-----Original Message-----
From: John Storms [mailto:jstorms@livingston.com]
Sent: Tuesday, June 30, 1998 9:55 PM
To: Jeff Woods
Cc: portmaster-users@livingston.com
Subject: Re: (PM) MTU size?
Lowering the MTU size improves speed when their is some noise on the
line.
The smaller MTU means a smaller frame which is less a target for noise.
When a frame does need to be retransmitted then there is not as much to
resend. In this sense it is faster. However, the smaller MTU means
more
frames, and with each frame comes a header so there is more overhead
with
the smaller MTU.
So in a nutshell, lowering MTU on noisy lines can improve performance.
Lowering MTU on a perfectly good line will degrade performance.
If your line is really noisy then lowering the MTU will only delay the
inevitable by a few minutes.
At 03:00 PM 6/30/98 -0400, Jeff Woods wrote:
>Several of the magazine rags (PCWorld, etc) have been recommending
users to
>drop their MTU's to 576 bytes for a significant speedup. I've tried
this
>on a modem connection, and by george if it doesn't work. Should we
>consider dropping the NAS-side MTU on async connections to 576 as well,
and
>if we did, what negative repercussions would there be?
>
>FWIW, Microsoft has made 576 the default MTU in Win98 now, too,
>acknowledging that it made a mistake in selecting 1500 for its
Winsock....
>
>Comments?
>
>At 01:25 PM 6/30/98 -0500, you wrote:
>>From: Jorg B. [mailto:jorg_b@cwo.com]
>>Sent: Tuesday, June 30, 1998 12:46 PM
>>> Is there a way to restrict ISDN connections based on user names ?
>>> For example: User name tom is allowed to establish a ISDN
>>> connection but
>>> user name peter can only connect using a "non ISDN" modem.
>>> PM3 (PRI connected)
>>
>>In /etc/raddb/users (assuming /etc/passwd is used for authentication),
>>use something like this:
>>
>>AsyncUser Auth-Type = System, NAS-Port-Type = Async
>> Service-Type = Framed-User,
>> Framed-Protocol = PPP,
>> Framed-Address = 255.255.255.254,
>> Framed-Netmask = 255.255.255.255,
>> Framed-MTU = 1500
>>
>>64kISDNUser Auth-Type = System
>> Service-Type = Framed-User,
>> Framed-Protocol = PPP,
>> Framed-Address = 255.255.255.254,
>> Framed-Netmask = 255.255.255.255,
>> Framed-MTU = 1500
>> Port-Limit = 1
>>
>>128kISDNUser Auth-Type = System
>> Service-Type = Framed-User,
>> Framed-Protocol = PPP,
>> Framed-Address = 255.255.255.254,
>> Framed-Netmask = 255.255.255.255,
>> Framed-MTU = 1500
>> Port-Limit = 2
>>
>>Hope this helps...
>>
>>--Kevin
>>
>>Kevin Sawyer - President/CEO - sawyerk@apci.net
>>Applied Personal Computing, Inc. - APCiNet - http://www.apci.net
>>6001 Old Collinsville Road, Building #3, Fairview Heights, IL 62208
>>Office: (618) 632-7282 FAX: (618) 632-7287 Support: (618) 628-2Net
>>
>>
>>-
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>-
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--- jstorms@lucent.com Diplomacy: The art of saying good doggie while seaching for a big rock. - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message. Searchable list archive: <URL:http://www.livingston.com/Tech/archive/> - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message. Searchable list archive: <URL:http://www.livingston.com/Tech/archive/>