Configuring Cisco Routers for ISDN Paul Fischer  $55.00  0-07-022073-5

The OSI reference model for networking is a ten-layer model and the TCP/IP protocol model has eight layers. Most of you know about the standard seven layers in the OSI model listed in Table 1-1.

Table 1-1. Caption: The seven layer OSI networking model.

Table 1-2 lists the standard 5 layers in the TCP/IP protocol model.

Table 2-1. Caption: The five-layer TCP/IP model.

Users are mostly concerned with the applications layer, which governs what they see and how they do their work. Network administrators are typically concerned with the transport, network, data link, and physical layers. These network layers need management on a daily basis and provide the infrastructure the users rely on. Apparently, no one is concerned with layers 5 and 6. Perhaps that is why TCP/IP is the dominant protocol on networks everywhere, as it has already dispensed with two whole layers no one cared about.

But where do the missing three layers come in? Anyone who has been involved in making decisions about networks knows them intimately. These are the three layers that come into play around the conference table when management, accounting, and technical people try to decide upon the products which will be used to build their network. The hidden three layers are most appropriately known as the technical layer, the administration (or, more informally, the "boss") layer, and the accounting (or "bean counter") layer.

There are many practical reasons to buy Cisco products that meet all three hidden layers of the networking models. Technical people know Cisco products are solid and feature-rich. They also know that Cisco support and software distributions are excellent. Management can look at the long prestigious list of Cisco customers and facts like 85% of the Internet backbone (the part of the Internet that links ISP’s to each other over extremely high speed lines) uses high-end Cisco routers. Accounting also likes the price. While less flexible on pricing than some of their competitors, Cisco still prices their products reasonably.

Cisco technical support is legendary in the networking industry. They do true 24x7 support, with support centers in enough time zones to be able to pass problems from engineer to engineer. Their internal trouble call tracking system allows incoming engineers to track problems as the outgoing engineers go off duty. This allows customers to have continuity in support while they work on a single problem. The customer might not have the manpower to have someone else take up the task when they leave, but Cisco can keep rotating engineers through the problem so the customer always has fresh technical help. In a real crisis, it is not unheard of for Cisco support engineers to build custom versions of IOS for the customer, thereby getting bug fixes in the hands of users immediately. Cisco tracks these changes to make sure they get back to the mainstream IOS code.

But Cisco support goes way beyond even this. There are multitudes of resources available on Cisco’s WWW (World Wide Web) site at http://www.cisco.com. This includes IOS and other software updates, management information bases (MIB) for use with SNMP (simple network management protocol) based tools like HP OpenView and Cisco Works, troubleshooting engines, and documentation. Users with support contracts can log-in to the web site and gain access to pricing, more technical information, and the ability to open support calls without being forced to wait on hold until a support engineer is available.

Cisco also offers a tantalizing advantage in their training and education opportunities. Aside from the normal array of basic and advances classes, they also offer certifications. Unlike some other certifications like MCSE (Microsoft Certified Systems Engineer) and CNE (Certified NetWare Engineer), which have tended to become almost ubiquitous in the employment market, the CIE (Cisco Internetworking Expert) is the cream of the crop. CIEs command salaries starting above $100,000 per year. It is not a simple course, and less than 7% of those who make it to the final exam pass. Those who do, however, can practically write their own ticket in the job market.

Cisco management tends to focus on what the rest of the companies their size are doing. They also focus on what larger companies are doing, especially companies that are currently where Cisco would like to go in the future. With clear market leadership, Cisco is a manager’s dream choice for a network equipment vendor. Companies of all shapes and sizes use Cisco networking equipment. They hold large parts of the market in telecommunications providers, ISP’s, large corporate backbones, and wide area networks. Cisco’s products scale to support the smallest networking needs (such as simply connecting two sites together) up to huge routers and switches for Enterprise wide networking. They provide products in a multitude of technologies, including ISDN, ASDL, Frame Relay, Ethernet, Fast Ethernet, ATM, and FDDI. Speed for these connections scale from 9600 bits per second and below to one gigabit per second and above. With such a huge range of products and technologies, it is easy to see why corporate management loves Cisco.

