A while ago we had an internal discussion whether or not a Virtual Connect (HP Blade Technology) is to be considered as an active component or as a patch panel. The answer is that it is kinda like a switch. It cannot be seen as an actual switch, where it comes close to a virtual switch (like defined by VMware). More details can be found op page 25 in the document (linked below), where a nice comparison table is listed.
Source :HP Virtual Connect: Common Myths, Misperceptions, and Objections, Second Edition (Google cache / quickviewer)
#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. …
#18: VC Ethernet doesn’t provide Layer 3 routing capabilities
Correct: Virtual Connect is not a router, therefore, Virtual Connect does not provide Layer 3 capabilities (routing).
#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. One feature, SmartLink, is used to disable a server blade NIC port anytime the NIC is connected to an external network where all VC uplink(s) have failed. In other words, VC can be configured to proactively disable a server NIC port whenever the server NIC is isolated from the external network. VC’s SmartLink feature, combined with NIC Teaming on the server, allows for highly available network configuration with no single point of failure.
#3: VC Ethernet doesn’t support Spanning Tree (STP)
Correct: Much to the delight of VC users, Spanning Tree support on VC is not needed. VC provides HP server blade network connectivity just like a hypervisor provides virtual server network connectivity and neither of these technologies require Spanning Tree support. VC doesn’t have to support Spanning Tree just like hypervisor hosts don’t have to support it, yet both provide network redundancy and load balancing. Just like a hypervisor host, VC provides network redundancy and load balancing features that are modeled after NIC Teaming/bonding technology instead of switch technologies like Spanning Tree. A Spanning Tree configuration error on any single switch in the data center can negatively affect any other connected switch in the network, in addition to all servers connected to the same network. With Virtual Connect, any redundancy and load balancing configuration problems only affect a single blade enclosure1
Fundamentally, VC doesn’t require support for protocols like STP because VC presents itself to the network as a “termination endpoint”, as does a typical server or a hypervisor host. VC is not and does not present itself as a “transit device”, as does a traditional switch.
#24: VC Ethernet doesn’t support the Cisco Discovery Protocol (CDP)
Correct: VC supports Link Layer Discovery Protocol (LLDP) – the industry standard (IEEE) version of the Cisco proprietary protocol CDP. Many Cisco devices support both CDP and LLDP (for example, 14 ). The use of the IEEE standard version, LLDP, is recommended by HP to ensure customers are not locked into a proprietary protocol.
#17: VC only supports a limited number of VLANs
Correct: The supported limit is 320 VLANs per Virtual Connect Ethernet module when using Shared Uplink Sets. The VC architecture supports 1000+ VLANs per c-Class enclosure.
Karim Vaes 