Link Aggregation on HP Moonshot – A Neat Trick
The Broadcom switching OS running on HP's Moonshot 45G and 180G switches can do a neat trick1 that I haven't seen on other platforms.Background: LACP-Individual
The trick revolves around interfaces that are sometimes aggregated, and sometimes run as individuals. Lots of platforms don't support this behavior. On those platforms, if an interface is configured to attempt aggregation but doesn't receive LACP PDUs, the interface won't forward traffic at all. Less broken platforms make this behavior configurable or have some goofy in-between mode which allows one member of the aggregation to forward traffic.
If the Moonshot were saddled with one of these broken2 switching OSes, we'd be in a real pickle: Moonshot cartridges (my m300s, anyway) require PXE in order to become operational, and PXE runs in the option ROM of an individual network interface. Even if that interface could form an one-member aggregation, it wouldn't be able to coordinate its operation with the other interface, and neither of their LACP speaker IDs would match the one chosen by the operating system that eventually gets loaded.
I suppose we could change the switch configuration: Add and remove individual interfaces from aggregations depending on the mode required by the Continue reading
F5 Featured White Paper: Programmability Makes SDN a Reality
What will make SDN more than just a promise? Programmability. Read the F5 white paper to learn how.
Explaining the Pervasive Kludgeitis
I found a great explanation for hodgepodge of kludges found in "organically grown" solutions (legacy precursors to SD-WAN come to mind):
In a long-lived project, components are being replaced. Nice reusable components are easy to replace and so they are. Ugly non-reusable components are pain to replace and each replacement means both a considerable risk and considerable cost. Thus, more often then not, they are not replaced. As the years go by, reusable components pass away and only the hairy ones remain. In the end the project turns into a monolithic cluster of ugly components melted one into another.
Note: You really should read the whole blog post.
On being different
The METNAV shop at McGuire AFB was hard to miss, if you could get into the right area, and you know what you were looking for. Out across the flightline, across the old 18 runway, and across a winding series of roads, a small squat building sat — no antennas or other identifying marks. Just plain, white, one story, with a small parking lot and a few trucks, either camouflaged or USAF blue. Driving into the parking lot, you’d find an odd collection of vehicles, but many of us drove 4wd’s of some sort. A good number of the pieces of equipment we worked on were only reachable through off road routes. If you owned a 4wd vehicle, the fateful pager call at 2am didn’t require a trip to the shop, across the flight line, old runways, and in the winter piles of snow pushed up against the sides of the airplane routes, to get a truck usable to reach the failed piece of equipment.
In the line of cars, you would see one that was, well, different. This particular car was, in fact, the subject of a number of discussions in the shop — you’d almost think our little Continue reading
Would You Believe NFV Is Already a $2.3B Market?
DPI and policy functions give NFV a head start, by Infonetics' reckoning.
knowing stuff
Knowing Stuff. I have to admit, this second post is not as technical as I would prefer, but something that is on my mind a lot. How do we know what we know. How do we constantly work on what is as essential to us as air. Is it the same for everyone, or is […]
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The post knowing stuff appeared first on Packet Pushers Podcast and was written by Doug Sheehan.