snmp-server command , its concept (server or client)

[zillah]

My understanding to client and server are this:

1- Managed station (agent or Network element) can be router, switch, hub, printer, ,,,etc runs software called server program.

2- Network Managemnet Station (NMS) which is normally PC runs software called client program.

3- Managed station (agent, that runs server program) send trap to (NMS, that runs client program), but not vice versa.

http://www.comptechdoc.org/os/windows/wintcp/wtcpsnmp.html
Trap - A command or message used by the agent to inform the manager of a certain event.

If we have this command in a router configuration :
Router (config)#snmp-server host 193.10.1.101 forumTRAP

Now my understanding to the command is this: router (agent, or server program or snmp-server) will send trap to a host which its ip address 193.10.1.101 (NMS, client program), with password forumTRAP (which it should be configured on an agent and a Manager,,,both of them),,,,Am I right ?

I get confused with this phrase :
"Ideally you need to configure only one command to enable the SNMP client on your Cisco router. These commands are:,,,,,,"......kindly look at the link below

http://expertanswercenter.techtarget.com/eac/knowledgebaseAnswer/0,295199,sid63_gci975314,00.html

[oracle128]

You're making too many assumptions here. SNMP defines only the protocol in which the metadata is sent. If does not define which device should be the server, and which should be the client. They are interchangable, however "Agent" and "Manager" are not; the agent is the network device which holds the SNMP information content (eg. a router), the manager is the device which receives this info and manages it (log file analysis, long-term storage of logs, etc).

A network device (agent) can either send SNMP blindly to a pre-configured location; or, it can await a request for the data (much like an HTTP request). My educated guess is, Cisco routers do the former. Thus, they need to be configured with an IP Address to send the metadata.
I get confused with this phrase :
"Ideally you need to configure only one command to enable the SNMP client on your Cisco router. These commands are:,,,,,
What about the phrase confuses you? If you want something more in depth, you might want to look here (http://www.netcraftsmen.net/welcher/papers/snmprouter.html). Note the paragraph:Cisco routers and switches contain SNMP agents that can respond to standard SNMP get and set operations. That is, a management station can ask the Cisco device for information via an SNMP get, or it can tell the device to change some setting or take some actions, via a set operation. The device can also spontaneously originate traps or SNMPv2c inform notifications.

[zillah]

Thanks oracle128 for your reply.
SNMP defines only the protocol in which the metadata is sent. If does not define which device should be the server, and which should be the client. They are interchangable,
May be you misuderstood me, my post is not pointing to which device is a client and which device is a server.

My post is concern, that an agent device should run a program called server program, and a manager device should run a program called client program.

You're making too many assumptions here
You are right, to explain my question in detail. The source for this information is "TCP/IP Suite" book , by Forouzan Ed3,,,,however the slide #18 in the link below, shows you part of the definitions, that I have quoted from the book. Kindly see this :
http://highered.mcgraw-hill.com/sites/0072460601/student_view0/chapter23/powerpoint_slides.html
slide # 18

and please see this also:
http://www.wtcs.org/snmp4tpc/snmp.htm
SNMP defines a client/server relationship. The client program (called the network manager) makes virtual connections to a server program (called the SNMP agent) executing on a remote network device.


www.zilog.com/docs/ez80acclaim/appnotes/an0181.pdf
The client program (called the network manager) makes virtual connections to a server program (called the SNMP agent) executing on a remote network device. The data base controlled by the SNMP agent is referred to as the Management







What about the phrase confuses you?
""Ideally you need to configure only one command to enable the SNMP client on your Cisco router,,,,,,etc".
According to the explaination above, the SNMP server (not SNMP client) should run Cisco router (Agent device).

[oracle128]

My post is concern, that an agent device should run a program called server program, and a manager device should run a program called client program.It's the same thing. A client runs a client program, a server runs a server program. However, while the network device with the SNMP metadata is usually called the "server" (ie. running the server program), and the log receiver is usually called the "client" (running the client program), that specification is not defined as part of the SNMP concept, it is only the 'usual' setup that is used in reality. Any definition that mentions otherwise is wrong. In the same way, a network device capable of HTML protocol transfer (such as a PC) may be either a client or server, depending on how it is used. If the definition of "client=manager, server=agent" is specified, it is not talking about SNMP the protocol, but how SNMP is usually used in reality.
""Ideally you need to configure only one command to enable the SNMP client on your Cisco router,,,,,,etc".
According to the explaination above, the SNMP server (not SNMP client) should run Cisco router (Agent device).This explanation is merely misusing the terms. With Cisco routers, the agent runs the server, and the manager runs the client.

[zillah]

Any definition that mentions otherwise is wrong
If the definition of "client=manager, server=agent" is specified, it is not talking about SNMP the protocol, but how SNMP is usually used in reality.

When I read your reply, I could not match it with the article below (Source is "Loca Area Network" book page 455) :
"A management station, called a manager, is a host that runs the SNMP client program. A managed station, called an agent, is a router (or a host) that runs the SNMP server program. Managemnet is achieved through simple interaction between a manager and an agent".


Could you kindly comment the book article, because I feel there is a contradiction between the quoted above and the book's article.

May be there is typo in the book, so I can send the author a comment about that.

[oracle128]

"A management station, called a manager, is a host that runs the SNMP client program. A managed station, called an agent, is a router (or a host) that runs the SNMP server program. Managemnet is achieved through simple interaction between a manager and an agent".Yes, that is correct. A manager will (usually) run the SNMP client, which retrieves data from the agent, (usually) running an SNMP server. As correct as that information is, as far as I know it is not part of the SNMP protocol definition. In fact, all current network protocols I know of define only the structure of the data, none of them specify how the servers/clients should interact. That is the point I was trying to make.