FDDI would be my last choice. 100MB ethernet can be run full duplex, is less expensive, and far easier to troubleshoot. At 07:42 PM 2/5/98 -0500, Charles Sprickman wrote:
Hi,
We colocate with our upstream, so we (thankfully) don't have to deal with Bell Atlantic for our main Internet connection. We are currently running a 10Mb ethernet link to our provider, but our contract allows for more than that should we ever need it. Since the Bay ASN we now use will soon be history and will be replaced by a shiny new(?) Cisco, I'm thinking of upgrading the link now rather than later.
We have a choice of FDDI or 100Mb ethernet. I'm thinking FDDI is better, and not too much more expensive for our side. Are there any negatives with FDDI? How does the 4000(?) Byte MTU affect things? All of our outgoing links, T1 and ether are all 1500. Does the work of fragmenting the packets down to 1500 amount to anything? All this talk about MTUs has got me wondering.
Thanks,
Charles
~~~~~~~~~ ~~~~~~~~~~~ Charles Sprickman Internet Channel INCH System Administration Team (212)243-5200 spork@inch.com access@inch.com
Lewis Eatherton Network Architect SegaSoft, Inc 650.654.2318
FDDI can run full duplex, as for the other two things its a matter of opinion & conditions. (One I agree with, but still opinion). -Deepak. On Thu, 5 Feb 1998, Lewis Eatherton wrote:
FDDI would be my last choice. 100MB ethernet can be run full duplex, is less expensive, and far easier to troubleshoot.
At 07:42 PM 2/5/98 -0500, Charles Sprickman wrote:
Hi,
We colocate with our upstream, so we (thankfully) don't have to deal with Bell Atlantic for our main Internet connection. We are currently running a 10Mb ethernet link to our provider, but our contract allows for more than that should we ever need it. Since the Bay ASN we now use will soon be history and will be replaced by a shiny new(?) Cisco, I'm thinking of upgrading the link now rather than later.
We have a choice of FDDI or 100Mb ethernet. I'm thinking FDDI is better, and not too much more expensive for our side. Are there any negatives with FDDI? How does the 4000(?) Byte MTU affect things? All of our outgoing links, T1 and ether are all 1500. Does the work of fragmenting the packets down to 1500 amount to anything? All this talk about MTUs has got me wondering.
Thanks,
Charles
~~~~~~~~~ ~~~~~~~~~~~ Charles Sprickman Internet Channel INCH System Administration Team (212)243-5200 spork@inch.com access@inch.com
Lewis Eatherton Network Architect SegaSoft, Inc 650.654.2318
At 2:35 PM -0500 2/6/98, Deepak Jain wrote:
FDDI can run full duplex, as for the other two things its a matter of opinion & conditions. (One I agree with, but still opinion).
For desktops, I agree completely that fast ethernet is the way to go. Fast ether hubs are cheaper and easier to wire than cddi hubs (no cross over cables required). For a backbone, though, I would point out that FDDI is a token ring protocol, so performance is always predictable. Ethernet, and fast ethernet have performance knees. (Actually, I'm assuming Fast Ethernet will have a knee at around 70% utilization. I haven't tested that it really does). Also, both Fiber and Copper can be implemented with dual attached rings which might be an advantage for a backbone link. --Dean ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP http://www.av8.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Okay. Playing my usual devil's advocate role, please tell me what migration path lies beyond FDDI for faster connectivity? - paul At 04:17 PM 2/6/98 -0500, Dean Anderson wrote:
For desktops, I agree completely that fast ethernet is the way to go. Fast ether hubs are cheaper and easier to wire than cddi hubs (no cross over cables required).
For a backbone, though, I would point out that FDDI is a token ring protocol, so performance is always predictable. Ethernet, and fast ethernet have performance knees. (Actually, I'm assuming Fast Ethernet will have a knee at around 70% utilization. I haven't tested that it really does). Also, both Fiber and Copper can be implemented with dual attached rings which might be an advantage for a backbone link.
Beowulf Project uses 100 & now Gb Ethernet. Draw your own conclusions.... <http://cesdis.gsfc.nasa.gov/linux/beowulf/beowulf.html> -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
I have started to look at "Fast Ethernet" and see "Full-Duplex Switched Fast Ethernet". I mean, the switch ports are SO cheap, why do anything less... On Fri, Feb 06, 1998 at 04:17:53PM -0500, Dean Anderson wrote:
At 2:35 PM -0500 2/6/98, Deepak Jain wrote:
FDDI can run full duplex, as for the other two things its a matter of opinion & conditions. (One I agree with, but still opinion).
For desktops, I agree completely that fast ethernet is the way to go. Fast ether hubs are cheaper and easier to wire than cddi hubs (no cross over cables required).
