile audio, especially for conference calls. There are better alternatives. You’re doing your customers and colleagues a disservice by using mobile audio. It’s time we moved on. PSTN is not much better either – switch to VoIP, and give your ears a break from crappy audio connections.

Refresher: Audio Quality Standards

There are many different methods of encoding speech for transmission across networks. There are trade-offs with each, balancing bandwidth, voice quality, and endpoint requirements. The interesting point is that there is not a direct relationship between bandwidth and quality. Half the bandwidth does not have to mean half the quality.

The Mean opinion score test provides a way of ‘scoring’ the quality of a call. 1 is Bad, 5 is Excellent. G.711 encoding has a score of 4.1, which is very good quality, but uses 64kbps per call. GSM has a score of 3.5, which is the minimum acceptable level…but it only uses 12.2kbps. Pretty good tradeoff if you’re in a bandwidth-constrained environment.

But we’re no longer constrained by bandwidth. We don’t need to squeeze that audio call down to only a few kbps. We can use other options such as FaceTime, Continue reading

Relocated at last

Just a quick note to let you know that I am now based in the San Francisco Bay Area. After much preparation, and administrative hassle, everything is now sorted. My company has relocated me to the Bay Area, where I will work at the San Jose HQ.

Anna has of course joined me. We’re living in short-term accommodation in San Francisco right now, and over the next couple of months we’ll figure out where we want to stay long-term.

Lots to do, and lots to learn. But I think it will be a good move for me professionally, and I hope that Anna enjoys it too.

If you live in the Bay Area, or you’re passing through, I’d love to catch up with you, once we get settled. I’m looking forward to being able to unpack my bags in about a week or so!

netmiko support for Brocade ICX and MLXe

netmiko is a “Multi-vendor library to simplify Paramiko SSH connections to network devices,” written by Kirk Byers. It doesn’t solve all of your pain with dealing with CLI-only network devices, but it tries to at least take away the low-level hassle of setting up a connection, and handling variations with things like enable mode, line-breaks, etc.

I’ve submitted a couple of PRs over the last few days to support Brocade ICX and MLXe devices – #235, #236 and #237. These have now been merged into the master code.

This has not yet had extensive testing. Please try it out, and report any issues.

I’m currently looking at VDX support. Looks like a few oddities around detecting the prompt, and dealing with the banner. Feel free to pitch in!

VRRP Skew Time (and always be learning…)

It’s funny how you can work with something for years, but miss a small detail. This week I learnt about Skew Time for VRRP. The reason for it is completely obvious once you think about it, but for some reason the detail had escaped me for all these years.

VRRP Hellos

VRRP sends out a “hello” multicast every <hello> seconds. Usually this is something like every 1 or 3 seconds. Unlike HSRP, only the current master sends out hello messages. This contains the current master priority & status.

The backup devices listen out for this hello message. If they think they have a higher priority, or if they fail to hear the hello message, they will assume the role of master.

Down Interval

Changing from backup to master because of one missed hello could cause network instability. There’s a common rule used for all keepalive-type messages, where backup devices will wait for three missed polls/keepalives before declaring something ‘down.’

NB: HSRP is slightly different here – the holdtime can be manually specified, including to a shorter time than the hello time, if you’re feeling spectacularly stupid.

VRRP is similar. It waits three poll intervals before declaring the master ‘down,’ and attempting to Continue reading

Travel Badge of Shame

All frequent flyers strive to the top tier of their program. Qantas Platinum, BA Gold, KrisFlyer Elite Gold, United Premier 1K. They all want that extra level of benefits, those extra upgrades.

But a former manager said:

“You don’t really want to be on the top tier. You want to be on the tier just below, where you get most of the useful benefits like priority check-in, priority luggage, and lounge access. The top tier is actually a badge of shame, because it says you travel too much.”



Yeah. After spending the last few years at AirNZ Gold, I’ve now moved up a level to Elite. Too much travel in the last year, almost all of it in Economy. Four trips to the US, 2 trips to Europe, 2 trips to Australia, plus a few domestic trips. Too damn much.

