Extreme Networks ExtremeWare XOS Guide Manual page 667

U
unicast
untagged VLAN
USM
V
virtual link
virtual router
virtual router MAC address
VLAN
VLSM
VMAN
ExtremeWare XOS 11.3 Concepts Guide
A unicast packet is communication between a single sender and a
single receiver over a network.
A VLAN remains untagged unless you specifically configure the IEEE
802.1Q value on the packet. A port cannot belong to more than one
untagged VLAN using the same protocol.
User-based security model. In SNMPv3, USM uses the traditional
SNMP concept of user names to associate with security levels to
support secure network management.
In OSPF, when a new area is introduced that does not have a direct
physical attachment to the backbone, a virtual link is used. Virtual
links are also used to repair a discontiguous backbone area.
In the Extreme Networks implementations, virtual routers allow a
single physical switch to be split into multiple virtual routers. Each
virtual router has its own IP address and maintains a separate logical
forwarding table. Each virtual router also serves as a configuration
domain. The identity of the virtual router you are working in
currently displays in the prompt line of the CLI. The virtual routers
discussed in relation to Extreme Networks switches themselves are not
the same as the virtual router in VRRP.
In VRRP, the virtual router is identified by a virtual router (VRID) and
an IP address. A router running VRRP can participate in one or more
virtual routers. The VRRP virtual router spans more than one physical
router, which allows multiple routers to provide redundant services to
users.
In VRRP, RFC 2338 assigns a static MAC address for the first five
octets of the VRRP virtual router. These octets are set to 00-00-5E-00-
01. When you configure the VRRP VRID, the last octet of the MAC
address is dynamically assigned the VRID number.
Virtual LAN. The term VLAN is used to refer to a collection of devices
that communicate as if they are on the same physical LAN. Any set of
ports (including all ports on the switch) is considered a VLAN. LAN
segments are not restricted by the hardware that physically connects
them. The segments are defined by flexible user groups you create
with the CLI.
Variable-length subnet masks. In OSPF, VLSMs provide subnets of
different sizes within a single IP block.
Virtual MAN. In ExtremeWare XOS software, VMANs are a bi-
directional virtual data connection that creates a private path through
the public network. One VMAN is completely isolated from other
VMANs; the encapsulation allows the VMAN traffic to be switched
over Layer 2 infrastructure. You implement VMAN using an
additional 892.1Q tag and a configurable EtherType; this feature is
also known as Q-in-Q switching.
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