HP Virtual Connect: Common Myths, Misperceptions, and Objections, Second Edition

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Table of contents

Abstract ............................................................................................................................................................... 3

Target Audience ............................................................................................................................................ 3

Prerequisites and Versioning ........................................................................................................................ 3

Introduction ......................................................................................................................................................... 3

Myths, Misconceptions and Objections .......................................................................................................... 5

#1: VC Ethernet is just another switch ........................................................................................................ 5

Comparing VC and Server Virtualization Hypervisor Networking Technology ................................. 5

#2: VC Ethernet is really a ProCurve switch and may not be interoperable with 3rd party network

switches .......................................................................................................................................................... 7

#3: VC Ethernet doesn’t support Spanning Tree (STP) .............................................................................. 7

#4: VC can cause duplicate MACs and WWNs on the network. .......................................................... 7

#5: VC users cannot leverage existing network management tools (for example, CiscoWorks) ........ 8

#6: VC doesn’t provide secure external management .............................................................................. 8

#7: VC Ethernet doesn’t support Private VLANs ........................................................................................ 8

#8: VC doesn’t provide deterministic load balancing for multiple LACP channels ............................... 9

#9: VC Ethernet doesn’t support VLAN Trunking to Server Blade NICs ................................................. 9

#10: VC Ethernet and Fibre Channel modules require a clunky hardware failure recovery (RMA)

process ............................................................................................................................................................ 9

#11: VC doesn’t provide network visibility into the VC Domain for network administrators ............. 10

#12: Many customers experience problems with VC deployment consistency ................................... 10

#13: VC doesn’t support non-disruptive firmware upgrades (“hot code load”) .................................. 10

#14: HP server blade NICs stay active even after VC Ethernet uplink failure ..................................... 11

#15: VC is proprietary to HP; VC locks a user to a single blade vendor............................................. 11

#16: VC modules form a master/slave relationship with separate IP addresses that aren’t

transferred during a failover. When multiple VC modules are present, only one module is elected to

forward traffic .............................................................................................................................................. 11

#17: VC only supports a limited number of VLANs ................................................................................ 12

#18: VC Ethernet doesn’t provide Layer 3 routing capabilities ............................................................. 12

#19: VC’s CX4 cables are not ideal for 10Gbe uplinks because of distance limitation .................... 12

#20: VC doesn’t support stacking multiple VC modules ........................................................................ 13

#21: VC doesn’t offer Access Control Lists or VLAN Access Control Lists (ACLs or VACLs) .............. 13

#22: VC Ethernet doesn’t support user configurable Quality of Service (QoS) features .................... 13

#23: VC Ethernet doesn’t provide diagnostic tools (SPAN) ................................................................... 13

#24: VC Ethernet doesn’t support the Cisco Discovery Protocol (CDP) ................................................ 13

HP Virtual Connect: Common Myths,

Misperceptions, and Objections, Second Edition

A technical discussion of common myths, misperceptions, and objections to the

deployment and use of HP Virtual Connect technology

Summary of content (32 pages)

