V

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.

Virtual Ethernet Port Aggregator. This is a Virtual Machine (VM) server feature that works with the ExtremeXOS Direct Attach Feature to support communications between VMs.

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 Machine. A VM is a logical machine that runs on a VM server, which can host multiple VMs.

Virtual MAN. In ExtremeXOS 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.

Virtual Network Services. An Extreme Networks-specific technique that provides a means of mapping wireless networks to a wired topology.

Voice over Internet Protocol is an Internet telephony technique. With VoIP, a voice transmission is cut into multiple packets, takes the most efficient path along the Internet, and is reassembled when it reaches the destination.

Virtual private network. A VPN is a private network that uses the public network (Internet) to connect remote sites and users. The VPN uses virtual connections routed through the Internet from a private network to remote sites or users. There are different kinds of VPNs, which all serve this purpose. VPNs also enhance security.

This virtual router (VR) is part of the embedded system in Extreme Networks switches. VR-Control is used for internal communications between all the modules and subsystems in the switch. It has no ports, and you cannot assign any ports to it. It also cannot be associated with VLANs or routing protocols. (Referred to as VR-1 in earlier ExtremeXOS software versions.)

This VR is part of the embedded system in Extreme Networks switches. VR-Default is the default VR on the system. All data ports in the switch are assigned to this VR by default; you can add and delete ports from this VR. Likewise, VR-Default contains the default VLAN. Although you cannot delete the default VLAN from VR-Default, you can add and delete any user-created VLANs. One instance of each routing protocol is spawned for this VR, and they cannot be deleted. (Referred to as VR-2 in earlier ExtremeXOS software versions.)

This VR is part of the embedded system in Extreme Networks switches. VR-Mgmt enables remote management stations to access the switch through Telnet, SSH, or SNMP sessions; and it owns the management port. The management port cannot be deleted from this VR, and no other ports can be added. The Mgmt VLAN is created VR-Mgmt, and it cannot be deleted; you cannot add or delete any other VLANs or any routing protocols to this VR. (Referred to as VR-0 in earlier ExtremeXOS software versions.)

In VRRP, the VRID identifies the VRRP virtual router. Each VRRP virtual router is given a unique VRID. All the VRRP routers that participate in the VRRP virtual router are assigned the same VRID.

Virtual Router Redundancy Protocol. VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IP address(es) associated with a virtual router is called the master router, and forwards packets sent to these IP addresses. The election process provides dynamic failover in the forwarding responsibility should the master router become unavailable. In case the master router fails, the virtual IP address is mapped to a backup router's IP address; this backup becomes the master router. This allows any of the virtual router IP addresses on the LAN to be used as the default first-hop router by end-hosts. The advantage gained from using VRRP is a higher availability default path without requiring configuration of dynamic routing or router discovery protocols on every host. VRRP is defined in RFC 2338.

Any router that is running VRRP. A VRRP router can participate in one or more virtual routers with VRRP; a VRRP router can be a backup router for one or more master routers.

Vendor Specific Attribute. An attribute for a RADIUS server defined by the manufacturer.(compared to the RADIUS attributes defined in the original RADIUS protocol RFC 2865). A VSA attribute is defined in order that it can be returned from the RADIUS server in the Access Granted packet to the Radius Client.