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7
Networking and
Desktop Protocols
Terms you’ll need to understand:
✓ Internetwork Packet Exchange (IPX)
✓ Routing Information Protocol (RIP)
✓ NetWare Link State Protocol (NLSP)
✓ Enhanced Interior Gateway Routing Protocol (EIGRP)
✓ AppleTalk
✓ Routing Table Maintenance Protocol (RTMP)
✓ AppleTalk EIGRP
✓ DECnet
✓ OSI
✓ NetBIOS
✓ NetBEUI
✓ Windows Internet Naming Service (WINS)
✓ Dynamic Host Configuration Protocol (DHCP)
Techniques you’ll need to master:
✓ Describing how desktop protocols function
✓ Explaining the routing mechanisms for desktop protocols
✓ Managing and configuring desktop support on
Cisco routers
✓ Explaining how Windows clients browse a network
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Chapter 7
This chapter describes some of the more commonly used desktop protocols, with
an emphasis on topics covered in the CCIE Routing and Switching exam. The
following CCIE blueprint objectives, as defined by the Cisco Systems CCIE

Keep in mind that GNS requests are sent as broadcast frames, and excessive
broadcasts reduce bandwidth for end users. Later in this chapter, we’ll examine
how to manage GNS requests and SAPs.
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Networking and Desktop Protocols
NetWare Protocol Suite
At this point, let’s take a look at the NetWare protocol suite (shown in Figure 7.1)
and how Novell’s implementation of a proprietary protocol relates to the OSI
model. As you can see in Figure 7.1, the Novell protocol suite provides applica-
tion services through NetBIOS, the NetWare shell determines whether the ap-
plication requires network services. The routing protocol used by Novell by default
is IPX RIP Let’s discuss each layer and associated protocols of the IPX model.
Application Layer (NCP)
The higher layers of IPX (layers 5 through 7) provide end users with the ability to
view files on servers. NetWare Core Protocol (NCP) is used to send and receive
files, send print jobs, and provide security. These are just some of NCP’s major
functions that are performed by the Application layer of the IPX protocol suite.
The service access point application protocol rests on top of IPX and is used to
advertise IPX services, such as file servers and printers. SAPs are sent as broad-
casts, so if you have a lot of servers and printers, you can significantly increase
your broadcast traffic. SAP services are identified in the IPX packet. For ex-
ample, the file server SAP has a type code 4, and printers have a type code 7. A
complete list of all the SAP codes is available on Novell’s Web site (search for the
keyword SAP on www.novell.com).
Application
Presentation
Session
Transport
Network

An IPX address is made up of 80 bits. The first 32 bits identify the network, and
the next 48 bits are taken from the MAC address. Together, these create an IPX
address. Having all these SAPs and addresses is a benefit of IPX, however, the
next question is how does IPX route all this across the wide area network (WAN)?
To populate the IPX routing table so that routers can route IPX traffic across the
WAN, Cisco routers can use the following protocols:
➤ IPX RIP—IPX Routing Information Protocol
➤ IPX NLSP—IPX NetWare Link State Protocols
➤ IPX EIGRP—IPX Enhanced Interior Gateway Routing Protocol
NLSP is the latest implementation used to address the concerns of IPX RIP,
such as poor convergence times and hop count limits. IPX RIP supports a maxi-
mum hop count of only 15 hops, whereas IPX NLSP supports up to 127 hops.
Therefore, IPX NLSP is more scalable because the increased hop count allows
for a greater network diameter. NLSP is a link-state protocol, which means an
administrator can take advantage of all the qualities of link-state protocols as
opposed to distance-vector protocols. These qualities include faster convergence
after a network change and NLSP’s support for hierarchical network design, which
allows for networking devices to be grouped into areas and domains. There is no
need to use an Address Resolution Protocol (ARP), because the node address is
taken from the unique MAC address.
Note: The node portion of an IPX address (the last 48 bits) on a serial interface is
taken from a LAN interface, because serial interfaces do not have a MAC address.
This portion of the IPX address is taken from the first active Ethernet, Token Ring,
and then FDDI interfaces.
Data Link and Physical Layer
The Data Link and Physical layers are designed to provide physical connectivity
at an electrical level, that is the Physical layer, and they provide a reliable transit
of data across the Physical layer, that is the Data Link layer. IPX can run over
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sap Ethernet_802.2
arpa Ethernet_II
snap Ethernet_Snap
Token Ring sap Token-Ring
snap Token-Ring_Snap
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Chapter 7
IPX RIP Configuration Task List
Now, let’s examine the configuration of a simple IPX network using IPX RIP.
Later in this chapter, we’ll use the same network to demonstrate using NLSP
and EIGRP to route IPX.
As you can see in Figure 7.2, there are two routers—R1 and R2. Both routers
have a local IPX segment. In this section, you’ll apply the default encapsulation
on all segments to novell-ether (which means that no additional configuration is
required because novell-ether is the default). Listing 7.1 displays the configura-
tion required on both routers.
Listing 7.1 IPX configuration on routers R1 and R2.
hostname R1
ipx routing 0000.0c75.d97e
interface Ethernet0
ipx network 1
interface Serial0
ipx network BAD
....
hostname R2
ipx routing 0000.0c8e.774b
interface Ethernet0
ipx network 2
interface Serial0

