PPP is recognized throughout the routing industry as a standardized serial line data-link protocol providing an efficient multivendor interoperable means of establishing WAN connections in internetwork topologies. NetWare Link/PPP includes the following advantages:
All compliant PPP implementations are not alike. Because of the wide range of point-to-point connectivity requirements, the PPP specification, by design, specifies more capabilities and services than any single implementation might provide. However, differences in PPP implementation capabilities are reconciled at link establishment time when the two PPP peer nodes negotiate a common set of supported services.
- Any given implementation of PPP can include either asynchronous or synchronous framing, or both. NetWare Link/PPP supports both framing types. Bit synchronous framing is required for high-speed leased lines and switched circuits, whereas asynchronous framing supports the use of low-speed modems with PSTNs.
- Any given implementation can support one or more Network-layer protocols. There is no specific prescribed set of protocols that must be supported. Currently, Novell supports AppleTalk, TCP/IP, IPX, and source route bridging.
- PPP does not require modem control signals (such as RTS, CTS, DCD, and DTR), even though such signals do allow greater functionality. However, NetWare Link/PPP uses these modem control signals to provide switched-circuit device management.
- Scripted logins are provided for users who use asynchronous PPP connections to log in to online services. With minimum modification, these standard scripts enable many common logins. It is also possible to develop customized login scripts tailored to meet the needs of a specific site.
- Backup call associations ensure that new connections are made successfully and that permanent connections are maintained, even if a primary WAN call destination goes down. When a backup call association is configured, two previously configured WAN call destinations are specified to have an association with one another. One destination is defined as the primary call destination; the other, as its backup. In the event that the primary destination becomes unavailable, NetWare Link/PPP switches automatically to the backup destination.
- The NetWare Link/PPP Link Control Protocol (LCP) implementation includes the following options:
- Maximum Receive Unit (MRU )---Allows the sender to inform the peer that it can receive larger frames than the default, or to request that the peer send smaller frames. Even if smaller frames are sent, the ability to receive 1,500-octet LCP frames is required in case link synchronization is lost.
NetWare Link/PPP supports MRU values with the range of 128 to 4,500 bytes.
- Magic Number ---Provides a way to detect failure of a remote peer node, as well as loopback links and other Data-Link layer anomalies.
- LCP Echo Request ---Provides a positive method of verifying the presence of a remote PPP peer or detecting a loopback line. Echo requests, generated on a periodic basis, serve to elicit keep-alive echo responses from the remote peer.
- PAP and CHAP Call Authentication ---Limits dial-in access to authorized remote systems only. PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol) are authentication protocols that protect against unauthorized access. This option is an integral part of the NetWare Link/PPP on-demand routing implementation, providing identification of each remote system.
- Asynchronous Control Character Map (ACCM) ---Allows user-configured hardware control character mapping on behalf of a variety of manufacturers' modems.
- Address and Control Field Compression ---Provides a 2-byte per packet performance optimization by eliminating the fixed HDLC address and control fields from each PPP header.
- Protocol Field Compression ---Provides a 1-byte per packet performance optimization by eliminating one of the two PPP protocol ID bytes.
- Data Compression ---Provides a major performance optimization by encoding Network-layer payload data into more compact character sequences based on recurring patterns.
- Compression Control Protocol (CCP) ---Supports CCP for the negotiation and selection of a common data compression protocol between systems.
In addition, Novell Internet Access Server 4.1 maintains backward compatibility with NetWare MultiProtocol RouterTM 3.1 software, NetWare MultiProtocol Router 3.0, and NetWare MultiProtocol Router 2.11 PPP data compression.
- Bandwidth Allocation Control Protocol and Multilink Protocol ---Greatly increase your total available bandwidth. Bandwidth Allocation Control Protocol and Multilink Protocol enable you to use multiple physical ports on one or more WAN boards to represent a single logical link to one location. When the bandwidth threshold of one port is reached, the bandwidth of the next port becomes available. More ports are added to the connection if bandwidth requirements continue to increase beyond the threshold of the ports currently in use.
