Semaphore Corporation blogs about technology and the internet

Aruba Partner Summit 2011

Apr15
2011 Leave a Comment Written by Garth Brown

Last week, I had the pleasure of attending the Aruba Networks 2011 Partner Summit. This event ran from Monday 4/4 through Wednesday 4/6 with the most significant density of activity on Tuesday.

I took about 14 pages of notes – more than usual for an event of this sort and feel like the event was worthwhile, in spite of the invariable backlog I accumulated back at the office.

We’ve been working with the Aruba Air Mesh (their outdoor industrial mesh product acquired from Azalea Networks) since 2008, but are a “newly-minted” Aruba Indoor Partner, so I had a lot of ground to cover.

First and foremost, I walked away with a very crisp vision of Aruba’s place in the market – how they view their products and the marketplace itself. Understanding the way they see the world helped me to understand a lot of things, especially their recent entrance into the closet switching market (see their Mobility Access Switches).

I’ll have to admit that, though the switching platforms seemed like great devices, I didn’t understand why Aruba would want to increase their competitive overlap with big players like Cisco, Juniper (did you know we’re now a Juniper partner?!) and HP. It didn’t make a lot of sense on the surface – until I heard from the Aruba CEO, Dominic Orr. READ MORE »

Posted in Aruba Networks, Business, Networking

A phased approach to IPv6 adoption

Apr14
2011 Leave a Comment Written by Dylan Vanderhoof

There’s been much noise about IPv4 address runout and IPv6 adoption lately, even as far as some poorly written articles in the mainstream media.  The IANA address pool was depleted on February 3rd, 2011, with the final /8 blocks being assigned to the RIRs for allocation.  (ARIN article on IANA runout)  Now, just over 2 months later, APNIC appears to be close to exhausting their assignable address pool, the first of the RIRs to do so.  (IPv4 Address Report)

So, what does all this mean for non-carrier companies who haven’t adopted IPv6 yet?  Will your networks fall off the face of the internet?  Will websites become unavailable to your employees, or even worse, your customers?

Well, no.  In fact, you probably won’t notice anything at all.  IPv4/IPv6 dual-stack hosts will be the norm for the foreseeable future in most regions.  However, we are facing the possibility of IPv6 only clients starting to show up in the Asia/Pacific region.  This means that even though the sky isn’t falling, steps should be taken to adopt IPv6 in a manageable fashion, particularly if you have a global presence including a customer base in Asia.

Here at Semaphore Corporation, we’ve been running down this road for some time both to migrate our own network, as well as prepare ourselves for the process of assisting our customers in their migration.  I’ll present a straightforward high-level roadmap of how we recommend handling IPv6 adoption based on our own experiences.

READ MORE »

Posted in IPv6, Networking, Technology

Multicast propagation through L3 switches without PIM support

Apr11
2011 Leave a Comment Written by Garth Brown

I recently had chance to interact with a customer network I designed several years ago that reminded me of their multicast problem and the creative solution we implemented.

The customer has a Cisco IP phone system with centralized CallManager servers running Music on Hold (“MoH”) services at their Headquarters location. Branch offices were connected by T1 lines (often bundles of them) terminating on 2800 series routers. The Headquarters router is a 3800 series router. I’m simplifying things somewhat, but this is the gist of it.

Each branch location used L3 switches in the core of the branch network to allow faster connectivity between multiple local VLANs than would be possible if we’d configured the WAN router as the L3 gateway for the networks (either using physical ports or router-on-a-stick).

This was all well and good until it came time to deal with MoH. Unfortunately, given the limited bandwidth and several other constraints, the customer MoH source was multicast and the L3 switches at each site were 3560 switches (IP Base) which have NO PIM SUPPORT. The customer also deployed broadcast paging software which relied on multicast, so we had to find a solution that didn’t involve upgrading all of their branch core switches.

What to do? READ MORE »

Posted in Tech Tricks, Technology, Voice - Tagged , , ,

95th percentile bandwidth metering explained and analyzed

Apr04
2011 Leave a Comment Written by Dylan Vanderhoof

We frequently see a fair amount of confusion from new customers as to what 95th percentile bandwidth metering and billing is and how it works.  While we have a nice text description of how its calculated, I figured since its such a prevalent billing method I’d explain it with a more visual representation, as well as providing some analysis of 95th percentile vs. other potential metering methods and why it is used at all.  Hopefully our future posts here will be somewhat more technically interesting, but this topic is at least informative and answers a question we hear a lot.

What is 95th Percentile metering?

The short answer is that 95th percentile is a way to meter bandwidth usage that allows a customer to burst beyond their committed base rate, and still provides the carrier with the ability to scale their billing with the cost of the infrastructure and transit commits (if any).  Its an alternative to either capped ports with fixed billing or actual data transferred, which are models more frequently seen outside the datacenter where occasional bursting is either not allowed or penalized with higher bills.

Carriers sample the amount of data transferred on a customer’s port(s) every 5 minutes and use that value to derive a data rate (typically in megabits per second or Mbps) for that 5 minute interval.  Over the course of a customers monthly billing cycle, around 8000 of these samples are taken.  These values are then sorted and ranked by percentile, and the value that falls on the 95th percentile will be the customer’s bill for the month if it exceeds their base commit rate.  The higher a customer’s base commit rate, the lower their per-Mbps cost will be, allowing to bulk purchase of bandwidth and well as less volatility in the event their 95th percentile rate exceeds their base commit.  For a fairly normal business traffic pattern, that provides a value that is fair to both the carrier and the customer in terms of service delivered to the customer and the ability of the carrier to scale its infrastructure to meet customer needs over time.

That’s all well and good, but without having a month’s worth of data in front of you, its hard to tell what exactly that means.  I’ll provide some samples of traffic patterns, beginning with a fairly typical one, as well as some more abnormal patterns later on, to explain both how 95th percentile works, as well as how it compares with other burstable and non-burstable methods. READ MORE »

Posted in Business, Networking - Tagged , ,