As you can see in Listing 7.2, the IPX routing table is very similar to an IP
routing table. The table displays, which IPX networks, are reachable locally (C)
and remotely (R). The network highlighted in Listing 7.2 has been discovered
dynamically using the IPX RIP (indicated by the letter R) protocol. The delay
and hop count is described in square brackets [07/01], where 07 is the delay, 01 is
the hop count. The next hop address is indicated as BAD.0000.0c8e.774b via
Serial 0 (Se0). On R1 in Listing 7.2, you can see that the remote IPX network
number 2 is reachable via the serial 0 interface. Notice also that the network was
sourced by the IPX RIP protocol, because this network is designated with the R
on the left side.
Let’s look at some useful show commands that describe the state of IPX. Listing
7.3 displays the configuration parameters on an interface by using the show ipx
interface <interface number> command.
Listing 7.3 The show ipx interface command.
R1# show ipx interface Ethernet 0
Ethernet0 is up, line protocol is up
IPX address is 1.0000.0c75.d97e, NOVELL-ETHER [up]
Delay of this IPX network, in ticks is 1 throughput 0 link delay 0
IPXWAN processing not enabled on this interface.
IPX SAP update interval is 1 minute(s)
IPX type 20 propagation packet forwarding is disabled
Incoming access list is not set
Outgoing access list is not set
IPX helper access list is not set
SAP GNS processing enabled,delay 0ms,output filter list is not set
SAP Input filter list is not set
SAP Output filter list is not set
SAP Router filter list is not set
Input filter list is not set
Output filter list is not set

Listing 7.4 describes two services available, namely a server called server1 and a
printer named printer1. As you can see in the table, the services are reachable
through serial 0 with a hop count of 2.
Finally, here are a number of commands that you can use to troubleshoot IPX
RIP (including the commands mentioned earlier in this section):
➤ debug ipx routing—Displays information about IPX routing packets.
➤ debug ipx sap activity—Provides detailed output of SAP packets, including
displays of services in SAP packets.
➤ ipx maximum paths <number>—Defines the maximum allowed paths for load
balancing. The default is set to 1, which means there is no load balancing.
➤ show ipx interface—Describes the IPX interface configuration.
➤ show ipx route—Displays the IPX routing table.
➤ show ipx server—Displays the SAPs seen by the router.
➤ show ipx traffic—Displays IPX statistics.
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Networking and Desktop Protocols
NetWare Link State Protocol (NLSP)
Instead of using a distance-vector protocol to route IPX and have all the associ-
ated problems (such as convergence time and full routing updates), you can use
NLSP to carry network information so that remote networks can be visible to
each other by populating an IPX routing table. NLSP provides the ability to
propagate IPX networks without the need to send periodic updates. NLSP pro-
vides a number of advantages over IPX RIP, including:
➤ No periodic updates are sent. Updates are sent only when a change occurs.
The whole link-state database is exchanged at a predefined interval. The de-
fault is 2 hours on a Cisco router.
➤ NLSP uses a better metric than hops and ticks; instead, NLSP is based on
cost. The cost-based approach provides the administrator with the ability to
define preferred links by assigning differing costs.

ipx network BAD
ipx nlsp enable
! Enable NLSP with the following command. The area command defines
! which networks are in NLSP. A value of 0 indicates to place all
! networks in NLSP
ipx router nlsp
area-address 0 0
!
! IPX RIP is disabled with the following command.
no ipx router rip
.....
Listing 7.6 Enabling NLSP and disabling IPX RIP on router R2.
hostname R2
ipx routing 0000.0c8e.774b
ipx internal-network 20
interface Ethernet0
ipx network 2
ipx nlsp enable
!
interface Serial0
ipx network BAD
ipx nlsp enable
! Enable NLSP with the following command. The area command defines
! which networks are in NLSP. A value of 0 indicates to place all
! network in NLSP.
ipx router nlsp
area-address 0 0
!
! IPX RIP is disabled with the following command.
no ipx router rip

