Incast is a many-to-one communication pattern commonly found in cloud data centers implementing scale out distributed storage and computing frameworks such as Hadoop, MapReduce, HDFS, Cassandra, etc. — powering applications such as web search, maps, social networks, data warehousing and analytics. Incast can also more specifically be referred to as TCP Incast, as the cloud [...]
Cisco UCS Networking videos (in HD), Updated & Improved!
March 8, 2011 By 28 Comments
Cisco Nexus 7000 connectivity solutions for Cisco UCS
December 1, 2010 By 10 Comments
Last summer I was invited by the Nexus 7000 product management team at Cisco to help co-author a whitepaper covering general guidelines and best practices for network integration of Cisco UCS with Cisco Nexus 7000. The idea was to take a lot of the content already presented in my video series Cisco UCS Networking Best Practices (in [...]
Setting the stage for TRILL, rethinking data center switching
May 7, 2010 By 44 Comments
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 [...]
Top of Rack vs End of Row Data Center Designs
April 5, 2009 By 25 Comments
Outage Story with VTP
December 2, 2007 By 4 Comments
Switchport Configurations Explained
November 27, 2007 By 4 Comments
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 [...]
VLAN Trunking using IEEE 802.1Q
November 27, 2007 By 1 Comment
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 [...]
VLAN Trunking using ISL
November 26, 2007 By 3 Comments
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 [...]
Things to know about VTP
November 21, 2007 By 2 Comments
Some notes about VTP (VLAN Trunking Protocol): Cisco switches running Cisco IOS store VTP and VLAN information in a separate database stored in Flash, in file called vlan.dat. Cisco switches running CatOS store VTP and VLAN information in the main switch configuration file, stored in NVRAM. VTP information is only transmitted over trunk ports. A [...]
Identifying Ethernet Multicast
November 21, 2007 By 4 Comments
Just like there are 3 different Ethernet header types, there are also 3 different types of Ethernet addresses: Unicast Broadcast Multicast A unicast frame contains the unique MAC address of the destination receiver. A broadcast frame contains all binary 1′s as the destination address (FFFF.FFFF.FFFF). A multicast frame contains the unique multicast MAC address of [...]
Identifying Ethernet Header Types
November 19, 2007 By 3 Comments
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