Frame Relay, ISDN and DS3

[thequietstorm]

Can someone explain me the different/advantages between frame relay, ISDN and DS3. Which one of these technologies would be the most economical and provide more bandwidth for a remote office of 15 users who will be doing a lot of file sharing? I am planning on installing 2 routers the primary router will be attached to the frame relay the second/backup router will be on dial backup. Which one of the followings: frame relay, ISDN, or DSL would be best for my dial backup? Any general ideal will help.
Thanks

 

[wybnormal]

There are whole books written on these items.. I'm assuming you want the short version ;-)

Frame Relay- packet switched *cloud* which you can either have a point to point path through it or a switched path through the cloud. Bandwidth can be from 64Kbps to normally 1.54Mbps(T1) There is normally a commited rate from the telco (CIR) and a burst rate.

ISDN- This is normally used for either remote office with on demand dialing, back up links or SOHO. Consists of 3 channels.. 1 D channel which is the signaling and 2 B channels of 64Kbps each. Nominal data rate is 128Kbps. The telco's normally charge on a usage basis for ISDN which is why it tends to be a on demand design. But nowdays, you can sometimes get a flat fee. Also, a DSL technology based on ISDN is called IDSL where they use ISDN lines/cards but put DSL signaling over it. Another name is long reach DSL.

DS-3 This is not really a technology but a package. It's 44.736Mbps of bandwidth made up by bundling 672 DS0 channels. Each DS) channel is 64Kbps. I think the math works out as 29 DS-1s (T1s). Needless to say a DS-3 will cost you a large amount of money per month.

For a small office, look at Frame , DSL or Commercial Cable for your access. And then it will come down to how badly does it need to be up. Neither DSL or Cable is a mature technology for business. But while Frame is mature, you pay more for it. So a choice needs to be made.

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[thequietstorm]

Thank you wybnormal that was very useful. As you probably noticed, I am kind of new to networking. Currently I have a very small project I am working on. I need to setup a network for a small remote office. it's for about 15 users.
There will be a lot of file sharing, so therefore bandwidth is my concerns, but at the same time I am trying to stay within a budget. In term of equipments, what type of routers would you recommend? What do you recommend as a dial backup line for the secondary router? As I can see you are very knowledgeable. I am hoping you can educate me a little with my design.

Thanking you in advance for you help.

 

[CCIEWANNABE]

refers to the bit format.

Frame relay is a high-speed, packet based, data transmission service used in wide area networks (WANs) to connect multiple locations. Monthly cost starts at $500 per location.

ISDN supports data transfer rates of 64 Kbps. Thats about 5 times faster then a moem. You would be better served by a 56Kb/sec Frame Relay instead of ISDN, as it's flat rate.


T3 not DS-3 "refers to a bit Format" and is a dedicated connection made up of the equivalent of 28 T-1s. Last bill I saw was about 10,000 per month with loop charges.
Route once; switch many

 

[CCIEWANNABE]

One last note consider using SDSL, which is about 90 dollars a month. May not be available at your location. Your location must be close to a phone company. SDSLhas a limited range of 12000 feet. "5280 ft equal 1 mile". Route once; switch many

 

[wybnormal]

If I had to guess.. since we are lacking some information here, I would offer up the following ideas...

Get DSL with at least a 800Kbps data rate. Why DSL? because many cable companies block VPNs which is the second step. Most DSL circuits will pass it.. always ask first.

The quick and dirty way is this way ( one of many)

HeadquartersLAN---router--PIX501--internetDSL--PIX501---RemoteLAN

Note the following items..
1: twp PIX 501 firewalls.. why? because you can open a VPN between them via the internet to pass your traffic which more then likely will include NB protocol stuff like PDC logins, WINS, DHCP broadcasts and so on. THe VPN allows the remote site to look like a local segment for all intents and purposes. The PIXs will also act as firewalls for protection of the LANs.

2: 1 router at the Corp site.. this is to run multiple subnets.. one for the LAN and one for the remote site.

If you want a dial back up solution, then you end up with a 2nd router at the remote site also. More then likely ISDN but I think I mentioned this to you before about running dual Frame connections? It really depends on the bandwidth requirements. Getting a whole remote site on ISDN is tough since you will drop from 800Kbps to 128Kbps(standard ISDN link) You could have special access-lists that when you roll to ISDN, everything no important (like web access) is blocked.. this would help alot. File sharing across 128Kbps would be painful. So perhaps a dual DSL link.. make sure the Telco knows that it's for backup and NOT to run them through the same switch/POP. It would be possible to load balance across the two links. It's possible to keep the single PIX with it's two ports but you need to make sure the 2 DSLs are within the same subnet.. you would use a cheapo hub to consolidate the two DSLs into one link with the correct subnet mask on it.

-----DSL1---------|
-----DSL2---------|Hub|-----PIX---LAN

I've done this and it works pretty well.

As you can see, alot goes into a network design.

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[jeter]

DLS will work with a router or a modem. The router would need to have to ports open to access your vpn. A modem is passive and will allow anything to flow through. A firewall is a good idea with a modem. Small correction on the SDSL is will work up tho 18,000 ft. Sprint has new technology out that will eliminate distance problems. Las Vegas and other site should have 100% dsl coverage in 5years. Given everything goes as planned. “Reserve your right to think, for even to think wrongly is better than not to think at all”

Fisher CCNA,(CCNP-Routing)
UOP Student BSIT