Listing 7.8 The show ipx nlsp neighbors command on R1.
R1#show ipx nlsp neighbors
NLSP Level-1 Neighbors: Tag Identifier = notag
System Id Interface State Holdtime Priority Circuit Id
R2 Se0 Up 44 0 01
The display in Listing 7.8 details which other NLSP routers are adjacent to R1.
In the case of R1, it is adjacent to router R2. From R1’s point-of-view once more,
the SAP table shown in Listing 7.9 tells you that NLSP discovered a server and
printer.
Listing 7.9 The show ipx route command on R1.
R1#sh ipx route
5 Total IPX routes. Up to 1 parallel paths and 16 hops allowed.
L 10 is the internal network
C 1 (NOVELL-ETHER), Et0
C BAD (HDLC), Se2
N 2 [45][05/01] via 20.0000.0000.0001, 65s, Se2
N 20 [45][06/01] via 20.0000.0000.0001, 65s, Se2
In Listing 7.9, the N designator on the left indicates NLSP advertised services.
In effect, these services will not be advertised again unless they are unavailable.
This saves bandwidth on the serial link between routers R1 and R2, thereby
saving bandwidth for end users to use to send data.
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Chapter 7
As with IPX RIP, NLSP has a number of commands that you can use to monitor
and troubleshoot NLSP, such as (including the commands mentioned earlier in
this section):
➤ show ipx nslp database—Displays the link-state database.
➤ show ipx nlsp neigbors—Displays NLSP speaking routers.
➤ show ipx nslp spf-log—Displays how many times the SPF algorithm has been

interface Ethernet0
ipx network 1
!
interface Serial0
ipx network BAD
! Enable IPX EIGRP in AS 1
ipx router eigrp 1
network 1
network BAD
! Disable IPX RIP
no ipx router rip
....
Listing 7.11 Enabling EIGRP and disabling IPX RIP on router R2.
hostname R2
ipx routing 0000.0c8e.774b
!
interface Ethernet0
ipx network 2
!
interface Serial0
ipx network BAD
ipx router eigrp 1
network 2
network BAD
no ipx router rip
....
The autonomous system number used here is set to 1. The autonomous system
number identifies a group of routers under the same administrator that will share
information with each other. Therefore, routers in the same autonomous system
number, 1 in this example, will share IPX routing information.

listed here (including the commands mentioned earlier in this section):
➤ show ipx eigrp interface—Displays which interfaces are running IPX EIGRP
and if there is a peer on that interface.
➤ show ipx eigrp neighbor—Displays neighbors.
➤ show ipx eigrp topology—Details specific information about how IPX net-
works have been acquired.
➤ show ipx route—Displays the contents of the IPX routing table.
➤ show ipx server—Lists the services available as announced via SAPs.
Now that we have defined the three available methods to route IPX using Cisco
IOS commands, it’s time for us to examine how you can use access lists to man-
age traffic sent by IPX devices.
In addition to using access lists, you can send IPX traffic over an IP
backbone using a tunnel interface. This can help reduce IPX WAN-
based traffic and provide more bandwidth for user data based traffic.
IPX and Access Lists
In the first portion of this chapter, we discussed how IPX is broadcast intensive.
We also discussed ways to use Cisco’s propriety routing protocol (IPX EIGRP)
to reduce broadcasts. Another way to conserve bandwidth is to use access lists.
Access lists can help you manage IPX traffic. The access list numbers that are
available for use with IPX are:
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Networking and Desktop Protocols
➤ Standard IPX filters—Ranges from decimal 800 through 899
➤ Extended IPX filters—Ranges from decimal 900 through 999
➤ SAP filters—1000 through 1099; SAP filters are also used to limit GNS re-
quests
Note: Cisco IOS allows you to modify other parameters that limit the way IPX sends
and receives updates. For example, you can change the default IPX SAP update
interval (ipx sap-interval <seconds>) and IPX RIP update interval (ipx update-

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Chapter 7
Listing 7.15 The show ip route command after filtering network 2 as show
in Listing 7.14.
R1#sh ipx route
4 Total IPX routes. Up to 1 parallel paths and 16 hops allowed.
C 1 (NOVELL-ETHER), Et0
C 3 (UNKNOWN), Lo0
C BAD (HDLC), Se0
R 4 [07/01] via BAD.0000.0c8e.774b, 39s, Se0
Token
Ring
Sends SAP
IPX
RIP
Sends SAP
Tok0
Router
Listens to SAPs
Sends and listens to
IPX Routing updates (IPX RIP)
Send
GNS queries
IPX RIP
SAP
E0
Serial0
Printer
Printer