gigabit networks

[SOSAGES]

Having read a bit about this now im a bit confused - some things i read say it will only work with special copper/fibre cables other say normal rg45 will work at the top speed other reports say i need gigabit certified rg45 cable

I also read on the dell website that 1000 will not work at 100/10 speeds.

So im confused and was wondering if some network guru could help me out, i only ask as i have a 100 switch and a load of desktops that use 100 and i will be replacing the desktops with dells that have 1000 nic's in them and i figured may as well get a 1000 switch then and then i hit the minefield that is 1000 networking or so it seems

Thanks in advance

[Chris W]

google is my friend....

Despite the considerable effort made to enable 1000Base-T to operate on cables meeting the Cat 5 specifications, some additional specifications were required (Cat 5e). Fortunately, most Cat 5 cables manufactured actually meets the additional Cat5e specifications. So Gigabit Ethernet should work with most Cat 5 cables, but if new cables are being purchased, one should check that the cables meet the Cat 5e specification. Cables that exceed the Cat 5e specification rated for 350MHz may be only moderately more expensive than Cat 5, while Cat 6 cables that support 500MHz are more expensive.

from here

any use?

MB

[Bazooka_Boy]

The fibre is used to connect the gigabit switch to your backbone (where I think you have to have a core builder). We've recently put in a gigabit switch 1.5k by the way for a 24 port. Once the switch was in and the fibre connected up I used the exisiting Rj45 cables in the server room which are at least 3 or 4 years old and connected up the servers with the gigabit cards.


now 1gb transfer between to of these servers took less than 25 secs sweet

Baz

[SOSAGES]

ahh right so server to switch fibre the rest cat 5e (or 6?)

ok last question - is there a limit to the range that i will achive the 1000 speed on? i know normal 100/10 cat 5 is 100 meters (i think) does 1000 share that restriction or is it infact less than that? it couldbe 20 meters for all know thanks so far

[Chris W]

IIRC the limit is 25m when you are using CAT5e

[SOSAGES]

i better have a think about my switch placement then or get 2 switches ...

Any idea if a "managed" switch is a must have as they are expensive and id rather save some cash before the MD gets to grumpy with me

Out of interest, what benefit do you expect to get from switching your desktops to Gigabit ?

[SOSAGES]

none really - i was hoping for a little more speed thats all and as the dells im getting have the 1000 nic's in them and we wont have any 100 cards about i figured its time to go for 1000 base. so i need new switch / server nic and cables..

i wonder how it will work out

[Bazooka_Boy]

when your trying to get performance don't scrimp on price (easy to say went it is not your money). You can have bigger distances with the fibre than the cat5 so could use this to get your switch nice and close for the cat5 side of things.

I didn't know that cat5e had such a short max length I'd have thought you could go the same distance as standard cat5 after all that length is due to the drop off in signal not the throughout of data????

[gazzae]

Originally Posted by Bazooka_Boy

when your trying to get performance don't scrimp on price (easy to say went it is not your money). You can have bigger distances with the fibre than the cat5 so could use this to get your switch nice and close for the cat5 side of things.

I didn't know that cat5e had such a short max length I'd have thought you could go the same distance as standard cat5 after all that length is due to the drop off in signal not the throughout of data????

It is to do with the drop off in signal CAT5E can be up to 100m in length, same as CAT5.

[SOSAGES]

so it will be working at 1000 if its over 25m ?

[gazzae]

Originally Posted by SOSAGES

so it will be working at 1000 if its over 25m ?

Yes

http://www.pctechguide.com/29network...t_Ethernet.htm

The topology rules for 1000Base-T are the same as those used for 100Base-T, Category 5 link lengths being limited to 100 metres and only one CSMA/CD repeater being allowed in a collision domain. Migration to 1000Base-T is further simplified both by the fact that 1000Base-T uses the same auto-negotiation system employed by 100Base-TX, and the availability of product components capable of both 100 Mbit/s and 1000 Mbit/s operation.

[...]

In Fast Ethernet, the maximum cable length is reduced to a maximum of 100 metres, with the minimum frame size and slot time left intact. maintains the minimum and maximum frame sizes of Ethernet. Since it's 10 times faster than Fast Ethernet, for Gigabit Ethernet to maintain the same slot size, the maximum cable length would have to be reduced to about 10 metres, which is impractical. Instead, Gigabit Ethernet uses a larger slot size of 512 bytes.