dberry@sei.cmu.edu (Daniel Berry) (06/12/91)
I am not in the networks area. Hence there is a question which I cannot easily answer. Please send me either answers or pointers to where the information is published.. 1. What is used commercially to implement 16bps toekn-ring hubs and to avoid jitter accumulation by these hubs? Thanks Dan Prof. Daniel M. Berry, Computer Science Department, Technion, Haifa 32000 ISRAEL +972-4-294325, DBERRY@TECHSEL.bitnet dberry@cs.technion.ac.il Dr. Daniel M. Berry, Software Engineering Institute, Carnegie Mellon Institute Pittsburgh, PA 15213, +1-412-268-7778 dberry@sei.cmu.edu FAX:+1-412-268-5758
lstowell@pyrnova.pyramid.com (Lon Stowell) (06/12/91)
In article <26845@as0c.sei.cmu.edu> dberry@sei.cmu.edu (Daniel Berry) writes: >I am not in the networks area. Hence there is a question which I cannot >easily answer. Please send me either answers or pointers to where the information is published.. > >1. What is used commercially to implement 16bps toekn-ring hubs and to >avoid jitter accumulation by these hubs? > There are two types of hubs....active and passive. Usually hubs are known as MAU's or MSAU's. The passive hubs do no amplification, etc, so they add essentially no jitter. SOME hubs amplify but perform no clean-up of the signal so they do cause some jitter....depending on exactly WHAT is done to the signal. Some hubs go so far as to put a ring station in the hub. This would add exactly the same jitter as any other ring station. There are several techniques for removing jitter at a hub or any ring station.....some actually interfere with the ability of diagnostic packages to diagnose Active Monitor contention problems....where stations detect sufficient problems with ring clocking that they insist that the AM drop its master clocking. You may want to check with MSAU vendors....each has a rational for what they have done...and strategies to cover the problems their implementations might have caused... Try RAD, StarTek, Proteon, and IBM as sources....IBM also has an excellent school for Token Ring...
lstowell@pyramid.UUCP (Lon Stowell) (06/12/91)
In article <26845@as0c.sei.cmu.edu> dberry@sei.cmu.edu (Daniel Berry) writes: >I am not in the networks area. Hence there is a question which I cannot >easily answer. Please send me either answers or pointers to where the information is published.. > >1. What is used commercially to implement 16bps toekn-ring hubs and to >avoid jitter accumulation by these hubs? > There are two types of hubs....active and passive. Usually hubs are known as MAU's or MSAU's. The passive hubs do no amplification, etc, so they add essentially no jitter. SOME hubs amplify but perform no clean-up of the signal so they do cause some jitter....depending on exactly WHAT is done to the signal. Some hubs go so far as to put a ring station in the hub. This would add exactly the same jitter as any other ring station. There are several techniques for removing jitter at a hub or any ring station.....some actually interfere with the ability of diagnostic packages to diagnose Active Monitor contention problems....where stations detect sufficient problems with ring clocking that they insist that the AM drop its master clocking. You may want to check with MSAU vendors....each has a rational for what they have done...and strategies to cover the problems their implementations might have caused... Try RAD, StarTek, Proteon, and IBM as sources....IBM also has an excellent school for Token Ring...