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WAN: Frame Relay or ISDN.?

Hi All,

whilst studying for CCNA, I come across a lot of reference to ISDN being a good backup technology. I know this might sound like a stupid question, but, what is used mostly in WAN environments.? Over here, in Tokyo, I get told that Frame Relay is not used that much, as opposed to ISDN. What do you guys see most in your environments.? Cheers.


VIP Purple

Re: WAN: Frame Relay or ISDN.?


AFAIK, frame relay is a service offered by most ISP's in Japan, and also quite heavily used (check the link below). It is usually much cheaper than ISDN, and therefore often the primary method of connectivity. Over here in Europe, ISDN is available almost everywhere, while, AFAIR, it is not that heavily used in the US...

Japan ISPs for Country Code +81



Community Member

Re: WAN: Frame Relay or ISDN.?

Hi All,

ok, then perhaps I need to improve my listening. Thanx for your reply. It's all helpful. Cheers.


Re: WAN: Frame Relay or ISDN.?


It horses for courses really, and here we are talking two rather different breeds of horses.

ISDN is a dialup technology, and it usually charged by the minute. This makes it very suitable for a backup connection, or for a link that is used on an occasional basis. The abonnement costs are usually quite low compared with the per-minute costs. Here in Luxembourg it is one of the standard domestic telephone services on offer - I have it at home. It has the flexibility that once you have an ISDN line you can use it to dial any other ISDN line - or even to a modem line if you have a modem integrated in your router - or just use it as a telephone line.

Frame Relay, on the other hand, is an "always on" service. It is set up as PVCs, so your endpoints have to be agreed in advance with your provider. Generally you only pay an abonnement cost for the PVC, and no incremental costs per minute or per data volume.

The pricing structures are different in each country, so would have to do your own calculations based on your traffic expectations. I did a study here comparing a local leased 64 kbps line against an ISDN dialup. I found that the ISDN was cheaper if it was open less than 24 hours per month, but got very expensive if it was heavily used.

Does that help?

Kevin Dorrell


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