HP OpenVMS Systems Documentation
DECnet-Plus for DIGITAL UNIX supports ported user-written DECnet-ULTRIX Phase IV applications. However, these programs cannot take advantage of certain new features, such as location-independent services (network objects).
DECnet-Plus network management implements a new architectural model, has a new structure, and provides the new NCL command interface. Once you install DECnet-Plus software on a node, you must use DECnet-Plus network management to manage that node. You should consider the following network management issues before you start your transition:
To manage the local DECnet-Plus node and remote DECnet-Plus nodes, use NCL. To manage remote Phase IV nodes, use the Network Control Program (NCP). Refer to DECnet-Plus Network Control Language Reference for information about how to issue NCL and NCP commands on a DECnet-Plus node.
You cannot manage a DECnet-Plus system remotely from a Phase IV node.
DECnet-Plus network management is based on the draft ISO Common
Management Information Protocol (CMIP) standard for
network management operations. DECnet-Plus, using DNA CMIP, provides
local and remote management support with the CMIP requester and
126.96.36.199 Phase IV Protocols in User Applications (OpenVMS Only)
DECnet Phase IV user applications that call in NML or NICE must be
modified to use CML and CMIP in order to run on Phase V systems. Refer
to DECnet-Plus for OpenVMS Introduction and User's Guide for more information.
1.8.3 Managing Multivendor OSI-Compliant Systems
DECnet-Plus systems do not support remote management of other vendors'
OSI-compliant systems because DNA CMIP is not compliant with OSI CMIP.
1.9 Noncompatibility with Pre-Phase IV Systems
DECnet-Plus does not interoperate with Phase III or Phase II implementations of DECnet. However, you can configure Phase III systems, such as a DECnet-RT system and a DECnet-RSX-11M-PLUS system, as end nodes in a Phase IV area if the Phase III system is adjacent to a Phase IV router (not a DECnet Phase V router running routing vector).
If your network has nodes running Phase III software, your migration plan must take this into account. You have the following options:
The following products and functions will not migrate to DECnet-Plus:
For additional product support information for DECnet-Plus, consult the DECnet-Plus for OpenVMS Release Notes, as well as DECnet-Plus for OpenVMS Installation and Basic Configuration and DECnet-Plus for DIGITAL UNIX Installation and Configuration.
You have the following transition options:
You need to decide what to do with these systems and functions during migration and what place, if any, they will eventually have in the configuration of your DECnet Phase V network. You may decide to replace them, either immediately or in the future, with DECnet-Plus products.
This chapter helps you plan for an orderly, efficient transition from a Phase IV network to a DECnet Phase V network.
Whatever the size or complexity of the network, a successful transition requires planning. Planning helps to ensure continued communication throughout the network during migration, with a minimum of disruption to users.
Use the checklist of transition-planning steps in Table 2-1 to draw up your network's transition plan and, later, to coordinate and execute the transition. Before using this checklist, note that:
|Step 1: Document the current network configuration:|
|||Identify the name, address, operating system, and DECnet version of each node.|
|||Identify the nodes that are routers, network management stations, load hosts, and name servers.|
|||Identify any existing DNS Version 1 servers and DECdns Version 2 servers.|
|||Identify the hardware and software that cannot move to DECnet-Plus.|
|||Identify the router types and locations.|
|||Identify the network topology: show all end nodes, level 1 routers, and level 2 routers.|
|||Identify any multivendor routers.|
|||Identify the Phase IV applications that use the NICE Protocol.|
|||Identify any applications that depend on a particular operating system version.|
|Step 2: Determine your transition strategy:|
|||Decide which DECnet Phase V features the network needs: OSI interoperability and/or OSI addressing.|
|||Determine if the network needs DECnet Phase IV areas.|
|||Decide which DECnet-Plus software components provide each feature you need, and which optional components to install.|
|Step 3: Develop a new network configuration:|
|||Consider the new network configurations available with DECnet-Plus.|
|||Decide if you can use the default IDP, or if you need a unique one.|
|||Determine the address scheme: Phase IV-compatible and/or addresses beyond Phase IV limitations.|
|||Determine if you will continue to use Phase IV routers.|
|||For Phase V routers, determine the type of routing to run: Phase IV and/or Phase V routing algorithm.|
|||Determine which nodes go to DECnet-Plus, which stay at Phase IV.|
|||Select which nodes will be end systems, routers, and area routers.|
|Step 4: Plan for your name services and DECdts Time Service:|
|||Choose your name services --- Local namespace and/or DECdns distributed namespace, or Domain (DNS/BIND) --- for the network and for individual nodes.|
|||If you will use the DECdns distributed namespace, choose the systems that will be name servers and time servers.|
|||Plan for converting DNS Version 1 namespaces to DECdns Version 2 namespaces.|
|Step 5: Choose the first end system to migrate:|
|||Examine recommendations and evaluate the available nodes.|
|||Select the first node to migrate.|
2.1 Step 1: Document the Current Network Configuration
Planning the migration of a network requires an accurate, up-to-date
picture of the network's current state. This picture should be a
detailed topological map of the network. Use the information you gather
in developing this map as input for decisions you make in the following
For example, information on products that cannot make the transition to DECnet-Plus can help determine the configuration of end systems and routers. Identifying all the routers in your network, and determining each one's type, helps you in Step 2 to decide which routing algorithm to use for each Phase V router. Therefore, the more complete your topological map, the more informed your decisions can be.
|COLLECT||Collects specified information from specified nodes|
|REPORT||Creates a report from the data gathered by COLLECT|
The tool offers another command, SHOW PATH, that displays the possible paths that node-to-node communication might take through the network, helping to determine what effect the transition has had on the network's communication paths. For complete information about using decnet_migrate, see your network management manual.
