CMIP: Beginners Questions and Answers


1) What is CMIP?

CMIP, the common management information protocol, is another protocol used to manage networks. It is more complete, yet larger, than SNMP.

2) What communications suite does it use (or run under)?

One of the reasons why CMIP has not been commercially popular is due to the fact that it runs under the Open Systems Interconnection (OSI) network communication protocol. OSI is similar to the previously-described TCP/IP in purpose: both are designed to be vendor inspecific network communication protocols; and structure: both use the ISO 7 layer network communication model that was described in the network management document. However, it is different from TCP/IP in almost every respect. For starters, OSI performs almost all of the communications functions that TCP/IP does plus many more. It is thus thought to be a much more complete network communication package. However, with this increased completeness comes a massive increase in system resources that OSI takes to implement (it was once mentioned that network resources would have to be increased by almost a factor of 10 to support OSI). It is thus no wonder why OSI has not been very popular with the computer industry. As a sidenote, one would think that a combination of the perpetual increase in network resources and the shrinking of OSI would result in its widespread implementation; yet OSI has grown proportionally with system resources. I think there is only one network in Canada that is running with a full 7- layer OSI system.

3) Is there any way for the common sysadmin to implement CMIP?

Not that I know of!

4) What is CMISE?

Whenever one wants to research CMIP, they are usually forced to read about CMISE first. Since one of the reasons of this document is to make further readings of CMIP easier to digest, I will give a quick explanation of CMISE so when you want to read about just CMIP you can skip the CMISE chapter (although this is not recommended). We know from the 7 layer network management model that the seventh layer is used for applications. In this layer, there is this application known as the Comman Management Information Services Element (CMISE) that works hand-in-hand with CMIP. The purpose of CMISE is to transfer network management information from one system to another (Scoggins, 416). CMIP then maps every CMISE operation to a remote (CMIP) operation. (Scoggins, 421). For an example of this lets say you wanted to set a terminals IP address. In this case you would send out a CMISE service element M-SET, and it would call the CMIP operation m-set to set the terminals information. In all cases, it is CMISE that summons CMIP to set (or get) the desired information. It is thus CMIP, and not CMISE, that releases the PDUs. On the receiving end it is CMIP that translates the terminals response and CMISE that reports this to the user.

If you are confused after reading this then dont worry, CMISE is a very difficult concept (I hardly understand it myself). The bottom line is that it is an application that invokes CMIP. Think of it as the users interface to CMIP. This, however, is an extremely high-level summary.

If you desire more information on CMISE, then a real good source on this is the Scoggins book, it is referenced at the bottom of this document.

5) What are ASEs?

ASEs are applications residing in the seventh layer of OSI. CMISE, for example, is an ASE. It stands for Application Service Element.

6) Why is CMIP superior to SNMP?

CMIP is superior to SNMP because (as explained in the Advantages to CMIP link above) it can provide greater control over a network by a sysadmin. For instance, its security and notification services equal or surpass those available in SNMPv2. Read the aforementioned link for more information.

7) Will CMIP or even OSI ever see widespread use?

The way it stands today, TCP/IP and its network management protocol SNMP are in widespread use today. They have almost total control of the inter-network communication protocol market. With these facts, many people would write OSI (and thus CMIP) off as a dead protocol, too big for its own good. OSI however does have several pros going for it: firstly, it was funded by governments and large corporations. If OSI ever becomes usable on current networks then it will immediately have a very large market (ie. the governments and corporations that funded it). Secondly, it is much more powerful than SNMP. Unfortunately, this poses the system resources problem and also makes the protocol quite hard to understand.

8) Where can I find out more information?

A good book for beginners is either the Stallings book (referenced in the main pages References link) or for a very brief (yet easy to understand description) check out:

Fang, Karen and Allan Leinwald. Network Management: A Practical Perspective. Addison Wesley: Don Mills, 1993.

A good book for more experienced users is:

Scoggins, Sophia and Adrian Tang. Open Networking with OSI. Prentice-Hall: Toronto, 1992.