I’ve been very busy lately with several large analyst/research writing projects so less links than usual this week. It will be sometime before I return to a more regular blogging schedule. You should check out Packet Pushers in the next few days where we will be launching a new feature – we are writing our own [...]
Merchant Silicon Evolution, 40GbE Arriving in 2015 & Impact on Data Centre Design
10th February 2013 by 4 Comments
I’ve been reading a presentation from Sharkfest 2012 where a engineers from Microsoft are presenting on their
Microsoft’s Demon – Datacenter Scale Distributed Ethernet Monitoring Appliance. The whole presentation is interesting but this particular slide caught my attention:
Tech Notes: What Is Shortest Path Bridging IEEE 802.1aq – Brief
9th January 2013 by 5 Comments
Summary of the key elements of the Shortest Path Bridging Protocol IEEE 802.1aq.
Nexus 5500 Packet Forwarding – Cut Through or Store & Forward
23rd October 2012 by 3 Comments
Was reading through some documentation as noticed that the Nexus 5500 series has some unusual behaviours for Store and Forward. I made myself notes about the functional modes. Cut-Through vs Store and Forward In cut-through mode of operation a switch will start transmitting a frame before the frame has been completely received and this is the [...]
Basics: What’s the Difference Between STP BPDU Guard and Root Guard
9th July 2012 by 3 Comments
BPDU Guard and Root Guard are enhancements to Spanning Tree Protocol (STP) enhancements that improve the reliability of the protocol to unexpected events ad are primarily to ensure design enforcement ( integrity / security). There they must configured in specific locations in the networks.
Tech Notes: Juniper QFabric – A Perspective on Scaling Up
14th February 2012 by 12 Comments
Juniper QFabric is a new approach to Ethernet Switch Fabrics. When it was announced last year,it was noted that the underlying physical design is a completely different approach to building Switch Fabrics. Here I’m taking a loosely research based approach to understand how Juniper QFabric is different from all other approaches to the problem, and also a look at some of the challenges ahead.
Can Fibre Optic Ethernet Cables Be Longer Than the Standard ?
1st January 2012 by 8 Comments
Short Answer is “It depends, but usually yes.” Long answer follows with a discussion of launch power, receiver sensitivity, and cable losses.
Responding: On Optimizing Traffic for Network Virtualization
23rd December 2011 by 15 Comments
I’m responding to Brad Hedlund’s post “On optimizing traffic for network virtualization” where he seems to missed a key point. It’s about cost of ownership in terms of ability to troubleshoot.
Ethernet Jumbo Frames, Full Duplex and Why Jumbo Frames Are 9000 Bytes)
3rd December 2011 by 19 Comments
I’ve been doing some research into Ethernet and the use of Jumbo frames for some content I’ve been writing and come across something interesting. The documents state that Jumbo frames can only be used on Full Duplex Ethernet connections.
What Are 10 Gigabit Ultra Short Reach (USR) Optics ?
20th November 2011 by 5 Comments
A couple of weeks back I posted this article comparing pricing and features on Cisco Fabric Ethernet Transceivers as a low cost option compared to 10GbaseSR SFP+ optics in when building 10GbE networks – Cisco Nexus 5000 / 2000 Pricing Bundles and Fabric Extension Transceivers (FETs) vs 10GbaseSR SFPs.
