Also sprach Lewis Bergman
I am told that all services incoming (T1/PRI) must come from same provider per card. Not sure if thats true but thats what was stated, referred to timing but you would think you could work around it....I could be worng.
I would think that would be the case. You tell the card where to get its timing from. If you get it from the line then the card will time all four T's from the single T it syncs with. All the T's plugged into that card not coming from the CO that the card is synced to would be out of frame.
Actually, its probably not that big of a deal since pretty much all telco's will be working from a shared timing source *somewhere* up the chain. Otherwise they'll have their own timing source, but it will be accurate enough that you won't have slips. If you think about it...this is almost necessary to be the case since, if it weren't, how would the telco's handle T1's between each other...if they're using different timings, a T1 between the two telco's would always be slipping. The suggestion/requirement probably is said that way from 3Com for much the same reason that many of their other suggestions/requirements are...because they assume that the bulk of their customers won't understand the intricacies of the situation and will, as a result, screw up their configuration...and they're probably right. :)
In my case I have my own class5 switch so its not an issue.
Then you probably deal with clocking issues on your class 5 already. They are not really any different with PRI cards in TC equipment. As long as the timing is accurate/consistent between the different spans, you'll be fine. -- Jeff McAdams Email: jeffm@iglou.com Head Network Administrator Voice: (502) 966-3848 IgLou Internet Services (800) 436-4456