Customer Network Ports
Customer Network Ports (CNPs) are edge switch ports that accept all tagged
and untagged CVLAN traffic and route it over a single VMAN. A CNP is simpler to configure than
a CEP, because it supports one VMAN on a physical port and requires no configuration of CVIDs.
The VMAN service provider does not need to know anything about the CVLAN traffic in the VMAN.
The service provider simply manages the VMAN, and the ingress CVLAN traffic is managed by the
customer or another service provider. This separation of CVLAN and VMAN management reduces the
dependence of the separate management teams on each other, and allows both management teams to
make changes independent of the other.
The CNP term is
defined in the IEEE 802.1ad standard and is also called a port-based service interface. The
CNP operation is similar to a MEF 13 UNI Type 1.2, and in releases before ExtremeXOS
CNPs were known as VMAN access ports or untagged vman ports. With the addition of CEPs, the
term VMAN access port is now a generic term that refers to CNPs and CEPs.
A PBN can support up to 4094 VMANs, and each VMAN can support up to 4094
CVLANs. Because each CNP connects to only one VMAN, the maximum number of customer VMANs on an
edge switch is equal to the total number of switch ports minus one, because at least one port
is required to serve as the PNP (Provider Network Port).