what would scooby do

Our ISP has told us we can go for a cheaper load balanced set of 3 E1's @2Mbit each giving 6Mbit or go for a pukka E3 capped at whatever speed we want..

my question is - what are the issues with using loadbalanced/aggregated lines - surely there must be a downside ??

WillieF

Depends on how they plan to aggregate them.

Some providers will take multiple 2megs and put them on seperate serail interfaces on one router. Others will combine on a single mux then provide a single x21 interface for your router.

Personally I have avoided either solution as it all just sounds a little too messy.

Where are they providing this? At your site or in a datacentre. If it is a datacentre then there is little reason for them to provide anything less than 10Meg.
If it is on site fibre connections are that cheap now that the multiple 2meg is a bit of a waste of effort..

SiCotty

Not much difference between the two as the load balancing techniques within routers (Cisco) are very good at load sharing between multiple (equal cost) links. The ISP has a number of options that include per packet, per stream, or per destination load sharing. Alternatively they could use Multilink PPP that binds the three E1 links together to form one large virtual link. With regards to the E3 link this will give you the option to increase your bandwidth when you want to without any additional installation costs. If you go for an E3 you will probably get a bigger (but more expensive) router. If you have the money go for the E3.

[Edited by SiCotty - 5/22/2003 8:43:33 PM]

P1Fanatic

I would personally go the E3 route - mainly because its hardware bandwidth i.e. you arent using router software to aggregate 3= 2mb lines. Also as was said you get the option to upgrade BW to anything up to 34mb - most ISPs can do this in hours these days. Of course the suitability of this is dependant upon your businesses needs.

The only benefit of the multiple E1 setup I can think of (other than the cheaper cost) is some basic resiliency at your site e.g. 3 different router interfaces (on the e3 if that one interface fails u have no connectivity), different cabling etc from the telco CSU/DSU, maybe different tribs etc.

Seeing as BT provide about 90% of leased lines in the UK Im guessing your line will be with them. Believe me when I say that anything other than a standard setup will always incur additonal time to repair when it goes faulty.

The main bug bear to look for is whether your circuit is aggregated at the ISP end (A end). Most use channelised STM1's (155mb) these days and troubleshooting problems at the A end are a biatch cos u have 63 E1 customers etc on one fibre link. Saying that I doubt most ISPs would give u the choice.

Simon.

P1Fanatic

Oh forgot to say - if you do go E3 make sure you get a router from your ISP that accepts a direct feed from the telco line (G703 BNC) and avoid setups that require an additional multiplexor. We used to use Cisco 7210's for this but not sure what the latest and greatest equivalent is.

Simon.

what would scooby do

Cheers chappies - all makes sense to me.

We have every tail provider in our building already as there are about 10 different companies sharing the building.

We will categorically refuse to use BT as they are ****.

P1Fanatic

Well they can be the best and they can be the worst. They have a lot of specialist network depts if the sh*t really does hit the fan and you get into really detailed troubleshooting. I deal with them every day and they have their good and bad days. From an ISP perspective they are the easiest to deal with as they offer a lot of online repair tools which greatly speed up the repair process.

Simon.