Installing and Administering OSI Transport Services

72 Chapter 2

Planning Your Network

Determine the Vendors Involved

Another factor in determining the ultimate layout of your network is the

equipment various vendors use to communicate.

Not all vendors provide every OSI service. A given vendor may only

provide some subset of functionality for a given layer. For example, HP

does not currently provide the Virtual Terminal service. Another vendor

may not provide X.500. Or another vendor may provide a Network

Management Agent, but have no facilities to manage the resources local

to that node.

When planning your network, you need to take such factors into

consideration. Listed below is a checklist of items you should investigate

to help ensure your success.

• Does the vendor provide this service?

If you wish to communicate with a piece of equipment, it must

support the service. Access to mid-stack layers (Session, Transport)

cannot be assumed just because a vendor provides a seven layer

stack.

• Does this service coexist with other facilities I want to use on this

node?

Determine what effects installing this product has on the other

operations of your system. Especially check on its coexistence with

other non-OSI networking services you may be using.

• What version of this service is provided?

Some standards are evolving. For example, Session provides both

Version 1 and Version 2. Verify that the version supported is

acceptable to all nodes of communication you intend to use.

• What functional units of this service are provided?

Many OSI implementations are a subset of the full service. You

should understand what facilities you require from this service and

ensure that each vendor supports those.

• What lower layer protocols does this product use? What versions are

these? Can I use it over the link I want?