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HP Virtual Connect: Common Myths, Misperceptions, and Objections, Second Edition A technical discussion of common myths, misperceptions, and objections to the deployment and use of HP Virtual Connect technology Table of contents Abstract............................................................................................................................................................... 3 Target Audience ................................................................................................
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#25: VC requires a separate web management window to manage each VC module..................... 14 #26: VC doesn’t support IGMP Snooping ............................................................................................... 14 #27: VC Fibre Channel doesn’t support nested NPIV ............................................................................
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Abstract This whitepaper discusses some of the common myths, misperceptions, and objections to the deployment and use of HP’s Virtual Connect technology in data center networks. Technical answers are provided for these common assertions, whether correct or incorrect, to help the reader sort the facts. In addition, this paper includes an in-depth discussion and comparison of the Virtual Connect feature set and capabilities when compared to the deployment of traditional LAN and SAN switches.
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1. Virtual Connect reduces the number of cables required to connect servers to LANs and SANs without having to increase the number of traditional Ethernet or Fibre Channel switches to manage. a. Presents the entire c-Class enclosure to the LAN and SAN in the same way as a server virtualization hypervisor (for example, VMware ESX, Microsoft Hyper-V, Citrix XenServer, etc.)) b. Doesn’t require configuring all the traditional switch-to-switch protocols (STP, VTP, etc.) 2.
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Myths, Misconceptions and Objections #1: VC Ethernet is just another switch Incorrect: While VC uses tried-and-true, IEEE standard, Layer 2 bridging functionality, its primary purpose is to provide many server virtualization and management features that are non-existent in traditional switches. VC may perform some functions like a traditional switch; however, VC has many additional features which clearly distinguish it from a traditional switch.
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are assigned to one of the vSwitches and the vSwitches are then associated with real physical NICs residing in I/O slots on the hypervisor host. The vSwitches can have one or more physical NICs (uplinks) assigned to them to provide external network connectivity. If more than one physical NIC is assigned to the same vSwitch, network redundancy and/or load balancing is provided for the internal servers (VMs) assigned to that vSwitch.
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entire c-Class blade enclosure and makes it behave on the network like a single host running a hypervisor. #2: VC Ethernet is really a ProCurve switch and may not be interoperable with 3rd party network switches Incorrect: VC is not a ProCurve switch product and VC is interoperable with any other IEEE compliant network device. VC is a product engineered, developed and sold by the HP BladeSystem division independently of the HP ProCurve division.
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#5: VC users cannot leverage existing network management tools (for example, CiscoWorks) Incorrect: Virtual Connect supports configuration scripting via a CLI interface (SSH) and Virtual Connect supports monitoring using SNMP. Any management tools that support CLI scripting can be used to remotely configure Virtual Connect. Any management tool that supports SNMP can be used to monitor Virtual Connect. VC Ethernet supports applicable groups within the following MIBs: Table 1.
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#8: VC doesn’t provide deterministic load balancing for multiple LACP channels Incorrect: Virtual Connect utilizes a deterministic load balancing algorithm for frames load balanced across a single LACP channel and VC provides a deterministic algorithm for determining active vs. standby LACP channels assigned to the same Virtual Connect network (vNET). VC’s algorithm for frame load balancing within a LAG (port trunk/channel) is automatic based on the protocol information in the frame.
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#11: VC doesn’t provide network visibility into the VC Domain for network administrators Incorrect: Virtual Connect provides several user interfaces options and features for managing and monitoring Virtual Connect to fit with the variety of methods our customers use. VC supports both a Web interface (HTTPS) and a CLI interface (SSH). In addition, VC supports per-interface statistics for every server NIC port, server HBA port, VC Ethernet uplink port, and VC Fibre Channel uplink port.
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for Fibre Channel). This is analogous to a server having NICs connected to multiple switch modules in a Cisco 6500 and independently upgrading each of the switch modules. #14: HP server blade NICs stay active even after VC Ethernet uplink failure Incorrect: Virtual Connect provides many features for ensuring highly available network connectivity for HP server blades.
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always used by the active VC module within a VC Domain. This optional feature is called the “Virtual Connect Domain IP Address”. While only one VC module provides the active VC Domain management interface (Virtual Manager), all VC Ethernet and Fibre Channel modules can be used simultaneously to network connectivity for HP server blades.
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#20: VC doesn’t support stacking multiple VC modules Incorrect: As of VC firmware v2.10, Virtual Connect fully supports stacking up to 8 VC Ethernet modules within a single enclosure, or up to 32 total Virtual Connect modules (16 Ethernet and 16 Fibre Channel) across a maximum of 4 enclosures. All 32 modules are managed using a single GUI or CLI interface. Any external VC Ethernet port can be used as a stacking link, an uplink to the external network, or a network analyzer port.
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Cisco 3120 8). The use of the IEEE standard version, LLDP, is recommended by HP to ensure customers are not locked into a proprietary protocol. #25: VC requires a separate web management window to manage each VC module Incorrect: A single Web management window or CLI prompt is used to manage all VC modules in the same VC Domain. If using Virtual Connect Enterprise Manager (VCEM), a single VCEM User Interface can be used to manage server profile management (creation, deletion, movement, etc.
