| Well, there's different answers, depending on the management station's
capabilities.
With the 'smartest' mgt station (ie, HUBwatch under DECmcc/MSU [Ultrix])
you'll be able to manage several DEChub 90's with one agent
(DENMA). It will _not_ matter whether the DENMA is clicked into a
DEChub 90 or left standalone on the same extended LAN (a 'floater', in
our informal parlance). As long as the DENMA can 'reach' the DECbridge
90, and the DECserver 90L modules, you're in business. (This extended
LAN restriction is due to the fact that the DENMA communicates to the
bridge and server via LAN-based, (non-routable) protocols such as RBMS
and MOP/console_carrier. If, however, you have _routers_ between the
standalone DENMA and the rest of the hub modules, you're out of
business.
With the current level of support with DECmcc/Director [VMS], (ie,
none), you'll need one management module per hub. This is because the
SNMP architecture (SNMP Access Module) under MCC cannot handle proxies
the way we need to. It cannot, for example, access _discreet_
manageable entities that have the _same_ IP address in common, and only
differ by the SNMP community name. But, when the HUBwatch application
reaches a point of stability for MSU, we'll port the whole mess over to
Director, and the restriction of one DENMA per DEChub 90 should be
removed. There should be no difference in the quality of management
from either MCC or MSU at that point.
With our joint development effort with DSI, they'll also be
able to take advantage of using one DENMA per "many" DEChubs 90s.
As for other vendors' management stations, it depends on their ability
to offer proxy the way we need. So far, most management stations have
very limited flexibility (out of the box) to support our proxy method.
But, since the new SNMP security model is closing in on becoming a
standard, I'd expect that more and more agents will support this. This
new proposal offers more than just security - it _standardizes_ the
notion of proxy. At that point, it's "simply" a matter of time to
switch our method over to align with the new proposal.
.bl
|
| In addition, let me provide a bit of an illustration to accompany .1 :
D E C h u b 9 0
network :- - - - - - - - - - - - - - - - - - - - - - - - - -:
management ------->: DENMA :
station : +-------> DECbridge 90 -------> DECrepeater 90C :
: | :
: +-------> DECserver 90L :
: :
:- - - - - - - - - - - - - - - - - - - - - - - - - -:
This situation will work.
D E C h u b 9 0
network :- - - - - - - - - - - - - - - - - - - - - - - - - -:
management --> R -->: DENMA :
station ^ : +-------> DECbridge 90 -------> DECrepeater 90C :
| : | :
| : +-------> DECserver 90L :
| : :
| :- - - - - - - - - - - - - - - - - - - - - - - - - -:
|
(this is an IP router)
This situation will also work.
network
management
station D E C h u b 9 0
| :- - - - - - - - - - - - - - - - - - - - - - - - - -:
| (IP) : (RBMS) (private) :
v : +-------> DECbridge 90 --------> DECrepeater 90C :
DENMA ----> R -------+ :
: +-------> DECserver 90L :
: (MOP) :
:- - - - - - - - - - - - - - - - - - - - - - - - - -:
This will _NOT_ work. There is a Router (R) in between the DENMA and
both the DECbridge and DECserver. The DENMA communicates to the bridge
via RBMS (LAN only), and to the server via MOP (LAN only). The Router
will _block_ these protocols, so the management traffic will not flow
to the hub modules.
Hope this helps.
.bl
|
| A DECagent will manage at least 4 extended (double hubs) on the same
extended LAN. It may be able to manage more, but we will not know how
many until we have run some more tests. This means you could manage 15
slots of repeaters per hub if you had the agent running stand alone.
This is definitely different than our competitors who require one
agent per hub.
FUTURES: Newer terminal servers will have agents in them as the 90TL
does. Repeaters will probably never have agents, altho we are thinking
of modifying the agent so it can manage the repeaters directly without
a bridge and also using a router instead of the bridge to manage the
repeaters (might even have its own agent in the router)
|