On Thu, 30 Aug 2001 12:18:53 -0400 David Grove wrote:

Well, Rick, I'm no network expert, but I have noticed a difference between what people tell me, what the box says, and real life.

I use the LNE100TX and 3Com 3C905B/C cards only. Now, supposedly, when I have a 10Mbps card going to my hub, it's supposed to slow the whole network down to 10Mbps. However, I seem to have an oddball (advanced or something) hub where only the 10Mbps line would run at 10Mbps. (Everyone: No, this is not a switch. This is not a switch. This is not a switch.) Anyway, plugging in a 10Mbps card into a primarily 100Mbps hub is /supposedly/ going to slow everything down.

However (from the verbiage on the side of my new switches (ahem)), it doesn't make any difference because the 100Mbps is shared among the machines

You will link at 100 if your card is 100, but the traffic is still only 10. Don't confuse what you bind at and the actual data transfer speed. It is not physically possible to have a single network segment (what a hub gives) running at two speeds. It's not a matter of "well, my hub is different". No, it's not. that are

talking on "most" hubs. Hubs also "are only capable of half duplex" meaning 50Mbps up and 50Mbps down, shared among machines. Now, this I can attest to because I ran into it building my own linux distro (linuxfromscratch.org, not recommended to the impatient or anyone with a sex life), my NIC belched out that the network was running half duplex.

This is not corrent either. Switches or hubs or NICs can run at either full or half duplex, depending on their construction. Lots of 10 & 100 full duplex hubs out there.

Thank you. I figured someone would want to be hostile. I think the hub I was using calls itself an "auto-switching" hub, but I've been told that's "something different entirely". I just know that it works this way. Anyway, thanks. On Thursday 30 August 2001 13:58, Tor Sigurdsson wrote:

Þann fimmtudagur 30 ágúst 2001 17:30 skrifaðir þú:

...

On Thu, 30 Aug 2001 12:18:53 -0400

[SNIP]

...

You will link at 100 if your card is 100, but the traffic is still only 10. Don't confuse what you bind at and the actual data transfer speed. It is not physically possible to have a single network segment (what a hub gives) running at two speeds. It's not a matter of "well, my hub is different". No, it's not.

Uhm, I beg to differ :-)

There are things called "swithcing hubs" which are in fact two hubs ( one 10Mbit and one 100Mbit ) with a two-port switch built in to bridge the 10/100 gap. That way, you get "pure" 100<-->100 where possible, "pure" 10<->10, and a 10<->100 switched bridge. They cost about the same as a true switch tho, so I'd rather recommend switches. ( beware tho that some companies sell these things as "personal switches" - which they are not. )

[SNIP]

-tosi

On Thursday 30 August 2001 16:57, Tony White wrote:

Hi Tor,

Most 10/100 hubs these days are, in effect, two hubs and a 2-port switch. Ports 'auto switch' to either the 10Mbps segment or the 100Mbps segment. Inter-segment traffic is decided by MAC address 'learning' So... if two 100Mbps devices are communicating - they are on the same segment, and will communicate at 100Mbps. Similarly for two 10Mbps devices. The whole only drops to 10Mbps with cross-segment 10-100 traffic.

At least somebody believes me for a change.

I hope that makes sense.

And BTW - full duplex is 100Mbps TX AND 100Mbps RX simultaneously.

Like I can learn much from the side of a D-Link box. ;-) Dave

I think I'm clear on what you're asking. Answer: no. As long as your hub (whether it 'switches' or not) isn't plugged into your 10Mbps NIC, it's not going to slow you down. If you have a NIC plugged straight into your internet connection (router), and a second NIC (100Mbps) hooked to the hub, you're fine. Look at it as though the hub that slows things down, not the NIC or the computers. That's not precise, but it's a good description. Dave On Thursday 30 August 2001 18:07, Ricardo Rodriguez wrote:

yes but what if my 10mbp is providing connection to the router that is the one providing to my internal network. Does that really reflect in the performance of my internal network internet access??

IPS --- 100<LinuxBox>10 --- ROUTER (Linksys) --- NetW

so, my ISP is sending me something at 100 that is going trough my linux box and it decrease to 10, so are all my computers after the router accessing at 10?

That may be a bad assumption or a stupid question for must of you but all this is new for me.....

Thnx.

--- David Grove wrote:

...

On Thursday 30 August 2001 16:57, Tony White wrote:

...

Hi Tor,

Most 10/100 hubs these days are, in effect, two

hubs and a 2-port

...

switch. Ports 'auto switch' to either the 10Mbps

segment or the 100Mbps

...

segment. Inter-segment traffic is decided by MAC

address 'learning'

...

So... if two 100Mbps devices are communicating -

they are on the same

...

segment, and will communicate at 100Mbps.

Similarly for two 10Mbps

...

devices. The whole only drops to 10Mbps with

cross-segment 10-100 traffic.

At least somebody believes me for a change.

...

I hope that makes sense.

And BTW - full duplex is 100Mbps TX AND 100Mbps RX

simultaneously.

Like I can learn much from the side of a D-Link box. ;-)

Dave

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Thank you.

I figured someone would want to be hostile. I think the hub I was using calls itself an "auto-switching" hub, but I've been told that's "something different entirely". I just know that it works this way.

