nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

VEM physical ports are classified into the three port types:
• VMware NIC
• Uplink port
• Ethernet port
Each physical NIC in VMware is represented by an interface called a VMNIC. The VMNIC
number is allocated during VMware installation, or when a new physical NIC is installed,
and remains the same for the life of the host. Each uplink port on the host represents a
physical interface. It acts like an lvEth port; however, because physical ports do not move
between hosts, the mapping is 1:1 between an uplink port and a VMNIC. Each physical port
added to Cisco Nexus 1000V appears as a physical Ethernet port, just as it would on a
hardware-based switch.
Note
For more information on interface relationship mapping, read the Overview section
from the Cisco Nexus 1000V Installation and Upgrade Guide, Release
4.2(1)SV1(5.1) at Cisco.com: http://tinyurl.com/bc6ujq5.
The Nexus 1000V does not run Spanning Tree Protocol (STP); the Nexus 1000V adheres to
the following rules to obtain loop prevention without STP:
• STP BDPUs are dropped.
• No switching from physical NIC to NIC.
• Layer 2 local MAC address packets are dropped on ingress.
Figure 9-3 shows how the VEM achieves loop prevention without running STP.
Each VEM learns independently and maintains a separate MAC table. The virtual machine
MAC addresses are statically mapped including vEthernet interfaces, vmknics, and vswifs;
devices external to the VEM are learned dynamically.