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Steelhead Appliance Installation and Configuration Guide
Glossary
SYN-ACK.
To establish a connection TCP uses a three-way handshake. Before a client attempts to connect
with a server, the server must first bind to a port to open it for connections (a passive open). After the
passive open is established, a client can initiate an active open. To establish a connection, the three-way
handshake occurs: 1) the active open is performed by the client sending a SYN to the server, 2) in response,
the server replies with a SYN-ACK, 3) finally, the client sends an ACK back to the server.
TCP.
Transmission Control Protocol. The error correcting Transport layer (Layer-4) in the TCP/IP protocol
suite.
TCP/IP.
Transmission Control Protocol/Internet Protocol. The protocol suite used in the Internet, intranets,
and extranets. TCP provides transport functions, which ensures that the total amount of bytes sent is
received correctly at the other end. TCP/IP is a routable protocol, and the IP part of TCP/IP provides this
capability.
Throttle.
To adjust the CPU speed.
VIF.
Virtual Interface. A logical interface created for the physical interface. Like a physical Ethernet
interface, each VIF can have multiple addresses assigned to it.
VLAN.
Virtual Local Area Network. A VLAN is an administratively configured LAN or broadcast domain.
Instead of going to the wiring closet to move a cable to a different LAN, network administrators can
remotely configure a port on an 802.1Q-compliant switch to belong to a different VLAN. A 802.1Q VLAN
enables network administrators to move end stations to different broadcast domains by setting
membership profiles for each port on centrally managed switches.
Virtual Filer.
Independent network entity that has its own set of IP addresses and routing tables, DNS
names, and domain membership.
Virtual Server.
Network entity that uses its own name and IP address to serve data just like a physical
server. It mounts volumes from external filers and exports shares that you can mount and access. Multiple
virtual servers can share physical resources and run concurrently on the same appliance.
Volume.
A partition on the filer disk. A volume is not an IP network entity; you cannot ping or connect to
a volume. Volumes belong to virtual servers. The volume administrator can create shares for various
directories on the volume. Volumes contain shares you can export and access. When a virtual server fails
over to another filer, volumes follow the virtual server.
WAN Visibility Mode.
Pertains to how packets traversing the WAN are addressed.
XOR.
Exclusive OR logic or exclusive disjunction logic. It yields true if exactly one (but not both) of two
conditions is true. XOR hardware logic is used in RAID engines designed to perform complex parity
calculations.
