VoIP requires a lot of redundancy, from my experience so far. Granted, each site has all it's voice and data trunks going to the same CO. For instance in a current install: 12 Small offices (10-20 phones): 4 voice trunks 2 backup BRIs (for extra voice trunks and/or backup data) Full/Fractional T1 to frame relay cloud Main site (80 phones): T1 PRI for voice w/DID T1 PRI for data (analog dialup users mainly, backup lines for remote BRIs) Multiple T1s to frame clouds If all local trunks at a branch are in use, the last line forwards to a DID on the PRI and forwards back internally to that site. If the frame goes down, we've got enough BRIs to still function (in a much more limited capacity, but the VoIP network has priority and won't go down, data will suffer but still work and is primarilly terminal/text based or Citrix clients). We purposely have a small number of trunks at each site (most sites originally had 6-10 trunks), but part of the goal here is to save money with less trunks and also do toll-bypass (this customer has suppliers/customers/sites all over California, Neveda and Oregon). Also there is the advantage of faster data paths when the dynamically allocated VoIP isn't in use. So far, it seems to work good (only 2 remote sites up so far, working out kinks with other items like Unity voicemail/faxing and just waiting on frame circuits to be upgraded). 3 remote sites will probably be brought up in the next month, so we'll see how well it all scales (shouldn't matter, the hardest was just getting it all working right with the first 2 remote sites). Even though it's not dynamic, if for instance one sites local telco was having analog trunk problems, we could block all calls from being routed out those trunks (which I guess you can do in a traditional PBX system, but you probably wouldn't be doing with key systems which would be going in these small offices). We're actually doing that for the second of two sites to keep the local trunks open for incoming calls as the local telco goofed on a date to have the trunks forward long distance, so if all 4 local trunks are in use the 5th+ caller get forwarded to the other 4 trunks no longer in use and get a "disconnect" message. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ ""John Neiberger"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > >Aside from Priscilla (not Geoff Huston): What if the phone system had > >evolved this way? How many companies have redundant trunk lines? Don't > we > >just assume that the "phone company" will always provide service? We > don't > >multihome to the phone system, (do we?) > > [Warning: Slightly OT] > > Actually, here at our corporate headquarters we have redundant fiber > connections to separate telco central offices. The fiber links exit on > opposite sides of the building to frustrate Backhoe Bob in case he tries > to cut through them. These links carry two separate channelized DS-3s > that carry our voice and data circuits. Theoretically, you could bomb > one of the CO and we'd be just fine; both DS-3s would stay up and > running without a hiccup. I hope we never have occasion to test this. > > > John > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=5621&t=5621 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
