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Steelhead Appliance Installation and Configuration Guide
Glossary
Layer-4.
A communications protocol (called the transport layer) responsible for establishing a connection
and ensuring that all data has arrived safely. The application delivers its data to the communications system
by passing a stream of data bytes to the transport layer along with the socket (the IP address of the station
and a port number) of the destination machine.
MAC address.
Unique serial number or physical station address burned into Ethernet and Token Ring
adapters to identify that network card from all others.
MAPI.
Messaging API. A programming interface from Microsoft that enables a client application to send
and receive mail from Exchange Server or a Microsoft Mail (MS Mail) messaging system. Microsoft
applications such as Outlook, the Exchange client, and Microsoft Schedule use MAPI.
Microsoft Exchange.
Messaging and groupware software for Windows from Microsoft. The Exchange
server is an Internet-compliant messaging system that runs under Windows systems and can be accessed
by Web browsers, the Windows In-box, Exchange client, or Outlook. The Exchange server is also a storage
system that can hold anything that needs to be shared.
MSI Package.
An MSI package is the Microsoft Software Installer (MSI) used to install Mobile Client
software onto endpoint clients.
Multiprotocol Filer.
Filer that supports both the NFS and CIFS protocols.
Netmask.
A 32-bit mask which shows how an Internet address is divided into network, subnet, and host
parts. The netmask has ones in the bit positions in the 32-bit address which are used for the network and
subnet parts, and zeros for the host part. The mask must contain at least the standard network portion (as
determined by the class of the address), and the subnet field should be contiguous with the network
portion.
Neural Network.
A modeling technique based on the observed behavior of biological neurons and used to
mimic the performance of a system. It consists of a set of elements that start out connected in a random
pattern, and, based upon operational feedback, are molded into the pattern required to generate the
required results. It is used in applications such as robotics, diagnosing, forecasting, image processing, and
pattern recognition.
NFS.
Network File System. The file sharing protocol in a UNIX network.
NIS.
Network Information Services. A naming service that allows resources to be easily added, deleted, or
relocated.
Opportunistic Lock.
Also known as oplock. A lock requested by a client on a file that resides on a remote
server. To prevent any compromise to data integrity, the Steelhead appliance only optimizes data where
exclusive access is available (in other words, when locks are granted). When an oplock is not available, the
Steelhead appliance does not perform application-level latency optimizations but still performs Scalable
Data Referencing and compression on the data as well as TCP optimizations. Therefore, even without the
benefits of latency optimization, Steelhead appliances still increase WAN performance, but not as
effectively as when application optimizations are available.
OSPF.
Open Shortest Path First. An interior gateway routing protocol developed for IP networks based on
the shortest path first or link-state algorithm. Routers use link-state algorithms to send routing information
to all nodes in an internetwork by calculating the shortest path to each node based on a topography of the
Internet constructed by each node. Each router sends that portion of the routing table (which keeps track of
routes to particular network destinations) that describes the state of its own links. It also sends the complete
routing structure (topography).