Accountants also like Cisco. While their products tend to cost slightly more than the competition, only the shortsighted look at the initial cost of hardware the sole gauge of the total cost of ownership. Studies have shown for years that administrative and support costs in later years can significantly affect the cost of networking equipment. Some of the things that make Cisco cheaper to operate in the 'out' years are low maintenance costs, access to a large pool of trained professionals and training. That even accidental administrators can run small Cisco networks part time with little or no training also helps keep 'out' year costs to a minimum.

Seldom can all three of the "hidden network layers" agree on a single vendor. Many times, votes are cast and recast until a single solution bubbles to the top. Cisco products are always a good compromise if all parties cannot agree outright that Cisco be their one and only network equipment provider.

Not into Star Trek? Well, the Borg are a half-biological, half-technological race that gobbles up other species to improve themselves. (Trust me, the analogy works).

Cisco Systems Inc., is the Borg of the networking world. Unlike some companies who might try to develop every new technology that comes along, Cisco assimilates smaller companies that have already developed the technology they want. They do this by purchasing large stakes in these companies or simply buying them outright. This strategy has helped them advance their product line and stock price at a fantastic rate year after year (see Figure 1-2 for a graph of Cisco's stock price). Figure 1-1 shows a timeline of Cisco acquisitions and buy-ins. Although you may not have heard of some of these companies, their products have become some of the products you know and love today.

Figure 1-2. Caption: As you can see from this graph, a dollar invested in Cisco Systems Inc. (CSCO on the NASDAQ stock exchange) in March of 1990 would have been worth $65.00 in March of 1998. By comparison, a dollar invested in the Dow Jones Industrial Average would only be worth $5.00.

Other companies have sometimes handled a strategy of acquisition badly, resulting in poor products, a large loss of technical knowledge through attrition, or poor support for old and new products resulting from apathy. If the Combinet acquisition is any measure of Cisco commitment to companies they assimilate, then clearly they do not suffer from this particular failing.

When Cisco wanted to enter the rapidly growing ISDN SOHO (Small Office/Home Office) and RO (Remote Office) market, they purchased Combinet. Combinet’s main product was a small router with single ISDN and single Ethernet ports. It was slow to boot, cumbersome to work with, hard to upgrade, and did not support the Novell IPX/SPX networking protocol. However, it was stable, and once configured, it ran for a long time without problems. Cisco initially repackaged the Combinet products as the Cisco 750 series of ISDN routers. They added support for the Novell protocol, added more IOS like commands, and also added more command line help.

Shortly after releasing the Cisco 750 router series, Cisco introduced the 760 series. These routers had a markedly different appearance. Their edges were smoother and rounder. They stacked well on top of each other, while still providing the necessary airflow to keep them from overheating, and they looked far more modern. Technically speaking, this was far more than a repackaging of Combinet’s products. The Cisco 760 series boots in less than one quarter the time that it takes a 750. It also synchronized with the phone company (telco) lines faster, making the leap from power-on to connection in record time. Further, the 760 series marked the first time Cisco ISDN routers had POTS (Plain Old Telephone Service) ports on the back, making them more that just a router. Now a small or home office could be supplied completely and flexibly with voice, fax, and data connections at a fraction of the previous cost. To top it all off, the initial cost on the 760 routers was cheaper than the 750’s.

Cisco has continually advanced their product line with the technical capabilities assimilated from Combinet ever since the acquisition. They have recently released the 770 series of routers, which replace the single Ethernet port in the 760 series with a four port Ethernet hub. Cisco has likely used technology acquired from Combinet to introduce and expand the ISDN capabilities on the 1000, 1600, 2500, and 3600 router series. New features continue to make the products more useful to the SOHO and RO network user. These have included staggeringly useful capabilities like DHCP (Dynamic Host Configuration Protocol) and NAT (Network Address Translation).

The DHCP protocol allows the router to configure automatically client workstation network parameters. NAT allows a SOHO or RO network to hide behind a single network address issued by an ISP. NAT saves you money on your Internet connection (making many users look like one to the Internet), and acts as a virtually unbreakable security firewall, since no one can make a connection into your private network behind the router.

Although it is only one example in a long history, the Combinet acquisition illustrates the synergy attainable if 'assimilation' is handled properly. By strengthening their product line through acquisition without suffering any of the downsides, Cisco has become an excellent case study for both managerial and technical techniques. Many large companies have earned bad reputations for improper handling of mergers and acquisitions, but so far, Cisco is not one of them.

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