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Archive for the ‘UCS’ tag

Cisco Announces ESXi 4.1 Support

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Just released this week, Cisco now officially supports ESXi 4.1 for most of the UC applications.

Link: Unified Communications VMWare Requirements

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Written by Matthew Berry

March 8th, 2011 at 10:23 am

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UC on UCS Update – Feb 2011

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This was a great update on UC on UCS from Cisco’s Dan Keller.  Very good introduction for virtualization “n00bs” like me.

Contents include:

  • Fundamentals of UC on UCS Architecture
  • UC on UCS Tested Reference Configurations (TRC)
  • Virtual Machine Sizing and Placement
  • UCS Server Selection
  • VMware/vCenter Design Best Practices
  • LAN/SAN Design Best Practices
  • Migration Strategies

Written by Matthew Berry

February 17th, 2011 at 4:56 pm

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CUCM 8.X SRND – UC Networking

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Having finished the CCIE Voice v3 lab, I’ve turned to the CUCM 8.x SRND to look for the latest updates. Here are just a few notes I gathered while on the plane.  More to come!

    Network Infrastructure

  • Limit the number of devices per VLAN to 512, roughly equivalent to two Class C subnets (e.g.
  • Enable root guard or BPDU guard on all access ports to prevent a rouge switch from taking the Spanning Tree root position.  Such an action causes STP re-convergence events and could affect network traffic flows.
  • Best practice remains to leave the Layer 2/3 demarcation on the access switches.  This is a best practice move from the old standard that placed the demarcation on the distribution switches. With this configuration, Hot Standby Router Protocol (HSRP) or Gateway Load Balancing Protocol (GLBP) virtual gateway addresses are no longer necessary.
  • The most apparent advantages to the Layer 3 Access model are: (1) improved convergence, (2)  simplified multicast configuration, (3) dynamic traffic load balancing, (4) single control plane, (5) and a single set of troubleshooting tools (for example, ping and traceroute).
  • It’s a good idea to use the passive-interface command on all interfaces facing the access layer in order to prevent routing adjacencies to be advertised out through these interfaces.  This constitutes a small, but present and unnecessary, CPU drain on the access switches.
  • Voice marking for QoS remains at CoS 5 (IP Precedence 5, PHB EF, or DSCP 46).
  • Videoconferencing marking for QoS remains at CoS 4 (IP Precedence 4, PHB AF41, or DSCP 34).
  • Call signaling for voice and videoconferencing is now classified as CoS 3 (IP Precedence 3, PHB CS3, or DSCP 24) but was previously classified as PHB AF31 or DSCP 26.

    Virtual Unified Communications with Cisco UCS

  • With the emergence of UC on UCS, there are three virtual switching platforms available for UC applications running on top of VMware: (1) Local VMware vSwitch, (2) Distributed VMware vSwitch, (3) and the Nexus 1000V switch.  The Nexus 1000V requires the Enterprise Plus Edition of the VMware ESXi 4.0.
  • The virtual machines send traffic to the software switch (options listed above) and then on to the physical UCS Fabric Interconnect Switch (UCS 6100 Series) through its blade server’s Network Adapter and Fabric Extender.
  • The UCS 6100 carries both the IP and fibre channel SAN traffic via Fibre Channel over Ethernet (FCoE) on a single wire. IP traffic is sent onward to an IP switch (Catalyst/Nexus) and SAN traffic is sent to a Fibre Channel SAN switch (e.g. Cisco MDS)
  • By default, the UCS 6100 creates a fibre-channel priority QoS class for traffic destined for the SAN Switch. This FC QoS class has no drop and marks traffic as CoS 3.
    • VMware local/distributed vSwitches and the UCS 6100 cannot map L3 DSCP values to L2 CoS values.  Traffic can only be prioritized or de-prioritized within the UCS 6100 based on L2 CoS only.
  • UC applications mark L3 DSCP values only.  In order to make sure UC on UCS traffic is classified appropriately, you must configure all traffic originating from a blade server Network Adapter to be marked with a single L2 CoS value.
  • Nexus 1000V software switch has the ability to map L3 DSCP values to L2 CoS values, and vice versa, like traditional Cisco physical switches such as the Catalyst Series Switches.

Written by Matthew Berry

January 26th, 2011 at 9:12 pm