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A virtualized MAC address or WWN is an address that is not really owned and used by a physical NIC or HBA. Often, a virtualized address is an address that replaces the real MAC or WWN address of a physical NIC without the server’s knowledge. In other words, the server thinks it is communicating on the network with MAC address X, however, some device (switch) is replacing real MAC address X with a virtual MAC address Y.
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have an impact on the performance of the network or storage switch. Alternatively, VC’s use of managed MAC addresses and WWNs means the server actually transmits and receives using the VC managed address. No device on the network (VC or switch) is required to manipulate the server’s frames. This results in absolutely no performance impact on the network.
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Table 4. VC Comparison • • • • • • Virtual Connect Doesn’t: • o Keeps the same SAN assignments with the server Does keep the server serial number the same after hardware replacement. o Prevents problems with application licensing if application uses server serial number as part of license data Does keep the server UUID the same after hardware replacement. Does keep the server MAC addresses the same after hardware replacement.
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#33: VC implements an immature loop avoidance mechanism Incorrect: Since the Virtual Connect loop avoidance mechanism is modeled after both NIC Teaming/bonding and after simple layer 2 path redundancy features (for example, Cisco’s Flex Link feature 10), the mechanism inherits the maturity that these seasoned technologies provide.
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upgrade, repair, and move server blades within the data center while minimizing the negative effects on the LANs, SANs, and OS images. Cisco VFrame Data Center is a higher level management product that interfaces with other data center device management tools and products such as Virtual Connect. In other words, Cisco VFrame Data Center scripting capability could be used to control device management tools such as Virtual Connect via its CLI.
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Table 5.
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Managed Server Identities Internal Server Identity Virtual Connect manages a server’s internal identity in order to provide hardware transparency to OS images. If server blade hardware components must be replaced or if an OS image is moved from a server blade to a completely different server blade, the hardware changes will usually negatively affect the OS image (or installed applications)… unless Virtual Connect is used to provide the virtualization layer between the OS and the hardware.
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“LAN Safe” Network Connectivity Virtual Connect Ethernet allows an entire HP c-Class enclosure full of server blades to connect to the external network sharing one or more VC uplink ports and presents itself to the external network in a way similar to how a large virtual server hypervisor (for example, VMware) full of virtual machines sharing one or more NIC uplink ports presents itself to the external network.
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across the data center. Since the Virtual Connect Server Profile contains the server’s internal and external identity (as discussed above), a server blade can be added to, or removed from, any blade enclosure or moved between blade enclosures without impact to the external LAN and SAN.
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Table 6.
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Table 6.
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Additional Resources and References Virtual Connect Cookbook: http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01471917/c01471917.pdf -orwww.hp.com/go/bladeconnect (see the Virtual Connect Interest Group) Virtual Connect Documentation: www.hp.com/go/bladesystem/documentation Virtual Connect Firmware: www.hp.com/go/bladesystemupdates HP NIC Teaming for Windows Whitepaper: ftp://ftp.compaq.com/pub/products/servers/networking/TeamingWP.pdf HP Services: www.hp.
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Appendixes Appendix A: Frequently Asked Questions Q1: Why do I see lots of dropped frames (discards) on standby VC uplink ports? A1: An external switch has no concept of which VC link is the active uplink and which is the standby uplink. As far as the external switch is concerned, one of the uplinks is just a whole lot busier. That means that the external switch is still going to send some types of frames down the standby link and the standby link is going to discard them.
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uplink ports. Any VC uplink on any VC Ethernet module can be used to provide external connectivity for any downlink on any VC Ethernet module. Q9: I need more NICs on my server blades.
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A19: No, only HP branded SFP and XFP modules are supported. Q20: Will upgrading the VC firmware require an outage? A20: In general, HP recommends upgrading VC firmware during a scheduled maintenance window. However, VC is able to perform a rolling, non-intrusive upgrade of all modules so long as redundancy is configured throughout the solution.
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Appendix B: Definitions Table 1. Definitions Term Definition ACL (VACL) Access Control List or VLAN Access Control List: A set of rules that allows or disallows network traffic to flow between network devices Bridge Protocol Data Unit: A spanning tree configuration frame exchanged between switches in the same spanning tree domain An industry standard cabling specification used by VC for network connectivity using 10Gb Ethernet over copper.
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Table 1. Definitions Term Definition classification, prioritization, queuing, marking, etc . Server Profile VC-Enet An object within the Virtual Connect domain that is assigned to a server bay and contains the server’s LAN and SAN connectivity settings (vNet assignments, managed MAC addresses & WWNs, server boot parameters, PXE configuration, and Fibre Channel boot parameters). Hot-pluggable transceiver that can provide either 1Gb (SFP) or 10Gb (SFP+) connectivity.
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Table 1. Definitions Term Definition connectivity at 10Gb speeds. Technology for better business outcomes © Copyright 2010 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty.