Studies in Data Center Networking, Virtualization, Computing
May 07 2010
As data centers become increasingly dynamic and dense with virtualization – how the classic Ethernet switching design adopts to these new models and scales becomes an important and challenging question. Virtualization and cloud based services says that any workload can exist anywhere, at anytime, on demand, and move to any location without disruption. This is [...]
Dec 02 2007
One of my accounts had an unfortunate network outage that lasted about an hour. This outage was caused by human error with VTP but not in the classic revision number way we have heard about before.
Here is what happened…
Nov 27 2007
It always helps me to think of the English translation when trying to memorize and understand some the Cisco IOS settings I think are important.
Here are some Cisco IOS switchport configurations translated into English:
‘switchport mode trunk‘ says: “Always trunk on this end, and I will send DTP to attempt to negotiate a trunk on the [...]
Nov 27 2007
IEEE 802.1Q (sometimes referred to as 1Q or DOT1Q) is a industry standards based implementation of carring traffic for multiple VLANs on a single trunking interface between two Ethernet switches. 802.1Q is for Ethernet networks only.
Unlike ISL , 802.1Q does not encapsulate the original Ethernet frame.
For Ethernet V2 frames, 802.1Q inserts a new 4-byte [...]
Nov 26 2007
Inter-Switch Link (ISL) is a Cisco specific implementation of trunking multiple VLANs between two Cisco switches where a single interface will carry traffic for more than one VLAN. ISL was designed to work with Ethernet, FDDI, Token Ring, and ATM.
ISL completely encapsulates the original Ethernet frame by adding a new 26 byte header and [...]
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