This section describes the various functions and features of the Novell® implementation of source route bridging included in the Novell Internet Access Server 4.1 routing software. Many of the functions and features of the source route bridge software are described in terms of how the software can be configured to provide the most commonly required applications.
Novell source route bridge software enables you to link token ring networks and create an extended network. This functionality is compatible with the source route bridging mechanism used by IBM* to handle the flow of data between token ring networks. Source route bridging allows supporting end stations to discover routes dynamically and determine which one to use when sending data to any particular destination.
Novell Internet Access Server 4.1 supports concurrent routing and bridging of all major protocols. Novell Internet Access Server 4.1 can be configured to route or bridge the Internetwork Packet ExchangeTM (IPXTM) protocol, TCP/IP protocol, and AppleTalk protocol, and to bridge unroutable protocols such as IBM's NetBIOS and SNA. Because you cannot bridge and route the same protocol on the same interface, Novell Internet Access Server 4.1 also provides a mechanism for automatically disabling bridging for a given protocol, when routing of that protocol is enabled.
Novell Internet Access Server 4.1 can also bridge over point-to-point (PPP), X.25, and frame relay wide area telecommunications links. Multiple PPP links, X.25 virtual circuits, and frame relay virtual circuits can be used to connect multiple remote sites or to create backup links between two locations, providing fault tolerance if one link fails.
The use of source route bridging prevents packets sent between end stations on the same ring from passing on to other connected rings. Preventing extraneous traffic across networks increases the available bandwidth on all networks. Performance can be further enhanced by limiting traffic through the use of custom filters that permit packets from certain stations to pass while blocking packets from other stations. The filter can also increase network security by not allowing users on one ring to access another ring that contains sensitive information.
As token ring networks have grown, they have become increasingly difficult to manage. The standards-based SNMP management protocol allows organizations to install equipment from multiple vendors and manage the entire network from one centralized monitoring console. Novell Internet Access Server 4.1 supports IBM LAN Network Manager and the SNMP MIB variables, as defined in RFC 1286, Bridging MIB. These MIB variables can be managed using the Novell ManageWise® product or any other SNMP-based management console.