Collection of useful, relevant or inane places on the the Internets for 17 Jan 11:
- F5?s iHealth | steverossen.com – Talks about F5 iHealth tool which looks very cool. One way to justify the overpriced F5 solution and no doubt very useful. Helps to explain why F5’s share price is doing so well.
- Virtualization, Data Center, and Networking: Do we need spanning tree ? –
The network finally recovered!
Observations / Lessons learned:
– Never disable spanning tree globally on a switch
– Spanning-tree portfast disables spanning tree on an interface
– consider running on every switch bpduguard
I love war stories.
- 8Gb Fibre Channel or 10Gb Ethernet w/ FCoE? | The Unified Computing Blog –
1, 2, 4, and 8 Gb Fibre Channel all use 8b/10b encoding. Meaning, 8 bits of data gets encoded into 10 bits of transmitted information ñ the two bits are used for data integrity. Well, if the link is 8Gb, how much do we actually get to use for data ñ given that 2 out of every 10 bits arenít ìuserî data? FC link speeds are somewhat of an anomaly, given that theyíre actually faster than the stated link speed would suggest. Original 1Gb FC is actually 1.0625Gb/s, and each generation has kept this standard and multiplied it. 8Gb FC would be 8◊1.0625, or actual bandwidth of 8.5Gb/s. 8.5*.80 = 6.8. 6.8Gb of usable bandwidth on an 8Gb FC link.
Just like Token Ring, FC chooses worst case physcical design. Note that the 16Gb FC assumes that the physical layer is reliable and changes to a 64b/66b encoding and is more efficient. Too little too late, FC was so resistant to change that they didn’t even make this change until too late.
- New Cisco Compact Switches! ´ FryGuy’s Blog –
These really have my attention from an Enterprise perspective. I cannot tell you how many conference rooms we have that have either the 2940 or the 3560-8 switches mounted under the table. Those switches work great, except for the fact that we need to also run a power-cord to them. I cannot tell you how many times our NOC has contacted us with regards to a switch being reset due to power-on and it turning out someone kicked the power cord. We run the Cisco 3560-8 at places where we need PoE ports for phones and such, and the 2940/2960 series are used where no PoE is required.
Jeff Fry tells us about why the Cisco Compact switches will work in unusual use cases. Makes some good points.
- End-of-Sale and End-of-Life Announcement for the 32-port Async/Sync Serial Network Module† [Cisco 3800 Series Integrated Services Routers] – Cisco Systems –
Cisco announces the end-of-sale and end-of life dates for the NM-32A 32-port Async/Sync Serial network module.
Although the HWIC-16A is ok, it’s not dense enough to be a lab or live console server. Guess I won’t be buying any more Cisco gear as console servers or putting them under maintenance either. Shame, I much prefer Cisco as a console server for Network Equipment. I’ve always wondered why Cisco didn’t produce a console only image and compete with KVM market. A cheap version of IOS license and it would work out nicely.
More head shaking stuff.