Slaying SPOFs Some of you know I took on a new job earlier this year, where the challenge was (and is) to transform a globally distributed network for a growing company into an enterprise class operation. A major focus area has been eliminating single points of failure (SPOFs): single links, single … [Read more...]
The Scaling Limitations of Etherchannel -Or- Why 1+1 Does Not Equal 2
December 7, 2010 by Leave a Comment
Breaking The Network, One /24 At A Time
November 3, 2010 by Leave a Comment
The Setup Yea and verily, ponder ye the diagram that followeth below, and I shall spin ye a tale o’ sorrow. Was that Olde English or pirate? I really have no idea. Maybe an Olde English pirate sailing the seas of Ethernet. Seriously though, this diagram helps explain something I broke the other … [Read more...]
Coping Mechanisms For A Lying ARP Cache
October 14, 2010 by 1 Comment
Image via Wikipedia I Swear To Tell The Truth Prevarication. Untruths. Misdirection. Deceit. Call it what you will, lying is ugly. While we expect lying from people (there’s an American TV show built around this premise), we expect our network gear to tell only the truth. The command line is … [Read more...]
Traveling East-West Might Get A Little Easier: Highlights from the TRILL RFC5556
October 11, 2010 by Leave a Comment
The Problem TRILL Aims to Solve TRILL – TRansparent Interconnection of Lots of Links – is proposed with no technical implementation details in RFC5556. TRILL’s proposal can be encapsulated thusly: shove the logic of a layer 3 routing protocol down into layer 2. Why? So that switches … [Read more...]
Don’t Drop The Baby: Data Center Bridging Wants Storage To Trust Ethernet
October 8, 2010 by 1 Comment
Convergence: The Early Days “Convergence” is a buzzword seen in the IT press constantly these days. All convergence means is placing communications that used to ride on its own network onto one unified network; Ethernet’s cheapness, ubiquity, and ever-growing link speeds makes it the … [Read more...]
Assembly Required – Interconnecting 2 Ethernet Chassis Switches
June 28, 2010 by Leave a Comment
You’ve been tasked with interconnecting two ethernet chassis switches. There are lots of reasons you might want to do this. The link you’re building might be between two core switches acting as your main data center routers. The link could be connecting a core switch and distribution … [Read more...]