Semester 3, Chapter 7 Allan Johnson Novell IPX Semester 3, Chapter 7 Allan Johnson

Novell IPX Overview Novell IPX is a proprietary suite of protocols that includes the following: A connectionless layer 3 protocol that does not require an acknowledgement for each packet. A layer 3 hierarchical addressing scheme with an 80 bit (10 byte) number that specifies the network and node. Why is it important to your CCNA? Novell’s NOS, called NetWare, is the most popular client/server application for connecting PCs to the network. It is implemented in more than 5 million networks connecting more than 50 million clients.

The Novell IPX Protocol Suite Novell Protocols and their corresponding OSI layer. Application SAP NCP NetWare Shell Presentation Session Transport SPX Network IPX Novell RIP

The Novell IPX Protocol Suite Protocols discussed in detail are in Red. Application SAP NCP NetWare Shell Presentation Session Transport SPX Network IPX Novell RIP

Protocol Descriptions SAP Service Advertising Protocol advertises network services in an SAP packet (includes GNS) IPX Internet Packet Exchange provides layer 3 connectionless addressing (network + node) Novell RIP facilitates the exchange of routing information and chooses the best path based on hops and ticks. NCP NetWare Core Protocol provides client-to-server connections and applications (like GroupWise) SPX Sequenced Packet Exchange (like TCP) provides layer 4 connection-oriented services

IPX Addressing The IPX address contains two parts: The network number assigned by the network administrator and... the node number which is usually the MAC address of the device (no subnets!). The network address is 32 bits (like an IP) that is expressed in hexadecimal format. Notice in the graphic only 16 bits are shown. The leading bits are zeros. The full network address is 00004A1d.

A Brief Encapsulation History The evolution of IEEE specs for Ethernet was too slow for Novell. So Novell came out with NetWare versions based on what they thought IEEE’s Ethernet frame would look like. When IEEE came out with the final 802.3 frame format, it included the Logical Link Control sublayer of the Data-Link Layer. This made Novell’s NetWare versions incompatible. So Novell came out with newer versions.

A Brief Encapsulation History Needless to say, all this confusion causes headaches for the network administrator trying to set the correct encapsulation on an Ethernet interface. To make things more complicated, Cisco has its own names for the various Novell and IEEE Ethernet formats. On the next slide, these frame formats and their corresponding names are listed. Memorize them! You’ll be asked to show you know these encapsulations on the CCNA exam.

Multiple Novell Encapsulations Novell Name Novell Version Cisco Name Ethernet_802.3 3.11 or earlier novell-ether Ethernet_802.2 3.12 or later sap Ethernet_II compatible with TCP/IP arpa Ethernet_SNAP compatible with TCP/IP and AppleTalk snap When configuring a router’s Ethernet interface, you need to enter the “Cisco name” above for the correct encapsulation type.

Novell RIP Novell RIP is a distance-vector routing protocol that uses two metrics: hop count and ticks (1/18th of a second), which is different than the tick of a processor. A CPU’s tick is one clock cycle. A 100MHz clock has 100million ticks per second. techweb Novell RIP will choose the path with the best tick metric (lower is better). Defaults: 1 for LANs; 6 for WANs If more than one path has the same tick count, then Novell RIP will choose the one with the least hops. If hop count is also equal, Novell RIP implements load sharing if it has been configured.

Load Sharing To configure a Cisco router to load share across equal paths, you must use the ipx maximum-paths paths command. paths can be a value from 1 to 512. The default is 1. That’s why you must configure the router to load share. IPX load shares on a packet-by-packet basis in round-robin fashion. The first packet is sent along the first path, the second packet along the second path, and so on. When the final path is reached, the next packet is sent to the first path, the next to the second path, and so on.

Service Advertising Protocol SAP is used by network devices, such as servers and printers, to advertise their service to clients and build SAP tables. SAP updates are sent every 60 seconds Routers attached to Novell segments listen to all SAPs and also build SAP tables. If a client requests service (GNS) and a server does not exist on the same segment, then the router will respond with a server address from its SAP table. The client can then send packets directly to the server.

Get Nearest Server GNS packets are broadcasted as a client is attempting to login. The GNS locates the nearest server. If there is a NetWare server on the same LAN as the client, it will respond to the GNS request. Otherwise, the router will respond.

Configuration Overview Global Configuration Tasks: Enable Novell RIP with the ipx routing [node] command. If no node is specified, the router uses the MAC of the interface. Node must be specified if there are only serial interfaces. Define the number of paths to load share using the ipx maximum-paths paths command if multiple paths exist to a destination. Interface Configuration Tasks: Define the network using the ipx network network command. Define the Novell encapsulation used on Ethernet interfaces with the ipx encapsulation cisco-name command.

Things to Remember You can configure multiple networks on the same interface. In order to do so, you must... Use subinterfaces (e.g. e0.1, e0.2, e0.3, etc.) Use different network numbers on each subinterface. If you have multiple paths to the same destination, be sure to use the ipx maximum-paths command to provide load sharing. Take advantage of the e-Lab activities for this chapter--especially 7.4.2 and 7.4.3. You can follow this link to Del Mar’s site.

Monitoring & Managing IPX Networks Do the e-Labs to practice these commands!! Command Displays Monitoring Commands show ipx interface IPX status and parameters show ipx route Routing table show ipx servers IPX server list show ipx traffic Number & type of packets Troubleshooting Commands debug ipx routing activity Info about RIP updates debug ipx sap Info about SAP upsdates ping testing connectivity