[HECnet] How do I get a DS10's onboard NIC into 100 mbps mode?

[hvlems at zonnet.nl]

The ascii graphics are pretty muche useless on my phone display. Your questions, as I undertand them, are:
1 the linkspeed is between station and switch?
2 how come other stations are affected?

The linkspeed is indeed an "agreement" between switch and system. Two characteristics are importand: bitrate and half or full duplex. The bitrate must match this is   essential. The duplex attribute may mismatch and on low traffic links you might get away with it. 
Generally, coax links are always half duplex and UTP ports tend to be full duplex. There is very little 10 Mb/s equipment that supports full duplex though. 
Auto sensing tends to err on the safe side and your system ends up at 10 or 100 Mb/s half duplex. Auto negotiating mode will result in an appropriate setting, 100 Mb/s or 1 Gb/s full duplex. 
Old ethernet equipment, 10BASExxx gear won't do this at all. You're lucky if you can select between AUI and thinwire coax, sometimes UTP is offered.   

The second question depends on the quality of the switch. If a switch receives data at 10 Mb/s and transmits them over a 1000 Mb/s link then it depends on the design on how well this speed difference is handled and the way it is hidden for the other ports. 
If the switch has very little own memory, it must forward each packet as quickly as possible. In the mean time all other ports may receive less attention. Store and forward may be a better strategy to handle these differences in linkspeeds. The cheaper the switch is, it will probably offer just one strategy andd usually this works best in homogeneous networks (everything operates at the same bitrate and duplex mode). 
A cheap switch offers about the same throughput volume as an old fashioned repeater: then traffic between any set of two ports and all other traffic gets backed up at the systems. 
Is this an answer to your question?
Hans 
-----Original Message-----
From: Mark Wickens <mark at wickensonline.co.uk>
Sender: owner-hecnet at Update.UU.SE
Date: Wed, 28 Sep 2011 09:20:30 
To: <hecnet at Update.UU.SE>
Reply-To: hecnet at Update.UU.SESubject: Re: [HECnet] How do I get a DS10's onboard NIC into 100 mbps mode?

I used 'fastfd' as was hinted at in the <document found via random google 
hit> I was looking at at the time.

On this subject, if you don't mind me asking, am I right in thinking that 
the speed that is setup for the network connection exists solely 
between the machine and the switch?

I was experiencing some weird behaviour the other day that suggested 
otherwise.

I have my work machine and a VAXstation 4000/VLC connected to a gigabit 
switch, which is in turn wired down to another gigabit switch in the 
basement. The VAXstation is a diskless satellite node off an AlphaServer 
1000A.

(I can feel an ascii art diagram coming on)


Attic               VAXstation   O   O   Work Sunray + VPN Router
		10MB	|   |	100MB
  			------
			|       | GB switch
			______
			  |
			  | 1GB link
			  ~
			  ~
			------
			|       | GB switch
			------
		100MB	|   | 100MB
	AlphaServer 100A O   O Vigor ADSL Router
			      ~
			      * big, wide world

So why, if I a have a terminal on the VAXstation scrolling at high speed 
do I see my work machine (which is connected to the internet) 
significantly slow down?

It looks to me like the whole link between the two GB switches is being 
dragged down to 10MB. Would the 10MB link working at half-duplex make any 
difference to the question?

Thanks for the help,

Mark.

  On Wed, 28 Sep 2011, hvlems at zonnet.nl wrote:

Fast translates as 100 Mb/s half duplex and you wouldn't want that.
Auto is not always sufficient. There are two auto modes, auto negotiate and auto sensing. IMHO the latter is better avoided.
------Origineel bericht------
Van: Oleg Safiullin
Afzender: owner-hecnet at Update.UU.SE
Aan: hecnet at Update.UU.SE
Beantwoorden: hecnet at Update.UU.SE
Onderwerp: Re: [HECnet] How do I get a DS10's onboard NIC into 100 mbps mode?
Verzonden: 28 september 2011 08:31

Use "set ewb0_mode fast" or "set ewb0_mode auto" SRM command.


Sampsa Laine wrote:
I   just looked at CHIMPY's network device and noticed it's in 10 mbps mode.

--- snip ---
$ show dev ewb0/full

Device EWB0:, device type DE500, is online, network device, error logging is
      enabled, device is a template only.

      Error count                                       2       Operations completed                                   0
      Owner process                                 ""       Owner UIC                                           [SYSTEM]
      Owner process ID               00000000       Dev Prot                           S:RWPL,O:RWPL,G,W
      Reference count                               0       Default buffer size                                 512

Operating characteristics: Link up.

      Speed (Mbits/sec)                         10
      Def. MAC addr   08-00-2B-87-5B-87       Current MAC addr           AA-00-04-00-91-21

-- snip --

I thought they support 100 mbps as well? How do I turn that on? It's currently connected to a Gbps switch.

Sampsa