Anyway, thanks.

On Thursday 30 August 2001 13:58, Tor Sigurdsson wrote:

...

Þann fimmtudagur 30 ágúst 2001 17:30 skrifaðir þú:

...

On Thu, 30 Aug 2001 12:18:53 -0400

[SNIP]

...

You will link at 100 if your card is 100, but the traffic is still only 10. Don't confuse what you bind at and the actual data transfer speed. It is not physically possible to have a single network segment (what a hub gives) running at two speeds. It's not a matter of "well, my hub is different". No, it's not.

Uhm, I beg to differ :-)

There are things called "swithcing hubs" which are in fact two hubs ( one 10Mbit and one 100Mbit ) with a two-port switch built in to bridge the 10/100 gap. That way, you get "pure" 100<-->100 where possible, "pure" 10<->10, and a 10<->100 switched bridge. They cost about the same as a

It's not a matter of being hostile, only being accurate. There is no such thing as a switching hub; this stuff is very well defined. As a person stated, what you might have is two hubs in the same box with a segment to link the two. Small differnece, but a difference none-the-less. On Thu, 30 Aug 2001 15:02:05 -0400 David Grove wrote: true

...

switch tho, so I'd rather recommend switches. ( beware tho that some companies sell these things as "personal switches" - which they are not. )

[SNIP]

-tosi

On Friday 31 August 2001 2:05 pm, James Oakley wrote:

On August 31, 2001 10:38 am, Timothy Reaves wrote:

...

It's not a matter of being hostile, only being accurate.

There is no such thing as a switching hub; this stuff is very well defined. As a person stated, what you might have is two hubs in the same box with a segment to link the two.

Small differnece, but a difference none-the-less.

Sometimes, 'switching hub' means an unmanaged desktop switch.

It's bad terminology. A hub broadcasts traffic along its backplane. A switch doesn't. If a hub does something more than just broadcasting (e.g. dual-speed, or SNMP compliance, or similar), then you can call it a 'smart hub', but you *shouldn't* call it a 'switching hub'. I worked as a tech support for 3Com for 4 years, and came across a classic example of this... The bog-standard 10Mbps 3Com hub was called the FMS (flexible media stack) II, until it got renamed the Superstack II Hub 10 in 1996. In autumn 1996, 3Com used some of the old Chipcom technology to produce a smart hub; they thought it would replace the Hub 10. This thing had 4 backplanes, all at 10 Mbps; and you could move ports from one backplane to another, so you could have, say, 20 people on one backplane (sharing 1 10 Mbps segment!) and 2 or 3 'power users' on another segment. It was a nice little toy, even if it was technically obsolete by the time they released it (and *way* overpriced). But they had the *idiocy* to call it the Superstack II Port Switch Hub. So people, looking to buy a switch, saw 'switch' in the title; and this thing was cheaper than switches were then (since it was a hub, to all intents and purposes). So people bought them, then discovered that they had just bought rather expensive hubs instead of switches. At which point they usually returned them, along with some really nasty letters. (The phone calls were fun, too. For those of us working on the helldesk.) People who wanted hubs generally stuck with the Hub 10, since everyone knew it. The Port Switch Hub sold almost *no* units, since it fell between two stools, and was confusingly named. So, to try and sell them off, they renamed them; the Port Switch Hub became the PS Hub 40 (since it had 4 x 10Mbps backplanes), and had the price slashed (to the point where it was cheaper than the Hub 10). It never really sold well; and it certainly didn't replace the Hub 10 (as it was supposed to in 1997). 3Com had to continue selling both of them; it couldn't afford to junk the PS Hub, and people still wanted the Hub 10. If you go to 3Com's web site, and look up 'managed hubs' in the product section, you will find both of them, both still available, and left high and dry by the vast numbers of cheap switches you can get nowadays. That's a classic example of why bad terminology (when talking about switches and hubs) can be a really stupid thing to do; even if you're a big company. Gideon.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On August 30, 2001 04:02 pm, David Grove wrote:

Thank you.

I figured someone would want to be hostile. I think the hub I was using calls itself an "auto-switching" hub, but I've been told that's "something different entirely". I just know that it works this way.

Do yourself a favour and play with bing. The man page says not to use your own IP in the measurements, but most of the time, the numbers I get out of it are realistic. I have measured between 20 and 60 Mb over 100 Mb networks, depending on the NICs used. Intel EEPros are super-fast... I measured 10 Mb on 3Com's 10Mb VDSL, 900 Kb on some HPNA gear over here, etc. It works well. I can't wait to get some Gb ethernet to play with... As far as the 100Mb being desirable, the card that connects to my cable modem is a 10Mb, but the rest of my network is 100Mb. I do a lot of XSessions, network backups, etc. on my internal side. The 100Mb is definitely worth it. - -- James Oakley Engineering - SolutionInc Ltd. joakley@solutioninc.com http://www.solutioninc.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.5 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE7j5hb+FOexA3koIgRAslZAKCe+CfBIsfqI3nsWbnazGlHSdieJACfcT73 tk3dePB+ic0V4hMCUCSe6Co= =JY/h -----END PGP SIGNATURE-----