I don’t think I’ll be able retain it beyond this year. Will have to make the most of it for my upcoming Asia + US trips. Elite Airpoints Dollar Upgrades look like the most useful thing, since the couple of free upgrades get used up pretty quickly. If only I could also use those upgrades on trips to Europe via Asia…

GCP, and Regaining Trust

Google is telling us they’re serious about the cloud. They’re hiring the right people, spending the big bucks, and even (gasp!) talking to customers! (Oh how that must stick in their craw). They have great technology, they’ve proved it out at scale, and the price is right.

There’s just one nagging doubt in the back of our minds. Is Google serious about this? Are they going to turn around one day and say “GCP is too hard to maintain, we’re dropping it. Besides, self-driving Segways are the future.”

Fool me once…

Because they have form in this. I present Exhibit A, Google Reader. Yes, that old saw. Yes, yes I am still bitter. No, I won’t let it go.

I used Google Reader daily. I loved it. It came from a pre-Twitter, pre-Facebook time. A time when we used to have to visit a list of sites to keep up with things. We’d have to remember to check our friend’s travel blog every few weeks, just in case there was a new post. Sure, we used Slashdot as an aggregator, but everyone knows that’s been dead/dying since Rob Malda sold out to the man. (Has Netcraft has Continue reading

Networking’s not so bad

Ivan’s post this week was a good reminder that other parts of IT aren’t perfect either. It’s not all roses on the other side of the fence. Networking has done many good things, and often showed the way.

Consider a conversation between a sysadmin & a network engineer:

Look at how I can virtualise these systems! Now I can isolate users and consolidate hardware resources. They have no idea they’re on the same hardware. It’s incredible!

Oh. Bit like these VLANs, VRFs, and VDCs we’ve been doing for 15+ years now?

Look at how I can use Puppet to define this server’s complete configuration using a single text file! This is amazing! I can use version control for my infrastructure!

Oh. You mean like this single text file that defines the configuration of my network device here? Yes, yes that does seem useful.

Why do you networking people have so many different ways of configuring systems? Why don’t you just have one common API?

Oh. You mean like the way that there’s a Universal install script Linux systems?

SNMP sucks. The data format is terrible, implementations are inconsistent. Why don’t you switch to gRPC?

Wait, weren’t you telling me last Continue reading

War Stories: Backup NICs, DNS and AD

A return to our sporadic series of networking war stories. This time it’s fun with dedicated backup networks, DNS auto-registration, and Active Directory. Thank God it’s a lot easier these days with virtualisation. But back then…

Backups suck, but you need to do them somehow

Back in the olden days we had a dedicated tape drive connected to each server. Daily/weekly backups were written to the local tape drive using a SCSI connection. Someone would walk around the servers each day and change the tapes. It was simple, and it worked, but it doesn’t scale.

Two things happened – server numbers started exploding, and Gigabit Ethernet became practical. That meant that it became practical to have centralised ‘backup’ servers connected to tape drives, and to stream backup data across the network. Much better scale – we only needed to install an agent on each server, and the centralised backup servers needed to have enough tapes + tape drives. This also gave us much better central control & visibility of our backups.

Of course, we were worried about the impact of streaming large backup files across the network. We didn’t want that to affect production traffic, so we installed dedicated backup Continue reading

Efficiency vs Effectiveness

I’ve been wondering about how we’re approaching networking change. We know we need to make things better. Are we changing the ‘right’ things? I’ve got a feeling that we’re not, but I suspect that we’re too constrained by higher-order systems.

Simon Wardley wrote a great post on Efficiency vs Effectiveness. He gave a slightly contrived example of an organisation that is optimising the wrong thing. They plan on using robotics to automate server modifications to fit their custom racks. The problem is that they miss the point altogether. Yes, they’re optimising their flow. But they should ask: Is this the right flow?

Cheques: Apparently people still use them?

Recently I came across the “Wells Fargo Mobile Deposit” application. It sounds good – a faster way to deposit cheques(checks):

Mobile Deposit is secure, easy to use, and convenient.

  • Deposit checks directly into your eligible account using your Android or Apple® mobile device or your Windows Phone.
  • Take photos of the front and back of your check and submit. It’s that easy.
  • Get confirmation on your device and by email for each successful deposit.
  • Save time with fewer trips to an ATM or store.

Except…did anyone tell them that cheques Continue reading

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