To complete Step 1:
DECnet-Plus offers various transition strategies to suit individual customer networks. Most strategies can be divided into two categories, based on your answer to the following question: Does the network need DECnet Phase V areas?
If your network needs Phase IV addressing, your general strategy will be to move the network partially to a DECnet-Plus environment, at least for the near future. You will have a configuration with both Phase IV areas and DECnet Phase V areas.
If your network is ready to use OSI addresses that are beyond the
limits of Phase IV and, therefore, not compatible with Phase IV
addresses, your strategy will be to move the network entirely to the
DECnet-Plus environment with no Phase IV areas and no Phase IV nodes.
2.2.1 If the Network Is Not Moving Entirely to the DECnet-Plus Environment
If the network needs to remain in a DECnet Phase IV environment for at least one area, an appropriate transition strategy might be that the network has DECnet-Plus systems with Phase IV-compatible addresses. These systems will be able to communicate with the remaining Phase IV nodes.
Another option is that you decide to gain experience using DECnet-Plus in one part of your network before migrating the entire network to DECnet-Plus. You can migrate one area to the DECnet-Plus environment, while the network as a whole operates in the transition environment.
In addition, as part of your "partial" transition strategy, you can use the Local namespace to maintain DECnet-Plus node-name and OSI addressing information until it is more convenient to design and move to a distributed namespace.
Install DECnet-Plus software onto each system that is ready to migrate
and assign it a Phase IV-compatible address during the configuration
procedure. The network transition plan, then, would highlight the order
of migration for individual nodes.
2.2.2 If the Network Is Moving Entirely to the DECnet-Plus Environment
If you need at least one DECnet Phase V area, determine whether or not
the entire network can move to DECnet-Plus. For example, consider a
small, single-area LAN of approximately 20 nodes. If it has no Phase
III nodes or other products that cannot migrate, you can migrate it
entirely to a DECnet-Plus environment by installing DECnet-Plus
software on every end system.
2.3 Step 3: Develop a New Network Configuration
To develop a network configuration, make the following decisions:
Your planning activities include:
As you create your new network configuration, review the information in Chapter 1 for:
In addition, to determine the configuration of end systems and routers, use the following information to guide your decisions:
In the Phase IV environment, LANs can have multiple areas. In the DECnet-Plus environment, however, a LAN can have only one DECnet Phase V area address: an area over 63. This area can have a virtually limitless number of systems, but they all must reside in that single DECnet Phase V area address space. In the transition environment, you can give a LAN multiple areas if the area numbers are within Phase IV limits: 63 or less.
If you plan to migrate a multiple Phase IV-area LAN to the DECnet-Plus
environment, during the migration, the DECnet-Plus end systems will be
multihomed to a Phase IV-compatible area as well as to an area in the
larger DECnet Phase V address space.
188.8.131.52 End-System-Only LAN Configurations
A LAN can consist of end systems only. A DECnet-Plus LAN without routers has virtually no limit on the number of systems it can contain.
The end system to intermediate system (ES-IS) routing exchange protocol (ISO 9542) provides the process by which end nodes communicate with routers, or with each other, to exchange configuration information. In a DECnet-Plus end-system-only network, end systems on a LAN use the ES-IS protocol to communicate directly with each other without depending on a router.
DECnet-Plus end systems communicate directly by using a multicast address called "All End Systems." All end systems normally listen to this address for Router Hello messages, identifying routers to end systems. An end system also uses this multicast address when sending a packet to an end system for which it does not have a cache entry.
When an end system receives a multicast data packet that belongs to itself, it makes a cache entry for the sending end system and sends back an End System Hello, which causes the other end system to make an entry in its cache. When it has another packet to send, the end system checks its cache and uses the cached address instead of the multicast address.
In a LAN with only end systems, these systems can have Phase IV-compatible addresses, extended DECnet Phase V addresses, or a mixture of both. You can allow end systems to autoconfigure their OSI addresses, or you can manually assign them Phase IV-compatible addresses.
When end systems do not have an assigned Phase IV address, they construct an NSAP for each transport operating over routing. Each NSAP is constructed by concatenating the default local area address (49::00-40), the node ID, and the selector representing the transport (NSP or OSI transport). The Figure 2-1 illustrates a network address, or NSAP, of an autoconfigured end system in an end-system-only network:
Figure 2-1 Autoconfigured End System NSAP
When an end system does have an assigned Phase IV address, it constructs an NSAP for each transport operating over routing by concatenating the local AFI (49), 2 octets containing the area portion of the Phase IV address, a Phase IV-style LAN address (aa-00-04-00-xx-xx), and the selector representing the transport. Figure 2-2 illustrates this type of NSAP.
Figure 2-2 Assigned Phase IV Address NSAP
The corresponding Phase IV address is 12.23.
Instead of allowing an end system to autoconfigure its address, you can assign it an OSI address. To manually configure, use the DECnet-Plus configuration utility, net$configure.com (for OpenVMS) or decnetsetup (for DIGITAL UNIX), or use NCL. For details, see your network management guide.