For a backbone, though, I would point out that FDDI is a token ring protocol, so performance is always predictable. Ethernet, and fast ethernet have performance knees. (Actually, I'm assuming Fast Ethernet will have a knee at around 70% utilization. I haven't tested that it really does). Also, both Fiber and Copper can be implemented with dual attached rings which might be an advantage for a backbone link.
--Dean
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP http://www.av8.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Depends on the switch. Some switches, (notably Bay 28115Rs) perform poorly in fast ethernet/full duplex mode whereas they perform like champs in half-duplex mode. What they say they "do", and what they really do well are sometimes not the same thing. -Deepak. On Fri, 6 Feb 1998, Dorn Hetzel wrote:
I have started to look at "Fast Ethernet" and see "Full-Duplex Switched Fast Ethernet". I mean, the switch ports are SO cheap, why do anything less...
On Fri, Feb 06, 1998 at 04:17:53PM -0500, Dean Anderson wrote:
At 2:35 PM -0500 2/6/98, Deepak Jain wrote:
FDDI can run full duplex, as for the other two things its a matter of opinion & conditions. (One I agree with, but still opinion).
For desktops, I agree completely that fast ethernet is the way to go. Fast ether hubs are cheaper and easier to wire than cddi hubs (no cross over cables required).
For a backbone, though, I would point out that FDDI is a token ring protocol, so performance is always predictable. Ethernet, and fast ethernet have performance knees. (Actually, I'm assuming Fast Ethernet will have a knee at around 70% utilization. I haven't tested that it really does). Also, both Fiber and Copper can be implemented with dual attached rings which might be an advantage for a backbone link.
--Dean
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP http://www.av8.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
At 05:09 PM 2/6/98 -0500, you wrote:
I have started to look at "Fast Ethernet" and see "Full-Duplex Switched Fast Ethernet". I mean, the switch ports are SO cheap, why do anything less...
It's even cheaper to cascade 10mbps/repeaters off of hdx switch 10's and aggregate them into 100's. Regards, -- Martin Hannigan hannigan@xcom.net Sr. Network Engineer Network Operations XCOM Technologies, INC. F:617.500.0002 V:617.500.0108
On Fri, Feb 06, 1998 at 05:16:36PM -0500, Martin Hannigan wrote:
At 05:09 PM 2/6/98 -0500, you wrote:
I have started to look at "Fast Ethernet" and see "Full-Duplex Switched Fast Ethernet". I mean, the switch ports are SO cheap, why do anything less...
It's even cheaper to cascade 10mbps/repeaters off of hdx switch 10's and aggregate them into 100's.
Regards,
-- Martin Hannigan hannigan@xcom.net Sr. Network Engineer Network Operations XCOM Technologies, INC. F:617.500.0002 V:617.500.0108
10Mbps switches with 100Mbps FDX uplink ports are rather cheap these days. Just use those and fergit about it; your backbone is then 100Mbps FDX, and the drops are either switched 10 or 100Mbps (depending on where you drop from). We have been smurfed at *sustained* rates in excess of 70Mbps (two full-bore DS3s worth - peaks right up at 44.7 X 2) and haven't managed to saturate this back-office network fabric :-) Want a second free tip? CMD RAID controllers :-) -- -- Karl Denninger (karl@MCS.Net)| MCSNet - Serving Chicagoland and Wisconsin http://www.mcs.net/ | T1's from $600 monthly to FULL DS-3 Service | NEW! K56Flex support on ALL modems Voice: [+1 312 803-MCS1 x219]| EXCLUSIVE NEW FEATURE ON ALL PERSONAL ACCOUNTS Fax: [+1 312 803-4929] | *SPAMBLOCK* Technology now included at no cost
From: Martin Hannigan <hannigan@xcom.net>
I have started to look at "Fast Ethernet" and see "Full-Duplex Switched Fast Ethernet". I mean, the switch ports are SO cheap, why do anything less...
It's even cheaper to cascade 10mbps/repeaters off of hdx switch 10's and aggregate them into 100's. Yeah, and then you can network a whole office building that way (who needs messy routers anyway?)... and be surprised when you discover that your 10mb ether segments are at 30% utilization in the middle of the night due to SAPs from Novell servers. And wonder why productivity goes to zero in the middle of the afternoon as the dark clouds of a broadcast storm gather in the west. No, I don't know of any Fortune 500 corporations in my immediate area whom this has happened to. ---Rob
participants (9)
-
David Lesher -
Dean Anderson -
Deepak Jain -
Dorn Hetzel -
Karl Denninger -
Lewis Eatherton -
Martin Hannigan -
Paul Ferguson -
Robert E. Seastrom