waters@viking.DEC (Lester Waters) (06/09/85)
Thanks to all of you who responded to my question about the impact of a DELNI in an ethernet configuration. Here are the results: A DELNI essentially represents a length of cable in the ethernet calculations: The lengths are: 3 people said: 5 meters 3 people said: 10 meters 1 person said: 15 meters *sigh* Lester Waters ...!decvax!decwrl!dec-rhea!dec-viking!waters Waters%Viking.DEC@DECWRL (ARPA)
russell@acf4.UUCP (06/10/85)
Quoting from the DEC "1985 April to June Edition of 'Networks & Communications Buyer`s Guide' pages 4.20-4.21 (Configuration Guidelines): The DELNI hierarchical stand-alone configuration (Fig 4.19) supports a combination of DELNIs and devices using standard Ethernet transceiver cables up to 50 meters (164 feet) away for other DELNI and between 40 and 45 meters (131.2 & 147.6 feet) depending on the communications controller. ... (DELNI connected to a H4000 transceiver) ... The total maximum length of transceiver cable is 40 meters (131.2 feet). This Buyer's Guide is a MUST (and it is FREE!!!) for anyone using DEC Ethernet objects. Just ask your DEC saleperson. Bill Russell, (user of at least 6 DELNIs) Manager of Networks
jmg@cernvax.UUCP (06/12/85)
In article <2740001@acf4.UUCP> russell@acf4.UUCP (Bill Russell) writes: >Quoting from the DEC "1985 April to June Edition of 'Networks & Communications >Buyer`s Guide' pages 4.20-4.21 (Configuration Guidelines): > >The DELNI hierarchical stand-alone configuration (Fig 4.19) supports a >combination of DELNIs and devices using standard Ethernet transceiver cables >up to 50 meters (164 feet) away for other DELNI and between 40 and 45 meters >(131.2 & 147.6 feet) depending on the communications controller. The DELNI Installation/Owners manual starts by saying that a DELNI allows work stations "over a 20 meter (65 foot) square". Then, later, it says "NOTE: Check for any cable length restrictions by referring to the appropriate installation manual for each station's ETHERNET controller. Can you imagine what happens when you want to use a non-DEC controller, and you ask the manufacturer of the controller what are the length restrictions? I have tried it, and the answer is non-informative. Also, DEC say that you should not hang a DELNI on a DELNI on a real ETHERNET. Of course, it works, and if we had the real DELNI specs we could perhaps see why. Maybe one can hang them n-deep (we have enough here to try small integers for n). My feeling is that we want a technical specification for a DELNI. Neither a buyer's guide (trying to get you to buy it) nor an installation manual (when you already have it) is the correct place for such a spec. p.s. After the various remarks about troubles with DELNIs I shall test an equivalent product from another manufacturer. Maybe the grass in the next field really will be greener.