This Product Bulletin (PB) provides a quick overview of NetWare Link Services Protocol (NLSP) which is supported in IOS 10.3. Specifically, it will outline the concepts of NLSP, explain the scope of the protocol, and direct readers to available support resources within Cisco.
NLSP is Novell's link-state routing protocol for IPX which has been developed to address the limitations of the IPX Routing Information Protocol and Service Advertisement Protocol (RIP/SAP). Because of their broadcast-oriented architecture, RIP and SAP demand large amounts of bandwidth and do not scale well. NLSP is a cousin of OSPF, but is derived from, and most closely related to, the OSI IS-IS routing protocol. NLSP was designed and specified by Novell.
NLSP was introduced first as a NetWare Loadable Module (NLM) for NetWare file servers for LAN support. And then, more recently, NLSP was introduced in the Novell MPR 3.0 internetworking product for WAN support. Although NLSP is designed as a scalable, hierarchical routing protocol, it is currently specified for only a single "area."
As a link-state routing protocol, NLSP fundamentally changes the way routing information is handled in an IPX network. Each router in an NLSP area keeps a complete topological map of the entire area network in its memory. As changes in topology, such as link failures, are noticed, routers send multicast packets to the other routers on the network advising them of the change. Routers receiving these update packets execute the "Dijkstra algorithm" and recalculate their complete area's topology. Because routing updates typically only occur upon changes to the network, (as opposed to the constant repetitive broadcasts used by distance-vector routing protocols such as RIP), more efficient use of bandwidth is achieved.
Novell designed NLSP to be used in a hierarchical network where different routing areas are created and linked together to form domains. Domains are in turn linked to create global internetworks. NLSP, as specified today, provides support only for single area, or Level 1, routing. Specifications for Level 2 and Level 3 routing have been promised for the future; however, today NLSP areas must be linked together using existing routing protocols such as IPX RIP or EIGRP.
RIP/SAP continues to be supported, not only to connect NLSP areas, but also because some older devices only support these protocols.
Novell has been vocal in its support for NLSP. You can expect to see a significant effort to migrate large customers to NLSP-based networks. The benefits of reduced LAN and WAN broadcast traffic, scalability, fault tolerance and standards compliance will be the reasons most often cited for a migration to NLSP. NLSP is a significant step for Novell in the effort to increase the functionality and acceptance of IPX as a viable internetworking protocol for the future.
Today's IPX networks often have network numbering schemes that could best be described as chaotic. Because NLSP provides the greatest benefit to users of hierarchical addressing, a migration to NLSP will sometimes provoke a renumbering of the IPX network. This is a serious undertaking for a user community and the planning may require the support of Cisco Systems Engineers or Consulting Engineers.
When designing NLSP based internetworks, Novell recommends that routing areas contain no more than 400 network numbers. Internetworks of greater size should be partitioned into multiple areas. They also recommend that address ranges be assigned hierarchically and be aligned with geographic locations.
Cisco has developed an implementation of NLSP internally. Cisco is the vendor most experienced with link-state protocols in large networks. Our implementation leverages over three years of operational experience with such link-state protocols as OSPF, IS-IS and Integrated IS-IS. Also, Cisco is committed to supporting future NLSP specifications including Level 2 and 3 routing as the specifications evolve.
Interoperability with Novell's NLSP products was assured through rigorous testing with Novell throughout the development cycle. Other major internetworking vendors have announced their intention to support NLSP, and as these vendors deliver their products Cisco will, of course, work to assure interoperability.
With the addition of NLSP support, Cisco continues to provide the widest range of options available for Novell routing. EIGRP for IPX provides a multiprotocol, easy-to-design, less-CPU-intensive alternative to RIP/SAP and NLSP. Reliable SAP Update Protocol (RSUP) with IPX RIP continues to provide value to our customers by reducing WAN overhead. And now, support for NLSP guarantees Novell internetworking interoperability in the future.
Additional information on NLSP is available online. The complete NLSP
specification is available from Novell at ftp.novell.com:
Anonymous FTP to ftp.novell.com
The file nlsp.exe is a self extracting copy of the NLSP specification in PostScript format.
Additionally, a helpful White Paper from Novell entitled "NetWare Link Services Protocol, A detailed description of link-state routing in a NetWare Environment" is available from Novell. The document number is 481-000085-001.
If you require additional expertise in designing or migrating your NLSP network, Cisco has extremely well-qualified Consulting Engineers that can help. If you find yourself needing the extra assistance, please contact your local Cisco sales representative for details.