Transcript Semester 3 Chapter 7 - Institute of Technology Sligo

Institute of Technology,
Sligo Dept of Computing
Novell IPX
Semester 3, Chapter 7
Novell IPX Overview
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Novell IPX is a proprietary suite of protocols that
includes the following:
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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?
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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
Presentation
SAP
NCP
NetWare
Shell
Session
Transport
Network
SPX
IPX
Novell RIP
Protocol Descriptions
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SAP
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IPX
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facilitates the exchange of routing information and
chooses the best path based on hops and ticks.
NCP
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Internet Packet Exchange provides layer 3
connectionless addressing (network + node)
Novell RIP
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Service Advertising Protocol advertises network
services in an SAP packet (includes GNS)
NetWare Core Protocol provides client-to-server
connections and applications (like GroupWise)
SPX
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Sequenced Packet Exchange (like TCP) provides
layer 4 connection-oriented services
IPX Addressing
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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.
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A Brief Encapsulation History
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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
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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.
3.11 or earlier
novell-ether
3
Ethernet_802.
3.12 or later
sap
2
compatible with
Ethernet_II
arpa
TCP/IP
Ethernet_SNA compatible with
snap you
When configuring a router’s Ethernet interface,
P
TCP/IP and AppleTalk
need to enter the “Cisco name” above for the correct
encapsulation type.
Novell RIP
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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
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To configure a Cisco router to load share across
equal paths, you must use the ipx maximumpaths 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.
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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
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SAP is used by network devices, such as
servers and printers, to advertise their service to
clients and build SAP tables.
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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
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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
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Global Configuration Tasks:
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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:
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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
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You can configure multiple networks on the
same interface. In order to do so, you must...
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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 maximumpaths 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
Info about RIP updates
activity
debug ipx sap
ping
Info about SAP upsdates
testing connectivity