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Configuration of MacIP required the following:

•  Packets between Macintosh clients and IP hosts had to pass through the router if the client was configured to use it as a MacIP server. This design could add overhead and an extra hop when the two nodes resided on the same subnet.
•  Router memory usage increased proportionally to the total number of active MacIP clients, consuming approximately 80 bytes per client.
•  In addition, the router had to be configured as follows:
•  AppleTalk routing had to be enabled on at least one interface.
•  At least one interface had to be configured for IP routing.
•  The MacIP zone name configured had to be associated with a configured or seeded zone name.
•  The MacIP server had to reside within the AppleTalk zone.
•  An IP address specified to the MacIP server using the appletalk macip command had to be associated with a specific IP interface on the router. The IP address had to be one to which ARP could respond.
•  Any access list for IP had to apply to MacIP sessions.

AppleTalk Interoperability

This chapter has already addressed a number of AppleTalk interoperability issues, including tunneling and the AppleTalk version of EIGRP. However, there are a few other items to keep in mind.

First, while AppleTalk generates a significant number of broadcasts in the network, the impact of other protocols on AppleTalk-only nodes is greatly reduced. Stated another way, IP and IPX broadcasts are discarded by AppleTalk-only devices at an earlier point than broadcasts in other protocols. In fact, AppleTalk-only stacks will discard all packets from all other Layer 3 protocols.

Second, the number of broadcasts in AppleTalk will significantly impact other devices on the network. Both IP and IPX stacks will process AppleTalk broadcasts like any other broadcast. Therefore, adding IP to Macintosh systems or running IPX- and IP-based PCs on segments with AppleTalk devices will greatly magnify the impact of broadcasts.

In most current networks, designers have removed, or are in the process of removing, AppleTalk. Where AppleTalk segments remain, the general guideline is to use less than 200 nodes to populate a segment.

Summary

The AppleTalk protocol is perhaps one of the most user-friendly networking protocols ever developed. Unfortunately, the scalability limitations of the protocol and the impact of the Internet (with its implied dependence on IP) have restricted its usage.

In this context, this chapter addressed the issues that confront network designers using AppleTalk in both large and small networks and also suggested methods by which the designer might address the limitations of the RTMP protocol. This might include the use of AppleTalk EIGRP, access lists, and specific naming and addressing conventions.

In addition, this chapter addressed some of the enhancements to the AppleTalk protocol, including AURP and the efficiency of using MacOS version 7. Also, filters specific to AppleTalk were reviewed.

Readers should be fairly comfortable with the features and benefits of AURP and AT EIGRP as they relate to the default RTMP as well. The operations of the Chooser in AppleTalk networks are also important concepts to understand.

Review Questions

1.  Which of the following are limitations of the AppleTalk protocol?
A.  No hierarchical addressing scheme
B.  No hierarchical naming scheme
C.  High dependence on broadcasts
D.  All of the above
2.  When using the AppleTalk version of EIGRP, what unique convention must be followed?
A.  The same AS number must be used on all routers in the domain.
B.  Different process numbers must be used on each router in the domain.
C.  RTMP must have the same AS number as AT EIGRP.
D.  There is no version of AppleTalk EIGRP.
3.  To connect two AppleTalk networks across an IP-only backbone, the designer must use which of the following?
A.  AppleTalk tunnels
B.  ZIP—Zone over IP
C.  AT CGMP
D.  AppleTalk cannot traverse IP-only segments.
4.  Which of the following would be a valid AppleTalk cable range?
A.  4–4
B.  Marketing_Zone
C.  10.12
D.  4–10
5.  Which of the following might be used to block zone information from reaching another AppleTalk administration domain?
A.  AppleTalk EIGRP
B.  AppleTalk RTMP
C.  AppleTalk ZIP reply filters
D.  AURP
6.  In order to reduce traffic on WAN links, designers should:
A.  Use AT EIGRP with route summarization enabled.
B.  Use AURP.
C.  Use RTMP.
D.  Use RTMP on the WAN and AURP on the LAN.
7.  How many updates may be included in an RTMP packet?
A.  25
B.  50
C.  100
D.  256
8.  In order to simplify troubleshooting AppleTalk networks, designers should:
A.  Design cable ranges that are numerically significant
B.  Use MacOS version 7 or greater
C.  Use RTMP
D.  Use AT EIGRP
9.  Network designers should work with the workstation administrators to:
A.  Configure WINS servers for AppleTalk segments
B.  Disable the Chooser Scanning Protocol (CSP)
C.  Use MacIP whenever possible
D.  Upgrade all workstations to a minimum of System 7
10.  True or false, AURP and AppleTalk GRE tunnels are the same.
A.  True
B.  False
11.  Before System 7, the Chooser requested zone information how frequently?
A.  Every 3 seconds
B.  Every 5 seconds
C.  Every 10 seconds
D.  Every 60 seconds
12.  Two devices are addressed as 4.5 and 7.9, respectively. Are they in the same network if the cable range is 1–9?
A.  Yes
B.  No
13.  Which routing protocol sends updates only?
A.  ZIP
B.  RTMP
C.  AURP
D.  None of the above
14.  Which of the following is true regarding MacIP?
A.  It is a compliant IP stack for interoperating with non-Macintosh systems.
B.  It provides TN3270 emulation.
C.  It is faster than TCP/IP for file transfers.
D.  It is similar to a proxy service.
15.  Which of the following is a reason to use tunnels for AppleTalk?
A.  Additional overhead and processing
B.  Transport of AppleTalk over IP-only networks
C.  Additional security
D.  Compatibility with CDP
16.  Node number 231 is on cable range 50–59. Which of the following is a possible AppleTalk address?
A.  50.59
B.  231.51
C.  50–59
D.  56.231
17.  Cisco recommends that nodes follow which naming convention?
A.  User name, last name first
B.  User name, first name first
C.  Same as AppleTalk address
D.  Named for famous people
18.  AppleTalk network numbers should:
A.  Be assigned sequentially
B.  Always start with a one
C.  Relate to a location, possibly using a site, building, and floor office model
D.  Be the same for all WAN segments
19.  Which of the following is not true regarding MacIP?
A.  It requires at least one IP network.
B.  It requires at least one AppleTalk network.
C.  The MacIP server must be in the AppleTalk network.
D.  It operates only with AppleTalk Remote Access (ARA).
20.  AppleTalk tunnels are best configured in:
A.  Star configurations
B.  Ring configurations
C.  Hierarchical configurations
D.  None of the above. Tunnels are available only on point-to-point serial links.

Answers to Review Questions

1.  D.
2.  B.
3.  A.
4.  A, D.
5.  C.
6.  B.
7.  C.
8.  A.
9.  D.
10.  B.
11.  A.
12.  A.
13.  C.
14.  D.
15.  B.
Some designers may note that tunnels can be encrypted, thus augmenting security. However, enhanced security is not a primary reason to use tunnels for AppleTalk in this context.
16.  D.
17.  A.
18.  C.
19.  D.
20.  A.


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