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Novell Internet Access Server 4.1 routing software provides not only the optimization tools available for all WAN connection types but also the following tools that can help you further optimize permanent connections:
Route and service information filters enable you to more effectively manage the LAN and WAN bandwidth used for routing and service overhead. Filters enable you to connect NetWare services over the WAN and support large NetWare networks. In addition, filters enhance network security by blocking unauthorized access to network segments or individual servers.
IMPORTANT: For IPX networks, the NetWare operating system requires an IPX network number in the routing table before it stores a corresponding service on that network in the bindery. You must carefully plan your implementation of RIP filters to ensure that you do not accidentally filter out services that are needed on your network.
On IPX networks, RIP filters are most useful in providing network security. Because SAP traffic is significantly higher than RIP traffic, filtering SAP traffic can produce much greater bandwidth improvement than filtering RIP traffic.
On IP networks, filters can reduce traffic. However, because of the default route, route filtering might be ineffective for providing security.
Similarly, on AppleTalk networks, router information filters can provide network security and traffic reduction, whereas device-hiding information filters are most useful for reducing traffic.
The Novell Internet Access Server 4.1 routing software offers inbound route and service filtering on any interface and supports outbound route and service filtering across any interface. These filters can be applied on a global or per-interface basis.
NOTE: By default, the time synchronization component of Novell Directory ServicesTM (NDSTM) software uses SAP to advertise the presence of time servers. Custom configuration turns off this SAP process and replaces it with a time configuration file on each server. Along with turning off the time-related SAP, this also avoids any disruption of time synchronization due to the incorrect configuration of new servers.
For further information about optimizing time synchronization, refer to Time Synchronization in NetWare 4.x in the November 1993 NetWare Application Notes. For more information about using IPX filters, refer to Effectively Managing RIP and SAP Traffic with Filtering in the September 1994 NetWare Application Notes.
Outbound filters are typically used for traffic management. Because route and service information is filtered in the updates produced by the router, different views of the network can be advertised from different interfaces. This capability enables you to give each remote site access only to the resources necessary for communications to that site.
For information about configuring filters, refer to Setting Up in the Filters documentation.
Routing protocols typically use one of two types of routing:
A traditional distance vector router maintains only enough information to tell it how to reach the next router (hop) on the network. Distance vector routers periodically forward this information to each other, even if it has not changed since the last broadcast. Such periodic updates create unnecessary traffic on the network and consume router CPU time.
A link state router builds and maintains a logical map of the entire internetwork. Instead of sending periodic broadcasts of routing tables, link state routers multicast their link information only when a change occurs in a route or service somewhere in the internetwork.
Link state routing offers several advantages over traditional distance vector routing, the most important advantage being network optimization from reduced network traffic.
Novell Internet Access Server routing software provides link state routing for IPX (NLSP) and TCP/IP (OSPF).
NLSP is an IPX routing protocol that reduces service and routing overhead on WANs. (For an in-depth description of NLSP, refer to NLSP Migration.) NLSP provides several advantages over RIP and SAP:
NLSP uses variable-length service advertisements (eliminating the need to pad overhead to 48 bytes) and allows more than seven services per advertisement in a single packet.
If no changes occur, NLSP sends an update every two hours. (In contrast, RIP and SAP update network routes and services every minute.)
With a larger metric, you can build a larger internetwork.
NLSP routers and servers maintain a complete map of the network built from information in the link state database. Unlike RIP's map, which stores information only about the next hop to the destination, NLSP's map includes the complete end-to-end path for a packet. Because each packet has an origination and sequence number, it can quickly notify the entire network of a change in network topology and service offerings. This capability enables NLSP networks to converge much more quickly than RIP networks.
For information about configuring NLSP, refer to Configuring NLSP in the IPX documentation and NLSP Migration.
Novell Internet Access Server 4.1 routing software provides OSPF as an alternative TCP/IP routing protocol to RIP. OSPF provides several advantages over RIP:
This is partly because OSPF does not have the count-to-infinity problem that RIP does and partly because OSPF link state information is flooded instantaneously rather than processed on each hop, as is done with RIP. Faster convergence prevents loss of connectivity and temporary routing loops.
Unlike RIP, which requires periodic updates, OSPF routers update their link state information only when the link state changes. Consequently, more bandwidth is available to the data traffic.
For information about configuring your TCP/IP router to use OSPF, see to Configuring OSPF in the TCP/IP documentation.
Novell Internet Access Server 4.1 routing software provides AURP (tunneling AppleTalk packets over IP) as an alternative to Routing Table Maintenance Protocol (RTMP), the routing protocol usually used by AppleTalk. AURP reduces bandwidth utilization by sending updates to peer routers only when network routing information changes, instead of sending periodic broadcasts of the routing table.
On a stable network, AppleTalk routers using RTMP broadcast the same information to each other continuously. Because most networks are stable after initial setup, these frequent broadcasts unnecessarily consume bandwidth that could be used to transport more user data. This consumption is particularly noticeable on slow WAN links. When AURP is used instead of RTMP, AppleTalk routers exchange routing information only when a change occurs in the internetwork.
For information about configuring AURP, refer to Setting Up in the IP Tunnels for IPX and AppleTalk documentation.
IMPORTANT: AURP routing is available only over an IP tunnel. If you must use RTMP, you can optimize an AppleTalk WAN connection by increasing the Routing Update Timer. Load NIASCFG and follow this path:
Select Configure NIAS > Protocols and Routing > Bindings
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